Prognostic value of the combination of volume, massiveness and fragmentation parameters measured on baseline FDG pet in high-burden follicular lymphoma.

The prognostic value of radiomic quantitative features measured on pre-treatment 18F-FDG PET/CT was investigated in patients with follicular lymphoma (FL). We conducted a retrospective study of 126 FL patients (grade 1-3a) diagnosed between 2006 and 2020. A dozen of PET/CT-derived features were extracted via a software (Oncometer3D) from baseline 18F-FDG PET/CT images. The receiver operating characteristic (ROC) curve, Kaplan-Meier method and Cox analysis were used to assess the prognostic factors for progression of disease within 24 months (POD24) and progression-free survival at 24 months. Four different clusters were identified among the twelve PET parameters analyzed: activity, tumor burden, fragmentation-massiveness and dispersion. On ROC analyses, TMTV, the total metabolic tumor volume, had the highest AUC (0.734) followed by medPCD, the median distance between the centroid of the tumors and their periphery (AUC: 0.733). Patients with high TMTV (HR = 4.341; p < 0.001), high Tumor Volume Surface Ratio (TVSR) (HR = 3.204; p < 0.003) and high medPCD (HR = 4.507; p < 0.001) had significantly worse prognosis in both Kaplan-Meier and Cox univariate analyses. Furthermore, a synergistic effect was observed in Kaplan-Meier and Cox analyses combining these three PET/CT-derived parameters (HR = 12.562; p < 0.001). Having two or three high parameters among TMTV, TVSR and medPCD was able to predict POD24 status with a specificity of 68% and a sensitivity of 75%. TMTV, TVSR and baseline medPCD are strong prognostic factors in FL and their combination better predicts disease prognosis.

Statistical Model for the Orientation of Nonspherical Particles Settling in Turbulence.

The orientation of small anisotropic particles settling in a turbulent fluid determines some essential properties of the suspension. We show that the orientation distribution of small heavy spheroids settling through turbulence can be accurately predicted by a simple Gaussian statistical model that takes into account particle inertia and provides a quantitative understanding of the orientation distribution on the problem parameters when fluid inertia is negligible. Our results open the way to a parametrization of the distribution of ice crystals in clouds, and potentially lead to an improved understanding of radiation reflection or particle aggregation through collisions in clouds.

Comparison of MR-arthrography and CT-arthrography in hyaline cartilage-thickness measurement in radiographically normal cadaver hips with anatomy as gold standard.

OBJECTIVE: To compare magnetic resonance (MR)-arthrography and multidetector-spiral-computed-tomography (MDSCT)-arthrography in cartilage-thickness measurement, in hips without cartilage loss, with coronal anatomic slices as gold standard. METHOD: Institutional review board permission to study cadavers of individuals who willed their bodies to science was obtained. Two independent observers measured femoral and acetabular cartilage thicknesses of 12 radiographically normal hips (six women, five men; age range, 52-98 years; mean age, 76.5 years), on MDSCT-arthrographic and MR-arthrographic reformations, and on coronal anatomic slices, excluding regions of cartilage loss. Inter- and intraobserver reproducibilities were determined. Analysis of variance (ANOVA) was used to test differences between MR-arthrographic and MDSCT-arthrographic measurement errors compared to anatomy. RESULTS: By MR-arthrography, cartilage was not measurable at approximately 50% of points on sagittal and transverse sections, compared to 0-6% of the points by MDSCT-arthrography. In the coronal plane, the difference between MDSCT-arthrographic and MR-arthrographic measurement errors was not significant (P=0.93). CONCLUSION: In the coronal plane, MR-arthrography and MDSCT-arthrography were similarly accurate for measuring hip cartilage thickness.

Universal intermittent properties of particle trajectories in highly turbulent flows.

