363 research outputs found
Late Relapse and Follow-up Protocols in Testicular Germ Cell Tumours: The Edinburgh Cancer Centre Experience and Review of the Literature
Aims To identify clinicopathological features and outcomes in patients with late relapse (LR) of testicular germ cell tumours (GCTs) in order to guide follow-up policy. Materials and Methods The Edinburgh Cancer Centre (ECC) database identified all patients diagnosed with testicular GCT between 1988 and 2002. Of 703 patients, six relapsed more than 24 months after their initial treatment. A retrospective casenote review was performed to extract clinical, pathological, treatment and outcome data. Results Six patients (0.85%) underwent late relapse. All patients presented initially with stage I disease and five were classified as good risk (International Germ Cell Consensus Classification, IGCCC). Median time to LR was 31 months. Two patients had previously relapsed less than 24 months from initial diagnosis. Markers at the time of relapse were normal in all patients. In all cases of late relapse disease was confined to axial lymphadenopathy. Three patients were treated with chemotherapy alone, two patients underwent surgical resection and one patient received combined treatment. All patients obtained a complete response and all remain disease free with a median follow-up of 52 months. Conclusions The incidence of late relapse in this series is low. Chemo-naive patients with LR were successfully salvaged with chemotherapy alone and patients previously exposed to cisplatin-based chemotherapy were salvaged with complete surgical excision. The optimal length of follow-up in patients with testicular germ cell tumours is not known and practice varies widely. In this cohort of 703 patients, only one patient who relapsed was picked up by additional clinic follow-up between 5 and 10 years. Thus, on the basis of this small series, the authors suggest that follow-up after five years may not be justified
Altered renal hemodynamics and impaired myogenic responses in the fawn-hooded rat
The present study examined whether an abnormality in the myogenic response
of renal arterioles that impairs autoregulation of renal blood flow (RBF)
and glomerular capillary pressure (PGC) contributes to the development of
renal damage in fawn-hooded hypertensive (FHH) rats. Autoregulation of
whole kidney, cortical, and medullary blood flow and PGC were compared in
young (12 wk old) FHH and fawn-hooded low blood pressure (FHL) rats in
volume-replete and volume-expanded conditions. Baseline RBF, cortical and
medullary blood flow, and PGC were significantly greater in FHH than in
FHL rats. Autoregulation of renal and cortical blood flow was
significantly impaired in FHH rats compared with results obtained in FHL
rats. Myogenically mediated autoregulation of PGC was significantly
greater in FHL than in FHH rats. PGC rose from 46 +/- 1 to 71 +/- 2 mmHg
in response to an increase in renal perfusion pressure from 100 to 150
mmHg in FHH rats, whereas it only increased from 39 +/- 2 to 53 +/- 1 mmHg
in FHL rats. Isolated perfused renal interlobular arteries from FHL rats
constricted by 10% in response to elevations in transmural pressure from
70 to 120 mmHg. In contrast, the diameter of vessels from FHH rats
increased by 15%. These results indicate that the myogenic response of
small renal arteries is altered in FHH rats, and this contributes to an
impaired autoregulation of renal blood flow and elevations in PGC in this
strain
Exact formula for currents in strongly pumped diffusive systems
We analyze a generic model of mesoscopic machines driven by the nonadiabatic
variation of external parameters. We derive a formula for the probability
current; as a consequence we obtain a no-pumping theorem for cyclic processes
satisfying detailed balance and demonstrate that the rectification of current
requires broken spatial symmetry.Comment: 10 pages, accepted for publication in the Journal of Statistical
Physic
Complications Associated With Anesthesia Services in Endoscopic Procedures Among Patients With Cirrhosis
