773 research outputs found

    Noisy Dynamics of a Vortex in a Partially Bose-Einstein Condensed Gas

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    We study the dynamics of a straight vortex line in a partially Bose-Einstein condensed atomic gas. Using a variational approach to the stochastic field equation that describes the dynamics of the condensate at nonzero temperature, we derive the stochastic equations of motion for the position of the vortex core. Using these results, we calculate the time it takes the vortex to spiral out of the condensate. Due to the fact that we include thermal fluctuations in our description, this lifetime of the vortex is finite even if its initial position is in the center of the condensate.Comment: 9 pages, no figure

    Therapeutic potentials of histamine H3 receptor agonists and antagonists

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    Identification of β2-adrenoceptors on guinea pig alveolar macrophages using (-)-3-[125I]iodocyanopindolol

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    The β-adrenoceptor antagonist (-)-3-[125I]iodocyanopindolol ([125I]ICYP) binds with high affinity and in a saturable way to membranes of guinea pig alveolar macrophages. The equilibrium dissociation constant for [125I]ICYP is 24.3 ± 1.2 pM, and the number of binding sites is 166.3 ± 13.7 fmol/mg protein (N=4, ±SEM). Displacement studies with selective antagonists showed that [125I]ICYP labels β2-adrenoceptors on guinea pig alveolar macrophages

    Development of a conformational histamine H(3) receptor biosensor for the synchronous screening of agonists and inverse agonists

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    The histamine H(3) receptor (H(3)R) represents a highly attractive drug target for the treatment of various central nervous system disorders, but the discovery of novel H(3)R targeting compounds relies on the assessment of highly amplified intracellular signaling events that do not only reflect H(3)R modulation and carry the risk of high false-positive and -negative screening rates. To address these limitations, we designed an intramolecular H(3)R biosensor based on the principle of bioluminescence resonance energy transfer (BRET) that reports the receptor's real-time conformational dynamics and provides an advanced tool to screen for both H(3)R agonists and inverse agonists in a live cell screening-compatible assay format. This conformational G-protein-coupled receptor (GPCR) sensor allowed us to characterize the pharmacological properties of known and new H(3) receptor ligands with unprecedented accuracy. Interestingly, we found that one newly developed H(3) receptor ligand possesses even stronger inverse agonistic activity than reference H(3)R inverse agonists including the current gold standard pitolisant. Taken together, we describe here the design and validation of the first screening-compatible H(3)R conformational biosensor that will aid in the discovery of novel H(3)R ligands and can be employed to gain deeper insights into the (in-)activation mechanism of this highly attractive drug target

    Prolactin

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    During an oral glucose tolerance test (OGTT) glucose and insulin levels were measured in 26 patients with prolactin-producing pituitary tumours without growth hormone excess. Basal glucose and insulin levels did not differ from the values of an age-matched control group. After glucose load the hyperprolactinaemic patients showed a decrease in glucose tolerance and a hyperinsulinaemia. Bromocriptine (CB 154), which suppressed PRL, improved glucose tolerance and decreased insulin towards normal in a second OGTT. — Human PRL or CB 154 had no significant influence on insulin release due to glucose in the perfused rat pancreas. — These findings suggest a diabetogenic effect of PRL. CB 154 might be a useful drug in improving glucose utilization in hormone-active pituitary tumours

    Follow-up study of sensory-motor polyneuropathy in Type 1 (insulin-dependent) diabetic subjects after simultaneous pancreas and kidney transplantation and after graft rejection

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    The influence of successful simultaneous pancreas and kidney transplantation on peripheral polyneuropathy was investigated in 53 patients for a mean observation period of 40.3 months. Seventeen patients were followed-up for more than 3 years. Symptoms and signs were assessed every 6 months using a standard questionnaire, neurological examination and measurement of sensory and motor nerve conduction velocities. While symptoms of polyneuropathy improved (pain, paraesthesia, cramps, restless-legs) and nerve conduction velocity increased, there was no change of clinical signs (sensation, muscle-force, tendon-reflexes). Following kidney-graft-rejection there was a slight decrease of nerve conduction verlocity during the first year, which was not statistically significant. Following pancreas-graft rejection there was no change of nerve conduction velocity during the first year. Comparing the maximum nerve conduction velocity of the patients with pancreas-graft-rejection to the nerve conduction velocities of these patients at the end of the study, there was a statistically significant decrease of 6.5 m/s. In conclusion, we believe that strict normalization of glucose metabolism alters the progressive course of diabetic polyneuropathy. It may be stabilized or partly reversed after successful grafting even in long-term diabetic patients

    Characterization of the binding site of the histamine H3 receptor. 1. Various approaches to the synthesis of 2-(1H-imidazol-4-yl)cyclopropylamine and histaminergic activity of (1R,2R)-and (1S,2S)-2-(1H-imidazol-4-yl)-cyclopropylamine.

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    Various approaches to the synthesis of all four stereoisomers of 2-(1H- imidazol-4-yl)cyclopropylamine (cyclopropylhistamine) are described. The rapid and convenient synthesis and resolution of trans-cyclopropylhistamine is reported. The absolute configuration of its enantiomers was determined by single-crystal X-ray crystallographic analysis. The distinct transcyclopropylhistamine enantiomers were tested for their activity and affinity on the histamine

    New Insights from Seafloor Mapping of a Hawaiian Marine Monument

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    On 15 June 2006, when U.S. President George W. Bush signed the proclamation creating the Papahānaumokuākea Marine National Monument (PMNM), he probably wasn’t thinking about underwater morphology. To fully understand the coral reefs and marine ecosystems that the monument was created to protect, however, scientists need to have a detailed picture of the seafloor features, home to corals and other species, as well as the geologic history of the area. Thanks to a recent, multi-institution expedition, such a seafloor features that will not only inform conservation efforts but also enable geologists and geophysicists to revise their understanding of Hawaii’s complex geologic past. Specifically, data should help scientists answer fundamental questions about the area’s regional geology. For instance, which seamounts were truly formed because of Hawaiian hotspot volcanism, and which seamounts were not
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