We present a collection of eight data sets from state-of-the-art experiments and numerical simulations on turbulent velocity statistics along particle trajectories obtained in different flows with Reynolds numbers in the range R{lambda}in[120:740]. Lagrangian structure functions from all data sets are found to collapse onto each other on a wide range of time lags, pointing towards the existence of a universal behavior, within present statistical convergence, and calling for a unified theoretical description. Parisi-Frisch multifractal theory, suitably extended to the dissipative scales and to the Lagrangian domain, is found to capture the intermittency of velocity statistics over the whole three decades of temporal scales investigated here.

Intermittency of velocity time increments in turbulence.

We analyze the statistics of turbulent velocity fluctuations in the time domain. Three cases are computed numerically and compared: (i) the time traces of Lagrangian fluid particles in a (3D) turbulent flow (referred to as the dynamic case); (ii) the time evolution of tracers advected by a frozen turbulent field (the static case); (iii) the evolution in time of the velocity recorded at a fixed location in an evolving Eulerian velocity field, as it would be measured by a local probe (referred to as the virtual probe case). We observe that the static case and the virtual probe cases share many properties with Eulerian velocity statistics. The dynamic (Lagrangian) case is clearly different; it bears the signature of the global dynamics of the flow.

Lagrangian velocity statistics in turbulent flows: effects of dissipation.

We use the multifractal formalism to describe the effects of dissipation on Lagrangian velocity statistics in turbulent flows. We analyze high Reynolds number experiments and direct numerical simulation data. We show that this approach reproduces the shape evolution of velocity increment probability density functions from Gaussian to stretched exponentials as the time lag decreases from integral to dissipative time scales. A quantitative understanding of the departure from scaling exhibited by the magnitude cumulants, early in the inertial range, is obtained with a free parameter function D(h) which plays the role of the singularity spectrum in the asymptotic limit of infinite Reynolds number. We observe that numerical and experimental data are accurately described by a unique quadratic D(h) spectrum which is found to extend from h(min) approximately 0.18 to h(max) approximately 1.

Dorsal pancreas agenesis: computed tomography appearance with three-dimensional volume rendering reconstruction.

We report a case of a very rare congenital variant consisting in a dorsal (or left) pancreas agenesis due to the lack of development of the dorsal embryonic bud of the gland. This variant is characterized using helical computed tomography (CT). Three-dimensional (3D) computed tomography reconstruction, especially using the volume rendering technique, is very helpful for assessing this entity, which it is important to recognize due to its potential clinical implication (diabetes mellitus). Associated variants of abdominal vessels were also clearly seen in our patient with this technique, including a hepatomesenteric trunk and left retro-aortic renal vein.

Long time correlations in lagrangian dynamics: a key to intermittency in turbulence.

Using a new experimental technique, based on the scattering of ultrasounds, we perform a direct measurement of particle velocities, in a fully turbulent flow. This allows us to approach intermittency in turbulence from a dynamical point of view and to analyze the Lagrangian velocity fluctuations in the framework of random walks. We find experimentally that the elementary steps in the walk have random uncorrelated directions but a magnitude that is extremely long range correlated in time. Theoretically, a Langevin equation is proposed and shown to account for the observed one- and two-point statistics. This approach connects intermittency to the dynamics of the flow.

Finite-mode spectral model of homogeneous and isotropic Navier-stokes turbulence: a rapidly depleted energy cascade.

An eddy-viscous term is added to Navier-Stokes dynamics at wave numbers k greater than the inflection point kc of the energy flux F(log(k)). The eddy viscosity is fixed so that the energy spectrum satisfies E(k) = E(kc) (k/kc)(-3) for k>kc. This resulting forcing induces a rapid depletion of the energy cascade at k>kc. It is observed numerically that the model reproduces turbulence energetics at k< or =kc and statistics of two-point velocity correlations at scales r>lambda (Taylor microscale). Compared to a direct numerical simulation of R(lambda) = 130 an equivalent run with the present model results in a gain of a factor 20 in CPU time.

