321 research outputs found
Polycation-Ο Interactions Are a Driving Force for Molecular Recognition by an Intrinsically Disordered Oncoprotein Family
Molecular recognition by intrinsically disordered proteins (IDPs) commonly involves specific localized contacts and target-induced disorder to order transitions. However, some IDPs remain disordered in the bound state, a phenomenon coined "fuzziness", often characterized by IDP polyvalency, sequence-insensitivity and a dynamic ensemble of disordered bound-state conformations. Besides the above general features, specific biophysical models for fuzzy interactions are mostly lacking. The transcriptional activation domain of the Ewing's Sarcoma oncoprotein family (EAD) is an IDP that exhibits many features of fuzziness, with multiple EAD aromatic side chains driving molecular recognition. Considering the prevalent role of cation-Ο interactions at various protein-protein interfaces, we hypothesized that EAD-target binding involves polycation- Ο contacts between a disordered EAD and basic residues on the target. Herein we evaluated the polycation-Ο hypothesis via functional and theoretical interrogation of EAD variants. The experimental effects of a range of EAD sequence variations, including aromatic number, aromatic density and charge perturbations, all support the cation-Ο model. Moreover, the activity trends observed are well captured by a coarse-grained EAD chain model and a corresponding analytical model based on interaction between EAD aromatics and surface cations of a generic globular target. EAD-target binding, in the context of pathological Ewing's Sarcoma oncoproteins, is thus seen to be driven by a balance between EAD conformational entropy and favorable EAD-target cation-Ο contacts. Such a highly versatile mode of molecular recognition offers a general conceptual framework for promiscuous target recognition by polyvalent IDPs. Β© 2013 Song et al
A Prospective Evaluation of Quick Intraoperative Parathyroid Hormone Assay at the Time of Skin Closure in Predicting Clinically Relevant Hypocalcemia after Thyroidectomy
BACKGROUND: Post-thyroidectomy hypocalcemia is a major contributing factor in delayed hospital discharge and dissuading surgeons from ambulatory thyroidectomy. We prospectively evaluated the accuracy and reliability of quick parathyroid hormone level measurement at skin closure (PTH-SC) in predicting clinically relevant hypocalcemia (i.e., patients requiring calcium +/- calcitriol supplements on hospital discharge). METHODS: Of the 117 patients who underwent a total or completion total thyroidectomy and PTH-SC, 17 (14.5 %) had hypocalcemic symptoms or adjusted calcium 1 pmol/L) had a higher specificity (95.0 %) and AUC (0.887) than serial calcium monitoring or PTH-D1 alone. Although 3/98 of patients with PTH-SC >1 pmol/L required calcium supplements on discharge, they required only the minimum amount to maintain normocalcemia. CONCLUSION: PTH-SC is an accurate and reliable means of predicting clinically relevant hypocalcemia. It would be reasonable to discharge those with PTH-SC >1 pmol/L on the same operative day as the risk of life-threatening hypocalcemia would seem unlikely.published_or_final_versio
The Demographic and Socioeconomic Factors Predictive for Populations at High-Risk for La Crosse Virus Infection in West Virginia
Although a large body of literature exists for the environmental risk factors for La Crosse virus (LACV) transmission, the demographic and socioeconomic risk factors for developing LACV infection have not been investigated. Therefore, this study investigated the demographic and socioeconomic risk factors for LACV infection in West Virginia from 2003 to 2007, using two forward stepwise discriminant analyses. The discriminant analyses were used to evaluate a number of demographic and socioeconomic factors for their ability to predict: 1) those census tracts with at least one reported case of LACV infection versus those census tracts with no reported cases of LACV infection and 2) to evaluate significantly high-risk clusters for LACV infection versus significantly low-risk clusters for LACV infection. In the first model, a high school education diploma or a general education diploma or less and a lower housing densit
Detection of porcine circovirus type 1 in commercial porcine vaccines by loop-mediated isothermal amplification
