157 research outputs found

    Phage typing or CRISPR typing for epidemiological surveillance of Salmonella Typhimurium?

    Get PDF
    Objective: Salmonella Typhimurium is the most dominant Salmonella serovar around the world. It is associated with foodborne gastroenteritis outbreaks but has recently been associated with invasive illness and deaths. Characterization of S. Typhimurium is therefore very crucial for epidemiological surveillance. Phage typing has been used for decades for subtyping of S. Typhimurium to determine the epidemiological relation among isolates. Recent studies however have suggested that high throughput clustered regular interspaced short palindromic repeats (CRISPR) typing has the potential to replace phage typing. This study aimed to determine the efficacy of highthroughput CRISPR typing over conventional phage typing in epidemiological surveillance and outbreak investigation of S. Typhimurium. Results: In silico analysis of whole genome sequences (WGS) of well-documented phage types of S. Typhimurium reveals the presence of different CRISPR type among strains belong to the same phage type. Furthermore, different phage types of S. Typhimurium share identical CRISPR type. Interestingly, identical spacers were detected among outbreak and non-outbreak associated DT8 strains of S. Typhimurium. Therefore, CRISPR typing is not useful for the epidemiological surveillance and outbreak investigation of S. Typhimurium and phage typing, until it is replaced by WGS, is still the gold standard method for epidemiological surveillance of S. Typhimurium

    Data management for prospective research studies using SAS® software

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Maintaining data quality and integrity is important for research studies involving prospective data collection. Data must be entered, erroneous or missing data must be identified and corrected if possible, and an audit trail created.</p> <p>Methods</p> <p>Using as an example a large prospective study, the Missouri Lower Respiratory Infection (LRI) Project, we present an approach to data management predominantly using SAS software. The Missouri LRI Project was a prospective cohort study of nursing home residents who developed an LRI. Subjects were enrolled, data collected, and follow-ups occurred for over three years. Data were collected on twenty different forms. Forms were inspected visually and sent off-site for data entry. SAS software was used to read the entered data files, check for potential errors, apply corrections to data sets, and combine batches into analytic data sets. The data management procedures are described.</p> <p>Results</p> <p>Study data collection resulted in over 20,000 completed forms. Data management was successful, resulting in clean, internally consistent data sets for analysis. The amount of time required for data management was substantially underestimated.</p> <p>Conclusion</p> <p>Data management for prospective studies should be planned well in advance of data collection. An ongoing process with data entered and checked as they become available allows timely recovery of errors and missing data.</p

    Predation and infanticide influence ideal free choice by a parrot occupying heterogeneous tropical habitats

    Get PDF
    The ideal free distribution (IFD) predicts that organisms will disperse to sites that maximize their fitness based on availability of resources. Habitat heterogeneity underlies resource variation and influences spatial variation in demography and the distribution of populations. We relate nest site productivity at multiple scales measured over a decade to habitat quality in a box-nesting population of Forpus passerinus (green-rumped parrotlets) in Venezuela to examine critical IFD assumptions. Variation in reproductive success at the local population and neighborhood scales had a much larger influence on productivity (fledglings per nest box per year) than nest site or female identity. Habitat features were reliable cues of nest site quality. Nest sites with less vegetative cover produced greater numbers of fledglings than sites with more cover. However, there was also a competitive cost to nesting in high-quality, low-vegetative cover nest boxes, as these sites experienced the most infanticide events. In the lowland local population, water depth and cover surrounding nest sites were related with F. passerinus productivity. Low vegetative cover and deeper water were associated with lower predation rates, suggesting that predation could be a primary factor driving habitat selection patterns. Parrotlets also demonstrated directional dispersal. Pairs that changed nest sites were more likely to disperse from poor-quality nest sites to high-quality nest sites rather than vice versa, and juveniles were more likely to disperse to, or remain in, the more productive of the two local populations. Parrotlets exhibited three characteristics fundamental to the IFD: habitat heterogeneity within and between local populations, reliable habitat cues to productivity, and active dispersal to sites of higher fitness

    Oncolytic and immunostimulatory efficacy of a targeted oncolytic poxvirus expressing human GM-CSF following intravenous administration in a rabbit tumor model

