1,717 research outputs found
Whole-tumor apparent diffusion coefficient measurements in nephroblastoma: Can it identify blastemal predominance?
PURPOSE: To explore the potential relation between whole-tumor apparent diffusion coefficient (ADC) parameters in viable parts of tumor and histopathological findings in nephroblastoma. MATERIALS AND METHODS: Children (n = 52) with histopathologically proven nephroblastoma underwent diffusion-weighted magnetic resonance imaging (MRI) (1.5T) before preoperative chemotherapy. Of these, 25 underwent an additional MRI after preoperative chemotherapy, shortly before resection. An experienced reader performed the whole-tumor ADC measurements of all lesions, excluding nonenhancing areas. An experienced pathologist reviewed the postoperative specimens according to standard SIOP guidelines. Potential associations between ADC parameters and proportions of histological subtypes were assessed with Pearson's or Spearman's rank correlation coefficient depending on whether the parameters tested were normally distributed. In case the Mann-Whitney U-test revealed significantly different ADC values in a subtype tumor, this ADC parameter was used to derive a receiver operating characteristic (ROC) curve. RESULTS: The 25(th) percentile ADC at presentation was the best ADC metric correlated with proportion of blastema (Pearson's r = -0.303, P = 0.026). ADC after preoperative treatment showed moderate correlation with proportion stromal subtype at histopathology (r = 0.579, P = 0.002). By ROC analysis, the optimal threshold of median ADC for detecting stromal subtype was 1.362 × 10(-3) mm(2) /s with sensitivity and specificity of 100% (95% confidence interval [CI] 0.65-1.00) and 78.9% (95% CI 0.57-0.92), respectively. CONCLUSION: ADC markers in nephroblastoma are related to stromal subtype histopathology; however, identification of blastemal predominant tumors using whole-tumor ADC measurements is probably not feasible. Level of Evidence 3 J. Magn. Reson. Imaging 2016;00:000-000
Competition-based model of pheromone component ratio detection in the moth
For some moth species, especially those closely interrelated and sympatric, recognizing a specific pheromone component concentration ratio is essential for males to successfully locate conspecific females. We propose and determine the properties of a minimalist competition-based feed-forward neuronal model capable of detecting a certain ratio of pheromone components independently of overall concentration. This model represents an elementary recognition unit for the ratio of binary mixtures which we propose is entirely contained in the macroglomerular complex (MGC) of the male moth. A set of such units, along with projection neurons (PNs), can provide the input to higher brain centres. We found that (1) accuracy is mainly achieved by maintaining a certain ratio of connection strengths between olfactory receptor neurons (ORN) and local neurons (LN), much less by properties of the interconnections between the competing LNs proper. An exception to this rule is that it is beneficial if connections between generalist LNs (i.e. excited by either pheromone component) and specialist LNs (i.e. excited by one component only) have the same strength as the reciprocal specialist to generalist connections. (2) successful ratio recognition is achieved using latency-to-first-spike in the LN populations which, in contrast to expectations with a population rate code, leads to a broadening of responses for higher overall concentrations consistent with experimental observations. (3) when longer durations of the competition between LNs were observed it did not lead to higher recognition accuracy
Measuring vertebrate telomeres: applications and limitations
Telomeres are short tandem repeated sequences of DNA found at the ends of eukaryotic
chromosomes that function in stabilizing chromosomal end integrity.
In vivo
studies of
somatic tissue of mammals and birds have shown a correlation between telomere length and
organismal age within species, and correlations between telomere shortening rate and
lifespan among species. This result presents the tantalizing possibility that telomere length
could be used to provide much needed information on age, ageing and survival in natural
populations where longitudinal studies are lacking. Here we review methods available for
measuring telomere length and discuss the potential uses and limitations of telomeres as
age and ageing estimators in the fields of vertebrate ecology, evolution and conservation
Diseases, Injuries, and Risk Factors in Child and Adolescent Health, 1990 to 2017 Findings From the Global Burden of Diseases, Injuries, and Risk Factors 2017 Study
IMPORTANCE Understanding causes and correlates of health loss among children and
adolescents can identify areas of success, stagnation, and emerging threats and thereby
facilitate effective improvement strategies.
OBJECTIVE To estimate mortality and morbidity in children and adolescents from 1990 to
2017 by age and sex in 195 countries and territories.
