357 research outputs found
Prevalence, incidence, and associated risk factors of tuberculosis in children with HIV living in the UK and Ireland (CHIPS): a cohort study
BACKGROUND: Tuberculosis is the most common serious co-infection in people living with HIV worldwide, but little is known about its incidence in HIV-infected children living in high-resource settings with low tuberculosis prevalence. We aimed to assess the incidence and prevalence of tuberculosis in children with HIV living in the UK and Ireland to understand rates, risk factors, and outcomes of the disease in this group. METHODS: We did an analysis of children enrolled in CHIPS, an observational multicentre cohort of children receiving HIV care in the UK and Ireland. We assessed characteristics and prevalence of tuberculosis at baseline, measured incidence of disease through the follow-up period using the CHIPS database, and calculated associated risk factors in these children with multivariable logistic and Cox regression models. FINDINGS: Between Jan 1, 1996, to Sept 18, 2014, data for 1848 children with 14 761 years of follow-up were reported to CHIPS. 57 (3%) children were diagnosed with tuberculosis: 29 children had tuberculosis at presentation (prevalent tuberculosis) and 29 had the disease diagnosed during follow-up (incident tuberculosis), including one child with recurrent tuberculosis events. Median age at diagnosis was 9 years (IQR 5-12). 25 (43%) children had pulmonary tuberculosis, 24 (41%) had extrapulmonary tuberculosis with or without pulmonary involvement, and the remainder (n=9; 16%) had unspecified-site tuberculosis. The overall incidence rate for the follow-up period was 196 cases per 100 000 person-years (95% CI 137-283). In our multivariable model, tuberculosis at presentation was associated with more severe WHO immunological stage at baseline (odds ratio 0·25, 95% CI 0·08-0·74; p=0·0331; for none vs severe) and being born abroad (odds ratio 0·28, 0·10-0·73; p=0·0036; for UK and Ireland vs abroad). Incident tuberculosis was associated with time-updated more severe WHO immunological stage (hazard ratio 0·15, 95% CI 0·06-0·41; p=0·0056; for none vs severe) and older age at baseline (1·11, 0·47-2·63; p=0·0027; for age >10 years vs 5-9 years). INTERPRETATION: Tuberculosis rates in HIV-infected children in the UK and Ireland were higher than those reported in the general paediatric population. Further study is warranted of tuberculosis screening and preventive treatment for children at high-risk of this disease to avoid morbidity and mortality in this population. FUNDING: NHS England, PENTA Foundation
Measurement batch differences and between-batch conversion of Alzheimer's disease cerebrospinal fluid biomarker values
Introduction: Batch differences in cerebrospinal fluid (CSF) biomarker measurement can introduce bias into analyses for Alzheimer's disease studies. We evaluated and adjusted for batch differences using statistical methods. Methods: A total of 792 CSF samples from 528 participants were assayed in three batches for 12 biomarkers and 3 biomarker ratios. Batch differences were assessed using Bland-Altman plot, paired t test, Pitman-Morgan test, and linear regression. Generalized linear models were applied to convert CSF values between batches. Results: We found statistically significant batch differences for all biomarkers and ratios, except that neurofilament light was comparable between batches 1 and 2. The conversion models generally had high R2 except for converting P-tau between batches 1 and 3. Discussion: Between-batch conversion allows harmonized CSF values to be used in the same analysis. Such method may be applied to adjust for other sources of variability in measuring CSF or other types of biomarkers
Intraspecific Correlations of Basal and Maximal Metabolic Rates in Birds and the Aerobic Capacity Model for the Evolution of Endothermy
The underlying assumption of the aerobic capacity model for the evolution of endothermy is that basal (BMR) and maximal aerobic metabolic rates are phenotypically linked. However, because BMR is largely a function of central organs whereas maximal metabolic output is largely a function of skeletal muscles, the mechanistic underpinnings for their linkage are not obvious. Interspecific studies in birds generally support a phenotypic correlation between BMR and maximal metabolic output. If the aerobic capacity model is valid, these phenotypic correlations should also extend to intraspecific comparisons. We measured BMR, Msum (maximum thermoregulatory metabolic rate) and MMR (maximum exercise metabolic rate in a hop-flutter chamber) in winter for dark-eyed juncos (Junco hyemalis), American goldfinches (Carduelis tristis; Msum and MMR only), and black-capped chickadees (Poecile atricapillus; BMR and Msum only) and examined correlations among these variables. We also measured BMR and Msum in individual house sparrows (Passer domesticus) in both summer, winter and spring. For both raw metabolic rates and residuals from allometric regressions, BMR