The rockefeller university

Background/Aims: The role of cytomegalovirus (CMV) reactivation during exacerbations of ulcerative colitis (UC) is yet a matter of debate, and assessment of CMV infection in UC patients remains an ongoing challenge. We aimed to identify associated parameters and compare detection methods for CMV infection during UC exacerbation. Methods: Clinical, pathological and virological parameters were retrospectively analyzed in all patients hospitalized in our institution for UC exacerbation between January 2009 and April 2015, who underwent full evaluation for CMV infection in colonic tissue by histopathology, immunohistochemistry (IHC) and CMV-PCR. Results: Of 28 patients who underwent full examination for tissue CMV-infection, 13 (46.4%) were found to be positive for CMV. Tissue CMV-PCR was more sensitive for the detection of CMV infection than histopathology and IHC. CMV-positive patients had a statistically higher frequency of recent steroid treatment and fever, with higher mean partial Mayo scores and lower mean albumin levels. There were no significant differences between CMV-positive and CMV-negative patients in terms of age, severity of colitis and disease duration. In a multivariable model, only recent steroid treatment and fever were independently associated with colonic CMV infection. Conclusions: This study provides a clinical model to detect the presence of CMV infection in patients hospitalized with UC exacerbation, which could direct proper investigation and facilitate timely empirical therapy (C) 2017 S. Karger AG, Basel

The interaction of glutamate and dopamine in the striatum is heavily dependent on signaling pathways that converge on the regulatory protein DARPP-32. The efficacy of dopamine/D1 receptor/PKA signaling is regulated by DARPP-32 phosphorylated at Thr-34 (the PKA site), a process that inhibits protein phosphatase 1 (PP1) and potentiates PKA action. Activation of dopamine/D1receptor/PKA signaling also leads to dephosphorylation of DARPP-32 at Ser-97 (the CK2 site), leading to localization of phospho-Thr-34 DARPP-32 in the nucleus where it also inhibits PP1. In this study the role of glutamate in the regulation of DARPP-32 phosphorylation at four major sites was further investigated. Experiments using striatal slices revealed that glutamate decreased the phosphorylation states of DARPP-32 at Ser-97 as well as Thr-34, Thr-75, and Ser-130 by activating NMDA or AMPA receptors in both direct and indirect pathway striatal neurons. The effect of glutamate in decreasing Ser-97 phosphorylation was mediated by activation of PP2A. In vitro phosphatase assays indicated that the PP2A/PR72 heterotrimer complex was likely responsible for glutamate/Ca2+-regulated dephosphorylation of DARPP-32 at Ser-97. As a consequence of Ser-97 dephosphorylation, glutamate induced the nuclear localization in cultured striatal neurons of dephospho-Thr-34/dephospho-Ser-97 DARPP-32. It also reduced PKA-dependent DARPP-32 signaling in slices and in vivo. Taken together, the results suggest that by inducing dephosphorylation of DARPP-32 at Ser-97 and altering its cytonuclear distribution, glutamate may counteract dopamine/D1 receptor/PKA signaling at multiple cellular levels.

Futility disputes are more likely to be resolved and relational breaches repaired by engaging in a process that fosters communication between clinicians, patients, and families. This essay calls for mediative fluency. The preemptive use of a futility definition can stifle conversation when it is needed most, exacerbating the very power imbalances and associated health disparities that often precipitate futility disputes. When clinicians, patients, and families engage in dialogue, clinicians can appreciate what motivates requests for what is thought to be futile care, and patients and families can better understand the limits of available therapies. This sharing of knowledge, values, and attitudes cannot be achieved through the unilateral invocation of a futility definition. Furthermore, futility definitions are prone to interpretative judgment by clinicians and can be informed by the norms and attitudes attendant to a practitioner's medical specialty. They also need to be interpreted in the context of emerging trends in medical therapeutics and in relation to the clinical details of each case. In the aggregate, these challenges make the application of a futility definition futile.

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels underlie the control of rhythmic activity in cardiac and neuronal pacemaker cells. In HCN, the polarity of voltage dependence is uniquely reversed. Intracellular cyclic adenosine monophosphate (cAMP) levels tune the voltage response, enabling sympathetic nerve stimulation to increase the heart rate. We present cryo-electron microscopy structures of the human HCN channel in the absence and presence of cAMP at 3.5 angstrom resolution. HCN channels contain a K+ channel selectivity filter-forming sequence from which the amino acids create a unique structure that explains Na+ and K+ permeability. The voltage sensor adopts a depolarized conformation, and the pore is closed. An S4 helix of unprecedented length extends into the cytoplasm, contacts the C-linker, and twists the inner helical gate shut. cAMP binding rotates cytoplasmic domains to favor opening of the inner helical gate. These structures advance understanding of ion selectivity, reversed polarity gating, and cAMP regulation in HCN channels.

The paraventricular nucleus of the thalamus (PVT) appears to participate in drug addiction. Recent evidence in rats shows that ethanol drinking is increased by orexin/hypocretin (OX) afferents from the hypothalamus, acting specifically in the anterior (aPVT) rather than posterior (pPVT) PVT subregion. The present study sought to identify neuropeptides transcribed within the PVT, which themselves might contribute to ethanol drinking and possibly mediate the actions of OX. We discovered that substance P (SP) in the aPVT can stimulate intermittent-access ethanol drinking, similar to OX, and that SP receptor [neurokinin 1 receptor/tachykinin receptor 1 (NK1R)] antagonists in this subregion reduce ethanol drinking. As with OX, this effect is site specific, with SP in the pPVT or dorsal third ventricle having no effect on ethanol drinking, and it is behaviorally specific, with SP in the aPVT reducing the drinking of sucrose and stimulating it in the pPVT. A close relationship between SP and OX was demonstrated by a stimulatory effect of local OX injection on SP mRNA and peptide levels, specifically in the aPVT but not pPVT, and a stimulatory effect of OX on SP expression in isolated thalamic neurons, reflecting postsynaptic actions. A functional relationship between OX and SP in the aPVT is suggested by our additional finding that ethanol drinking induced by OX is blocked by a local NK1R antagonist administered at a sub-threshold dose. These results, suggesting that SP in the aPVT mediates the stimulatory effect of OX on ethanol drinking, identify a new role for SP in the control of this behavior.

