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Find video protocols related to scientific articles indexed in Pubmed.
Controlled dehydration of a ruthenium complex-DNA crystal induces reversible DNA kinking.
J. Am. Chem. Soc.
PUBLISHED: 11-14-2014
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Hydration-dependent DNA deformation has been known since Rosalind Franklin recognised that the relative humidity of the sample had to be maintained to observe a single conformation in DNA fibre diffraction. We now report for the first time the crystal structure, at the atomic level, of a dehydrated form of a DNA duplex and demonstrate the reversible interconversion to the hydrated form at room temperature. This system, containing d(TCGGCGCCGA) in the presence of ?-[Ru(TAP)2(dppz)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene, dppz = dipyridophenazine), undergoes a partial transition from an A/B hybrid to the A-DNA conformation, at 84-79% relative humidity. This is accompanied by an increase in kink at the central step from 22° to 51°, with a large movement of the terminal bases forming the intercalation site. This transition is reversible on rehydration. Seven datasets, collected from one crystal at room temperature, show the consequences of dehydration at near-atomic resolution. This result highlights that crystals, traditionally thought of as static systems, are still dynamic and therefore can be the subject of further experimentation.
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A receptor binding protein of Campylobacter jejuni bacteriophage NCTC 12673 recognizes flagellin glycosylated with acetamidino-modified pseudaminic acid.
Mol. Microbiol.
PUBLISHED: 10-28-2014
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Bacteriophage receptor binding proteins (RBPs) confer host specificity. We previously identified a putative RBP (Gp047) from the campylobacter lytic phage NCTC 12673 and demonstrated that Gp047 has a broader host range than its parent phage. While NCTC 12673 recognizes the capsular polysaccharide (CPS) of a limited number of Campylobacter jejuni isolates, Gp047 binds to a majority of C. jejuni and related Campylobacter coli strains. In this study, we demonstrate that Gp047 also binds to acapsular mutants, suggesting that unlike the parent phage, CPS is not the receptor for Gp047. Affinity chromatography and far-western analyses of C. jejuni lysates using Gp047 followed by mass spectrometry indicated that Gp047 binds to the major flagellin protein, FlaA. Since C. jejuni flagellin is extensively glycosylated, we investigated this binding specificity further and demonstrate that Gp047 only recognizes flagellin decorated with acetamidino-modified pseudaminic acid. This binding activity is localized to the C-terminal quarter of the protein and both wild type and coccoid forms of C. jejuni are recognized. In addition, Gp047 treatment agglutinates vegetative cells and reduces their motility. Since Gp047 is highly conserved among all campylobacter phages sequenced to date, it is likely that this protein plays an important role in the phage lifecycle.
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A New Experimental Model for Assessing Drug Efficacy against Trypanosoma cruzi Infection Based on Highly Sensitive In Vivo Imaging.
J Biomol Screen
PUBLISHED: 10-10-2014
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The protozoan Trypanosoma cruzi is the causative agent of Chagas disease, one of the world's major neglected infections. Although development of improved antiparasitic drugs is considered a priority, there have been no significant treatment advances in the past 40 years. Factors that have limited progress include an incomplete understanding of pathogenesis, tissue tropism, and disease progression. In addition, in vivo models, which allow parasite burdens to be tracked throughout the chronic stage of infection, have been lacking. To address these issues, we have developed a highly sensitive in vivo imaging system based on bioluminescent T. cruzi, which express a red-shifted luciferase that emits light in the tissue-penetrating orange-red region of the spectrum. The exquisite sensitivity of this noninvasive murine model has been exploited to monitor parasite burden in real time throughout the chronic stage, has allowed the identification of the gastrointestinal tract as the major niche of long-term infection, and has demonstrated that chagasic heart disease can develop in the absence of locally persistent parasites. Here, we review the parameters of the imaging system and describe how this experimental model can be incorporated into drug development programs as a valuable tool for assessing efficacy against both acute and chronic T. cruzi infections.
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Do Drug-Dependent Patients Attending Alcoholics Anonymous Rather than Narcotics Anonymous Do As Well? A Prospective, Lagged, Matching Analysis.
Alcohol Alcohol.
PUBLISHED: 10-09-2014
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Alcoholics Anonymous (AA) is the most prevalent 12-step mutual-help organization (MHO), yet debate has persisted clinically regarding whether patients whose primary substance is not alcohol should be referred to AA. Narcotics Anonymous (NA) was created as a more specific fit to enhance recovery from drug addiction; however, compared with AA, NA meetings are not as ubiquitous. Little is known about the effects of a mismatch between individuals' primary substance and MHOs, and whether any incongruence might result in a lower likelihood of continuation and benefit. More research would inform clinical recommendations.
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Microplastic is an Abundant and Distinct Microbial Habitat in an Urban River.
Environ. Sci. Technol.
PUBLISHED: 10-06-2014
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Recent research has documented microplastic particles (< 5 mm in diameter) in ocean habitats worldwide and in the Laurentian Great Lakes. Microplastic interacts with biota, including microorganisms, in these habitats, raising concerns about its ecological effects. Rivers may transport microplastic to marine habitats and the Great Lakes, but data on microplastic in rivers is limited. In a highly urbanized river in Chicago, Illinois, USA, we measured concentrations of microplastic that met or exceeded those measured in oceans and the Great Lakes, and we demonstrated that wastewater treatment plant effluent was a point source of microplastic. Results from high-throughput sequencing showed that bacterial assemblages colonizing microplastic within the river were less diverse and were significantly different in taxonomic composition compared to those from the water column and suspended organic matter. Several taxa that include plastic decomposing organisms and pathogens were more abundant on microplastic. These results demonstrate that microplastic in rivers are a distinct microbial habitat and may be a novel vector for the downstream transport of unique bacterial assemblages. In addition, this study suggests that urban rivers are an overlooked and potentially significant component of the global microplastic life cycle.
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Spinster homolog 2 (spns2) deficiency causes early onset progressive hearing loss.
PLoS Genet.
PUBLISHED: 10-01-2014
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Spinster homolog 2 (Spns2) acts as a Sphingosine-1-phosphate (S1P) transporter in zebrafish and mice, regulating heart development and lymphocyte trafficking respectively. S1P is a biologically active lysophospholipid with multiple roles in signalling. The mechanism of action of Spns2 is still elusive in mammals. Here, we report that Spns2-deficient mice rapidly lost auditory sensitivity and endocochlear potential (EP) from 2 to 3 weeks old. We found progressive degeneration of sensory hair cells in the organ of Corti, but the earliest defect was a decline in the EP, suggesting that dysfunction of the lateral wall was the primary lesion. In the lateral wall of adult mutants, we observed structural changes of marginal cell boundaries and of strial capillaries, and reduced expression of several key proteins involved in the generation of the EP (Kcnj10, Kcnq1, Gjb2 and Gjb6), but these changes were likely to be secondary. Permeability of the boundaries of the stria vascularis and of the strial capillaries appeared normal. We also found focal retinal degeneration and anomalies of retinal capillaries together with anterior eye defects in Spns2 mutant mice. Targeted inactivation of Spns2 in red blood cells, platelets, or lymphatic or vascular endothelial cells did not affect hearing, but targeted ablation of Spns2 in the cochlea using a Sox10-Cre allele produced a similar auditory phenotype to the original mutation, suggesting that local Spns2 expression is critical for hearing in mammals. These findings indicate that Spns2 is required for normal maintenance of the EP and hence for normal auditory function, and support a role for S1P signalling in hearing.
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Religiosity as a Predictor of Adolescents' Substance Use Disorder Treatment Outcomes.
Subst Abus
PUBLISHED: 09-16-2014
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ABSTRACT. Background: A growing body of research on adults with substance use disorders (SUD) suggests that higher levels of religiosity and/or spirituality are associated with better treatment outcomes. However, investigation into the role of religiosity and spirituality in adolescent SUD treatment response remains scarce. The present study examines religiosity as a predictor of treatment outcomes in an adolescent sample, with alcohol/other drug problem recognition as a hypothesized moderator of this relationship. Problem recognition was selected as a moderator in an attempt to identify a subset of adolescents who would be more likely to use religious resources when attempting to change their substance use. Methods: 127 outpatient adolescents age 14 to 19 (M age = 16.7, SD = 1.2, 24% female) were followed for 1 year after treatment intake. Growth curve analyses were used to assess the impact of baseline religiosity and problem recognition on subsequent abstinence rates, drug-related consequences, and psychological distress. Results: On average, abstinence did not change significantly during the follow-up period, whereas drug-related consequences and psychological distress decreased significantly. Religiosity did not predict changes in abstinence or psychological distress over time. Religiosity did predict reductions in drug-related consequences over time (b = -0.20, t = -2.18, p = .03). However, when problem recognition was added to the model, the impact of religiosity on consequences became non-significant and there was no interaction between religiosity and problem recognition on consequences. Conclusions: The main hypothesis was largely unsupported. Possible explanations include that the sample was low in religiosity and few participants were actively seeking sobriety at treatment intake. Findings suggest adolescent outpatients with SUD may differ from their adult counterparts in the role that religiosity plays in recovery.