    Get PDF
    Targeted oncolytic poxviruses hold promise for the treatment of cancer. Arming these agents with immunostimulatory cytokines (for example, granulocyte-monocyte colony-stimulating factor; GM-CSF) can potentially increase their efficacy and/or alter their safety. However, due to species-specific differences in both human GM-CSF (hGM-CSF) activity and poxviruses immune avoidance proteins, the impact of hGM-CSF expression from an oncolytic poxvirus cannot be adequately assessed in murine or rat tumor models. We developed a rabbit tumor model to assess toxicology, pharmacodynamics, oncolytic efficacy and tumor-specific immunity of hGM-CSF expressed from a targeted oncolytic poxvirus JX-963. Recombinant purified hGM-CSF protein stimulated a leukocyte response in this model that paralleled effects of the protein in humans. JX-963 replication and targeting was highly tumor-selective after i.v. administration, and intratumoral replication led to recurrent, delayed systemic viremia. Likewise, hGM-CSF was expressed and released into the blood during JX-963 replication in tumors, but not in tumor-free animals. hGM-CSF expression from JX-963 was associated with significant increases in neutrophil, monocyte and basophil concentrations in the peripheral blood. Finally, tumor-specific cytotoxic T lymphocytes (CTL) were induced by the oncolytic poxvirus, and expression of hGM-CSF from the virus enhanced both tumor-specific CTL and antitumoral efficacy. JX-963 had significant efficacy against both the primary liver tumor as well as metastases; no significant organ toxicity was noted. This model holds promise for the evaluation of immunostimulatory transgene-armed oncolytic poxviruses, and potentially other viral species

    When Do Stalled Stars Resume Spinning Down? Advancing Gyrochronology with Ruprecht 147

    Get PDF
    This is the final version. Available on open access from IOP Publishing via the DOI in this recordRecent measurements of rotation periods () in the benchmark open clusters Praesepe (670 Myr), NGC 6811 (1 Gyr), and NGC 752 (1.4 Gyr) demonstrate that, after converging onto a tight sequence of slowly rotating stars in mass-period space, stars temporarily stop spinning down. These data also show that the duration of this epoch of stalled spin-down increases toward lower masses. To determine when stalled stars resume spinning down, we use data from the K2 mission and the Palomar Transient Factory to measure for 58 dwarf members of the 2.7 Gyr old cluster Ruprecht 147, 39 of which satisfy our criteria designed to remove short-period or near-equal-mass binaries. Combined with the Kepler data for the approximately coeval cluster NGC 6819 (30 stars with M ∗ > 0.85, our new measurements more than double the number of ≈2.5 Gyr benchmark rotators and extend this sample down to ≈0.55. The slowly rotating sequence for this joint sample appears relatively flat (22 ± 2 days) compared to sequences for younger clusters. This sequence also intersects the Kepler intermediate-period gap, demonstrating that this gap was not created by a lull in star formation. We calculate the time at which stars resume spinning down and find that 0.55 stars remain stalled for at least 1.3 Gyr. To accurately age-date low-mass stars in the field, gyrochronology formulae must be modified to account for this stalling timescale. Empirically tuning a core-envelope coupling model with open cluster data can account for most of the apparent stalling effect. However, alternative explanations, e.g., a temporary reduction in the magnetic braking torque, cannot yet be ruled out.National Science Foundation (NSF)European Union Horizon 2020NASADunlap FellowshipDanish National Research FoundationPennsylvania State UniversityEberly College of Scienc

    Effects of general practitioner training and family support services on the care of home-dwelling dementia patients - Results of a controlled cluster-randomized study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>More than 90% of dementia patients are cared for by their general practitioners, who are decisively involved in the diagnosis, therapy and recommendation of support services. <it>Objective: </it>To test whether special training of general practitioners alters the care of dementia patients through their systematic recommendation of caregiver counseling and support groups.</p> <p>Method</p> <p>129 general practitioners enrolled 390 dementia patients and their informal caregivers in a prospective, three-arm cluster-randomized 2-year study. Arm A constituted usual care, in Arm B and C support groups and caregiver counseling (in Arm B one year after baseline, in Arm C at baseline) were recommended by the general practitioners. The general practitioners received arm-specific training. Diagnostic and therapeutic behavior of physicians was recorded at baseline. Informal caregivers were questioned in follow-up after 2 years about the utilization of support services.</p> <p>Results</p> <p>The diagnostic behavior of the general practitioners conforms to relevant guidelines. The procedure in newly-diagnosed patients does not differ from previously diagnosed patients with the exception of the rate of referral to a specialist. About one-third of the newly-diagnosed dementia patients are given an anti-dementia drug. The utilization of support groups and counseling increased five- and fourfold, respectively. Utilization of other support services remained low (< 10%), with the exception of home nursing and institutional short-term nursing.</p> <p>Conclusion</p> <p>Trained general practitioners usually act in conformity with guidelines with respect to diagnosing dementia, and partly in conformity with the guidelines with respect to recommended drug therapy. Recommendations of support services for informal caregivers by the general practitioner are successful. They result in a marked increase in the utilization rate for the recommended services compared to offers which are not recommended by the general practitioner.</p> <p>Trial registration</p> <p>ISRCTN68329593</p