Niemann-Pick C1 (NPC1), amembrane protein of lysosomes, is required for the export of cholesterol derived from receptor-mediated endocytosis of LDL. Lysosomal cholesterol export is reportedly inhibited by itraconazole, a triazole that is used as an antifungal drug [Xu et al. (2010) Proc Natl Acad Sci USA 107:4764-4769]. Here we show that posaconazole, another triazole, also blocks cholesterol export from lysosomes. We prepared P-X, a photoactivatable cross-linking derivative of posaconazole. P-X cross-linked to NPC1 when added to intact cells. Cross-linking was inhibited by itraconazole but not by ketoconazole, an imidazole that does not block cholesterol export. Cross-linking of P-X was also blocked by U18666A, a compound that has been shown to bind to NPC1 and inhibit cholesterol export. P-X also crosslinked to purified NPC1 that was incorporated into lipid bilayer nanodiscs. In this in vitro system, cross-linking of P-X was inhibited by itraconazole, but not by U18666A. P-X cross-linking was not prevented by deletion of the N-terminal domain of NPC1, which contains the initial binding site for cholesterol. In contrast, P-X cross-linking was reduced when NPC1 contained a point mutation (P691S) in its putative sterol-sensing domain. We hypothesize that the sterol-sensing domain has a binding site that can accommodate structurally different ligands.

Hypertension in male and aging female rodents is associated with glutamate-dependent plasticity in the hypothalamus, but existing models have failed to capture distinct transitional menopausal phases that could have a significant impact on the synaptic plasticity and emergent hypertension. In rodents, accelerated ovarian failure (AOF) induced by systemic injection of 4-vinylcyclohexane diepoxide mimics the estrogen fluctuations seen in human menopause including the perimenopause transition (peri-AOF) and postmenopause (post-AOF). Thus, we used the mouse AOF model to determine the impact of slow-pressor angiotensin II (Ang ll) administration on blood pressure and on the subcellular distribution of obligatory N-methyl-D-aspartate (NMDA) receptor GIuN1 subunits in the paraventricular hypothalamic nu-cleus (PVN), a key estrogen-responsive cardiovascular regulatory area. Estrogen-sensitive neuronal profiles were identified in mice expressing enhanced green fluorescent protein under the promoter for estrogen receptor (ER) beta, a major ER in the PVN. Slow-pressor Angll increased arterial blood pressure in mice at peri-and post-AOF time points. In control oil-injected (nonhypertensive) mice, Angll decreased the total number of GIuN1 in ERR-containing PVN dendrites. In contrast, Angll resulted in a reapportionment of GIuN1 from the cytoplasm to the plasma membrane of ER beta-containing PVN dendrites in peri-AOF mice. Moreover, in post-AOF mice, Angll increased total GIuN1, dendritic size and radical production in ERR-containing neurons. These results indicate that unique patterns of hypothalamic glutamate receptor plasticity and dendritic structure accompany the elevated blood pressure in peri-and post-AOF time points. Our findings suggest the possibility that distinct neurobiological processes are associated with the increased blood pressure during perimenopausal and postmenopausal periods.

Shelterin is a six-subunit protein complex that plays crucial roles in telomere length regulation, protection, and maintenance. Although several shelterin subunits have been studied in vitro, the biochemical properties of the fully assembled shelterin complex are not well defined. Here, we characterize shelterin using ensemble biochemical methods, electron microscopy, and single-molecule imaging to determine how shelterin recognizes and assembles onto telomeric repeats. We show that shelterin complexes can exist in solution and primarily locate telomeric DNA through a three-dimensional diffusive search. Shelterin can diffuse along non-telomeric DNA but is impeded by nucleosomes, arguing against extensive one-dimensional diffusion as a viable assembly mechanism. Our work supports a model in which individual shelterin complexes rapidly bind to telomeric repeats as independent functional units, which do not alter the DNA-binding mode of neighboring complexes but, rather, occupy telomeric DNA in a "beads on a string'' configuration.

Taylor's power law (TPL) describes the variance of population abundance as a power-law function of the mean abundance for a single or a group of species. Using consistently sampled long-term (1958-2001) multimesh capture data of Lake Kariba in Africa, we showed that TPL robustly described the relationship between the temporal mean and the temporal variance of the captured fish assemblage abundance (regardless of species), separately when abundance was measured by numbers of individuals and by aggregate weight. The strong correlation between the mean of abundance and the variance of abundance was not altered after adding other abiotic or biotic variables into the TPL model. We analytically connected the parameters of TPL when abundance was measured separately by the aggregate weight and by the aggregate number, using a weight-number scaling relationship. We utilized TPL to find the number of samples required for fixed-precision sampling and compared the number of samples when sampling was performed with a single gillnet mesh size and with multiple mesh sizes. These results facilitate optimizing the sampling design to estimate fish assemblage abundance with specified precision, as needed in stock management and conservation.