Background and Aims: Anesthesia services for endoscopic procedures have proliferated with the promise of increased comfort and safety. Cirrhosis patients are higher risk for sedation, yet limited data are available describing anesthesia complications in this population. Approach and Results: This cross-sectional study utilized the National Anesthesia Clinical Outcomes Registry, a multicenter quality-improvement database from 2010 to 2015. Patients with cirrhosis undergoing an endoscopy were identified by International Classification of Diseases, Ninth Revision (ICD-9)/Current Procedures Terminology (CPT) codes. The outcome of interest was serious anesthesia-related complication defined as cardiovascular, respiratory, neurological, drug related, patient injury, death, or unexpected admission. A mixed-effects multivariate logistic regression model determined odds ratios (ORs) between variables and serious complications, adjusting for potential confounders. In total, 9,007 endoscopic procedures were performed among patients with cirrhosis; 92% were esophagogastroduodenoscopies. The majority (81%) were American Society of Anesthesiologists (ASA) class â„3, and 72% had a history of hepatic encephalopathy, ascites, varices, hepatorenal syndrome, or spontaneous bacterial peritonitis identified by ICD-9/CPT codes. In total, 87 complications were reported, 33 of which were serious. Frequency of serious complications was 0.4% or 378.6 per 100,000 procedures (95% confidence interval [CI], 260.8, 531.3). The majority of serious complications were cardiovascular (21 of 33), including 15 cardiac arrests. Serious complications were significantly associated with ASA 4/5 (OR, 3.84; 95% CI, 1.09, 13.57) and general anesthesia (OR, 4.71; 95% CI, 1.20, 18.50), adjusting for age, sex, ASA class, anesthesia type, inpatient status, portal hypertension history, and variable complication reporting practices. Conclusions: Anesthesia complications among endoscopic procedures in cirrhosis are rare overall. Serious complications were predominantly cardiac and associated with sicker patients undergoing general anesthesia. The complexity of end-stage liver disease may warrant more intensive care during endoscopic procedures, including anesthesia monitoring
Fluctuations of an evaporating black hole from back reaction of its Hawking radiation: Questioning a premise in earlier work
This paper delineates the first steps in a systematic quantitative study of
the spacetime fluctuations induced by quantum fields in an evaporating black
hole. We explain how the stochastic gravity formalism can be a useful tool for
that purpose within a low-energy effective field theory approach to quantum
gravity. As an explicit example we apply it to the study of the
spherically-symmetric sector of metric perturbations around an evaporating
black hole background geometry. For macroscopic black holes we find that those
fluctuations grow and eventually become important when considering sufficiently
long periods of time (of the order of the evaporation time), but well before
the Planckian regime is reached. In addition, the assumption of a simple
correlation between the fluctuations of the energy flux crossing the horizon
and far from it, which was made in earlier work on spherically-symmetric
induced fluctuations, is carefully analyzed and found to be invalid. Our
analysis suggests the existence of an infinite amplitude for the fluctuations
of the horizon as a three-dimensional hypersurface. We emphasize the need for
understanding and designing operational ways of probing quantum metric
fluctuations near the horizon and extracting physically meaningful information.Comment: 10 pages, REVTeX; minor changes, a few references added and a brief
discussion of their relevance included. To appear in the proceedings of the
10th Peyresq meeting. Dedicated to Rafael Sorkin on the occasion of his 60th
birthda
Heavy-light mesons with staggered light quarks
We demonstrate the viability of improved staggered light quarks in studies of
heavy-light systems. Our method for constructing heavy-light operators exploits
the close relation between naive and staggered fermions. The new approach is
tested on quenched configurations using several staggered actionsn combined
with nonrelativistic heavy quarks. The B_s meson kinetic mass, the hyperfine
and 1P-1S splittings in B_s, and the decay constant f_{B_s} are calculated and
compared to previous quenched lattice studies. An important technical detail,
Bayesian curve-fitting, is discussed at length.Comment: 38 pages, figures included. v2: Entry in Table IX corrected and other
minor changes, version appearing in Phys. Rev.