was not significantly correlated with either Msum or MMR in juncos. Moreover, no significant correlation between Msum and MMR or their mass-independent residuals occurred for juncos or goldfinches. Raw BMR and Msum were significantly positively correlated for black-capped chickadees and house sparrows, but mass-independent residuals of BMR and Msum were not. These data suggest that central organ and exercise organ metabolic levels are not inextricably linked and that muscular capacities for exercise and shivering do not necessarily vary in tandem in individual birds. Why intraspecific and interspecific avian studies show differing results and the significance of these differences to the aerobic capacity model are unknown, and resolution of these questions will require additional studies of potential mechanistic links between minimal and maximal metabolic output
Frequency and risk factors for the birth of small-for-gestational-age newborns in a public maternity hospital
Bryozoans are Major Modern Builders of South Atlantic Oddly Shaped Reefs
Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-27961-6.In major modern reef regions, either in the Indo-Pacific or the Caribbean, scleractinian corals are
described as the main reef framework builders, often associated with crustose coralline algae. We
used underwater cores to investigate Late Holocene reef growth and characterise the main framework
builders in the Abrolhos Shelf, the largest and richest modern tropical reef complex in the South
Western Atlantic, a scientifically underexplored reef province. Rather than a typical coralgal reef,
our results show a complex framework building system dominated by bryozoans. Bryozoans were
major components in all cores and age intervals (2,000 yrs BP), accounting for up to 44% of the reef
framework, while crustose coralline algae and coral accounted for less than 28 and 23%, respectively.
Reef accretion rates varied from 2.7 to 0.9 mm yr−1, which are similar to typical coralgal reefs.
Bryozoan functional groups encompassed 20 taxa and Celleporaria atlantica (Busk, 1884) dominated
the framework at all cores. While the prevalent mesotrophic conditions may have driven suspensionfeeders’
dominance over photoautotrophs and mixotrophs, we propose that a combination of historical
factors with the low storm-disturbance regime of the tropical South Atlantic also contributed to the
region’s low diversity, and underlies the unique mushroom shape of the Abrolhos pinnacles.We thank CNPq/FAPES-Sisbiota/PELD, CAPES/IODP, CAPES/Ciências do Mar, and ANP/Brasoil for long
term project funding. We also thank ICMBio for research permits and field logistic support, and Conservation
International for providing and authorizing the use of the IKONOS image. JMW and JCB are International
Visiting Researcher at UFES and JBRJ, supported by the Science Without Borders program. Zá Cajueiro
provided invaluable field support and Ronaldo Francini, Carlos Janovitch and Lucio Engler helped in the drilling
operations. This is a contribution from the Rede Abrolhos (abrolhos.org)
Inhibition of CCN6 (WISP3) expression promotes neoplastic progression and enhances the effects of insulin-like growth factor-1 on breast epithelial cells
INTRODUCTION: CCN6/WISP3 belongs to the CCN (Cyr61, CTGF, Nov) family of genes that contains a conserved insulin-like growth factor (IGF) binding protein motif. CCN6 is a secreted protein lost in 80% of the aggressive inflammatory breast cancers, and can decrease mammary tumor growth in vitro and in vivo. We hypothesized that inhibition of CCN6 might result in the loss of a growth regulatory function that protects mammary epithelial cells from the tumorigenic effects of growth factors, particularly IGF-1. METHOD: We treated human mammary epithelial (HME) cells with a CCN6 hairpin short interfering RNA. RESULTS: CCN6-deficient cells showed increased motility and invasiveness, and developed features of epithelial-mesenchymal transition (EMT). Inhibition of CCN6 expression promoted anchorage-independent growth of HME cells and rendered them more responsive to the growth effects of IGF-1, which was coupled with the increased phosphorylation of IGF-1 receptor and insulin receptor substrate-1 (IRS-1). CONCLUSION: Specific stable inhibition of CCN6 expression in HME cells induces EMT, promotes anchorage-independent growth, motility and invasiveness, and sensitizes mammary epithelial cells to the growth effects of IGF-1
Structural Characteristics and Stellar Composition of Low Surface Brightness Disk Galaxies
We present UBVI surface photometry of a sample of low surface brightness
(LSB) disk galaxies. LSB disk galaxies are fairly well described as exponential
disks with no preferred value for either scale length, central surface
brightness, or rotational velocity. Indeed, the distribution of scale lengths
is indistinguishable from that of high surface brightness spirals, indicating
that dynamically similar galaxies (e.g., those with comparable Rv^2) exist over
a large range in surface density.
