1 University of Pennsylvania, and
2 Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania; and
3 Biofluid, Tissue and Solid Mechanics for Medical Applications, IBiTech, Ghent ...University, Ghent, Belgium
Submitted April 6, 2009
; accepted in final form December 2, 2009
Although resting hemodynamic load has been extensively investigated as a determinant of left ventricular (LV) hypertrophy, little is known about the relationship between provoked hemodynamic load and the risk of LV hypertrophy. We studied central pressure-flow relations among 40 hypertensive and 19 normotensive adults using carotid applanation tonometry and Doppler echocardiography at rest and during a 40% maximal voluntary forearm contraction (handgrip) maneuver. Carotid-femoral pulse wave velocity (CF-PWV) was measured at rest. Hypertensive subjects demonstrated various abnormalities in resting and induced pulsatile load. Isometric exercise significantly increased systemic vascular resistance, aortic characteristic impedance (Zc), induced earlier wave reflections, increased augmentation index, and decreased total arterial compliance (TAC; all P 0.01). In hypertensive subjects, CF-PWV was the strongest resting predictor of LV mass index (LVMI) and remained an independent predictor after adjustment for age, gender, systemic vascular resistance, reflection magnitude, aortic Zc, and TAC (β = 2.52 m/s; P < 0.0001). Age, sex, CF-PWV, and resting hemodynamic indexes explained 48% of the interindividual variability in LVMI. In stepwise regression, TAC (β = –17.85; P < 0.0001) during handgrip, Zc during handgrip (β = –150; P < 0.0001), and the change in the timing of wave reflections during handgrip (β = –0.63; P = 0.03) were independent predictors of LVMI. A model that included indexes of provoked hemodynamic load explained 68% of the interindividual variability in LVMI. Hemodynamic load provoked by isometric exercise strongly predicts LVMI in hypertension. The magnitude of this association is far greater than for resting hemodynamic load, suggesting that provoked testing captures important arterial properties that are not apparent at rest and is advantageous to assess dynamic arterial load in hypertension.
arterial load; arterial compliance; wave reflections; aortic stiffness
Address for reprint requests and other correspondence: J. A. Chirinos, Division of Cardiology, 8B111, Philadelphia VA Medical Center, 3900 Woodland Ave., Philadelphia, PA 19104 (e-mail: Julio.chirinos{at}uphs.upenn.edu ).
Astronomical instruments able to detect the direct light of extra solar planets are currently under development. This paper focuses on instruments that will acquire a set of successive images where ...the planet (the source in more general purposes) moves in a known manner on a speckled background. Performant signal processing tools are required to account for the very low signal-to-noise ratio of the data. In the astrophysical context, the background arises mainly from the light scattered by the parent star. An accurate-but general-data model has been proposed in previous works to statistically describe optical images taking into account the spatial correlation of the wavefront complex amplitude. First, an estimator of the position and the intensity of the potential source is proposed. Because of several kinds of numerical constraints, it is derived from a simplified Gaussian data model. Under reasonable constraints on the motion of the source, the estimators are proved to be consistent, even under the accurate data model. For the detection test, we propose to threshold a linear statistics that arises from the intensity estimation. The threshold needs to be precisely related to the probability of false alarm (PFA) and the probability of detection (PD). Under the detailed model, the distribution of the data is only reachable through its moment generating function. We propose therefore to estimate analytically PFA and PD using the saddlepoint approximation. To evaluate the quality of these estimations, a Monte Carlo analysis is applied to monodimensional simulated data. The saddlepoint approximation proves to be very accurate, unlike the Gaussian approximation or even a low-order Gram-Charlier series approximation.
In hypertrophic cardiomyopathy, ejection fraction is normal or increased, and force-length relations are reduced. However, three-dimensional (3D) motion and deformation in vivo have not been assessed ...in this condition. We have reconstructed the 3D motion of the left ventricle (LV) during systole in 7 patients with hypertrophic cardiomyopathy (HCM) and 12 normal volunteers by use of magnetic resonance tagging.
Transmural tagging stripes were automatically tracked to subpixel resolution with an active contour model. A 3D finite-element model was used to interpolate displacement information between short- and long-axis slices and register data on a regional basis. Displacement and strain data were averaged into septal, posterior, lateral, and anterior regions at basal, midventricular, and apical levels. Radial motion (toward the central long axis) decreased slightly in patients with HCM, whereas longitudinal displacement (parallel to the long axis) of the base toward the apex was markedly reduced: 7.5 +/- 2.5mm (SD) versus 12.5 +/- 2.0 mm, P < .001. Circumferential and longitudinal shortening were both reduced in the septum (P < .01 at all levels). The principal strain associated with 3D maximal contraction was slightly depressed in many regions, significantly in the basal septum (-0.18 +/- 0.05 versus -0.22 +/- 0.02, P < .05) and anterior (-0.20 +/- 0.05 versus -0.23 +/- 0.02, P < .05) walls. In contrast, LV torsion (twist of the apex about the long axis relative to the base) was greater in HCM patients (19.9 +/- 2.4 degrees versus 14.6 +/- 2.7 degrees, P < .01).
