1,525 research outputs found

    Residual susceptibility to measles among young adults in Victoria, Australia following a national targeted measles-mumps-rubella vaccination campaign

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Past measles immunisation policies in Australia have resulted in a cohort of young adults who have been inadequately vaccinated, but who also have low levels of naturally acquired immunity because immunisation programs have decreased the circulation of wild virus. A measles-mumps-rubella (MMR) immunisation campaign aimed at addressing this susceptibility to measles among young adults was conducted in Australia in 2001–2. By estimating age-specific immunity, we aimed to evaluate the success of this campaign in the state of Victoria.</p> <p>Methods</p> <p>We conducted serosurveys after the young adult MMR program at state and national levels to estimate immunity among young adults born between 1968–82. We compared results of the Victorian (state) surveys with the Victorian component of the national surveys and compared both surveys with surveys conducted before the campaign. We also reviewed all laboratory confirmed measles cases in Victoria between 2000–4.</p> <p>Results</p> <p>The Victorian state serosurveys indicated no significant change in immunity of the cohort following the young adult MMR campaign (83.9% immune pre and 85.5% immune post campaign) while the Victorian component of the national serosurvey indicated a significant decline in immunity (91.0% to 84.2%; p = 0.006). Both surveys indicated about 15% susceptibility to measles among young Victorian adults after the campaign. Measles outbreaks in Victoria between 2000–4 confirmed the susceptibility of young adults. Outbreaks involved a median of 2.5 cases with a median age of 24.5 years.</p> <p>Conclusion</p> <p>In Victoria, the young adult MMR program appears to have had no effect on residual susceptibility to measles among the 1968–82 birth cohort. Young adults in Victoria, as in other countries where past immunisation policies have left a residual susceptible cohort, represent a potential problem for the maintenance of measles elimination.</p

    Small Cofactors May Assist Protein Emergence from RNA World: Clues from RNA-Protein Complexes

    Get PDF
    It is now widely accepted that at an early stage in the evolution of life an RNA world arose, in which RNAs both served as the genetic material and catalyzed diverse biochemical reactions. Then, proteins have gradually replaced RNAs because of their superior catalytic properties in catalysis over time. Therefore, it is important to investigate how primitive functional proteins emerged from RNA world, which can shed light on the evolutionary pathway of life from RNA world to the modern world. In this work, we proposed that the emergence of most primitive functional proteins are assisted by the early primitive nucleotide cofactors, while only a minority are induced directly by RNAs based on the analysis of RNA-protein complexes. Furthermore, the present findings have significant implication for exploring the composition of primitive RNA, i.e., adenine base as principal building blocks

    The Main Belt Comets and ice in the Solar System

    Get PDF
    We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies

    The mathematical review system: does reviewer status play a role in the citation process?

    Get PDF
    This paper revisits an aspect of citation theory (i.e., citer motivation) with respect to the Mathematical Review system and the reviewer’s role in mathematics. We focus on a set of journal articles (369) published in Singularity Theory (1974–2003), the mathematicians who wrote editorial reviews for these articles, and the number of citations each reviewed article received within a 5 year period. Our research hypothesis is that the cognitive authority of a high status reviewer plays a positive role in how well a new article is received and cited by others. Bibliometric evidence points to the contrary: Singularity Theorists of lower status (junior researchers) have reviewed slightly more well-cited articles (2–5 citations, excluding author self-citations) than their higher status counterparts (senior researchers). One explanation for this result is that lower status researchers may have been asked to review ‘trendy’ or more accessible parts of mathematics, which are easier to use and cite. We offer further explanations and discuss a number of implications for a theory of citation in mathematics. This research opens the door for comparisons to other editorial review systems, such as book reviews written in the social sciences or humanities

    Unintentional asphyxia, SIDS, and medically explained deaths:A descriptive study of outcomes of child death review (CDR) investigations following sudden unexpected death in infancy

