Actions of thyroid hormones in bone

Hormony tarczycy są niezbędne dla prawidłowego rozwoju układu kostnego i uzyskania szczytowej masy kostnej. Niedoczynność tarczycy u dzieci prowadzi do ograniczenia (opóźnienia) tempa wzrostu spowodowanego opóźnieniem rozwoju kości, podczas gdy nadczynność tarczycy przyspiesza dojrzewanie układu kostnego. U dorosłych hormony tarczycy regulują obrót kostny i gęstość mineralną układu kostnego. Stan eutyreozy jest więc istotny dla utrzymania optymalnej jakości układu kostnego. Wyniki badań populacyjnych wykazały, że zarówno niedoczynność, jak i nadczynność tarczycy są związane ze zwiększonym ryzykiem złamań kości. Mimo to mechanizm działania trijodotyroniny (T3) w kości nie jest do końca poznany. W badaniach zmutowanych myszy wykazano, że działanie T3 na kość zachodzi poprzez interakcje hormonu z receptorem a (TRα). W okresie młodości i wzrastania T3 wywiera na kość efekt anaboliczny i odpowiada za szczytowy przyrost kości. W późniejszym okresie życia T3 wywiera efekt kataboliczny, zwiększając resorpcję wapna i obrót kostny. W ostatnim okresie wyniki niektórych badań mogą wskazywać, że TSH ma bezpośredni wpływ na komórki kości, ale problem ten jest bardzo trudny do ostatecznego ustalenia w warunkach in vivo, wobec tego, że stężenie TSH i hormonu tarczycy jest utrzymywane w odwrotnym wzajemnym stosunku (sprzężeniu zwrotnym) przez układ podwzgórze-przysadka-tarczyca. Obecna wiedza w tym zakresie wynika z doświadczeń myszami, u których zmutowano geny kodujące TRα, TRβ i receptor TSH. Jednak nie można kategorycznie ustalić, czy wpływ tych mutacji na szkielet zależy od zmienionej ekspresji T3 w komórkach kośćca, czy jest następstwem tych mutacji na czynność innych układów endokrynnych, które regulują rozwój szkieletu i masę kostną. Blokowanie sygnału od hormonu tarczycy w poszczególnych tkankach i układach będzie konieczne, aby rozwiązać te niejasności. Przeprowadzenie takich badań pozwoli zidentyfikować kluczowe mechanizmy działania T3 na komórki kości i określić nowe cele w leczeniu osteoporozy.Thyroid hormones are required for skeletal development and establishment of peak bone mass. Hypothyroidism in children results in growth retardation with delayed skeletal development, whereas thyrotoxicosis accelerates bone maturation. In adults, T3 regulates bone turnover and bone mineral density, and normal euthyroid status is essential to maintain optimal bone strength. Population studies indicate that hypothyroidism and hyperthyroidism are both associated with an increased risk of fracture. Nevertheless, the mechanism of T3 action in bone is incompletely understood. Studies in mutant mice have demonstrated that T3 action in bone is mediated principally by T3 receptor α (TRα). T3 exerts anabolic actions during growth to stimulate peak bone mass acrrual, but has catabolic effects on the adult skeleton that increase bone turnover. Recent studies have also suggested that TSH may have direct actions in bone cells, but such effects are difficult to resolve in vivo because thyroid hormone and TSH concentrations are maintained in an inverse relationship by the hypothalamic-pituitary-thyroid axis. Current understanding is based on studies in mice that harbor germline mutations in the genes encoding TRα, TRβ or the TSH receptor and it is not clear whether the skeletal effects of these mutations result from disruption of primary T3 actions in bone cells or whether they are secondary to systemic effects on other endocrine pathways that regulate skeletal development and bone mass. Tissue-specific disruption of thyroid hormone signalling in bone cells will be required to address this issue. Such studies are likely to identify key components of the T3 signalling pathway that may represent suitable drug targets for treatment of osteoporosis

Some Pattern Recognition Challenges in Data-Intensive Astronomy

We review some of the recent developments and challenges posed by the data analysis in modern digital sky surveys, which are representative of the information-rich astronomy in the context of Virtual Observatory. Illustrative examples include the problems of an automated star-galaxy classification in complex and heterogeneous panoramic imaging data sets, and an automated, iterative, dynamical classification of transient events detected in synoptic sky surveys. These problems offer good opportunities for productive collaborations between astronomers and applied computer scientists and statisticians, and are representative of the kind of challenges now present in all data-intensive fields. We discuss briefly some emergent types of scalable scientific data analysis systems with a broad applicability.Comment: 8 pages, compressed pdf file, figures downgraded in quality in order to match the arXiv size limi

