360 research outputs found
Novel insights into the dynamics of green turtle fibropapillomatosis
Outbreaks of fibropapillomatosis (FP), a neoplastic infectious disease of marine turtles,
have occurred worldwide since the 1980s. Its most likely aetiological agent is a virus, but disease
expression depends on external factors, typically associated with altered environments. The
scarcity of robust long-term data on disease prevalence has limited interpretations on the impacts
of FP on turtle populations. Here we model the dynamics of FP at 2 green turtle foraging aggregations
in Puerto Rico, through 18 yr of capture-mark-recapture data (1997−2014). We observed
spatiotemporal variation in FP prevalence, potentially modulated via individual site-fidelity. FP
ex pression was residency dependent, and FP-free individuals developed tumours after 1.8 ± 0.8 yr
(mean ± SD) in the infected area. Recovery from the disease was likely, with complete tumour
regression occurring in 2.7 ± 0.7 yr (mean ± SD). FP does not currently seem to be a major threat
to marine turtle populations; however, disease prevalence is yet unknown in many areas. Systematic
monitoring is highly advisable as human-induced stressors can lead to deviations in host−
pathogen relationships and disease virulence. Finally, data collection should be standardized for
a global assessment of FP dynamics and impacts.Natural and Environmental Resources of Puerto Rico (DNER); US National Marine Fisheries Service (NMFSNOAA Section 6); US Fish and Wildlife Service, Chelonia; WIDECAST; Fundação para a Ciência e a Tecnologia (FCT)info:eu-repo/semantics/publishedVersio
Deep dives and aortic temperatures of emperor penguins: new directions for bio-logging at the isolated dive hole
In order to document deep (>100 m) dives and aortic temperature responses of emperor penguins (Aptenodytes forsteri) at an isolated dive hole, and also to evaluate a new catheterization technique, three birds were equipped with time depth recorders, temperature data loggers, and percutaneously-inserted aortic thermistors. After recovery from anesthesia, they were provided access for one day to the dive hole. The birds tolerated the experiment without complication. Mean diving duration (+ SE) of 83 dives was 5.9 + 3.1 min; 55% of dives were > 5.6 min, the previously determined aerobic dive limit; 36% were > 100 m in depth. Mean aortic temperatures during 3-h rest periods ranged from 37.3 + 0.2oC to 38.0 + 0.1oC. Mean dive temperature did not correlate with dive duration, and the grand mean of mean dive temperatures in each bird ranged from 38.3 + 0.2oC to 39.0 + 0.2oC; there was no evidence of core hypothermia during dives. Reliable, safe catheterizations, and the large percentage of deep/long dives of these birds should provide the basis both for future studies of pressure adaptation and hypoxemic tolerance in diving emperor penguins, and for investigation of deep-dive foraging behavior
Critical collapse of a massive vector field
We perform numerical simulations of the critical gravitational collapse of a
massive vector field. The result is that there are two critical solutions. One
is equivalent to the Choptuik critical solution for a massless scalar field.
The other is periodic.Comment: 7 pages, 4 figure
Genetic composition and origin of juvenile green turtles foraging at Culebra, Puerto Rico, as revealed by mtDNA
Marine migratory species encounter a range of threats as they move through coastal and oceanic
zones. Understanding the connectivity and dispersal patterns of such species is critical to their effective
conservation. Here we analyzed the temporal genetic composition and the most likely origin of juvenile green
turtles foraging at Puerto Manglar and Tortuga Bay, Culebra, Puerto Rico, using mitochondrial DNA control
region sequences. We identified 17 haplotypes, of which CM-A3 (51.5%), CM-A5 (19.4%) and CM-A1 (13.6%)
were the most common. Haplotype (h) and nucleotide (Ï€) diversities were 0.680 and 0.008, respectively. There
was no evidence of significant variation in the genetic composition of these aggregations throughout seven years
(2000-2006), suggesting that relative contributions from source populations did not significantly change during
this period. Mixed Stock Analysis (MSA), incorporating 14 Atlantic nesting populations as possible sources,
indicated four main contributing stocks to the Culebra foraging grounds: Costa Rica (34.9%), Mexico (29.2%),
East Central Florida (13.2%), and Suriname (12.0%). The regional pattern of connectivity among Wider
Caribbean rookeries and Culebra was further evidenced by a second MSA using Atlantic Regional Management
Units (RMUs) as sources, with 94.1% of the mixed stock attributed to this area. This study addresses the
information gap on the connectivity of the green turtle in the North Atlantic, and establishes an important
