3,619 research outputs found

    Reply to D.J. Sargent et al

    Get PDF

    Penicillin-binding proteins of protoplast and sporoplast membranes of Streptomyces griseus strains

    Get PDF
    Membrane-bound penicillin-binding proteins (PBPs) of two Streptomyces griseus strains that sporulate well in liquid and solid medium have been investigated during the course of their life-cycle. The PBP patterns were analyzed by sodium dodecylsulphate polyacrylamide-gel electrophoresis and fluorography. One strain (No. 45 H) has only a single band (mol wt: 27,000) in early log phase, and two additional PBPs of higher mol wt (69,000 and 80,000) in the late log phase. The other strain (No. 2682) possessed two bands with mol wts 27,000 and 38,000 which did not change during its vegetative phase. In strain No. 2682, a new PBP with a mol wt of 58,000 appeared in spore membranes while one of those (mol wt 38,000) present in mycelial membranes disappeared. Our results suggest that appearance of the new PBP in the spore may be associated with the sporulation process. The major PBP band (mol wt: 27,000) present in all stages of the life cycle of these strains, may be characteristic of S. griseus while the other PBPs reflect certain stages of the life cycle. A new method was developed for the production of spore protoplasts by consecutive enzymatic treatments.

    Relationship of Enhanced Liver Fibrosis Score with Pediatric Nonalcoholic Fatty Liver Disease Histology and Response to Vitamin E or Metformin

    Get PDF
    OBJECTIVES: To study the diagnostic performance of the enhanced liver fibrosis score (ELF) for detecting different stages of fibrosis and its usefulness in detecting histologic response to vitamin E or metformin in children with nonalcoholic fatty liver disease who participated in the Vitamin E or Metformin for the Treatment Of NAFLD In Children (TONIC) trial. STUDY DESIGN: ELF was measured at baseline and weeks 24, 48, and 96 on sera from 166 TONIC participants. Associations between ELF with baseline and end of trial (EOT) fibrosis stages and other histologic features were assessed using χ2 tests and logistic regression models. RESULTS: ELF was significantly associated with severity of fibrosis at baseline and EOT. ELF areas under the curve for discriminating patients with clinically significant and advanced fibrosis were 0.70 (95% CI, 0.60-0.80) and 0.79 (95% CI, 0.69-0.89), respectively. A 1-unit decrease in ELF at EOT was associated with overall histologic improvement (OR, 1.86; 95% CI, 1.11-3.14; P = .02), resolution of steatohepatitis (OR, 1.88; 95% CI, 1.09-3.25; P = .02), improvement in steatosis grade (OR, 1.76; 95% CI, 1.06-2.82; P = .03), and hepatocellular ballooning (OR, 1.79; 95% CI, 1.06-3.00; P = .03), but not with improvement in fibrosis stage (OR, 1.26; 95% CI, 0.78-2.03; P = .34). CONCLUSIONS: ELF was associated with fibrosis stage in children who participated in TONIC. Although not associated with improvement in fibrosis, a decrease in ELF at EOT was associated with Nonalcoholic Steatohepatitis resolution and improvement in nonalcoholic fatty liver disease histology. ELF may be a useful noninvasive test to monitor treatment response in children with nonalcoholic fatty liver disease

    A tool to improve pre-selection for deep brain stimulation in patients with Parkinson’s disease

    Get PDF
    Determining the eligibility of patients with Parkinson’s disease (PD) for deep brain stimulation (DBS) can be challenging for general (non-specialised) neurologists. We evaluated the use of an online screening tool (Stimulus) that aims to support appropriate referral to a specialised centre for the further evaluation of DBS. Implementation of the tool took place via an ongoing European multicentre educational programme, currently completed in 15 DBS centres with 208 referring neurologists. Use of the tool in daily practice was monitored via an online data capture programme. Selection decisions of patients referred with the assistance of the Stimulus tool were compared to those of patients outside the screening programme. Three years after the start of the programme, 3,128 patient profiles had been entered. The intention for referral was made for 802 patients and referral intentions were largely in accordance with the tool recommendations. Follow-up at 6 months showed that actual referral took place in only 28%, predominantly due to patients’ reluctance to undergo brain surgery. In patients screened with the tool and referred to a DBS centre, the acceptance rate was 77%, significantly higher than that of the unscreened population (48%). The tool showed a sensitivity of 99% and a specificity of 12% with a positive and negative predictive value of 79 and 75%, respectively. The Stimulus tool is useful in assisting general neurologists to identify appropriate candidates for DBS consideration. The principal reason for not referring potentially eligible patients is their reluctance to undergo brain surgery

