A calyceal diverticulum consists of a cystic eventration in the renal parenchyma that is lined with transitional cell epithelium with a narrow infundibular connection with the calyces or pelvis of ...the renal collector system; thus, the term pyelocalyceal diverticulum would be more accurate. Very rare in pediatric patients, calyceal diverticula can be symptomatic and require treatment. Calyceal diverticula are underdiagnosed because they can be mistaken for simple renal cysts on ultrasonography. To determine the approach to their follow-up and management, the diagnosis must be confirmed by excretory-phase computed tomography (CT) or magnetic resonance imaging (MRI).
This article aims to show the different ways that calyceal diverticula can present in pediatric patients; it emphasizes the ultrasonographic findings that enable the lesion to be suspected and the definitive findings that confirm the diagnosis on CT and MRI. It also discusses the differential diagnosis with other cystic kidney lesions and their treatment.
El divertículo calicial (DC) es una eventración quística intraparenquimatosa tapizada por epitelio celular transitorio con una estrecha conexión infundibular con los cálices o pelvis del sistema colector renal, por lo que el término más exacto es divertículo pielocalicial. Muy raro en la edad pediátrica, puede ser sintomático y requerir tratamiento. Está infradiagnosticado por confundirse con quistes renales simples por ecografía; su diagnóstico se confirma con tomografía computarizada (TC) o resonancia magnética (RM) en fase excretora, para determinar su seguimiento y manejo. Nuestro objetivo es mostrar las diferentes formas de presentación de los DC en la edad pediátrica, haciendo hincapié en los criterios ecográficos que permiten una aproximación diagnóstica y en los hallazgos definitivos en TC y RM. También discutimos el diagnóstico diferencial con otras lesiones quísticas renales y su tratamiento.
This paper sets forth a method for reachability analysis of linear dynamic systems in continuous time that can be used to compute time-domain bounds of states and outputs with floating-point ...precision. The focus is on the particular initial conditions and inputs that cause state or output trajectories to attain their extreme values in time. Inputs can be constant, arbitrary, or Lipschitz continuous waveforms. Uncertainties in initial conditions and inputs are modeled using zonotopes. The calculations exploit the definition of zonotopes and the modal information of the linear system dynamics.
This paper presents an investigation of hydro power plants with pelton-type turbine-generator sets that are coupled hydraulically and electrically. In particular, the dynamic behavior and speed ...performance of this type of power plants at black-start is analyzed using singular value decomposition (SVD) and relative gain array (RGA). Following, robust control theory is used to design a hydro-stabilizer that improves the performance of coupled turbines while accounting for typical uncertainties in actuators.
Fifty samples of honey collected from local markets of Portugal and Spain during year 2002 were analyzed for 42 organochlorine, carbamate, and organophosphorus pesticide residues. An analytical ...procedure based on solid-phase extraction with octadecyl sorbent followed by gas chromatography−mass spectrometry (GC−MS), for organochlorines, and by liquid chromatography−atmospheric pressure chemical ionization-mass spectrometry (LC−APCI-MS), for organophosphorus and carbamates, has been developed. Recoveries of spiked samples ranged from 73 to 98%, except for dimethoate (40%), with relative standard deviations from 3 to16% in terms of repeatability, and from 6 to 19% in terms of reproducibility. Limits of quantification were from 0.003 to 0.1 mg kg-1. Most of the pesticides found in honey were organochlorines. Among them, γ-HCH was the most frequently detected in 50% of the samples, followed by HCB in 32% of the samples and the other isomers of HCH (α-HCH and β-HCH) in 28 and 26% of the samples, respectively. Residues of DDT and their metabolites were detected in 20% of the samples. Of the studied carbamates, both methiocarb and carbofuran were detected in 10% of the samples, pirimicarb in 4% and carbaryl in 2%. The only organophosphorus pesticides found were heptenophos in 16%, methidathion in 4%, and parathion methyl in 2% of honey samples. Results indicate that Portuguese honeys were more contaminated than Spanish ones. However, honey consumers of both countries should not be concerned about the amounts of pesticide residues found in honeys available on the market.
Abstract Ovarian cysts are the most common abdominal cysts in female fetuses and newborn girls. Ultrasonography is the imaging technique of choice for diagnosing ovarian cysts because it makes it ...possible to differentiate them from other cystic lesions. Although most neonatal ovarian cysts regress in the first few months after birth, complications can occur during gestation or after birth. The manifestations of ovarian cysts on ultrasonography will depend on the complications. The management is controversial, although the current trend favors watchful waiting. We describe the different presentations of neonatal ovarian cysts with their complications and their patterns of findings on ultrasonography. We also discuss the differential diagnosis with other cystic abdominal lesions, and finally we discuss the therapeutic management of neonatal ovarian cysts.
