382 research outputs found

    Acylation of the Lipooligosaccharide of Haemophilus influenzae and Colonization: an htrB Mutation Diminishes the Colonization of Human Airway Epithelial Cells

    Get PDF
    Haemophilus influenzae is a commensal and opportunistic pathogen of the human airways. A number of surface molecules contribute to colonization of the airways by H. influenzae, such as adhesins, including structures found in the lipooligosaccharide (LOS). A human bronchiolar xenograft model was employed to investigate the host-bacterial interactions involved in the colonization of the airway by H. influenzae. Differential display was used to identify H. influenzae mRNA that reflect genes which were preferentially expressed in the xenograft compared to growth. Eleven mRNA fragments had consistent increased expression when the bacteria grew in xenografts. On sequencing these fragments, eight open reading frames were identified. Three of these had no match in the NCBI or the TIGR database, while an additional three were homologous to genes involved in heme or iron acquisition and utilization: two of the mRNAs encoded proteins homologous to enzymes involved in LOS biosynthesis: a heptosyl transferase (rfaF) involved in the synthesis of the LOS core and a ketodeoxyoctonate phosphate-dependent acyltransferase (htrB) that performs one of the late acylation reactions in lipid A synthesis. Inoculation of human bronchiolar xenografts revealed a significant reduction in colonization capacity by htrB mutants. In vitro, htrB mutants elicited lesser degrees of cytoskeletal rearrangement and less stimulation of host cell signaling with 16HBE14o- cells and decreased intracellular survival. These results implicate acylation of H. influenzae lipid A as playing a key role in the organisms' colonization of the normal airway

    Physical Activity, Physical Fitness, and Leukocyte Telomere Length: The Cardiovascular Health Study.

    Get PDF
    INTRODUCTION: The influence of physical activity (PA) and physical fitness (PF) at older ages on changes in telomere length (TL)--repetitive DNA sequences that may mark biologic aging--is not well-established. Few prior studies (mainly cross-sectional) have been conducted in older adults, and few studies have evaluated PF. METHODS: We investigated cross-sectional and prospective associations of PA and PF with leukocyte TL among 582 older adults (mean ± SD age, 73 ± 5 yr at baseline) in the Cardiovascular Health Study, with serial TL measures and PA and PF assessed multiple times. Cross-sectional associations were assessed using multivariable repeated-measures regression, in which cumulatively averaged PA and PF measures were related to TL. Longitudinal analyses assessed cumulatively averaged PA and PF against later changes in TL, and changes in cumulatively averaged PA and PF against changes in TL. RESULTS: Cross-sectionally, greater walking distance and chair test performance, but not other PA and PF measures, were each associated with longer TL (P trend = 0.007 and 0.04, respectively). In longitudinal analyses, no significant associations of baseline PA and PF with change in TL were observed. In contrast, changes in leisure-time activity and chair test performance were each inversely associated with changes in TL. CONCLUSIONS: Cross-sectional analyses suggest that greater PA and PF are associated with longer TL. Prospective analyses show that changes in PA and PF are associated with differences in changes in TL. Even later in life, changes in certain PA and PF measures are associated with changes in TL, suggesting that leisure-time activity and fitness could reduce leukocyte telomere attrition among older adults.This research was supported by contracts HHSN268201200036C, HHSN268200800007C, N01 HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086, and grant U01HL080295 from the National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by R01AG023629 the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. Luisa Soares-Miranda is supported by the Portuguese Foundation of Science and Technology (FCT), SFRH/BPD/76947/2011, PTDC/DES/099018/2008 - FCT/FCOMP-01- 0124-FEDER-009573, and The Research Centre in Physical Activity Health and Leisure is supported by UID/DTP/00617/2013. Dr Imamura received support from the Medical Research Council Epidemiology Unit Core Support (MC_UU_12015/5).This is the author accepted manuscript. The final version is available from Wolters Kluwer via http://dx.doi.org/10.1249/MSS.000000000000072