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Supramolecular approach to enantioselective DNA recognition using enantiomerically resolved cationic 4-amino-1,8-naphthalimide-based Tröger's bases.
J. Org. Chem.
PUBLISHED: 09-16-2014
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The synthesis and photophysical studies of two cationic Tröger's base (TB)-derived bis-naphthalimides 1 and 2 and the TB derivative 6, characterized by X-ray crystallography, are presented. The enantiomers of 1 and 2 are separated by cation-exchange chromatography on Sephadex C25 using sodium (-)-dibenzoyl-l-tartarate as the chiral mobile phase. The binding of enantiomers with salmon testes (st)-DNA and synthetic polynucleotides are studied by a variety of spectroscopic methods including UV/vis absorbance, circular dichroism, linear dichroism, and ethidium bromide displacement assays, which demonstrated binding of these compounds to the DNA grooves with very high affinity (K ? 10(6) M(-1)) and preferential binding of (-)-enantiomer. In all cases, binding to DNA resulted in a significant stabilization of the double-helical structure of DNA against thermal denaturation. Compound (±)-2 and its enantiomers possessed significantly higher binding affinity for double-stranded DNA compared to 1, possibly due to the presence of the methyl group, which allows favorable hydrophobic and van der Waals interactions with DNA. The TB derivatives exhibited marked preference for AT rich sequences, where the binding affinities follow the order (-)-enantiomer > (±) > (+)-enantiomer. The compounds exhibited significant photocleavage of plasmid DNA upon visible light irradiation and are rapidly internalized into malignant cell lines.
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Study of picosecond processes of an intercalated dipyridophenazine Cr(iii) complex bound to defined sequence DNAs using transient absorption and time-resolved infrared methods.
Dalton Trans
PUBLISHED: 09-04-2014
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Picosecond transient absorption (TA) and time-resolved infrared (TRIR) measurements of rac-[Cr(phen)2(dppz)](3+) () intercalated into double-stranded guanine-containing DNA reveal that the excited state is very rapidly quenched. As no evidence was found for the transient electron transfer products, it is proposed that the back electron transfer reaction must be even faster (<3 ps).
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Stop talking "dirty": clinicians, language, and quality of care for the leading cause of preventable death in the United States.
Am. J. Med.
PUBLISHED: 09-02-2014
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This Commentary is original and has not been published and is not under consideration elsewhere. All authors participated in the writing of the manuscript. Drs. John F. Kelly and Richard Saitz have received funding from the National Institutes of Health (NIH) to conduct research on alcohol and other drug use disorders, and to speak at universities and government events. Dr. Saitz has also testified as an expert witness for alcohol cases, and provided consultation to Uptodate and the British Medical Journal. Dr. Sarah E. Wakeman, has no conflicts of interest to report.
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Acute effects of TiO2 nanomaterials on the viability and taxonomic composition of aquatic bacterial communities assessed via high-throughput screening and next generation sequencing.
PLoS ONE
PUBLISHED: 08-27-2014
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The nanotechnology industry is growing rapidly, leading to concerns about the potential ecological consequences of the release of engineered nanomaterials (ENMs) to the environment. One challenge of assessing the ecological risks of ENMs is the incredible diversity of ENMs currently available and the rapid pace at which new ENMs are being developed. High-throughput screening (HTS) is a popular approach to assessing ENM cytotoxicity that offers the opportunity to rapidly test in parallel a wide range of ENMs at multiple concentrations. However, current HTS approaches generally test one cell type at a time, which limits their ability to predict responses of complex microbial communities. In this study toxicity screening via a HTS platform was used in combination with next generation sequencing (NGS) to assess responses of bacterial communities from two aquatic habitats, Lake Michigan (LM) and the Chicago River (CR), to short-term exposure in their native waters to several commercial TiO2 nanomaterials under simulated solar irradiation. Results demonstrate that bacterial communities from LM and CR differed in their sensitivity to nano-TiO2, with the community from CR being more resistant. NGS analysis revealed that the composition of the bacterial communities from LM and CR were significantly altered by exposure to nano-TiO2, including decreases in overall bacterial diversity, decreases in the relative abundance of Actinomycetales, Sphingobacteriales, Limnohabitans, and Flavobacterium, and a significant increase in Limnobacter. These results suggest that the release of nano-TiO2 to the environment has the potential to alter the composition of aquatic bacterial communities, which could have implications for the stability and function of aquatic ecosystems. The novel combination of HTS and NGS described in this study represents a major advance over current methods for assessing ENM ecotoxicity because the relative toxicities of multiple ENMs to thousands of naturally occurring bacterial species can be assessed simultaneously under environmentally relevant conditions.
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Mechanisms linking connexin mutations to human diseases.
Cell Tissue Res.
PUBLISHED: 08-26-2014
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Ubiquitously expressed connexins are tetra-spanning transmembrane proteins that form intercellular gap junction channels or cell surface hemichannels. Connexins share similar topology but no sequence homology with mammalian pannexins and CALHM1 (calcium homeostasis modulator 1), which are also large-pore transmembrane channels. Of these three channel types, clinical evidence and gene sequence analysis to date have revealed that inherited human diseases are only associated with mutations in the connexin gene family. Connexin-linked diseases often present at birth or early in life and range from mild developmental abnormalities to severe organ failure such as hearing loss. Inherited connexin gene mutations can manifest as a disease by causing anomalies or defects in connexin oligomerization, folding, ability to pass quality control mechanisms or unexpected gain- or loss-of-function. This review provides examples of the way that various connexin gene mutations can cause disease via a wide range of molecular mechanisms. We also reflect on exciting strategies being explored in the connexin field and beyond with a view of translating their findings into potential connexin-disease therapeutics.
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Is residential treatment effective for opioid use disorders? A longitudinal comparison of treatment outcomes among opioid dependent, opioid misusing, and non-opioid using emerging adults with substance use disorder.
Drug Alcohol Depend
PUBLISHED: 07-29-2014
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Opioid misuse and dependence rates among emerging adults have increased substantially. While office-based opioid treatments (e.g., buprenorphine/naloxone) have shown overall efficacy, discontinuation rates among emerging adults are high. Abstinence-based residential treatment may serve as a viable alternative, but has seldom been investigated in this age group.
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Skin thickness of the anterior, anteromedial, and anterolateral thigh: a cadaveric study for split-skin graft donor sites.
Arch Plast Surg
PUBLISHED: 07-20-2014
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The depth of graft harvest and the residual dermis available for reepithelization primarily influence the healing of split-skin graft donor sites. When the thigh region is chosen, the authors hypothesize based on thickness measurements that the anterolateral region is the optimal donor site.
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Chemical interactions between Nano-ZnO and Nano-TiO2 in a natural aqueous medium.
Environ. Sci. Technol.
PUBLISHED: 06-23-2014
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The use of diverse engineered nanomaterials (ENMs) potentially leads to the release of multiple ENMs into the environment. However, previous efforts to understand the behavior and the risks associated with ENMs have focused on only one material at a time. In this study, the chemical interactions between two of the most highly used ENMs, nano-TiO2, and nano-ZnO, were examined in a natural water matrix. The fate of nano-ZnO in Lake Michigan water was investigated in the presence of nano-TiO2. Our experiments demonstrate that the combined effects of ZnO dissolution and Zn adsorption onto nano-TiO2 control the concentration of dissolved zinc. X-ray absorption spectroscopy was used to determine the speciation of Zn in the particulate fraction. The spectra show that Zn partitions between nano-ZnO and Zn2+ adsorbed on nano-TiO2. A simple kinetic model is presented to explain the experimental data. It integrates the processes of nano-ZnO dissolution with Zn adsorption onto nano-TiO2 and successfully predicts dissolved Zn concentration in solution. Overall, our results suggest that the fate and toxicity potential of soluble ENMs, such as nano-ZnO, are likely to be influenced by the presence of other stable ENMs, such as nano-TiO2.
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A case of recurring multifocal giant cell tumour of the tendon sheath in a child.
Hand Surg
PUBLISHED: 05-31-2014
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Giant cell tumour of the tendon sheath is rare in children. We present an unusual case of a recurring multifocal giant cell tumour of the tendon sheath in the hand and wrist of an 11-year-old boy. We are not aware of any similar report in the literature.
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Substance use by same sex attracted young people: Prevalence, perceptions and homophobia.
Drug Alcohol Rev
PUBLISHED: 04-22-2014
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Research highlights that lesbian, gay, bisexual and transgender (LGBT) people use alcohol and drugs (AOD) more than heterosexual people; however, the incidence of AOD use by LGBT youth is less understood. The purpose of the current study was to ascertain AOD prevalence rates for LGBT youth compared with the Australian youth population; perceptions of AOD use within the LGBT community; and the impact of homophobia on AOD use.
