Gateway vectors for efficient artificial gene assembly in vitro and expression in yeast Saccharomyces cerevisiae

Peer reviewedPublisher PD

Model theory of finite and pseudofinite groups

This is a survey, intended both for group theorists and model theorists, concerning the structure of pseudofinite groups, that is, infinite models of the first-order theory of finite groups. The focus is on concepts from stability theory and generalisations in the context of pseudofinite groups, and on the information this might provide for finite group theory

Imports, unionization and racial age discrimination in the US

Past studies of the relationship between competition and racial wages find that domestic competition reduces racial wage discrimination of nonunion workers. This article examines the effects of foreign competition on racial wages of union and nonunion workers utilizing an empirical model which allows for cluster-adjusted SEs by industry. Such a procedure allows independence of observations across industries but not within industries, thereby not overstating the significance of industry invariant controls. In this analysis, clustered SEs prevent the overstatement of the significance of imports as a means to reduce earnings discrimination. We find evidence of a wage premium for nonunion white workers in concentrated industries; however, imports cause the wages of nonunion whites to converge towards market rates. In contrast, for union workers in concentrated industries, wage standardization provides a sanctuary from market power initiated discrimination such that imports play a limited role in reducing discrimination

ApoE influences regional white-matter axonal density loss in Alzheimer's disease

Mechanisms underlying phenotypic heterogeneity in young onset Alzheimer disease (YOAD) are poorly understood. We used diffusion tensor imaging and neurite orientation dispersion and density imaging (NODDI) with tract-based spatial statistics to investigate apolipoprotein (APOE) ε4 modulation of white-matter damage in 37 patients with YOAD (22, 59% APOE ε4 positive) and 23 age-matched controls. Correlation between neurite density index (NDI) and neuropsychological performance was assessed in 4 white-matter regions of interest. White-matter disruption was more widespread in ε4+ individuals but more focal (posterior predominant) in the absence of an ε4 allele. NODDI metrics indicate fractional anisotropy changes are underpinned by combinations of axonal loss and morphological change. Regional NDI in parieto-occipital white matter correlated with visual object and spatial perception battery performance (right and left, both p = 0.02), and performance (nonverbal) intelligence (WASI matrices, right, p = 0.04). NODDI provides tissue-specific microstructural metrics of white-matter tract damage in YOAD, including NDI which correlates with focal cognitive deficits, and APOEε4 status is associated with different patterns of white-matter neurodegeneration

Getting inside acupuncture trials - Exploring intervention theory and rationale

<p>Abstract</p> <p>Background</p> <p>Acupuncture can be described as a complex intervention. In reports of clinical trials the mechanism of acupuncture (that is, the process by which change is effected) is often left unstated or not known. This is problematic in assisting understanding of how acupuncture might work and in drawing together evidence on the potential benefits of acupuncture. Our aim was to aid the identification of the assumed mechanisms underlying the acupuncture interventions in clinical trials by developing an analytical framework to differentiate two contrasting approaches to acupuncture (traditional acupuncture and Western medical acupuncture).</p> <p>Methods</p> <p>Based on the principles of realist review, an analytical framework to differentiate these two contrasting approaches was developed. In order to see how useful the framework was in uncovering the theoretical rationale, it was applied to a set of trials of acupuncture for fatigue and vasomotor symptoms, identified from a wider literature review of acupuncture and early stage breast cancer.</p> <p>Results</p> <p>When examined for the degree to which a study demonstrated adherence to a theoretical model, two of the fourteen selected studies could be considered TA, five MA, with the remaining seven not fitting into any recognisable model. When examined by symptom, five of the nine vasomotor studies, all from one group of researchers, are arguably in the MA category, and two a TA model; in contrast, none of the five fatigue studies could be classed as either MA or TA and all studies had a weak rationale for the chosen treatment for fatigue.</p> <p>Conclusion</p> <p>Our application of the framework to the selected studies suggests that it is a useful tool to help uncover the therapeutic rationale of acupuncture interventions in clinical trials, for distinguishing between TA and MA approaches and for exploring issues of model validity. English language acupuncture trials frequently fail to report enough detail relating to the intervention. We advocate using this framework to aid reporting, along with further testing and refinement of the framework.</p