Adjoint "quarks" on coarse anisotropic lattices: Implications for string breaking in full QCD
A detailed study is made of four dimensional SU(2) gauge theory with static
adjoint ``quarks'' in the context of string breaking. A tadpole-improved action
is used to do simulations on lattices with coarse spatial spacings ,
allowing the static potential to be probed at large separations at a
dramatically reduced computational cost. Highly anisotropic lattices are used,
with fine temporal spacings , in order to assess the behavior of the
time-dependent effective potentials. The lattice spacings are determined from
the potentials for quarks in the fundamental representation. Simulations of the
Wilson loop in the adjoint representation are done, and the energies of
magnetic and electric ``gluelumps'' (adjoint quark-gluon bound states) are
calculated, which set the energy scale for string breaking. Correlators of
gauge-fixed static quark propagators, without a connecting string of spatial
links, are analyzed. Correlation functions of gluelump pairs are also
considered; similar correlators have recently been proposed for observing
string breaking in full QCD and other models. A thorough discussion of the
relevance of Wilson loops over other operators for studies of string breaking
is presented, using the simulation results presented here to support a number
of new arguments.Comment: 22 pages, 14 figure
Nonequilibrium wetting
When a nonequilibrium growing interface in the presence of a wall is
considered a nonequilibrium wetting transition may take place. This transition
can be studied trough Langevin equations or discrete growth models. In the
first case, the Kardar-Parisi-Zhang equation, which defines a very robust
universality class for nonequilibrium moving interfaces, with a soft-wall
potential is considered. While in the second, microscopic models, in the
corresponding universality class, with evaporation and deposition of particles
in the presence of hard-wall are studied. Equilibrium wetting is related to a
particular case of the problem, it corresponds to the Edwards-Wilkinson
equation with a potential in the continuum approach or to the fulfillment of
detailed balance in the microscopic models. In this review we present the
analytical and numerical methods used to investigate the problem and the very
rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
Risk factor burden, heart failure, and survival in women of different ethnic groups insights from the women's health initiative
BACKGROUND: The higher risk of heart failure (HF) in African-American and Hispanic women compared with white women is related to the higher burden of risk factors (RFs) in minorities. However, it is unclear if there are differences in the association between the number of RFs for HF and the risk of development of HF and death within racial/ethnic groups. METHODS AND RESULTS: In the WHI (Women's Health Initiative; 1993-2010), African-American (n=11996), white (n=18479), and Hispanic (n=5096) women with 1, 2, or 3+ baseline RFs were compared with women with 0 RF within their respective racial/ethnic groups to assess risk of developing HF or all-cause mortality before and after HF, using survival analyses. After adjusting for age, socioeconomic status, and hormone therapy, the subdistribution hazard ratio (95% confidence interval) of developing HF increased as number of RFs increased (P<0.0001, interaction of race/ethnicity and RF number P=0.18)-African-Americans 1 RF: 1.80 (1.01-3.20), 2 RFs: 3.19 (1.84-5.54), 3+ RFs: 7.31 (4.26-12.56); Whites 1 RF: 1.27 (1.04-1.54), 2 RFs: 1.95 (1.60-2.36), 3+ RFs: 4.07 (3.36-4.93); Hispanics 1 RF: 1.72 (0.68-4.34), 2 RFs: 3.87 (1.60-9.37), 3+ RFs: 8.80 (3.62-21.42). Risk of death before developing HF increased with subsequent RFs (P<0.0001) but differed by racial/ethnic group (interaction P=0.001). The number of RFs was not associated with the risk of death after developing HF in any group (P=0.25; interaction P=0.48). CONCLUSIONS: Among diverse racial/ethnic groups, an increase in the number of baseline RFs was associated with higher risk of HF and death before HF but was not associated with death after HF. Early RF prevention may reduce the burden of HF across multiple racial/ethnic groups
Dynamic ensemble prediction of cognitive performance in spaceflight
During spaceflight, astronauts face a unique set of stressors, including microgravity, isolation, and confinement, as well as environmental and operational hazards. These factors can negatively impact sleep, alertness, and neurobehavioral performance, all of which are critical to mission success. In this paper, we predict neurobehavioral performance over the course of a 6-month mission aboard the International Space Station (ISS), using ISS environmental data as well as self-reported and cognitive data collected longitudinally from 24 astronauts. Neurobehavioral performance was repeatedly assessed via a 3-min Psychomotor Vigilance Test (PVT-B) that is highly sensitive to the effects of sleep deprivation. To relate PVT-B performance to time-varying and discordantly-measured environmental, operational, and psychological covariates, we propose an ensemble prediction model comprising of linear mixed effects, random forest, and functional concurrent models. An extensive cross-validation procedure reveals that this ensemble outperforms any one of its components alone. We also identify the most important predictors of PVT-B performance, which include an individual's previous PVT-B performance, reported fatigue and stress, and temperature and radiation dose. This method is broadly applicable to settings where the main goal is accurate, individualized prediction of human behavior involving a mixture of person-level traits and irregularly measured time series
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