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A high prevalence of abnormal nutrition parameters found in predialysis end-stage kidney disease: is it a result of uremia or poor eating habits?
J Ren Nutr
PUBLISHED: 03-20-2014
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To describe the baseline nutritional characteristics of a cohort of end-stage kidney disease (ESKD) patients attending a pre-dialysis clinic.
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A high-resolution genetic map of yellow monkeyflower identifies chemical defense QTLs and recombination rate variation.
G3 (Bethesda)
PUBLISHED: 03-15-2014
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Genotyping-by-sequencing methods have vastly improved the resolution and accuracy of genetic linkage maps by increasing both the number of marker loci as well as the number of individuals genotyped at these loci. Using restriction-associated DNA sequencing, we construct a dense linkage map for a panel of recombinant inbred lines derived from a cross between divergent ecotypes of Mimulus guttatus. We used this map to estimate recombination rate across the genome and to identify quantitative trait loci for the production of several secondary compounds (PPGs) of the phenylpropanoid pathway implicated in defense against herbivores. Levels of different PPGs are correlated across recombinant inbred lines suggesting joint regulation of the phenylpropanoid pathway. However, the three quantitative trait loci identified in this study each act on a distinct PPG. Finally, we map three putative genomic inversions differentiating the two parental populations, including a previously characterized inversion that contributes to life-history differences between the annual/perennial ecotypes.
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Gene expression plasticity resulting from parental leaf damage in Mimulus guttatus.
New Phytol.
PUBLISHED: 02-26-2014
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Leaf trichome density in Mimulus guttatus can be altered by the parental environment. In this study, we compared global gene expression patterns in progeny of damaged and control plants. Significant differences in gene expression probably explain the observed trichome response, and identify additional responsive pathways. Using whole transcriptome RNA sequencing, we estimated differential gene expression between isogenic seedlings whose parents had, or had not, been subject to leaf damage. We identified over 900 genes that were differentially expressed in response to parental wounding. These genes clustered into groups involved in cell wall and cell membrane development, stress response pathways, and secondary metabolism. Gene expression is modified as a consequence of the parental environment in a targeted way that probably alters multiple developmental pathways, and may increase progeny fitness if they experience environments similar to that of their parents.
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Primary cutaneous mucinous carcinoma of the penis.
Can Urol Assoc J
PUBLISHED: 02-21-2014
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Primary cutaneous mucinous carcinoma (PCMC) is a rare, slow growing, malignant neoplasm arising from the sweat glands. Lesions are most commonly seen on the head and neck, and frequently mistaken for metastases from more common primary sites, such as the breast, gastrointestinal tract, lung, ovary, or prostate. We present what we believe is the first reported case of PCMC involving the penis.
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Bioluminescence imaging of chronic Trypanosoma cruzi infections reveals tissue-specific parasite dynamics and heart disease in the absence of locally persistent infection.
Cell. Microbiol.
PUBLISHED: 02-19-2014
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Chronic Trypanosoma cruzi infections lead to cardiomyopathy in 20-30% of cases. A causal link between cardiac infection and pathology has been difficult to establish because of a lack of robust methods to detect scarce, focally distributed parasites within tissues. We developed a highly sensitive bioluminescence imaging system based on T. cruzi expressing a novel luciferase that emits tissue-penetrating orange-red light. This enabled long-term serial evaluation of parasite burdens in individual mice with an in vivo limit of detection of significantly less than 1000 parasites. Parasite distributions during chronic infections were highly focal and spatiotemporally dynamic, but did not localize to the heart. End-point ex vivo bioluminescence imaging allowed tissue-specific quantification of parasite loads with minimal sampling bias. During chronic infections, the gastro-intestinal tract, specifically the colon and stomach, was the only site where T. cruzi infection was consistently observed. Quantitative PCR-inferred parasite loads correlated with ex vivo bioluminescence and confirmed the gut as the parasite reservoir. Chronically infected mice developed myocarditis and cardiac fibrosis, despite the absence of locally persistent parasites. These data identify the gut as a permissive niche for long-term T. cruzi infection and show that canonical features of Chagas disease can occur without continual myocardium-specific infection.
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Pure T7 sensory level as an isolated manifestation of Guillain-Barré syndrome.
J Clin Neuromuscul Dis
PUBLISHED: 02-19-2014
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Truncal sensory level (TSL) is a localizing sign for spinal cord pathology. However, in rare instances, lesions higher up in the spinothalamic tract can cause TSL.
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Mutations in Cx30 that are linked to skin disease and non-syndromic hearing loss exhibit several distinct cellular pathologies.
J. Cell. Sci.
PUBLISHED: 02-12-2014
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Connexin 30 (Cx30), a member of the large gap-junction protein family, plays a role in the homeostasis of the epidermis and inner ear through gap junctional intercellular communication (GJIC). Here, we investigate the underlying mechanisms of four autosomal dominant Cx30 gene mutations that are linked to hearing loss and/or various skin diseases. First, the T5M mutant linked to non-syndromic hearing loss formed functional gap junction channels and hemichannels, similar to wild-type Cx30. The loss-of-function V37E mutant associated with Clouston syndrome or keratitis-ichthyosis-deafness syndrome was retained in the endoplasmic reticulum and significantly induced apoptosis. The G59R mutant linked to the Vohwinkel and Bart-Pumphrey syndromes was retained primarily in the Golgi apparatus and exhibited loss of gap junction channel and hemichannel function but did not cause cell death. Lastly, the A88V mutant, which is linked to the development of Clouston syndrome, also significantly induced apoptosis but through an endoplasmic-reticulum-independent mechanism. Collectively, we discovered that four unique Cx30 mutants might cause disease through different mechanisms that also likely include their selective trans-dominant effects on coexpressed connexins, highlighting the overall complexity of connexin-linked diseases and the importance of GJIC in disease prevention.
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Spiritual dimensions of care: developing an educational package for hospital nurses in the Republic of Ireland.
Holist Nurs Pract
PUBLISHED: 02-08-2014
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The nurses' role in providing spiritual care to in-hospital patients is not clearly outlined in the Republic of Ireland (ROI). This and other deficits reveal that there are current gaps in nurses' knowledge and confidence in this area. In response, an educational innovation has been developed and this article reports on its development.
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Young adults with co-occurring disorders: substance use disorder treatment response and outcomes.
J Subst Abuse Treat
PUBLISHED: 02-04-2014
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Compared to other life stages, young adulthood (ages 18-24) is characterized by qualitative differences including the highest rates of co-occurring substance use and psychiatric disorders (COD). Little is known, however, regarding young adults' response to substance use disorder (SUD) treatment, especially those with COD. Greater knowledge in this area could inform and enhance the effectiveness and efficiency of SUD care for this patient population. The current study investigated differences between 141 COD and 159 SUD-only young adults attending psychiatrically-integrated residential SUD treatment on intake characteristics, during-treatment changes on clinical targets (e.g., coping skills; abstinence self-efficacy), and outcomes during the year post-discharge. Contrary to expectations, despite more severe clinical profiles at intake, COD patients showed similar during-treatment improvements on clinical target variables, and comparable post-treatment abstinence rates and psychiatric symptoms. Clinicians referring young adults with COD to specialized care may wish to consider residential SUD treatment programs that integrate evidence-based psychiatric services.
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Optimizing bioluminescence imaging to study protozoan parasite infections.
Trends Parasitol.
PUBLISHED: 01-14-2014
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Bioluminescence imaging is a non-invasive technique which can be used to monitor infections in real-time. However, its utility is restricted by difficulties in detecting pathogens in deep tissue. 'Red-shifted' luciferases, which emit light of longer wavelength than standard bioluminescence-generating proteins, greatly enhance sensitivity, and have wide applicability for studying parasite infections.
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Benznidazole-resistance in Trypanosoma cruzi: evidence that distinct mechanisms can act in concert.
Mol. Biochem. Parasitol.
PUBLISHED: 01-10-2014
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Benznidazole is the main drug used to treat Trypanosoma cruzi infections. However, frequent instances of treatment failure have been reported. To better understand potential resistance mechanisms, we analysed three clones isolated from a single parasite population that had undergone benznidazole-selection. These clones exhibited differing levels of benznidazole-resistance (varying between 9 and 26-fold), and displayed cross-resistance to nifurtimox (2 to 4-fold). Each clone had acquired a stop-codon-generating mutation in the gene which encodes the nitroreductase (TcNTR) that is responsible for activating nitroheterocyclic pro-drugs. In addition, one clone had lost a copy of the chromosome containing TcNTR. However, these processes alone are insufficient to account for the extent and diversity of benznidazole-resistance. It is implicit from our results that additional mechanisms must also operate and that T. cruzi has an intrinsic ability to develop drug-resistance by independent sequential steps, even within a single population. This has important implications for drug development strategies.