    Get PDF
    Background: A comprehensive Child Death Review (CDR) program was introduced in England and Wales in 2008 but as yet data have only been analysed at a local level, limiting the learning from deaths. The aim of this study is to describe the profile of causes and risk factors for Sudden Unexpected Death in Infancy (SUDI) as determined by the new CDR program. Methods: This was a descriptive outcome study using data from Child Death Overview Panel (CDOP) Form C for SUDI cases dying during 2010-2 in the West Midlands region of England. The main outcome measures were: cause of death, risk factors and potential preventability of death, and determination of deaths probably due to unintentional asphyxia. Results: Data were obtained for 65/70 (93%) SUDI cases. 20/65 (31%) deaths were initially categorised as due to medical causes; 21/65 (32%) as SIDS, and 24/65 (37%) as undetermined. Reanalysis suggested that 2/21 SIDS and 7/24 undetermined deaths were probably due to unintentional asphyxia, with 6 of these involving co-sleeping and excessive parental alcohol consumption. Deaths classified as ‘undetermined’ had significantly higher total family and environmental risk factor scores (mean 2.6, 95% CI 2.0– 3.3) compared to those classified as SIDS (mean 1.6, 95% CI 1.2-1.9), or medical causes for death (mean 1.1, 95% CI 0.8-1.3). 9/20 (47%) of medical deaths, 19/21 (90%) SIDS and 23/24 (96%) undetermined deaths were considered to be potentially preventable. There were inadequacies in medical provision identified in 5/20 (25%) of medically explained deaths. Conclusions: The CDR program results in detailed information about risk factors for SUDI cases but failed to recognise deaths probably due to unintentional asphyxia. The misclassification of probable unintentional asphyxial deaths and SIDS as ‘undetermined deaths’ is likely to limit learning from these deaths and inhibit prevention strategies. Many SUDI occurred in families with mental illness, substance misuse and chaotic lifestyles and most in unsafe sleep-environments. This knowledge could be used to better target safe sleep advice for vulnerable families and prevent SUDI in the future

    Short-Course, High-Dose Rifampicin Achieves Wolbachia Depletion Predictive of Curative Outcomes in Preclinical Models of Lymphatic Filariasis and Onchocerciasis

    Get PDF
    Lymphatic filariasis (LF) and onchocerciasis are priority neglected tropical diseases targeted for elimination. The only safe drug treatment with substantial curative activity against the filarial nematodes responsible for LF (Brugia malayi, Wuchereria bancrofti) or onchocerciasis (Onchocerca volvulus) is doxycycline. The target of doxycycline is the essential endosymbiont, Wolbachia. Four to six weeks doxycycline therapy achieves >90% depletion of Wolbachia in worm tissues leading to blockade of embryogenesis, adult sterility and premature death 18–24 months post-treatment. Long treatment length and contraindications in children and pregnancy are obstacles to implementing doxycycline as a public health strategy. Here we determine, via preclinical infection models of Brugia malayi or Onchocerca ochengi that elevated exposures of orally-administered rifampicin can lead to Wolbachia depletions from filariae more rapidly than those achieved by doxycycline. Dose escalation of rifampicin achieves >90% Wolbachia depletion in time periods of 7 days in B. malayi and 14 days in O. ochengi. Using pharmacokinetic-pharmacodynamic modelling and mouse-human bridging analysis, we conclude that clinically relevant dose elevations of rifampicin, which have recently been determined as safe in humans, could be administered as short courses to filariasis target populations with potential to reduce anti-Wolbachia curative therapy times to between one and two weeks

    Testate amoeba response to acid deposition in a Scottish peatland

    Get PDF
    Peatlands around the world are exposed to anthropogenic or volcanogenic sulphur pollution. Impacts on peatland microbial communities have been inferred from changes in gas flux but have rarely been directly studied. In this study, the impacts of sulphuric acid deposition on peatland testate amoebae were investigated by analysis of experimental plots on a Scottish peatland almost 7 years after acid treatment. Results showed reduced concentration of live amoebae and changes in community structure which remained significant even when differences in pH were accounted for. Several possible explanations for the impacts can be proposed including taphonomic processes and changes in plant communities. Previous studies have inferred a shift from methanogenic archaea to sulphate-reducing bacteria in sulphate-treated peats; it is possible that the impacts detected here might relate to this change, perhaps through testate amoeba predation on methanotrophs