Human Papillomaviruses and genital co-infections in gynaecological outpatients

<p>Abstract</p> <p>Background</p> <p>High grade HPV infections and persistence are the strongest risk factors for cervical cancer. Nevertheless other genital microorganisms may be involved in the progression of HPV associated lesions.</p> <p>Methods</p> <p>Cervical samples were collected to search for human Papillomavirus (HPV), bacteria and yeast infections in gynaecologic outpatients. HPV typing was carried out by PCR and sequencing on cervical brush specimens. <it>Chlamydia trachomatis </it>was identified by strand displacement amplification (SDA) and the other microorganisms were detected by conventional methods.</p> <p>Results</p> <p>In this cross-sectional study on 857 enrolled outpatients, statistical analyses revealed a significant association of HPV with <it>C. trachomatis </it>and <it>Ureaplasma urealyticum (</it>at high density) detection, whereas no correlation was found between HPV infection and bacterial vaginosis, <it>Streptococcus agalactiae</it>, yeasts, <it>Trichomonas vaginalis </it>and <it>U. urealyticum</it>. <it>Mycoplasma hominis </it>was isolated only in a few cases both in HPV positive and negative women and no patient was infected with <it>Neisseria gonorrhoeae</it>.</p> <p>Conclusion</p> <p>Although bacterial vaginosis was not significantly associated with HPV, it was more common among the HPV positive women. A significant association between HPV and <it>C. trachomatis </it>was found and interestingly also with <it>U. urealyticum </it>but only at a high colonization rate. These data suggest that it may be important to screen for the simultaneous presence of different microorganisms which may have synergistic pathological effects.</p

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

A Cell Motility Screen Reveals Role for MARCKS-Related Protein in Adherens Junction Formation and Tumorigenesis

Invasion through the extracellular matrix (ECM) is important for wound healing, immunological responses and metastasis. We established an invasion-based cell motility screen using Boyden chambers overlaid with Matrigel to select for pro-invasive genes. By this method we identified antisense to MARCKS related protein (MRP), whose family member MARCKS is a target of miR-21, a microRNA involved in tumor growth, invasion and metastasis in multiple human cancers. We confirmed that targeted knockdown of MRP, in both EpRas mammary epithelial cells and PC3 prostate cancer cells, promoted in vitro cell migration that was blocked by trifluoperazine. Additionally, we observed increased immunofluoresence of E-cadherin, β-catenin and APC at sites of cell-cell contact in EpRas cells with MRP knockdown suggesting formation of adherens junctions. By wound healing assay we observed that reduced MRP supported collective cell migration, a type of cell movement where adherens junctions are maintained. However, destabilized adherens junctions, like those seen in EpRas cells, are frequently important for oncogenic signaling. Consequently, knockdown of MRP in EpRas caused loss of tumorigenesis in vivo, and reduced Wnt3a induced TCF reporter signaling in vitro. Together our data suggest that reducing MRP expression promotes formation of adherens junctions in EpRas cells, allowing collective cell migration, but interferes with oncogenic β-catenin signaling and tumorigenesis

An outbreak of post-acupuncture cutaneous infection due to Mycobacterium abscessus

BACKGROUND: Despite the increasing popularity of acupuncture, the importance of infection control is not adequately emphasized in Oriental medicine. In December 2001, an Oriental medical doctor in Seoul, South Korea, encountered several patients with persistent, culture-negative skin lesions on the trunk and extremities at the sites of prior acupuncture treatment. We identified and investigated an outbreak of Mycobacterium abscessus cutaneous infection among the patients who attended this Oriental medicine clinic. METHODS: Patients were defined as clinic patients with persistent cutaneous infections at the acupuncture sites. Medical records for the previous 7 months were reviewed. Clinical specimens were obtained from the patients and an environmental investigation was performed. M. abscessus isolates, cultured from patients, were compared by pulsed-field gel electrophoresis (PFGE). RESULTS: Forty patients who attended the Oriental medicine clinic and experienced persistent cutaneous wound infections were identified. Cultures from five of these patients proved positive, and all other diagnoses were based on clinical and histopathologic examinations. All environmental objects tested were negative for M. abscessus, however, most were contaminated by various nosocomial pathogens. Molecular analysis using PFGE found all wound isolates to be identical. CONCLUSION: We have identified a large outbreak of rapidly growing mycobacterial infection among patients who received acupuncture at a single Oriental medicine clinic. Physicians should suspect mycobacterial infections in patients with persistent cutaneous infections following acupuncture, and infection control education including hygienic practice, should be emphasized for Oriental medical doctors practicing acupuncture

A Measurement of Rb using a Double Tagging Method

The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using displaced secondary vertices, and high momentum electrons and muons. Systematic uncertainties were reduced by measuring the b-tagging efficiency using a double tagging technique. Efficiency correlations between opposite hemispheres of an event are small, and are well understood through comparisons between real and simulated data samples. A value of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is statistical and the second systematic. The uncertainty on Rc, the fraction of Z to ccbar events in hadronic Z decays, is not included in the errors. The dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the deviation of Rc from the value 0.172 predicted by the Standard Model. The result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European Physical Journal