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Panx1 regulates cellular properties of keratinocytes and dermal fibroblasts in skin development and wound healing.
J. Invest. Dermatol.
PUBLISHED: 01-08-2014
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Pannexin1 (Panx1), a channel-forming glycoprotein is expressed in neonatal but not in aged mouse skin. Histological staining of Panx1 knockout (KO) mouse skin revealed a reduction in epidermal and dermal thickness and an increase in hypodermal adipose tissue. Following dorsal skin punch biopsies, mutant mice exhibited a significant delay in wound healing. Scratch wound and proliferation assays revealed that cultured keratinocytes from KO mice were more migratory, whereas dermal fibroblasts were more proliferative compared with controls. In addition, collagen gels populated with fibroblasts from KO mice exhibited significantly reduced contraction, comparable to WT fibroblasts treated with the Panx1 blocker, probenecid. KO fibroblasts did not increase ?-smooth muscle actin expression in response to TGF-?, as is the case for differentiating WT myofibroblasts during wound contraction. We conclude that Panx1 controls cellular properties of keratinocytes and dermal fibroblasts during early stages of skin development and modulates wound repair upon injury.
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Anthropogenic litter in urban freshwater ecosystems: distribution and microbial interactions.
PLoS ONE
PUBLISHED: 01-01-2014
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Accumulation of anthropogenic litter (i.e. garbage; AL) and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1) quantify AL density in urban freshwaters, 2) compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3) characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP) and community respiration (CR), and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond), but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves) had lower GPP than hard substrates (glass, plastic, aluminum and tiles). In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across multiple ecosystem types, and will benefit management and reduction of global AL accumulations.
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Temporal variations in the abundance and composition of biofilm communities colonizing drinking water distribution pipes.
PLoS ONE
PUBLISHED: 01-01-2014
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Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities within the pipes were analyzed by heterotrophic plate counts and tag pyrosequencing of 16S rRNA genes, respectively. Bacterial numbers varied significantly based on sampling date and were positively correlated with water temperature and the concentration of nitrate. However, there was no significant relationship between the concentration of disinfectant in the drinking water (monochloramine) and the abundance of bacteria within the biofilms. Pyrosequencing analysis identified a total of 677 operational taxonomic units (OTUs) (3% distance) within the biofilms but indicated that community diversity was low and varied between sampling dates. Biofilms were dominated by a few taxa, specifically Methylomonas, Acinetobacter, Mycobacterium, and Xanthomonadaceae, and the dominant taxa within the biofilms varied dramatically between sampling times. The drinking water characteristics most strongly correlated with bacterial community composition were concentrations of nitrate, ammonium, total chlorine and monochloramine, as well as alkalinity and hardness. Biofilms from the sampling date with the highest nitrate concentration were the most abundant and diverse and were dominated by Acinetobacter.
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Highly Sensitive In Vivo Imaging of Trypanosoma brucei Expressing "Red-Shifted" Luciferase.
PLoS Negl Trop Dis
PUBLISHED: 11-01-2013
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Human African trypanosomiasis is caused by infection with parasites of the Trypanosoma brucei species complex, and threatens over 70 million people in sub-Saharan Africa. Development of new drugs is hampered by the limitations of current rodent models, particularly for stage II infections, which occur once parasites have accessed the CNS. Bioluminescence imaging of pathogens expressing firefly luciferase (emission maximum 562 nm) has been adopted in a number of in vivo models of disease to monitor dissemination, drug-treatment and the role of immune responses. However, lack of sensitivity in detecting deep tissue bioluminescence at wavelengths below 600 nm has restricted the wide-spread use of in vivo imaging to investigate infections with T. brucei and other trypanosomatids.
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Attention network hypoconnectivity with default and affective network hyperconnectivity in adults diagnosed with attention-deficit/hyperactivity disorder in childhood.
JAMA Psychiatry
PUBLISHED: 10-18-2013
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IMPORTANCE The neurobiological underpinnings of attention-deficit/hyperactivity disorder (ADHD) and particularly those associated with the persistence of ADHD into adulthood are not yet well understood. The correlation patterns in spontaneous neural fluctuations at rest are known as resting-state functional connectivity (RSFC) and could characterize ADHD-specific connectivity changes. OBJECTIVE To determine the specific location of possible ADHD-related differences in RSFC between adults diagnosed as having ADHD in childhood and control subjects. DESIGN Using resting-state functional magnetic resonance imaging, we calculated and compared functional connectivity from attention, affective, default, and cognitive control networks involved in the psychopathology of ADHD between the ADHD and control groups. SETTING University psychiatric service and magnetic resonance imaging research center. PARTICIPANTS Sixteen drug-free adults (5 women and 11 men; mean age, 24.5 years) diagnosed with combined-type ADHD in childhood and 16 healthy controls matched for age (mean age, 24.4 years), sex, handedness, and educational level recruited from the community. INTERVENTION Functional magnetic resonance imaging. MAIN OUTCOMES AND MEASURES Connectivity data from ventral and dorsal attention, affective, default, and cognitive control networks and ADHD symptoms derived from ADHD-specific rating instruments. RESULTS Adults with ADHD showed significantly decreased RSFC within the attention networks and increased RSFC within the affective and default mode and the right lateralized cognitive control networks compared with healthy controls (P?<?.01, familywise error for whole-brain cluster correction). Lower RSFC in the ventral and dorsal attention network was significantly correlated with higher levels of ADHD symptoms (P?<?.001). CONCLUSIONS AND RELEVANCE These RSFC findings might underpin a biological basis for adult ADHD and are functionally related to persistent inattention, disturbance in cognitive control, and emotional dysregulation in adults with ADHD. These findings need to be understood in the context of all aspects of brain function in ADHD.
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Effects of Material Morphology on the Phototoxicity of Nano-TiO2 to Bacteria.
Environ. Sci. Technol.
PUBLISHED: 10-18-2013
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Nanostructured titania (nano-TiO2) is produced in diverse shapes, but it remains largely unknown how tuning the morphology of nano-TiO2 may alter its toxicity. Herein, we show that material morphology plays a critical role in regulating the phototoxicity of nano-TiO2 to bacteria. Low-dimensional nano-TiO2, including nanotubes, nanorods, and nanosheets, were synthesized hydrothermally, and their effects on the bacterial viability of Escherichia coli and Aeromonas hydrophila were compared to spherical nanostructures (anatase nanospheres and P25). Results reveal that TiO2 nanotubes and nanosheets are less phototoxic than their rod- and sphere-shape counterparts under simulated solar irradiation. None of the tested nano-TiO2 shows toxicity in the dark. In contrast to their diminished phototoxicity, however, TiO2 nanotubes and nanosheets exhibit comparable or even higher photoactivity than other nanostructures. Observations by scanning transmission electron microscopy suggest that material morphology influences nano-TiO2 phototoxicity by governing how nano-TiO2 particles align at the bacterial cell surface. Overall, when comparing materials with different morphologies and dimensionality, nano-TiO2 phototoxicity is not a simple function of photocatalytic reactivity or ROS production. Instead, we propose that the evaluation of nano-TiO2 phototoxicity encompasses a three-pronged approach, involving the intrinsic photoactivity, aggregation of nano-TiO2, and the nano-TiO2/bacteria surface interactions.
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Changes in bedtime schedules and behavioral difficulties in 7 year old children.
Pediatrics
PUBLISHED: 10-14-2013
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Causal links between disrupted sleep and behavioral problems in nonclinical populations are far from clear. Research questions were as follows: Are bedtime schedules associated with behavioral difficulties? Do effects of bedtime schedules on behavior build up over early childhood? Are changes in bedtime schedules linked to changes in behavior?
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Synthesis, spectroscopic and biological studies of a fluorescent Pt(II) (terpy) based 1,8-naphthalimide conjugate as a DNA targeting agent.
Chem. Commun. (Camb.)
PUBLISHED: 08-15-2013
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The bi-functional complex [Pt(II)(terpy)(py-naphth)](NO3)2(), incorporating both 2,2:6,2-terpyridine and 4-N,N-dimethylamino-1,8-naphthalimide moieties, displays a high binding affinity for DNA as well as displaying cytotoxicity towards and inducing apoptosis in malignant cell lines.
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X-ray crystal structure of rac-[Ru(phen)2dppz]2+ with d(ATGCAT)2 shows enantiomer orientations and water ordering.
J. Am. Chem. Soc.
PUBLISHED: 08-14-2013
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We report an atomic resolution X-ray crystal structure containing both enantiomers of rac-[Ru(phen)2dppz](2+) with the d(ATGCAT)2 DNA duplex (phen = phenanthroline; dppz = dipyridophenazine). The first example of any enantiomeric pair crystallized with a DNA duplex shows different orientations of the ? and ? binding sites, separated by a clearly defined structured water monolayer. Job plots show that the same species is present in solution. Each enantiomer is bound at a TG/CA step and shows intercalation from the minor groove. One water molecule is directly located on one phenazine N atom in the ?-enantiomer only.