HCM patients had reduced 3D myocardial shortening on a regional basis; however, LV torsion was increased.
Synovial sarcoma (SS) is an aggressive soft-tissue tumor. Despite being considered as a chemosensitive disease, the real impact of perioperative chemotherapy on metastasis-free survival (MFS) is ...controversial. We have shown that metastatic relapse of SS is strongly associated with genomic complexity. There are no data regarding the potential correlation between genomic complexity and response to chemotherapy.
The study population included 65 SS patients diagnosed between 1991 and 2013 and with available tissue material. Genomic profiling was carried out by using array-CGH. Forty-five SS out of the 65 patients were treated with neoadjuvant anthracycline/ifosfamide-based chemotherapy. Radiological response was assessed according to RECIST criteria. Histological response was defined by the percentage of recognizable tumor cells on the surgical specimen.
Genomic complexity was significantly associated with MFS. However, there was no statistically significant association between radiological or histological response and genomic complexity.
The absence of significant association between response to chemotherapy and genomic complexity suggests that the prognostic value of chromosome instability in SS is independent of response to chemotherapy; mechanisms leading to metastatic relapse of SS are intrinsic to the biology of the tumor and current cytotoxic drugs are only poorly efficient to prevent it.
Highlights • A high HCN concentration and medium CO level were detected in the blood of fire victims. • The carboxyhemoglobin (COHb) and HCN levels in 32 victims were used as a lethality index to ...predict the atmosphere in fire. • In this fire episode, methemoglobin (MetHb) was linearly correlated with COHb values. • Depletion of oxygen at the fire site should be considered when interpreting the laboratory data. • Fire simulation on mattress samples was performed to evaluate gases generated.
Background: Recent studies have shown that vitamin D status may be relevant for physical and cognitive performance in the older population. This association may be of particular interest to older ...people at risk for cognitive impairment and functional decline. Objective: The aim of this study was to determine the association between serum 25-hydroxyvitamin D 25(OH)D status and functional mobility in seniors assessed in a memory clinic. Methods: We conducted a cross-sectional study of outpatients (n = 404) in a memory clinic. Functional mobility was assessed with three endpoints: normal and fast walking speed and the Timed Up and Go (TUG) test. Adjusted multivariate analyses in all patients and two pre-planned subgroup analyses in vulnerable seniors (previous fall and MMSE score of ≥26 or no previous fall and MMSE score of <26) versus less vulnerable seniors (no previous fall and MMSE score of ≥26) were performed to assess the association of 25(OH)D and functional mobility. Results: Overall, mean 25(OH)D serum levels were 63.2 ± 33.9 nmol/l, and 41.3% were vitamin D deficient (<50 nmol/l). Seniors in the lowest 25(OH)D quartile (<39 nmol/l) had significantly worse functional mobility compared to the highest 25(OH)D quartile (>81 nmol/l); adjusted for all covariates, seniors in the highest quartile performed 9.4% better in normal (p = 0.02) and 9.2% better in fast (p = 0.004) walking speed, and 4.4% better in the TUG test (p = 0.24). The association between 25(OH)D status and functional mobility was most pronounced in less vulnerable seniors (p for trend significant for all three mobility tests). Seniors with a higher 25(OH)D status also had better cognitive function (MMSE score; p = 0.006). Conclusions: Lower serum 25(OH)D status is associated with poorer functional mobility and cognitive function, therefore supporting 25(OH)D assessment in this population at risk for both functional and cognitive decline.
The actual occurrence of Squalus megalops in the Mediterranean Sea has recently been questioned. Several research works which sought to assess available morphological and meristic features that ...differentiate S. megalops from other Squalus species in the Mediterranean Sea, revealed poor discriminatory power and high variability of the assessed characters, especially when comparing S. megalops and S. blainville. The application of molecular tools does not support the presence of S. megalops. In the present study, we screened spurdog species from the Strait of Sicily using a molecular taxonomy approach based on two mitochondrial DNA markers and we report the occurrence of two Squalus lineages characterizing specimens collected from the stretch of sea between Tunisia, southern Sicily, Malta and Libya. The results support the hypothesis that a common species, S. blainville, currently inhabits the Mediterranean Sea, while a second and rare species is probably an occasional visitor with high morphological similarity to the S. megalops and S. blainville but is genetically distinct from both. Within this perspective, the occurrence of S. megalops in the Mediterranean Sea is not confirmed and our study highlights the taxonomic uncertainties in relation to the occurrence and distribution of Squalus species in this region. We encourage the establishment of a coordinated international effort to implement a comprehensive and integrated taxonomic assessment on this genus which represents an irreplaceable component of the biodiversity of the area.
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