baseline that can be used to determine future changes in stock composition.Department of Natural and Environ-mental Resources of Puerto Rico; US National Marine Fisheries Service (NMFS-NOAA, Section 6, grant NA08NMF4720436); US Fish and Wildlife Service, Chelonia Inc, and WIDECAST. Work was conducted under permits by NMFS-NOAA (permit nos. 1253, 1518, 14949) and DNER (06-EPE-016). ARP had the support of the Portuguese Foundation for Science and Technologyinfo:eu-repo/semantics/publishedVersio
Universally Coupled Massive Gravity, II: Densitized Tetrad and Cotetrad Theories
Einstein's equations in a tetrad formulation are derived from a linear theory
in flat spacetime with an asymmetric potential using free field gauge
invariance, local Lorentz invariance and universal coupling. The gravitational
potential can be either covariant or contravariant and of almost any density
weight. These results are adapted to produce universally coupled massive
variants of Einstein's equations, yielding two one-parameter families of
distinct theories with spin 2 and spin 0. The theories derived, upon fixing the
local Lorentz gauge freedom, are seen to be a subset of those found by
Ogievetsky and Polubarinov some time ago using a spin limitation principle. In
view of the stability question for massive gravities, the proven non-necessity
of positive energy for stability in applied mathematics in some contexts is
recalled. Massive tetrad gravities permit the mass of the spin 0 to be heavier
than that of the spin 2, as well as lighter than or equal to it, and so provide
phenomenological flexibility that might be of astrophysical or cosmological
use.Comment: 2 figures. Forthcoming in General Relativity and Gravitatio
A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus
The Trojan population consists of two swarms of asteroids following the same
orbit as Jupiter and located at the L4 and L5 Lagrange points of the
Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid
617 Patroclus is the only known binary Trojan (Merline et al. 2001). The orbit
of this double system was hitherto unknown. Here we report that the components,
separated by 680 km, move around the system centre of mass, describing roughly
a circular orbit. Using the orbital parameters, combined with thermal
measurements to estimate the size of the components, we derive a very low
density of 0.8 g/cc. The components of Patroclus are therefore very porous or
composed mostly of water ice, suggesting that they could have been formed in
the outer part of the solar system.Comment: 10 pages, 3 figures, 1 tabl
Intraoperative MET-receptor targeted fluorescent imaging and spectroscopy for lymph node detection in papillary thyroid cancer:novel diagnostic tools for more selective central lymph node compartment dissection
PURPOSE: Patients undergoing prophylactic central compartment dissection (PCLND) for papillary thyroid cancer (PTC) are often overtreated. This study aimed to determine if molecular fluorescence-guided imaging (MFGI) and spectroscopy can be useful for detecting PTC nodal metastases (NM) and to identify negative central compartments intraoperatively. METHODS: We used a data-driven prioritization strategy based on transcriptomic profiles of 97 primary PTCs and 80 normal thyroid tissues (NTT) to identify tumor-specific antigens for a clinically available near-infrared fluorescent tracer. Protein expression of the top prioritized antigen was immunohistochemically validated with a tissue microarray containing primary PTC (n = 741) and NTT (n = 108). Staining intensity was correlated with 10-year locoregional recurrence-free survival (LRFS). A phase 1 study (NCT03470259) with EMI-137, targeting MET, was conducted to evaluate safety, optimal dosage for detecting PTC NM with MFGI, feasibility of NM detection with quantitative fiber-optic spectroscopy, and selective binding of EMI-137 for MET. RESULTS: MET was selected as the most promising antigen. A worse LRFS was observed in patients with positive versus negative MET staining (81.9% versus 93.2%; p = 0.02). In 19 patients, no adverse events related to EMI-137 occurred. 0.13 mg/kg EMI-137 was selected as optimal dosage for differentiating NM from normal lymph nodes using MFGI (p < 0.0001) and spectroscopy (p < 0.0001). MFGI identified 5/19 levels (26.3%) without NM. EMI-137 binds selectively to MET. CONCLUSION: MET is overexpressed in PTC and associated with increased locoregional recurrence rates. Perioperative administration of EMI-137 is safe and facilitates NM detection using MFGI and spectroscopy, potentially reducing the number of negative PCLNDs with more than 25%. CLINICAL TRIAL REGISTRATION: NCT03470259
Machine-perfused donor kidneys as a source of human renal endothelial cells