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Triclosan exposure increases triclosan resistance and influences taxonomic composition of benthic bacterial communities.
Environ. Sci. Technol.
PUBLISHED: 07-25-2013
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Triclosan (TCS) is a broad-spectrum antimicrobial compound that is incorporated into numerous consumer products. TCS has been detected in aquatic ecosystems across the U.S., raising concern about its potential ecological effects. We conducted a field survey and an artificial stream experiment to assess effects of TCS on benthic bacterial communities. Field sampling indicated that TCS concentrations in stream sediments increased with degree of urbanization. There was significant correlation between sediment TCS concentration and the proportion of cultivable benthic bacteria that were resistant to TCS, demonstrating that the levels of TCS present in these streams was affecting the native communities. An artificial stream experiment confirmed that TCS exposure could trigger increases in TCS resistance within cultivable benthic bacteria, and pyrosequencing analysis indicated that TCS resulted in decreased benthic bacterial diversity and shifts in bacterial community composition. One notable change was a 6-fold increase in the relative abundance of cyanobacterial sequences and a dramatic die-off of algae within the artificial streams. Selection of cyanobacteria over algae could have significant implications for higher trophic levels within streams. Finally, there were no observed effects of TCS on bacterial abundance or respiration rates, suggesting that bacterial density and function were highly resilient to TCS exposure.
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The effect of the 4-amino functionality on the photophysical and DNA binding properties of alkyl-pyridinium derived 1,8-naphthalimides.
Org. Biomol. Chem.
PUBLISHED: 07-23-2013
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The synthesis and characterisation of two cationic pyridinium based 4-amino-1,8-naphthalimide derivatives (2 and 3) are described and compared to those of compound 1. The photophysical properties of 2 and 3 are shown to vary greatly with the solvent polarity and H-bonding ability. The dimethylamino substitution in 3 results in a weak quantum yield of fluorescence emission due to faster non-radiative deactivation of the excited singlet state than that seen for 2. As with 1, the fluorescence of 2 was found to be enhanced in its 1 : 1 complex with 5-adenosine-monophosphate (5-AMP) while it was partially quenched in its complex with 5-guanosine-monophosphate (5-GMP). In contrast, the fluorescence of 3 was enhanced (switched on) in the presence of both adenine and guanine rich sequences. Linear and circular dichroism studies showed that each of 1, 2 and 3 binds to double-stranded DNA by intercalation. However, 2 and 3 do not show the preference for AT-rich DNA observed for 1. Comparative fluorescence studies with double stranded DNA show that the emission of was 16 times enhanced in its DNA bound form, suggesting potential use of this structure as a spectroscopic probe for studying nucleic acid structure.
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Common freshwater bacteria vary in their responses to short-term exposure to nano-TiO2.
Environ. Toxicol. Chem.
PUBLISHED: 07-09-2013
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Nanostructured titania (nano-TiO2 ) is an engineered nanomaterial that can be cytotoxic primarily as a result of its ability to generate reactive oxygen species when illuminated. Production of nano-TiO2 has increased rapidly over the last decade, leading to concerns about its release into aquatic environments. To address the possible ecological impacts of nano-TiO2 , the authors used high-throughput screening to assess the responses of 4 bacteria representative of genera common in freshwater to short-term exposure (1-2?h) in 2 natural aqueous media (stream water and lake water) to 2 widely used TiO2 products, pigment white 6 (PW6) and P25. Under simulated solar illumination PW6 and P25 reduced the abundance of viable Bacillus subtilis and Aeromonas hydrophila, confirming the cytotoxicity of nano-TiO2 . In contrast, PW6 and P25 stimulated growth of Arthrobacter sp. and Klebsiella sp., which the authors hypothesize was driven by oxidation of organic matter in these natural waters into more labile compounds. This hypothesis is supported by data demonstrating PW6 photo-oxidation of organic matter in stream water, which subsequently supported enhanced bacterial growth. The results indicate that bacterial responses to nano-TiO2 can be species-specific, suggesting that nano-TiO2 may alter bacterial community composition and function. Finally, the results indicate that bacterial responses to nano-TiO2 are influenced by the water matrix, emphasizing the importance of assessing bacterial responses to nanomaterials in natural environmental media. Environ Toxicol Chem 2014;33:XX-XX. © 2013 SETAC.
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Improving biophysical properties of a bispecific antibody scaffold to aid developability: quality by molecular design.
MAbs
PUBLISHED: 07-08-2013
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While the concept of Quality-by-Design is addressed at the upstream and downstream process development stages, we questioned whether there are advantages to addressing the issues of biologics quality early in the design of the molecule based on fundamental biophysical characterization, and thereby reduce complexities in the product development stages. Although limited number of bispecific therapeutics are in clinic, these developments have been plagued with difficulty in producing materials of sufficient quality and quantity for both preclinical and clinical studies. The engineered heterodimeric Fc is an industry-wide favorite scaffold for the design of bispecific protein therapeutics because of its structural, and potentially pharmacokinetic, similarity to the natural antibody. Development of molecules based on this concept, however, is challenged by the presence of potential homodimer contamination and stability loss relative to the natural Fc. We engineered a heterodimeric Fc with high heterodimeric specificity that also retains natural Fc-like biophysical properties, and demonstrate here that use of engineered Fc domains that mirror the natural system translates into an efficient and robust upstream stable cell line selection process as a first step toward a more developable therapeutic.
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Identification of genes involved in the biosynthesis of the third and fourth sugars of the Methanococcus maripaludis archaellin N-linked tetrasaccharide.
J. Bacteriol.
PUBLISHED: 07-08-2013
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N-glycosylation is a protein posttranslational modification found in all three domains of life. Many surface proteins in Archaea, including S-layer proteins, pilins, and archaellins (archaeal flagellins) are known to contain N-linked glycans. In Methanococcus maripaludis, the archaellins are modified at multiple sites with an N-linked tetrasaccharide with the structure Sug-1,4-?-ManNAc3NAmA6Thr-1,4-?-GlcNAc3NAcA-1,3-?-GalNAc, where Sug is the unique sugar (5S)-2-acetamido-2,4-dideoxy-5-O-methyl-?-l-erythro-hexos-5-ulo-1,5-pyranose. In this study, four genes--mmp1084, mmp1085, mmp1086, and mmp1087--were targeted to determine their potential involvement of the biosynthesis of the sugar components in the N-glycan, based on bioinformatics analysis and proximity to a number of genes which have been previously demonstrated to be involved in the N-glycosylation pathway. The genes mmp1084 to mmp1087 were shown to be cotranscribed, and in-frame deletions of each gene as well as a ?mmp1086?mmp1087 double mutant were successfully generated. All mutants were archaellated and motile. Mass spectrometry examination of purified archaella revealed that in ?mmp1084 mutant cells, the threonine linked to the third sugar of the glycan was missing, indicating a putative threonine transferase function of MMP1084. Similar analysis of the archaella of the ?mmp1085 mutant cells demonstrated that the glycan lacked the methyl group at the C-5 position of the terminal sugar, indicating that MMP1085 is a methyltransferase involved in the biosynthesis of this unique sugar. Deletion of the remaining two genes, mmp1086 and mmp1087, either singularly or together, had no effect on the structure of the archaellin N-glycan. Because of their demonstrated involvement in the N-glycosylation pathway, we designated mmp1084 as aglU and mmp1085 as aglV.
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Time for bed: associations with cognitive performance in 7-year-old children: a longitudinal population-based study.
J Epidemiol Community Health
PUBLISHED: 07-08-2013
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Little is known about the links between the time that young children go to bed and their cognitive development. In this paper we seek to examine whether bedtimes in early childhood are related to cognitive test scores in 7-year-olds.
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The genomic signal of partial sweeps in Mimulus guttatus.
Genome Biol Evol
PUBLISHED: 07-06-2013
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The molecular signature of selection depends strongly on whether new mutations are immediately favorable and sweep to fixation (hard sweeps) as opposed to when selection acts on segregating variation (soft sweeps). The prediction of reduced sequence variation around selected polymorphisms is much stronger for hard than soft sweeps, particularly when considering quantitative traits where sweeps are likely to be incomplete. Here, we directly investigate the genomic signal of soft sweeps within an artificial selection experiment on Mimulus guttatus. We first develop a statistical method based on Fishers angular transformation of allele frequencies to identify selected loci. Application of this method identifies about 400 significant windows, but no fixed differences between phenotypically divergent populations. With two notable exceptions, we find a modest average effect of partial sweeps on the amount of molecular variation. The first exception is a polymorphic inversion on chromosome 6. The increase of the derived haplotype has a broad genomic effect due to recombination suppression coupled with substantial initial haplotype structure within the population. Second, we found significant increases in nucleotide variation around selected loci in the population evolving larger flowers. This suggests that "high" alleles for flower size were initially less frequent than "low" alleles. This result is consistent with prior studies of M. guttatus and illustrates how molecular evolution can depend on the allele frequency spectrum at quantitative trait loci.