DESIGN, SETTING, AND PARTICIPANTS This study examined levels, trends, and spatiotemporal
patterns of cause-specific mortality and nonfatal health outcomes using standardized
approaches to data processing and statistical analysis. It also describes epidemiologic
transitions by evaluating historical associations between disease indicators and the
Socio-Demographic Index (SDI), a composite indicator of income, educational attainment,
and fertility. Data collected from 1990 to 2017 on children and adolescents from birth
through 19 years of age in 195 countries and territories were assessed. Data analysis occurred
from January 2018 to August 2018.
EXPOSURES Being under the age of 20 years between 1990 and 2017.
MAIN OUTCOMES AND MEASURES Death and disability. All-cause and cause-specific deaths,
disability-adjusted life years, years of life lost, and years of life lived with disability.
RESULTS Child and adolescent deaths decreased 51.7% from 13.77 million (95% uncertainty
interval [UI], 13.60-13.93 million) in 1990 to 6.64 million (95% UI, 6.44-6.87 million) in 2017,
but in 2017, aggregate disability increased 4.7% to a total of 145 million (95% UI, 107-190
million) years lived with disability globally. Progress was uneven, and inequity increased, with
low-SDI and low-middle–SDI locations experiencing 82.2% (95% UI, 81.6%-82.9%) of deaths,
up from 70.9% (95% UI, 70.4%-71.4%) in 1990. The leading disaggregated causes of
disability-adjusted life years in 2017 in the low-SDI quintile were neonatal disorders, lower
respiratory infections, diarrhea, malaria, and congenital birth defects, whereas neonatal
disorders, congenital birth defects, headache, dermatitis, and anxiety were highest-ranked in
the high-SDI quintile.
CONCLUSIONS AND RELEVANCE Mortality reductions over this 27-year period mean that
children are more likely than ever to reach their 20th birthdays. The concomitant expansion
of nonfatal health loss and epidemiological transition in children and adolescents, especially
in low-SDI and middle-SDI countries, has the potential to increase already overburdened
health systems, will affect the human capital potential of societies, and may influence the
trajectory of socioeconomic development. Continued monitoring of child and adolescent
health loss is crucial to sustain the progress of the past 27 years
Comparison of outcomes following a cytological or histological diagnosis of malignant mesothelioma
Background: Survival with the epithelioid subtype of malignant mesothelioma (MM) is longer than the biphasic or sarcomatoid subtypes. There is concern that cytology-diagnosed epithelioid MM may underdiagnose the biphasic subtype. This study examines survival differences between patients with epithelioid MM diagnosed by cytology only and other subtypes diagnosed by histology. Methods: Demographics, diagnosis method, MM subtype and survival were extracted from the Western Australia (WA) Mesothelioma Registry, which records details of all MM cases occurring in WA. Results: A total of 2024 MM cases were identified over 42 years. One thousand seven hundred forty-four (86.2%) were male, median (IQR) age was 68.6 (60.4–77.0) years. A total of 1212 (59.9%) cases were identified as epithelioid subtype of which 499 (41.2%) were diagnosed using fluid cytology only. Those with a cytology-only diagnosis were older than the histology group (median 70.2 vs 67.6 years, P<0.001), but median survival was similar (cytology 10.6 (5.5–19.2) vs histology 11.1 (4.8–19.8) months, P=0.727) and Cox regression modelling adjusting for age, sex, site and time since first exposure showed no difference in survival between the different diagnostic approaches. Conclusions: Survival of cytologically and histologically diagnosed epithelioid MM cases does not differ. A diagnostic tap should be considered adequate to diagnose epithelioid MM without need for further invasive testing
Spatiotemporal mortality and demographic trends in a small cetacean: Strandings to inform conservation management
With global increases in anthropogenic pressures on wildlife populations comes a responsibility to manage them effectively. The assessment of marine ecosystem health is challenging and often relies on monitoring indicator species, such as cetaceans. Most cetaceans are however highly mobile and spend the majority of their time hidden from direct view, resulting in uncertainty on even the most basic population metrics. Here, we discuss the value of long-term and internationally combined stranding records as a valuable source of information on the demographic and mortality trends of the harbour porpoise (Phocoena phocoena) in the North Sea. We analysed stranding records (n = 16,181) from 1990 to 2017 and demonstrate a strong heterogeneous seasonal pattern of strandings throughout the North Sea, indicative of season-specific distribution or habitat use, and season-specific mortality. The annual incidence of strandings has increased since 1990, with a notable steeper rise particularly in the southern North Sea since 2005. A high density of neonatal strandings occurred specifically in the eastern North Sea, indicative of areas important for calving, and large numbers of juvenile males stranded in the southern parts, indicative of a population sink or reflecting higher male dispersion. These findings highlight the power of stranding records to detect potentially vulnerable population groups in time and space. This knowledge is vital for managers and can guide, for example, conservation measures such as the establishment of time-area-specific limits to potentially harmful human activities, aiming to reduce the number and intensity of human-wildlife conflicts