Probing the Structure of the Pomeron

We suggest that the pseudo-rapidity cut dependence of diffractive deep-inelastic scattering events at HERA may provide a sensitive test of models of diffraction. A comparison with the experimental cross section shows that the Donnachie-Landshoff model and a simple two-gluon exchange model of the pomeron model are disfavoured. However a model with a direct coupling of the pomeron to quarks is viable for a harder quark--pomeron form factor, as is a model based on the leading-twist operator contribution. We also consider a direct-coupling scalar pomeron model. We comment on the implications of these results for the determination of the partonic structure of the pomeron.We suggest that the pseudo-rapidity cut dependence of diffractive deep-inelastic scattering events at HERA may provide a sensitive test of models of diffraction. A comparison with the experimental cross section shows that the Donnachie-Landshoff model and a simple two-gluon exchange model of the pomeron model are disfavoured. However a model with a direct coupling of the pomeron to quarks is viable for a harder quark--pomeron form factor, as is a model based on the leading-twist operator contribution. We also consider a direct-coupling scalar pomeron model. We comment on the implications of these results for the determination of the partonic structure of the pomeron

Cognitive effects following acute wild blueberry supplementation in 7 – 10 year old children

Purpose: Previously, anthocyanin-rich blueberry treatments have shown positive effects on cognition in both animals and human adults. However, little research has considered whether these benefits transfer to children. Here we describe an acute time-course and dose–response investigation considering whether these cognitive benefits extend to children. Methods: Using a double-blind cross-over design, on three occasions children (n = 21; 7–10 years) consumed placebo (vehicle) or blueberry drinks containing 15 or 30 g freeze-dried wild blueberry (WBB) powder. A cognitive battery including tests of verbal memory, word recognition, response interference, response inhibition and levels of processing was performed at baseline, and 1.15, 3 and 6 h following treatment. Results: Significant WBB-related improvements included final immediate recall at 1.15 h, delayed word recognition sustained over each period, and accuracy on cognitively demanding incongruent trials in the interference task at 3h. Importantly, across all measures, cognitive performance improved, consistent with a dose–response model, with the best performance following 30 g WBB and the worst following vehicle. Conclusion: Findings demonstrate WBB-related cognitive improvements in 7- to 10-year-old children. These effects would seem to be particularly sensitive to the cognitive demand of task

Children exposed to intimate partner violence: Identifying differential effects of family environment on children\u27s trauma and psychopathology symptoms through regression mixture models

The majority of analytic approaches aimed at understanding the influence of environmental context on children\u27s socioemotional adjustment assume comparable effects of contextual risk and protective factors for all children. Using self-reported data from 289 maternal caregiver-child dyads, we examined the degree to which there are differential effects of severity of intimate partner violence (IPV) exposure, yearly household income, and number of children in the family on posttraumatic stress symptoms (PTS) and psychopathology symptoms (i.e., internalizing and externalizing problems) among school-age children between the ages of 7–12 years. A regression mixture model identified three latent classes that were primarily distinguished by differential effects of IPV exposure severity on PTS and psychopathology symptoms: (1) asymptomatic with low sensitivity to environmental factors (66% of children), (2) maladjusted with moderate sensitivity (24%), and (3) highly maladjusted with high sensitivity (10%). Children with mothers who had higher levels of education were more likely to be in the maladjusted with moderate sensitivity group than the asymptomatic with low sensitivity group. Latino children were less likely to be in both maladjusted groups compared to the asymptomatic group. Overall, the findings suggest differential effects of family environmental factors on PTS and psychopathology symptoms among children exposed to IPV. Implications for research and practice are discussed

Assessing Recognition of Sexist Language: Development and Use of the Gender-Specific Language Scale

Teaching effective writing in the social sciences includes teaching recognition of sexist language. The development and teaching uses of the Gender-Specific Language Scale (GSLS), an instrument designed to assess recognition of sexist language, are described. Three experiments with predominantly European-American male and female students provide support for the reliability and validity of the GSLS, and suggest that it measures a different construct than an essay questionnaire used in previous studies of sexist language. Implications for teaching are discussed

Exploring the Time Domain With Synoptic Sky Surveys

Synoptic sky surveys are becoming the largest data generators in astronomy, and they are opening a new research frontier, that touches essentially every field of astronomy. Opening of the time domain to a systematic exploration will strengthen our understanding of a number of interesting known phenomena, and may lead to the discoveries of as yet unknown ones. We describe some lessons learned over the past decade, and offer some ideas that may guide strategic considerations in planning and execution of the future synoptic sky surveys.Comment: Invited talk, to appear in proc. IAU SYmp. 285, "New Horizons in Time Domain Astronomy", eds. E. Griffin et al., Cambridge Univ. Press (2012). Latex file, 6 pages, style files include