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Pharmaceuticals suppress algal growth and microbial respiration and alter bacterial communities in stream biofilms.
Ecol Appl
PUBLISHED: 06-06-2013
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Pharmaceutical and personal care products are ubiquitous in surface waters but their effects on aquatic biofilms and associated ecosystem properties are not well understood. We measured in situ responses of stream biofilms to six common pharmaceutical compounds (caffeine, cimetidine, ciprofloxacin, diphenhydramine, metformin, ranitidine, and a mixture of each) by deploying pharmaceutical-diffusing substrates in streams in Indiana, Maryland, and New York. Results were consistent across seasons and geographic locations. On average, algal biomass was suppressed by 22%, 4%, 22%, and 18% relative to controls by caffeine, ciprofloxacin, diphenhydramine, and the mixed treatment, respectively. Biofilm respiration was significantly suppressed by caffeine (53%), cimetidine (51%), ciprofloxacin (91%), diphenhydramine (63%), and the mixed treatment (40%). In autumn in New York, photosynthesis was also significantly suppressed by diphenhydramine (99%) and the mixed treatment (88%). Pyrosequencing of 16S rRNA genes was used to examine the effects of caffeine and diphenhydramine on biofilm bacterial community composition at the three sites. Relative to the controls, diphenhydramine exposure significantly altered bacterial community composition and resulted in significant relative increases in Pseudomonas sp. and decreases in Flavobacterium sp. in all three streams. These ubiquitous pharmaceuticals, alone or in combination, influenced stream biofilms, which could have consequences for higher trophic levels and important ecosystem processes.
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Evidence that transport of iron from the lysosome to the cytosol in African trypanosomes is mediated by a mucolipin orthologue.
Mol. Microbiol.
PUBLISHED: 06-02-2013
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Bloodstream-form Trypanosoma brucei acquire iron by receptor-mediated endocytosis of host transferrin. However, the mechanism(s) by which iron is then transferred from the lysosome to the cytosol are unresolved. Here, we provide evidence for the involvement of a protein (TbMLP) orthologous to the mammalian endolysosomal cation channel Mucolipin 1. In T.?brucei, we show that this protein is localized to the single parasite lysosome. TbMLP null mutants could only be generated in the presence of an expressed ectopic copy, suggesting that the protein is essential. RNAi-mediated ablation resulted in a growth defect in vitro and led to a sevenfold increase in susceptibility to the iron-chelators deferoxamine and salicylhydroxamic acid. Conditional null mutants remained viable when the ectopic copy was repressed, but were hypersensitive to deferoxamine and displayed a growth defect similar to that observed following RNAi. The conditional nulls also retained virulence in vivo in the absence of the doxycycline inducer. These data provide strong evidence that TbMLP has a role in import of iron into the cytosol of African trypanosomes. They also indicate that even when expression is greatly reduced, there is sufficient protein, or an alternative mechanism, to provide the parasite with an adequate supply of cytosolic iron.
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Therapeutic activation of macrophages and microglia to suppress brain tumor-initiating cells.
Nat. Neurosci.
PUBLISHED: 05-21-2013
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Brain tumor initiating cells (BTICs) contribute to the genesis and recurrence of gliomas. We examined whether the microglia and macrophages that are abundant in gliomas alter BTIC growth. We found that microglia derived from non-glioma human subjects markedly mitigated the sphere-forming capacity of glioma patient-derived BTICs in culture by inducing the expression of genes that control cell cycle arrest and differentiation. This sphere-reducing effect was mimicked by macrophages, but not by neurons or astrocytes. Using a drug screen, we validated amphotericin B (AmpB) as an activator of monocytoid cells and found that AmpB enhanced the microglial reduction of BTIC spheres. In mice harboring intracranial mouse or patient-derived BTICs, daily systemic treatment with non-toxic doses of AmpB substantially prolonged life. Notably, microglia and monocytes cultured from glioma patients were inefficient at reducing the sphere-forming capacity of autologous BTICs, but this was rectified by AmpB. These results provide new insights into the treatment of gliomas.
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Quality and safety implications of emergency department information systems.
Ann Emerg Med
PUBLISHED: 05-20-2013
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The Health Information Technology for Economic and Clinical Health Act of 2009 and the Centers for Medicare & Medicaid Services "meaningful use" incentive programs, in tandem with the boundless additional requirements for detailed reporting of quality metrics, have galvanized hospital efforts to implement hospital-based electronic health records. As such, emergency department information systems (EDISs) are an important and unique component of most hospitals electronic health records. System functionality varies greatly and affects physician decisionmaking, clinician workflow, communication, and, ultimately, the overall quality of care and patient safety. This article is a joint effort by members of the Quality Improvement and Patient Safety Section and the Informatics Section of the American College of Emergency Physicians. The aim of this effort is to examine the benefits and potential threats to quality and patient safety that could result from the choice of a particular EDIS, its implementation and optimization, and the hospitals or physician groups approach to continuous improvement of the EDIS. Specifically, we explored the following areas of potential EDIS safety concerns: communication failure, wrong order-wrong patient errors, poor data display, and alert fatigue. Case studies are presented that illustrate the potential harm that could befall patients from an inferior EDIS product or suboptimal execution of such a product in the clinical environment. The authors have developed 7 recommendations to improve patient safety with respect to the deployment of EDISs. These include ensuring that emergency providers actively participate in selection of the EDIS product, in the design of processes related to EDIS implementation and optimization, and in the monitoring of the systems ongoing success or failure. Our recommendations apply to emergency departments using any type of EDIS: custom-developed systems, best-of-breed vendor systems, or enterprise systems.
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On the importance of balancing selection in plants.
New Phytol.
PUBLISHED: 05-13-2013
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45 I. 46 II. 46 III. 47 IV. 48 V. 50 VI. 52 VII. 53 VIII. 54 54 References 54 SUMMARY: Balancing selection refers to a variety of selective regimes that maintain advantageous genetic diversity within populations. We review the history of the ideas regarding the types of selection that maintain such polymorphism in flowering plants, notably heterozygote advantage, negative frequency-dependent selection, and spatial heterogeneity. One shared feature of these mechanisms is that whether an allele is beneficial or detrimental is conditional on its frequency in the population. We highlight examples of balancing selection on a variety of discrete traits. These include the well-referenced case of self-incompatibility and recent evidence from species with nuclear-cytoplasmic gynodioecy, both of which exhibit trans-specific polymorphism, a hallmark of balancing selection. We also discuss and give examples of how spatial heterogeneity in particular, which is often thought unlikely to allow protected polymorphism, can maintain genetic variation in plants (which are rooted in place) as a result of microhabitat selection. Lastly, we discuss limitations of the protected polymorphism concept for quantitative traits, where selection can inflate the genetic variance without maintaining specific alleles indefinitely. We conclude that while discrete-morph variation provides the most unambiguous cases of protected polymorphism, they represent only a fraction of the balancing selection at work in plants.
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The effect of lean systems on person-centred care.
Nurs Times
PUBLISHED: 04-30-2013
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The drive to increase efficiency and reduce costs in the NHS has led many organisations to adopt lean management systems. However, the focus on standardisation makes it difficult to meet patients individual needs and denies health professionals the opportunity to exercise their skills and professional judgement.
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Efficacy of Crosslinking on Tailoring In Vivo Biodegradability of Fibro-Porous Decellularized Extracellular Matrix and Restoration of Native Tissue Structure: A Quantitative Study using Stereology Methods.
Macromol Biosci
PUBLISHED: 04-16-2013
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Cholecyst-derived extracellular matrix (CEM) is a fibro-porous decellularized serosal layer of porcine gall-bladder. CEM loses 90% of its weight at 48?h of in vitro collagenase digestion, but takes two months to be completely resorbed in vivo. Carbodiimide (EDC) crosslinking helps tailoring CEMs in vitro collagenase susceptibility. Here, the efficacy of EDC crosslinking on tailoring in vivo biodegradability of CEM is reported. CEM crosslinked with 0.0005 and 0.0033?×?10(3) M of EDC/mg that lose 80% and 0% of their weight respectively to in vitro collagenase digestion, were present even after 180 days in vivo. Quantitative histopathology using stereology methods confirmed our qualitative observation that even a tiny degree of crosslinking can significantly prolong the rate of in vivo degradation and removal of CEM.
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Genetic dissection of drug resistance in trypanosomes.