Time to tweak the TTO: results from a comparison of alternative specifications of the TTO
Abstract This article examines the effect that different
specifications of the time trade-off (TTO) valuation task
may have on values for EQ-5D-5L health states. The new
variants of the TTO, namely lead-time TTO and lag-time
TTO, along with the classic approach to TTO were compared
using two durations for the health states (15 and
20 years). The study tested whether these methods yield
comparable health-state values. TTO tasks were administered
online. It was found that lag-time TTO produced
lower values than lead-time TTO and that the difference
was larger in the longer time frame. Classic TTO values
most resembled those of the lag-time TTO in a 20-year
time frame in terms of mean absolute difference. The relative
importance of different domains of health was systematically
affected by the duration of the health state. In
the tasks with a 10-year health-state duration, anxiety/
depression had the largest negative impact on health-state
values; in the tasks with a 5-year duration, the pain/discomfort
domain had the largest negative impact
Reply: An inverse association between tumour size and overdiagnosis may explain the results by Bucchi et al
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Consumption patterns of sweet drinks in a population of Australian children and adolescents (2003–2008)
<p>Abstract</p> <p>Background</p> <p>Intake of sweet drinks has previously been associated with the development of overweight and obesity among children and adolescents. The present study aimed to assess the consumption pattern of sweet drinks in a population of children and adolescents in Victoria, Australia.</p> <p>Methods</p> <p>Data on 1,604 children and adolescents (4–18 years) from the comparison groups of two quasi-experimental intervention studies from Victoria, Australia were analysed<it>.</it> Sweet drink consumption (soft drink and fruit juice/cordial) was assessed as one day’s intake and typical intake over the last week or month at two time points between 2003 and 2008 (mean time between measurement: 2.2 years).</p> <p>Results</p> <p>Assessed using dietary recalls, more than 70% of the children and adolescents consumed sweet drinks, with no difference between age groups (p = 0.28). The median intake among consumers was 500 ml and almost a third consumed more than 750 ml per day. More children and adolescents consumed fruit juice/cordial (69%) than soft drink (33%) (p < 0.0001) and in larger volumes (median intake fruit juice/cordial: 500 ml and soft drink: 375 ml). Secular changes in sweet drink consumption were observed with a lower proportion of children and adolescents consuming sweet drinks at time 2 compared to time 1 (significant for age group 8 to <10 years, p = 0.001).</p> <p>Conclusion</p> <p>The proportion of Australian children and adolescents from the state of Victoria consuming sweet drinks has been stable or decreasing, although a high proportion of this sample consumed sweet drinks, especially fruit juice/cordial at both time points.</p
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Truth Commissions after Economic Crises: Political Learning or Blame Game?
This article addresses an important but understudied aspect of the recent Great Recession in Europe: the institutional strategies political elites deployed to learn from past policy failures and address accountability, more specifically, truth commissions. We raise two overlapping puzzles. The first concerns the timing of the decision to adopt an economic truth commission: while Iceland established a truth commission at an early stage of the crisis, Greece and Ireland did so much later. What accounts for ‘early’ versus ‘delayed’ truth seekers? The second concerns variations in learning outcomes. Iceland’s commission paved the way for learning institutional lessons, but truth commissions in Greece and Ireland became overtly politicised. What accounts for these divergences? This article compares truth commissions in Iceland, Greece and Ireland and identifies two types of political learning – institutional and instrumental – related to the establishment of a truth commission. It argues that political elites in countries with higher pre-crisis levels of trust in institutions and public transparency are more likely to establish economic truth commissions quickly; this is the ‘institutional logic’ of learning. The ‘instrumental logic’ of learning, in contrast, leads governments interested in apportioning blame to their predecessors to establish commissions at a later date, usually proximal to critical elections
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