Search results for "Polycyclic Compounds"
showing 10 items of 373 documents
Transgenic overexpression of corticotropin releasing hormone provides partial protection against neurodegeneration in an in vivo model of acute excit…
2008
Abstract Corticotropin releasing hormone (CRH) is the central modulator of the mammalian hypothalamic–pituitary–adrenal (HPA) axis. In addition, CRH affects other processes in the brain including learning, memory, and synaptic plasticity. Moreover, CRH has been shown to play a role in nerve cell survival under apoptotic conditions and to serve as an endogenous neuroprotectant in vitro . Employing mice overexpressing murine CRH in the CNS, we observed a differential response of CRH-overexpressing mice (CRH-COE hom -Nes) to acute excitotoxic stress induced by kainate compared with controls (CRH-COE con -Nes). Interestingly, CRH-overexpression reduced the duration of epileptic seizures and pre…
Photo-DHEA--a functional photoreactive dehydroepiandrosterone (DHEA) analog.
2011
Abstract The steroid hormone dehydroepiandrosterone (DHEA) has beneficial effects on vascular function, survival of neurons, and fatty acid metabolism. However, a specific receptor for DHEA has not been identified to date. Here, we describe the synthesis of a photoreactive DHEA derivative (Photo-DHEA). In Photo-DHEA, typical characteristics of DHEA are conserved: (i) a “planar” tetracyclic ring system with a Δ 5 double bond, (ii) a 3β-hydroxyl group, and (iii) a keto group at C17. In cell-based assays, Photo-DHEA showed the same properties as DHEA. We conclude that Photo-DHEA is suitable for radioiodination to yield a tool for the identification of the elusive DHEA receptor.
Effects of dexamethasone on human synovial fibroblast-like cells, from osteoarthritic joints, in culture.
1990
The effect of Dexamethasone (DEX) on cell division and macromolecular synthesis was investigated in a line (McCoy cells, A 9) of synovial fibroblast-like cells derived from human osteoarthritic joints. DEX markedly reduced the proliferation of McCoy cells in a time and dose-dependent manner. The maximal inhibition (45%) was found at 500 nM DEX 24 h after incubation and was accompanied by the appearance of giant macrophage-like cells. After DEX treatment cells showed increased content of DNA, proteins and RNA together with the reduction of [3H]-thymidine incorporation into the TCA-precipitable fraction.
Respiratory Parameters after Systemic Corticotropin-Releasing Hormone Administration
1991
Neuroanatomical studies on the distribution of corticotropin-releasing hormone (CRH) and its receptors (7) as well as physiological data suggest a regulatory function of endogenous CRH in hypothalamic and extrahypothalamic brain areas [1, 4]. Endogenous CRH acts within the endocrine hypothalamo-pituitary-adrenal axis and affects cardiovascular regulation and respiration through extrahypothalamic pathways. CRH also stimulates gluconeogenesis and release of plasma-catecholamines. Our experiments in humans also demonstrate an influence on respiration and on heart rate activity after systemic application of CRH. Respiratory parameters and heart rate were analyzed during steady-state conditions …
Context dependent variation in corticosterone and phenotypic divergence of Rana arvalis populations along an acidification gradient
2022
Background Physiological processes, as immediate responses to the environment, are important mechanisms of phenotypic plasticity and can influence evolution at ecological time scales. In stressful environments, physiological stress responses of individuals are initiated and integrated via the release of hormones, such as corticosterone (CORT). In vertebrates, CORT influences energy metabolism and resource allocation to multiple fitness traits (e.g. growth and morphology) and can be an important mediator of rapid adaptation to environmental stress, such as acidification. The moor frog, Rana arvalis, shows adaptive divergence in larval life-histories and predator defense traits along an acidi…
Visually induced motion sickness and presence in videogames: The role of sound
2012
Visually induced motion sickness (VIMS) is a well-known phenomenon in virtual environments, simulators, and videogames. We conducted an experiment to analyze the role of sound on the severity of VIMS and the feeling of presence in videogames. Thirty-two subjects first watched a pre-recorded sequence of the game “Mirrors Edge” and then played the game actively. Game-play sound was activated for half of the participants. VIMS was measured via the Simulator Sickness Questionnaire and the Fast Motion Sickness Scale, presence was captured using the Presence Questionnaire. Results showed severe VIMS in all participants during the passive video session, whereas active-play revealed only moderate …
Elevated polycyclic aromatic hydrocarbons in a river floodplain soil due to coal mining activities
2007
Elevated PAH concentrations were found in soil samples collected along the Mosel River. These contaminations were associated with the occurrence of coal particles found in the soil. The majority of the PAH contamination in the soils was linked to coal mining activities in the Saar region. Density and grain size separation showed a similar PAH distribution pattern in all of the fractions, indicating a uniform origin of PAHs. Together with coal petrography a good correlation between TOC and PAHs concentration confirmed the impact of former coal mining activity on the PAHs distribution in study area.
Comparative effectiveness of helicopter emergency medical services compared to ground emergency medical services
2013
Physician-staffed helicopter emergency medical services (HEMS) are a well-established component of prehospital trauma care in Germany. Reduced rescue times and increased catchment area represent presumable specific advantages of HEMS. In contrast, the availability of HEMS is connected to a high financial burden and depends on the weather, day time and controlled visual flight rules. To date, clear evidence regarding the beneficial effects of HEMS in terms of improved clinical outcome has remained elusive.Traumatized patients (Injury Severity Score; ISS≥9) primarily treated by HEMS or ground emergency medical services (GEMS) between 2007 and 2009 were analyzed using the TraumaRegister DGU® o…
Chiral cyclohexane based fluorescent chemosensors for enantiomeric discrimination of aspartate
2008
Some new chiral cyclohexyl based fluorescent anion receptors have been synthesized and their absolute configuration has been determined by using circular dichroism (CD). Complexation experiments have been carried out with several dicarboxylates, and stoichiometries and complexation constants for the corresponding complexes have been determined. The chiral discrimination ability of these ligands for chiral dicarboxylates has been studied and the best results have been obtained with TMA aspartate.
Domain formation in monolayers
1995
For phospholipids at the air/water interface we demonstrate that molecular chirality in some, but not in all, cases influences the domain shapes. In other cases chirality in the head group region can cause a chiral structure considering the tail arrangement. This indicates head group ordering. Minute changes of the molecular structure may change domain morphology from circular to dendritic. This can be related to slight changes of the lattice structure. In case of a dendritic domain the chains are more tilted, the deviation from hexagonal symmetry is more pronounced, and hence the lattice anisotropy is larger. This can be understood also in view of recent simulations considering diffusion-l…