Parasitology
PUBLISHED: 04-03-2013
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The trypanosomes cause two neglected tropical diseases, Chagas disease in the Americas and African trypanosomiasis in sub-Saharan Africa. Over recent years a raft of molecular tools have been developed enabling the genetic dissection of many aspects of trypanosome biology, including the mechanisms underlying resistance to some of the current clinical and veterinary drugs. This has led to the identification and characterization of key resistance determinants, including transporters for the anti-Trypanosoma brucei drugs, melarsoprol, pentamidine and eflornithine, and the activator of nifurtimox-benznidazole, the anti-Trypanosoma cruzi drugs. More recently, advances in sequencing technology, combined with the development of RNA interference libraries in the clinically relevant bloodstream form of T. brucei have led to an exponential increase in the number of proteins known to interact either directly or indirectly with the anti-trypanosomal drugs. In this review, we discuss these findings and the technological developments that are set to further revolutionise our understanding of drug-trypanosome interactions. The new knowledge gained should inform the development of novel interventions against the devastating diseases caused by these parasites.
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Posttranslational modification of flagellin FlaB in Shewanella oneidensis.
J. Bacteriol.
PUBLISHED: 03-29-2013
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Shewanella oneidensis is a highly motile organism by virtue of a polar, glycosylated flagellum composed of flagellins FlaA and FlaB. In this study, the functional flagellin FlaB was isolated and analyzed with nano-liquid chromatography-mass spectrometry (MS) and tandem MS. In combination with the mutational analysis, we propose that the FlaB flagellin protein from S. oneidensis is modified at five serine residues with a series of novel O-linked posttranslational modifications (PTMs) that differ from each other by 14 Da. These PTMs are composed in part of a 274-Da sugar residue that bears a resemblance to the nonulosonic acids. The remainder appears to be composed of a second residue whose mass varies by 14 Da depending on the PTM. Further investigation revealed that synthesis of the glycans initiates with PseB and PseC, the first two enzymes of the Pse pathway. In addition, a number of lysine residues are found to be methylated by SO4160, an analogue of the lysine methyltransferase of Salmonella enterica serovar Typhimurium.
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Efficient quenching of TGA-capped CdTe quantum dot emission by a surface-coordinated europium(III) cyclen complex.
Inorg Chem
PUBLISHED: 03-25-2013
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Extremely efficient quenching of the excited state of aqueous CdTe quantum dots (QDs) by photoinduced electron transfer to a europium cyclen complex is facilitated by surface coordination to the thioglycolic acid capping ligand. The quenching dynamics are elucidated using steady-state emission and picosecond transient absorption.
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A review of the interplay between tuberculosis and mental health.
Gen Hosp Psychiatry
PUBLISHED: 03-18-2013
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Tuberculosis and mental illness share common risk factors including homelessness, HIV positive serology, alcohol/substance abuse and migrant status leading to frequent comorbidity. We sought to generate a comprehensive literature review that examines the complex relationship between tuberculosis and mental illness.
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Perceptions of emergency department crowding in the commonwealth of pennsylvania.
West J Emerg Med
PUBLISHED: 03-02-2013
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Introduction: The state of emergency department (ED) crowding in Pennsylvania has not previously been reported.Methods: We assessed perceptions of ED crowding by surveying medical directors/chairs from Pennsylvania EDs in the spring of 2008.Results: A total of 106 completed the questionnaire (68% response rate). A total of 83% (86/104) agreed that ED crowding was a problem; 26% (27/105) reported that at least half of admitted patients boarded for more than 4 hours. Ninety-eight percent (102/104) agreed that patient satisfaction suffers during crowding and 79% (84/106) stated that quality suffers. Sixty-five percent (68/105) reported that crowding had worsened during the past 2 years. Several hospital interventions were used to alleviate crowding: expediting discharges, 81% (86/106); prioritizing ED patients for inpatient beds, 79% (84/106); and ambulance diversion, 55% (57/105). Almost all respondents who had improved ED operations reported that it had reduced crowding.Conclusion: ED crowding is a common problem in Pennsylvania and is worsening in the majority of hospitals, despite the implementation of a variety of interventions.
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Preparation of saline-stable, silica-coated triangular silver nanoplates of use for optical sensing.
J Colloid Interface Sci
PUBLISHED: 03-01-2013
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Triangular silver nanoplates (TSNPs) may find application in next generation optical bio-sensors owing to the high sensitivity of the spectral position of their main plasmon band to changes in local refractive index. Unfortunately, etching of the anisotropic nanoplates to spherical particles occurs upon exposure to chloride ions from salt, with a concomitant decrease in optical sensitivity. Herein are detailed two general methods for the silica coating of TSNPs, with the aim of forming a protective barrier against chloride etching. It has been necessary to modify literature approaches for the coating of spherical Ag nanoparticles, since these are either ineffective for anisotropic nanoplates or lead to their degradation. The first method is a modified Stöber approach using tetraethylorthosilicate (TEOS) as the alkoxide precursor and dimethylamine in low concentration as the basic catalyst, with prior priming of the nanoplate surfaces by diaminopropane. The thickness of the silica layer can be tuned between 7 and 20nm by varying the primer and alkoxide concentrations. The second method involves deposition of a thin dense layer of silica from sodium silicate solution onto mercaptopropyltriethoxysilane (MPTES) or mercaptopropyltrimethoxysilane (MPTMS) primed TSNPs. This latter method offers protection against anion etching - experiments suggest that the adsorbed MPTES provides much of the barrier to chloride ions, while the silica shell serves to prevent particle aggregation. It was found that the silica coated particles substantially retained the sensitivity to refractive index of the as-grown TSNPs while being able to withstand salt concentrations typical of bio-testing conditions.
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A pilot study describing access to emergency care in two states using a model emergency care categorization system.
Acad Emerg Med
PUBLISHED: 02-25-2013
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The Institute of Medicine (IOM)s "Future of Emergency Care" report recommended the categorization and regionalization of emergency care, but no uniform system to categorize hospital emergency care capabilities has been developed. The absence of such a system limits the ability to benchmark outcomes, to develop regional systems of care, and of patients to make informed decisions when seeking emergency care. The authors sought to pilot the deployment of an emergency care categorization system in two states.
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Molecular aspects of upper tract urothelial carcinoma.
Urol. Oncol.
PUBLISHED: 02-19-2013
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Primary upper tract urothelial carcinoma (UTUC) is a relatively rare tumor with up to 60% of cases being muscle invasive at presentation. In this article we review the molecular biology of UTUC, an understanding of which may help to address some of the dilemmas surrounding the diagnosis and treatment of this disease and ultimately lead to the introduction of personalized treatment plans.
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Connexin30-mediated intercellular communication plays an essential role in epithelial repair in the cochlea.
J. Cell. Sci.
PUBLISHED: 02-19-2013
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A role for connexin (Cx)30 in epithelial repair following injury was examined in the organ of Corti, the sensory epithelium of the cochlea. In this tissue, lesions caused by loss of the sensory hair cells are closed by the supporting cells that surround each one. Gap junctions in which Cx30 is the predominant connexin are large and numerous between supporting cells. In mice carrying a deletion in the gene (Gjb6) that encodes Cx30, the size and number of gap junction plaques, and the extent of dye transfer, between supporting cells was greatly reduced compared with normal animals. This corresponded with unique peculiarities of the lesion closure events during the progressive hair cell loss that occurs in these animals in comparison with other models of hair cell loss, whether acquired or as a result of a mutation. Only one, rather than all, of the supporting cells that contacted an individual dying hair closed the lesion, indicating disturbance of the co-ordination of cellular responses. The cell shape changes that the supporting cells normally undergo during repair of the organ of Corti did not occur. Also, there was disruption of the migratory activities that normally lead to the replacement of a columnar epithelium with a squamous-like one. These observations demonstrate a role for Cx30 and intercellular communication in regulating repair responses in an epithelial tissue.
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Cytotoxicity of commercial nano-TiO2 to Escherichia coli assessed by high-throughput screening: effects of environmental factors.
Water Res.
PUBLISHED: 01-29-2013
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The extensive use of nano-TiO2 in industry has led to growing concerns about its potential environmental impacts. However, negligible toxicity is commonly reported under insufficient illumination and artificial solution conditions in the literature, which rarely includes discussion of the regulating role of environmental factors. Herein, we report the results of a high-throughput screening assay to evaluate the acute cytotoxicity of six commercial nano-TiO2 materials to Escherichia coli (E. coli) using Lake Michigan water as a model for aquatic surface environments. In particular, we investigate the specific effects of illumination wavelength and natural organic matter (NOM) content. Under simulated solar irradiation, four anatase-based nano-TiO2 materials including Pigment White 6 exhibit significant bacterial toxicity (2 h-IC50 value of 2.7-9.1 mg/L), with toxicity thresholds much lower than previously reported. Negligible toxicity is caused either by pure-phase rutile or under dark condition. Formation of nano-TiO2 aggregates well beyond nano-scale does not eliminate their toxic effect, but photoactivity dominates over the primary size and extent of aggregation in determining the acute cytotoxicity of nano-TiO2. Under visible light irradiation (UVA&B blocked) the antibacterial activity of nano-TiO2 is essentially erased, whereas removing only UVB wavelengths slightly mitigates the toxicity. Suwannee River fulvic acid, acting as a natural dispersant, reverses the extent of nano-TiO2 aggregation, but also reduces its bacterial cytotoxicity. These results demonstrate that despite particle aggregation, the short-term cytotoxicity of nano-TiO2 is predominantly attributed to its phototoxicity, emphasizing the importance of illumination conditions in toxicological screening of photoactive nanomaterials. In the natural aquatic environment, however, this acute toxicity may be mitigated by the attenuation of UV irradiation and increased NOM concentration in the water column.