These LSB galaxies are strikingly blue. The complete lack of correlation
between central surface brightness and color rules out any fading scenario.
Similarly, the oxygen abundances inferred from HII region spectra are
uncorrelated with color so the low metallicities are not the primary cause of
the blue colors. While these are difficult to interpret in the absence of
significant star formation, the most plausible scenario is a stellar population
with a young mean age stemming from late formation and subsequent slow
evolution.
These properties suggest that LSB disks formed from low initial overdensities
with correspondingly late collapse times.Comment: Astronomical Journal, in press 45 pages uuencoded postscript (368K)
including 9 multipart figures also available by anonymous ftp @
ftp.ast.cam.ac.uk /pub/ssm/phot.uu CAP-30-210442962983742937
Impact of chronic stress protocols in learning and memory in rodents: systematic review and meta-analysis
The idea that maladaptive stress impairs cognitive function has been a cornerstone of decades in basic and clinical research. However, disparate findings have reinforced the need to aggregate results from multiple sources in order to confirm the validity of such statement. In this work, a systematic review and meta-analyses were performed to aggregate results from rodent studies investigating the impact of chronic stress on learning and memory. Results obtained from the included studies revealed a significant effect of stress on global cognitive performance. In addition, stressed rodents presented worse consolidation of learned memories, although no significantly differences between groups at the acquisition phase were found. Despite the methodological heterogeneity across studies, these effects were independent of the type of stress, animals' strains or age. However, our findings suggest that stress yields a more detrimental effect on spatial navigation tests' performance. Surprisingly, the vast majority of the selected studies in this field did not report appropriate statistics and were excluded from the quantitative analysis. We have therefore purposed a set of guidelines termed PROBE (Preferred Reporting Orientations for Behavioral Experiments) to promote an adequate reporting of behavioral experiments.This work was funded by the European Commission (FP7) "SwitchBox" (Contract HEALTH-F2-2010-259772) project and co-financed by the Portuguese North Regional Operational Program (ON.2 - O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER), and by Fundacao Calouste Gulbenkian (Portugal) (Contract grant number: P-139977; project "Better mental health during ageing based on temporal prediction of individual brain ageing trajectories (TEMPO)"). PSM is supported by an FCT fellowship grant, from the PhD-iHES program, with the reference PDE/BDE/113601/2015.info:eu-repo/semantics/publishedVersio
Attenuated reovirus displays oncolysis with reduced host toxicity
Background: Although the naturally occurring reovirus causes only mild symptoms in humans, it shows considerable potential as an oncolytic agent because of its innate ability to target cancer cells. In immunocompromised hosts, however, wild-type reovirus can target healthy tissues, including heart, liver, pancreas and neural structures. Methods: We characterized an attenuated form of reovirus (AV) derived from a persistently infected cell line through sequence analysis, as well as western blot and in vitro transcription and translation techniques. To examine its pathogenesis and oncolytic potential, AV reovirus was tested on healthy embryonic stem cells, various non-transformed and transformed cell lines, and in severe combined immunodeficiency (SCID) mice with tumour xenografts. Results: Sequence analysis of AV reovirus revealed a premature STOP codon in its sigma 1 attachment protein. Western blot and in vitro translation confirmed the presence of a truncated ?1. In comparison to wild-type reovirus, AV reovirus did not kill healthy stem cells or induce black tail formation in SCID mice. However, it did retain its ability to target cancer cells and reduce tumour size. Conclusion: Despite containing a truncated attachment protein, AV reovirus still preferentially targets cancer cells, and compared with wild-type reovirus it shows reduced toxicity when administered to immunodeficient hosts, suggesting the potential use of AV reovirus in combination cancer therapy
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