    Please mind the gap: students’ perspectives of the transition in academic skills between A-level and degree level geography

    Get PDF
    This paper explores first-year undergraduates’ perceptions of the transition from studying geography at pre-university level to studying for a degree. This move is the largest step students make in their education, and the debate about it in the UK has been reignited due to the government’s planned changes to A-level geography. However, missing from most of this debate is an appreciation of the way in which geography students themselves perceive their transition to university. This paper begins to rectify this absence. Using student insights, we show that their main concern is acquiring the higher level skills required for university learning

    Molecular differentiation of infectious pancreatic necrosis virus isolates from farmed and wild salmonids in Ireland

    Get PDF
    peer-reviewedThis study investigated the genotypes and sub-groups of infectious pancreatic necrosis virus (IPNV) present in farmed and wild salmonid fish in Ireland. An 1100-bp portion of the VP2 region of segment A from each of 55 IPNV isolates collected over 2003–2007 was amplified by reverse-transcription–polymerase chain reaction and the product directly sequenced. The nucleotide sequences of each isolate were aligned and compared with each other and with the corresponding sequences of a number of reference isolates. All the 55 sequenced isolates belonged to genogroup 5 (Sp serotype) and could be divided into two subgroups. Irish subgroup 1 consisted of isolates from farmed salmon originating from an Irish salmon broodstock. Irish subgroup 2 consisted of isolates from imported farmed stock and all reported clinical outbreaks of IPN were associated with isolates from subgroup 2. Isolates from wild fish were identical to some isolates from subgroup 2, and therefore are believed to have originated from infected farms. These results highlight the importance of import risk analysis for diseases not listed under current legislation

    Using Vignettes in Qualitative Research to Explore Barriers and Facilitating Factors to the Uptake of Prevention of Mother-to-Child Transmission Services in Rural Tanzania: A Critical Analysis.

    Get PDF
    Vignettes are short stories about a hypothetical person, traditionally used within research (quantitative or qualitative) on sensitive topics in the developed world. Studies using vignettes in the developing world are emerging, but with no critical examination of their usefulness in such settings. We describe the development and application of vignettes to a qualitative investigation of barriers to uptake of prevention of mother-to-child transmission (PMTCT) HIV services in rural Tanzania in 2012, and critique the successes and challenges of using the technique in this setting. Participatory Learning and Action (PLA) group activities (3 male; 3 female groups from Kisesa, north-west Tanzania) were used to develop a vignette representing realistic experiences of an HIV-infected pregnant woman in the community. The vignette was discussed during in-depth interviews with 16 HIV-positive women, 3 partners/relatives, and 5 HIV-negative women who had given birth recently. A critical analysis was applied to assess the development, implementation and usefulness of the vignette. The majority of in-depth interviewees understood the concept of the vignette and felt the story was realistic, although the story or questions needed repeating in some cases. In-depth interviewers generally applied the vignette as intended, though occasionally were unsure whether to steer the conversation back to the vignette character when participants segued into personal experiences. Interviewees were occasionally confused by questions and responded with what the character should do rather than would do; also confusing fieldworkers and presenting difficulties for researchers in interpretation. Use of the vignette achieved the main objectives, putting most participants at ease and generating data on barriers to PMTCT service uptake. Participants' responses to the vignette often reflected their own experience (revealed later in the interviews). Participatory group research is an effective method for developing vignettes. A vignette was incorporated into qualitative interview discussion guides and used successfully in rural Africa to draw out barriers to PMTCT service use; vignettes may also be valuable in HIV, health service use and drug adherence research in this setting. Application of this technique can prove challenging for fieldworkers, so thorough training should be provided prior to its use

    Panel 4 : Report of the Microbiology Panel

    Get PDF
    Objective. To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources. PubMed database of the National Library of Medicine. Review Methods. Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions. Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice. (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.Peer reviewe
    corecore