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Recent advances in the development of 1,8-naphthalimide based DNA targeting binders, anticancer and fluorescent cellular imaging agents.
Chem Soc Rev
PUBLISHED: 01-17-2013
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The development of functional 1,8-naphthalimide derivatives as DNA targeting, anticancer and cellular imaging agents is a fast growing area and has resulted in several such derivatives entering into clinical trials. This review gives an overview of the many discoveries and the progression of the use of 1,8-naphthalimides as such agents and their applications to date; focusing mainly on mono-, bis-naphthalimide based structures, and their various derivatives (e.g. amines, polyamine conjugates, heterocyclic, oligonucleotide and peptide based, and those based on metal complexes). Their cytotoxicity, mode of action and cell-selectivity are discussed and compared. The rich photophysical properties of the naphthalimides (which are highly dependent on the nature and the substitution pattern of the aryl ring) make them prime candidates as probes as the changes in spectroscopic properties such as absorption, dichroism, and fluorescence can all be used to monitor their binding to biomolecules. This also makes them useful species for monitoring their uptake and location within cells without the use of co-staining. The photochemical properties of the compounds have also been exploited, for example, for photocleavage of nucleic acids and for the destruction of tumour cells.
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Wastewater treatment effluent reduces the abundance and diversity of benthic bacterial communities in urban and suburban rivers.
Appl. Environ. Microbiol.
PUBLISHED: 01-11-2013
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In highly urbanized areas, wastewater treatment plant (WWTP) effluent can represent a significant component of freshwater ecosystems. As it is impossible for the composition of WWTP effluent to match the composition of the receiving system, the potential exists for effluent to significantly impact the chemical and biological characteristics of the receiving ecosystem. We assessed the impacts of WWTP effluent on the size, activity, and composition of benthic microbial communities by comparing two distinct field sites in the Chicago metropolitan region: a highly urbanized river receiving effluent from a large WWTP and a suburban river receiving effluent from a much smaller WWTP. At sites upstream of effluent input, the urban and suburban rivers differed significantly in chemical characteristics and in the composition of their sediment bacterial communities. Although effluent resulted in significant increases in inorganic nutrients in both rivers, surprisingly, it also resulted in significant decreases in the population size and diversity of sediment bacterial communities. Tag pyrosequencing of bacterial 16S rRNA genes revealed significant effects of effluent on sediment bacterial community composition in both rivers, including decreases in abundances of Deltaproteobacteria, Desulfococcus, Dechloromonas, and Chloroflexi sequences and increases in abundances of Nitrospirae and Sphingobacteriales sequences. The overall effect of the WWTP inputs was that the two rivers, which were distinct in chemical and biological properties upstream of the WWTPs, were almost indistinguishable downstream. These results suggest that WWTP effluent has the potential to reduce the natural variability that exists among river ecosystems and indicate that WWTP effluent may contribute to biotic homogenization.
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An E/Z conformational behaviour study on the trypanocidal action of lipophilic spiro carbocyclic 2,6-diketopiperazine-1-acetohydroxamic acids.
Tetrahedron Lett.
PUBLISHED: 01-08-2013
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An explanation for the vast difference observed in the trypanocidal activity between the new secondary (N-methylated) hydroxamic acids 5 and 6, and their primary (nonmethylated) congeners 1a and 2, based on their E/Z conformational behaviour in DMSO, is presented.
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Listening to youth: Adolescents reasons for substance use as a unique predictor of treatment response and outcome.
Psychol Addict Behav
PUBLISHED: 01-02-2013
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National efforts have focused on improving adolescent substance use disorder (SUD) treatment outcomes, yet improvements remain modest. Because adolescents are noteworthy for heterogeneity in their clinical profiles, treatment might be enhanced by the identification of clinical subgroups for which interventions could be more effectively tailored. Some of these subgroups, such as those based on abstinence motivation, substance involvement, and psychiatric status are promising candidates. This study examined the unique predictive utility of adolescents primary reason for alcohol and other drug use. Adolescent outpatients (N = 109; 27% female, aged 14-19) were assessed at treatment intake on their reason for substance use, as well as demographic, substance use, and clinical variables, and reassessed at 3, 6, and 12 months. Reason for use fell into two broad domains: using to enhance a positive state (positive reinforcement [PR]; 47% of youth) and using to cope with a negative state (negative reinforcement [NR]; 53% of youth). Compared with PR patients, NR patients were significantly more substance involved, reported more psychological distress, and had a more extensive treatment history. It is important to note that NR patients showed a significant treatment response, whereas PR patients showed no improvement. PR-NR status also uniquely predicted treatment response and outcome independent of a variety of other predictors, including abstinence motivation, self-efficacy, coping, and prior treatment. Adolescents primary reason for substance use may provide unique clinical information that could inform treatment planning and patient-treatment matching. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
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An in vivo patient-derived model of endogenous IDH1-mutant glioma.
Neuro-oncology
PUBLISHED: 12-13-2011
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Somatic mutations in the catalytic domain of isocitrate dehydrogenase (IDH) 1/2 and accumulation of the oncometabolite 2-hydroxyglutarate (2-HG) appear to be among the earliest events in gliomagenesis and may contribute to malignant transformation. The lack of cell lines with endogenous mutations has been one of the major challenges in studying IDH1/2-mutant glioma and developing novel therapeutics for these tumors. Here, we describe the isolation of a glioma brain tumor stem cell line (BT142) with an endogenous R132H mutation in IDH1, aggressive tumor-initiating capacity, and 2-HG production. The neurosphere culture method was used to establish a brain tumor stem cell line from an IDH1-mutant anaplastic oligoastrocytoma sample, and an orthotopic xenograft system was developed to allow its rapid expansion. Production of 2-HG by glioma cells with endogenous IDH1 mutations was confirmed by mass spectrometry. BT142 retained an endogenous R132H IDH1 mutation in culture and possessed aggressive tumor-initiating capacity, allowing it to be readily propagated in orthotopic xenografts of nonobese diabetic/severe combined immune deficiency (NOD SCID) mice. Endogenous 2-HG production by BT142 was detectable in both cell culture medium and xenograft animal serum. BT142 is the first brain tumor cell line with an endogenous IDH1 mutation and detectable 2-HG production both in vitro and in vivo, which thus provides a unique model for studying the biology of IDH1-mutant glioma and in vivo validation of compounds targeting IDH1-mutant cells.
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Single-incision laparoscopic cholecystectomy using a modified dome-down approach with conventional laparoscopic instruments.
Surg Endosc
PUBLISHED: 11-15-2011
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Single-incision laparoscopic cholecystectomy (SILC) may increase the risk of bile duct injury due to compromised operative exposure. Dome-down laparoscopic cholecystectomy provides the ability to evaluate the cystic duct circumferentially prior to its division, thus minimizing the risks of bile duct injury. This study assesses the feasibility and safety of SILC using a modified dome-down approach with all conventional laparoscopic instruments.
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Altitudinal variation at duplicated ?-globin genes in deer mice: effects of selection, recombination, and gene conversion.
Genetics
PUBLISHED: 10-31-2011
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Spatially varying selection on a given polymorphism is expected to produce a localized peak in the between-population component of nucleotide diversity, and theory suggests that the chromosomal extent of elevated differentiation may be enhanced in cases where tandemly linked genes contribute to fitness variation. An intriguing example is provided by the tandemly duplicated ?-globin genes of deer mice (Peromyscus maniculatus), which contribute to adaptive differentiation in blood-oxygen affinity between high- and low-altitude populations. Remarkably, the two ?-globin genes segregate the same pair of functionally distinct alleles due to a history of interparalog gene conversion and alleles of the same functional type are in perfect coupling-phase linkage disequilibrium (LD). Here we report a multilocus analysis of nucleotide polymorphism and LD in highland and lowland mice with different genetic backgrounds at the ?-globin genes. The analysis of haplotype structure revealed a paradoxical pattern whereby perfect LD between the two ?-globin paralogs (which are separated by 16.2 kb) is maintained in spite of the fact that LD within both paralogs decays to background levels over physical distances of less than 1 kb. The survey of nucleotide polymorphism revealed that elevated levels of altitudinal differentiation at each of the ?-globin genes drop away quite rapidly in the external flanking regions (upstream of the 5 paralog and downstream of the 3 paralog), but the level of differentiation remains unexpectedly high across the intergenic region. Observed patterns of diversity and haplotype structure are difficult to reconcile with expectations of a two-locus selection model with multiplicative fitness.
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