    The EHEC Type III Effector NleL Is an E3 Ubiquitin Ligase That Modulates Pedestal Formation

    Get PDF
    Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic colitis and may result in potentially fatal hemolytic uremia syndrome in humans. EHEC colonize the intestinal mucosa and promote the formation of actin-rich pedestals via translocated type III effectors. Two EHEC type III secreted effectors, Tir and EspFu/TccP, are key players for pedestal formation. We discovered that an EHEC effector protein called Non-LEE-encoded Ligase (NleL) is an E3 ubiquitin ligase. In vitro, we showed that the NleL C753 residue is critical for its E3 ligase activity. Functionally, we demonstrated that NleL E3 ubiquitin ligase activity is involved in modulating Tir-mediated pedestal formation. Surprisingly, EHEC mutant strain deficient in the E3 ligase activity induced more pedestals than the wild-type strain. The canonical EPEC strain E2348/69 normally lacks the nleL gene, and the ectopic expression of the wild-type EHEC nleL, but not the catalytically-deficient nleL(C753A) mutant, in this strain resulted in fewer actin-rich pedestals. Furthermore, we showed that the C. rodentium NleL homolog is a E3 ubiquitin ligase and is required for efficient infection of murine colonic epithelial cells in vivo. In summary, our study demonstrated that EHEC utilizes NleL E3 ubiquitin ligase activity to modulate Tir-mediated pedestal formation.National Institutes of Health (U.S.) (grant AI078092)National Institutes of Health (U.S.) (grant AI068655

    α-Mangostin extracted from the pericarp of the mangosteen (Garcinia mangostana Linn) reduces tumor growth and lymph node metastasis in an immunocompetent xenograft model of metastatic mammary cancer carrying a p53 mutation

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The mangosteen fruit has a long history of medicinal use in Chinese and Ayurvedic medicine. Recently, the compound α-mangostin, which is isolated from the pericarp of the fruit, was shown to induce cell death in various types of cancer cells in <it>in vitro </it>studies. This led us to investigate the antitumor growth and antimetastatic activities of α-mangostin in an immunocompetent xenograft model of mouse metastatic mammary cancer having a p53 mutation that induces a metastatic spectrum similar to that seen in human breast cancers.</p> <p>Methods</p> <p>Mammary tumors, induced by inoculation of BALB/c mice syngeneic with metastatic BJMC3879luc2 cells, were subsequently treated with α-mangostin at 0, 10 and 20 mg/kg/day using mini-osmotic pumps and histopathologically examined. To investigate the mechanisms of antitumor ability by α-mangostin, <it>in vitro </it>studies were also conducted.</p> <p>Results</p> <p>Not only were <it>in vivo </it>survival rates significantly higher in the 20 mg/kg/day α-mangostin group versus controls, but both tumor volume and the multiplicity of lymph node metastases were significantly suppressed. Apoptotic levels were significantly increased in the mammary tumors of mice receiving 20 mg/kg/day and were associated with increased expression of active caspase-3 and -9. Other significant effects noted at this dose level were decreased microvessel density and lower numbers of dilated lymphatic vessels containing intraluminal tumor cells in mammary carcinoma tissues.</p> <p><it>In vitro</it>, α-mangostin induced mitochondria-mediated apoptosis and G1-phase arrest and S-phase suppression in the cell cycle. Since activation by Akt phosphorylation plays a central role in a variety of oncogenic processes, including cell proliferation, anti-apoptotic cell death, angiogenesis and metastasis, we also investigated alterations in Akt phosphorylation induced by α-mangostin treatment both <it>in vitro </it>and <it>in vivo</it>. Quantitative analysis and immunohistochemistry showed that α-mangostin significantly decreased the levels of phospho-Akt-threonine 308 (Thr308), but not serine 473 (Ser473), in both mammary carcinoma cell cultures and mammary carcinoma tissues <it>in vivo</it>.</p> <p>Conclusions</p> <p>Since lymph node involvement is the most important prognostic factor in breast cancer patients, the antimetastatic activity of α-mangostin as detected in mammary cancers carrying a p53 mutation in the present study may have specific clinical applications. In addition, α-mangostin may have chemopreventive benefits and/or prove useful as an adjuvant therapy, or as a complementary alternative medicine in the treatment of breast cancer.</p
    corecore