As ice sheets load Earth's surface, they produce ice‐marginal depressions which, when filled with meltwater, become proglacial lakes. We include self‐consistently evolving proglacial lakes in a ...glacial isostatic adjustment (GIA) model and apply it to the Laurentide ice sheet over the last glacial cycle. We find that the locations of modeled lakes and the timing of their disappearance is consistent with the geological record. Lake loads can deflect topography by >10 m, and volumes collectively approach 30–45 cm global mean sea‐level equivalent. GIA increases deglaciation‐phase lake volume up to five‐fold and average along‐ice‐margin depth ≤90 m compared to glaciation‐phase ice volume analogs—differences driven by changes in the position and size of the peripheral bulge. Since ice‐marginal lake depth affects grounding‐line outflow, GIA‐modulated proglacial lake depths could affect ice‐sheet mass loss. Indeed, we find that Laurentide ice‐margin retreat rate sometimes correlates with proglacial lake presence, indicating that proglacial lakes aid glacial collapse.
Plain Language Summary
The Laurentide ice sheet grew to its greatest extent during the last glacial maximum, covering most of Canada and the northern part of the US. During its existence, lakes formed adjacent to the ice sheet as seasonal melt water filled the topography around its edge. As the ice sheet grew and melted it changed the topography of Earth's surface by warping the ground beneath the ice sheet and around its edges. In this paper we investigate how this topographic change affected lakes around the ice sheet. We find that it caused lakes to be much bigger during the deglaciation, when the ice sheet retreated and left lows in the topography that took thousands of years after the retreat to fully rebound. We also find that these lakes were deeper at the edge of the ice sheet as the ice sheet collapsed than as it grew, which might have caused faster ice sheet collapse since ice sheets lose mass faster if they end in a lake rather than if they end on land. Our finding shows that lakes might play an important role in how fast past ice sheets grew and collapsed.
Key Points
We self‐consistently model proglacial lakes that form around the Laurentide ice sheet over the last glacial cycle
Glacial isostatic adjustment increases the volume and lake depth of proglacial lakes during the deglaciation compared to the glaciation
When the ice margin retreated over areas of low‐lying topography, ice retreat was faster in areas that bordered proglacial lakes
Microvessel density (MVD) has been studied in a number of neoplasias, and apparently, there is a relationship between angiogenesis and tumor progression, response to treatment, and outcome. In ...pituitary adenoma, the association between MVD and vascular endothelial growth factor (VEGF) with tumor behavior has been described, but correlation with other angiogenic factors such as fetal liver kinase 1 (Flk-1) or proliferative markers is unknown. We investigated MVD, VEGF, and its receptor Flk-1 expression in 60 human pituitary adenomas: 13 growth hormone cell adenomas, 7 prolactin cell adenomas, 5 corticotroph cell adenomas, 2 thyrotroph cell adenomas, and 33 nonfunctioning adenomas (30 gonadotroph cell adenomas and 3 null cell adenomas). We performed immunohistochemistry for CD34, Ki-67, VEGF, and Flk-1. To evaluate MVD, we used 2 methods: the number of vessels per square millimeter and the Chalkley method. Immunohistochemistry results were correlated, as well as with clinicopathologic factors. Adenomas with higher MVD were thyrotroph cell adenomas (299.9 ± 87.5), and those with lower MVD were prolactin cell adenomas (168.6 ± 63.3;
P = .45, analysis of variance). We found a trend toward higher MVD in the adenomas of older patients (
P = .142), but no difference was found regarding sex, extrasellar extension, or Ki-67 (
P > .05). However, extrasellar extension was nearly significant when the Chalkley method score was high (
P = .056). Low expression of VEGF was seen predominantly in prolactin cell adenomas, and high in nonfunctioning adenomas, or in cases of older patients (
P ≤ .032). Flk-1 score correlated with VEGF (
P = .006). High expression was observed in nonfunctioning adenomas, cases presenting at older ages, and with extrasellar extension (
P ≤ .022). Our study shows that VEGF and Flk-1 are widely expressed in pituitary adenomas, predominantly in nonfunctioning adenomas and those presenting at older ages. Moreover, Flk-1 is associated with a more aggressive phenotype, and it may have potential therapeutic interest.
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