    Elastic Wave Scattering Methods: Assessments and Suggestions

    Get PDF
    I was asked by the meeting organizers to review and assess the developments over the past ten or so years in elastic wave scattering methods and to suggest areas of future research opportunities. I will highlight the developments, focusing on what I feel were distinct steps forward in our theoretical understanding of how elastic waves interact with flaws. For references and illustrative figures, I decided to use as my principal source the proceedings of the various annual Reviews of Progress in Quantitative Nondestructive Evaluation (NDE). These meetings have been the main forum not only for presenting results of theoretical research but also for demonstrating the relevance of the theoretical research for the design and interpretation of experiment. In my opinion a quantitative NDE is possible only if this relevance exists, and my major objective is to discuss and illustrate the degree to which relevance has developed. I apologize if any one feels slighted by my not mentioning a particular work To keep the size of “review” manageable, I had to be brief and to the point

    The cost of promiscuity: sexual transmission of Nosema microsporidian parasites in polyandrous honey bees

    Get PDF
    Multiple mating (and insemination) by females with different males, polyandry, is widespread across animals, due to material and/or genetic benefits for females. It reaches particularly high levels in some social insects, in which queens can produce significantly fitter colonies by being polyandrous. It is therefore a paradox that two thirds of eusocial hymenopteran insects appear to be exclusively monandrous, in spite of the fitness benefits that polyandry could provide. One possible cost of polyandry could be sexually transmitted parasites, but evidence for these in social insects is extremely limited. Here we show that two different species of Nosema microsporidian parasites can transmit sexually in the honey bee Apis mellifera. Honey bee males that are infected by the parasite have Nosema spores in their semen, and queens artificially inseminated with either Nosema spores or the semen of Nosema-infected males became infected by the parasite. The emergent and more virulent N. ceranae achieved much higher rates of infection following insemination than did N. apis. The results provide the first quantitative evidence of a sexually transmitted disease (STD) in social insects, indicating that STDs may represent a potential cost of polyandry in social insects

    Genetics, recombination and clinical features of human rhinovirus species C (HRV-C) infections; interactions of HRV-C with other respiratory viruses

    Get PDF
    To estimate the frequency, molecular epidemiological and clinical associations of infection with the newly described species C variants of human rhinoviruses (HRV), 3243 diagnostic respiratory samples referred for diagnostic testing in Edinburgh were screened using a VP4-encoding region-based selective polymerase chain reaction (PCR) for HRV-C along with parallel PCR testing for 13 other respiratory viruses. HRV-C was the third most frequently detected behind respiratory syncytial virus (RSV) and adenovirus, with 141 infection episodes detected among 1885 subjects over 13 months (7.5%). Infections predominantly targeted the very young (median age 6–12 months; 80% of infections in those <2 years), occurred throughout the year but with peak incidence in early winter months. HRV-C was detected significantly more frequently among subjects with lower (LRT) and upper respiratory tract (URT) disease than controls without respiratory symptoms; HRV-C mono-infections were the second most frequently detected virus (behind RSV) in both disease presentations (6.9% and 7.8% of all cases respectively). HRV variants were classified by VP4/VP2 sequencing into 39 genotypically defined types, increasing the current total worldwide to 60. Through sequence comparisons of the 5′untranslated region (5′UTR), the majority grouped with species A (n = 96; 68%, described as HRV-Ca), the remainder forming a phylogenetically distinct 5′UTR group (HRV-Cc). Multiple and bidirectional recombination events between HRV-Ca and HRV-Cc variants and with HRV species A represents the most parsimonious explanation for their interspersed phylogeny relationships in the VP4/VP2-encoding region. No difference in age distribution, seasonality or disease associations was identified between HRV-Ca and HRV-Cc variants. HRV-C-infected subjects showed markedly reduced detection frequencies of RSV and other respiratory viruses, providing evidence for a major interfering effect of HRV-C on susceptibility to other respiratory virus infections. HRV-C's disease associations, its prevalence and evidence for interfering effects on other respiratory viruses mandates incorporation of rhinoviruses into future diagnostic virology screening

    Geometric construction of D-branes in WZW models

    Get PDF
    The geometric description of D-branes in WZW models is pushed forward. Our starting point is a gluing condition\, J+=FJJ_{+}=FJ_- that matches the model's chiral currents at the worldsheet boundary through a linear map FF acting on the WZW Lie algebra. The equivalence of boundary and gluing conditions of this type is studied in detail. The analysis involves a thorough discussion of Frobenius integrability, shows that FF must be an isometry, and applies to both metrically degenerate and nondegenerate D-branes. The isometry FF need not be a Lie algebra automorphism nor constantly defined over the brane. This approach, when applied to isometries of the form F=RF=R with RR a constant Lie algebra automorphism, validates metrically degenerate RR-twined conjugacy classes as D-branes. It also shows that no D-branes exist in semisimple WZW models for constant\, F=RF=-R.Comment: 23 pages, discussion of limitations of the gluing condition approach adde
    corecore