    Modulation of phosphofructokinase (PFK) from Setaria cervi, a bovine filarial parasite, by different effectors and its interaction with some antifilarials

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Phosphofructokinase (ATP: D-fructose-6-phosphate-1-phosphotransferase, EC 2.7.1.11, PFK) is of primary importance in the regulation of glycolytic flux. This enzyme has been extensively studied from mammalian sources but relatively less attention has been paid towards its characterization from filarial parasites. Furthermore, the information about the response of filarial PFK towards the anthelmintics/antifilarial compounds is lacking. In view of these facts, PFK from <it>Setaria cervi</it>, a bovine filarial parasite having similarity with that of human filarial worms, was isolated, purified and characterized.</p> <p>Results</p> <p>The <it>S. cervi </it>PFK was cytosolic in nature. The adult parasites (both female and male) contained more enzyme activity than the microfilarial (Mf) stage of <it>S. cervi</it>, which exhibited only 20% of total activity. The <it>S. cervi </it>PFK could be modulated by different nucleotides and the response of enzyme to these nucleotides was dependent on the concentrations of substrates (F-6-P and ATP). The enzyme possessed wide specificity towards utilization of the nucleotides as phosphate group donors. <it>S. cervi </it>PFK showed the presence of thiol group(s) at the active site of the enzyme, which could be protected from inhibitory action of para-chloromercuribenzoate (p-CMB) up to about 76% by pretreatment with cysteine or β-ME. The sensitivity of PFK from <it>S. cervi </it>towards antifilarials/anthelmintics was comparatively higher than that of mammalian PFK. With suramin, the Ki value for rat liver PFK was 40 times higher than PFK from <it>S. cervi</it>.</p> <p>Conclusions</p> <p>The results indicate that the activity of filarial PFK may be modified by different effectors (such as nucleotides, thiol group reactants and anthelmintics) in filarial worms depending on the presence of varying concentrations of substrates (F-6-P and ATP) in the cellular milieu. It may possess thiol group at its active site responsible for catalysis. Relatively, 40 times higher sensitivity of filarial PFK towards suramin as compared to the analogous enzyme from the mammalian system indicates that this enzyme could be exploited as a potential chemotherapeutic target against filariasis.</p

    No evidence for selective follicle abortion underlying primary sex ratio adjustment in pigeons

    Get PDF
    Primary sex ratio adjustment in birds has been extensively studied, yet the underlying physiological mechanisms are far from understood. Avian females are the heterogametic sex (ZW), and the future sex of the offspring is determined at chromosome segregation during meiosis I, shortly before the oocyte is ovulated. Assuming that the mother can detect the sex of the developing oocyte before ovulation, it has been suggested that a follicle of the un-preferred sex could selectively be induced to become atretic and regress instead of being ovulated (selective follicle abortion). This potential mechanism has been proposed to underlie biased primary sex ratios in birds, including the homing pigeon (Columba livia domestica), which produces a modal clutch size of two eggs. However, without replacement by an additional, already mature follicle, abortion of a preovulatory follicle would most likely result in either reduced clutch sizes or laying gaps, since a not-yet-recruited follicle still needed to undergo the whole maturation phase. In the current study we killed female pigeons, which were adjusting embryo sex of first eggs according to change in body mass. We examined ovaries for signs of follicle abortion but did not find any supporting evidence. All females produced one or two mature follicles but only two out of the 56 experimental birds produced an additional third mature follicle. Therefore, our results do not corroborate the hypothesis that pigeon mothers manipulate primary offspring sex by selectively aborting follicles of the un-preferred sex
    • …
    corecore