A loop-mediated isothermal amplification (LAMP) method with a real-time monitoring system was developed for the detection of porcine circovirus type 1 (PCV1) in commercial swine vaccines. This method was highly specific for PCV1. No cross-reaction to porcine circovirus type 2, porcine parvovirus, pseudorabies virus, classical swine fever virus, and porcine reproductive and respiratory syndrome virus was observed. The analytical sensitivity of the LAMP for PCV1 DNA was 10Β copies/ΞΌl in the case of positive recombinant plasmid comparable to that obtained from the nested polymerase chain reaction (nested PCR). Furthermore, 25 commercial swine vaccines were tested by both the LAMP and the nested PCR, and three of them were tested positive for PCV1 DNA. These results indicate that PCV1 DNA can be real-time detected by the LAMP; the method was highly specific, sensitive, and rapid for the detection of PCV1 DNA, particularly in commercial swine vaccines
Healthcare in schizophrenia: effectiveness and progress of a redesigned care network
<p>Abstract</p> <p>Background</p> <p>The aim of this study was designed to investigate the care-effectiveness of different healthcare models for schizophrenic patients and the impact of it on caregivers.</p> <p>Methods</p> <p>Sample cases were randomly selected from southern Taiwan, 257 patients in redesigned care network, including a general hospital, a chronic ward, 10 outpatient clinics, and multialternative community programs, was compared to 247 patients in other traditional healthcare provider that were utilized as the control group. The quality of life (QOL) questionnaire and the Chinese health questionnaire (CHQ) were used.</p> <p>Results</p> <p>The controls had longer duration of illness (<it>p </it>= 0.001) and were older (<it>p </it>= 0.004). The average resource utilization in the study group (US 2041) (<it>t </it>= 7.91, <it>p </it>< 0.001). For the study group, the average length of stay was shorter, but the admission rate was higher. The QOL of the patients in the study group was better than that of the controls (<it>p </it>= 0.01). The family burden of the study group was lower (<it>p </it>= 0.035) and the score of general health questionnaire higher (<it>p </it>= 0.019).</p> <p>Conclusion</p> <p>We found that patients in the redesigned care network had a better QOL, lower family burden, decreased days of hospital stay, higher medical resource utilization and less frequent admission to a hospital, and the caregivers had better mental health. Although the costs were higher, the continued care network was more helpful in providing comprehensive mental illness services.</p
Integrating 5-Hydroxymethylcytosine into the Epigenomic Landscape of Human Embryonic Stem Cells
Covalent modification of DNA distinguishes cellular identities and is crucial for regulating the pluripotency and differentiation of embryonic stem (ES) cells. The recent demonstration that 5-methylcytosine (5-mC) may be further modified to 5-hydroxymethylcytosine (5-hmC) in ES cells has revealed a novel regulatory paradigm to modulate the epigenetic landscape of pluripotency. To understand the role of 5-hmC in the epigenomic landscape of pluripotent cells, here we profile the genome-wide 5-hmC distribution and correlate it with the genomic profiles of 11 diverse histone modifications and six transcription factors in human ES cells. By integrating genomic 5-hmC signals with maps of histone enrichment, we link particular pluripotency-associated chromatin contexts with 5-hmC. Intriguingly, through additional correlations with defined chromatin signatures at promoter and enhancer subtypes, we show distinct enrichment of 5-hmC at enhancers marked with H3K4me1 and H3K27ac. These results suggest potential role(s) for 5-hmC in the regulation of specific promoters and enhancers. In addition, our results provide a detailed epigenomic map of 5-hmC from which to pursue future functional studies on the diverse regulatory roles associated with 5-hmC
Visual Information Alone Changes Behavior and Physiology during Social Interactions in a Cichlid Fish (Astatotilapia burtoni)
Social behavior can influence physiological systems dramatically yet the sensory
cues responsible are not well understood. Behavior of male African cichlid fish,
Astatotilapia burtoni, in their natural habitat suggests
that visual cues from conspecifics contribute significantly to regulation of
social behavior. Using a novel paradigm, we asked whether visual cues alone from
a larger conspecific male could influence behavior, reproductive physiology and
the physiological stress response of a smaller male. Here we show that just