Renal endothelial cells (ECs) play crucial roles in vasorelaxation, ultrafiltration, and selective transport of electrolytes and water, but also in leakage of the glomerular filtration barrier and inflammatory processes like complement activation and leukocyte recruitment. In addition, they are target cells for both cellular and antibody-mediated rejection in the transplanted kidney. To study the molecular and cellular processes underlying EC behavior in renal disease, well-characterized primary renal ECs are indispensible. In this report, we describe a straightforward procedure to isolate ECs from the perfusion fluid of human donor kidneys by a combination of negative selection of monocytes/macrophages, positive selection by CD31 Dynabeads, and propagation in endothelium-specific culture medium. Thus, we isolated and propagated renal ECs from 102 donor kidneys, representative of all blood groups and major human leukocyte antigen (HLA) class I and II antigens. The obtained ECs were positive for CD31 and von Willebrand factor, expressed other endothelial markers such as CD34, VEGF receptor-2, TIE2, and plasmalemmal vesicle associated protein-1 to a variable extent, and were negative for the monocyte marker CD14 and lymphatic endothelial marker podoplanin. HLA class II was either constitutively expressed or could be induced by interferon-y. Furthermore, as a proof of principle, we showed the diagnostic value of this renal endothelial biobank in renal endothelium-specific cross-matching tests for HLA antibodies. NEW & NOTEWORTHY We describe a new and widely accessible approach to obtain human primary renal endothelial cells in a \standardized fashion, by isolating from the perfusate of machine-perfused donor kidneys. Characterization of the cells showed a mixed population originating from different compartments of the kidney. As a proof of principle, we demonstrated a possible diagnostic application in an endothelium-specific cross-match. Next to transplantation, we foresee further applications in the field renal endothelial research
Longitudinal Follow-Up of Children Born Preterm: Neurodevelopment From 2 to 10 Years of Age
Objective: To investigate the rate and stability of impairments in children born preterm by assessing (1) early and school-age outcome in four developmental domains and (2) individual changes in outcome at both timepoints.Design: Prospective, longitudinal cohort study in children born in 2006–2007, <32 weeks' gestation. Follow-up at 2 and 10 years of age included standardized neurological, motor, cognitive and behavioral assessments. Children were categorized as having no, mild or moderate-severe impairment in these four domains. A composite impairment score was composed and the number of domains with impairments counted. For each child, individual outcomes at both timepoints were compared.Results: Follow-up at both time-points was available in 71/113(63%) children. At group level, there were no significant changes in the severity of impairments per domain. However, at individual level, there were less children with a mild abnormal composite score at 10 years of age (44 vs. 20%; p = 0.006), and more with a moderate-severe abnormal composite score (12 vs. 35%; p = 0.001). Especially children with normal/mild outcome at 2 years were likely to shift to other outcome categories over time.Conclusions: Children with early severe impairment are likely experiencing impairments later on, but early normal/mild abnormal outcomes should be interpreted with care, considering the large individual shifts over time. Long-term follow-up in all children born very preterm should therefore be continued to at least school-age
Preoperative predictors for early and very early disease recurrence in patients undergoing resection of pancreatic ductal adenocarcinoma
BACKGROUND: This study aimed to identify predictors for early and very early disease recurrence in patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) resection with and without neoadjuvant therapy. METHODS: Included were patients who underwent PDAC resection (2014-2016). Multivariable multinomial regression was performed to identify preoperative predictors for manifestation of recurrence within 3, 6 and 12 months after PDAC resection. RESULTS: 836 patients with a median follow-up of 37 (interquartile range [IQR] 30-48) months and overall survival of 18 (IQR 10-32) months were analyzed. 670 patients (80%) developed recurrence: 82 patients (10%) <3 months, 96 patients (11%) within 3-6 months and 226 patients (27%) within 6-12 months. LogCA 19-9 (OR 1.25 [95% CI 1.10-1.41]; P < 0.001) and neoadjuvant treatment (OR 0.09 [95% CI 0.01-0.68]; P = 0.02) were associated with recurrence <3 months. LogCA 19-9 (OR 1.23 [95% CI 1.10-1.38]; P < 0.001) and 0-90° venous involvement on CT imaging (OR 2.93 [95% CI 1.60-5.37]; P < 0.001) were associated with recurrence within 3-6 months. A Charlson Age Comorbidity Index ≥4 (OR 1.53 [95% CI 1.09-2.16]; P = 0.02) and logCA 19-9 (OR 1.24 [95% CI 1.14-1.35]; P < 0.001) were related to recurrence within 6-12 months. CONCLUSION: This study demonstrates preoperative predictors that are associated with the manifestation of early and very early recurrence after PDAC resection. Knowledge of these predictors can be used to guide individualized surveillance and treatment strategies
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