seeing a larger, threatening male through a clear barrier can suppress dominant
behavior of a smaller male for up to 7 days. Smaller dominant males being
βattackedβ visually by larger dominant males through a clear barrier
also showed physiological changes for up to 3 days, including up-regulation of
reproductive- and stress-related gene expression levels and lowered plasma
11-ketotestesterone concentrations as compared to control animals. The smaller
males modified their appearance to match that of non-dominant males when exposed
to a larger male but they maintained a physiological phenotype similar to that
of a dominant male. After 7 days, reproductive- and stress- related gene
expression, circulating hormone levels, and gonad size in the smaller males
showed no difference from the control group suggesting that the smaller male
habituated to the visual intruder. However, the smaller male continued to
display subordinate behaviors and assumed the appearance of a subordinate male
for a full week despite his dominant male physiology. These data suggest that
seeing a larger male alone can regulate the behavior of a smaller male but that
ongoing reproductive inhibition depends on additional sensory cues. Perhaps,
while experiencing visual social stressors, the smaller male uses an
opportunistic strategy, acting like a subordinate male while maintaining the
physiology of a dominant male
Statistical Analysis of Molecular Signal Recording
A molecular device that records time-varying signals would enable new approaches in neuroscience. We have recently proposed such a device, termed a βmolecular ticker tapeβ, in which an engineered DNA polymerase (DNAP) writes time-varying signals into DNA in the form of nucleotide misincorporation patterns. Here, we define a theoretical framework quantifying the expected capabilities of molecular ticker tapes as a function of experimental parameters. We present a decoding algorithm for estimating time-dependent input signals, and DNAP kinetic parameters, directly from misincorporation rates as determined by sequencing. We explore the requirements for accurate signal decoding, particularly the constraints on (1) the polymerase biochemical parameters, and (2) the amplitude, temporal resolution, and duration of the time-varying input signals. Our results suggest that molecular recording devices with kinetic properties similar to natural polymerases could be used to perform experiments in which neural activity is compared across several experimental conditions, and that devices engineered by combining favorable biochemical properties from multiple known polymerases could potentially measure faster phenomena such as slow synchronization of neuronal oscillations. Sophisticated engineering of DNAPs is likely required to achieve molecular recording of neuronal activity with single-spike temporal resolution over experimentally relevant timescales.United States. Defense Advanced Research Projects Agency. Living Foundries ProgramGoogle (Firm)New York Stem Cell Foundation. Robertson Neuroscience Investigator AwardNational Institutes of Health (U.S.) (EUREKA Award 1R01NS075421)National Institutes of Health (U.S.) (Transformative R01 1R01GM104948)National Institutes of Health (U.S.) (Single Cell Grant 1 R01 EY023173)National Institutes of Health (U.S.) (Grant 1R01DA029639)National Institutes of Health (U.S.) (Grant 1R01NS067199)National Science Foundation (U.S.) (CAREER Award CBET 1053233)National Science Foundation (U.S.) (Grant EFRI0835878)National Science Foundation (U.S.) (Grant DMS1042134)Paul G. Allen Family Foundation (Distinguished Investigator in Neuroscience Award
A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4βΊ T-Cells to Recognition by Cytotoxic T-Lymphocytes
Resting CD4βΊ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8βΊ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8βΊ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8βΊ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8βΊ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8βΊ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand PamβCSKβ. In contrast, we did not observe CD8βΊ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist βALT-803β, an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8βΊ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8βΊ T-cells in HIV eradication strategies.United States. National Institutes of Health (AI111860
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