Shear effects in nonhomogeneous turbulence

Motivated by recent experimental and numerical results, a simple unifying picture of intermittency in turbulent shear flows is suggested. Integral structure functions (ISF), taking into account explicitly the shear intensity, are introduced on phenomenological grounds. ISF can exhibit a universal scaling behavior, independent of the shear intensity. This picture is in satisfactory agreement with both experimental and numerical data. Possible extension to convective turbulence and implication on closure conditions for large-eddy simulation of nonhomogeneous flows are briefly discussed.

Cloning and expression of an alpha-amylase encoding gene from the hyperthermophilic archaebacterium Thermococcus hydrothermalis and biochemical characterisation of the recombinant enzyme.

An alpha-amylase encoding gene from the extremely thermophilic Archaea Thermococcus hydrothermalis was cloned and expressed in Escherichia coli. The encoded alpha-amylase possesses molecular characteristics specific to the Archaea, especially from Pyrococcus species, with biochemical characteristics of the alpha-amylases from Thermococcus. The gene is 1374 bp long and encodes a protein of 457 amino acids composed of a 22 amino acid putative signal peptide and a 435 amino acid mature protein (calculated molecular mass 49236 Da). The T. hydrothermalis recombinant alpha-amylase is optimally active at 75-85 degrees C and at pH 5.0-5.5.

Close evolutionary relatedness of alpha-amylases from Archaea and plants.

The amino acid sequences of 22 alpha-amylases from family 13 of glycosyl hydrolases were analyzed with the aim of revealing the evolutionary relationships between the archaeal alpha-amylases and their eubacterial and eukaryotic counterparts. Two evolutionary distance trees were constructed: (i) the first one based on the alignment of extracted best-conserved sequence regions (58 residues) comprising beta2, beta3, beta4, beta5, beta7, and beta8 strand segments of the catalytic (alpha/beta)8-barrel and a short conserved stretch in domain B protruding out of the barrel in the beta3 --> alpha3 loop, and (ii) the second one based on the alignment of the substantial continuous part of the (alpha/beta)8-barrel involving the entire domain B (consensus length: 386 residues). With regard to archaeal alpha-amylases, both trees compared brought, in fact, the same results; i.e., all family 13 alpha-amylases from domain Archaea were clustered with barley pI isozymes, which represent all plant alpha-amylases. The enzymes from Bacillus licheniformis and Escherichia coli, representing liquefying and cytoplasmic alpha-amylases, respectively, seem to be the further closest relatives to archaeal alpha-amylases. This evolutionary relatedness clearly reflects the discussed similarities in the amino acid sequences of these alpha-amylases, especially in the best-conserved sequence regions. Since the results for alpha-amylases belonging to all three domains (Eucarya, Eubacteria, Archaea) offered by both evolutionary trees are very similar, it is proposed that the investigated conserved sequence regions may indeed constitute the "sequence fingerprints" of a given alpha-amylase.

Tricyclic antidepressant-induced extrapyramidal side effects.

Two cases of tricyclic antidepressant-related extrapyramidal side effects are reported and, the authors review the literature describing these effects. Despite clear case reports, these side effects are not well known. Given the wide prescription of tricyclic antidepressants (TCA) and the low number of case reports, the prevalence of these side effects is indeed low, but clinical implications exist. The extrapyramidal symptoms induced by TCA alone are acute or tardive dyskinesia, akathisia, myoclonus, rabbit syndrome and dystonia. These symptoms seem to be non age-related, but often dose-related, and were responders to antiparkinsonian agents or propranolol. The factors that predispose an individual to the development of these side effects are not completely understood. Some risk factors such as prior exposure to neuroleptics and/or lithium or estrogens could facilitate the development of these side effects. In some cases, they can disappear even though the same dose of TCA is continued, and they do not seem to be a drug class reaction. The susceptibility of each individual patient to the development of these disorders may be limited to only one or a few of these agents.

Effect of the interaction between transforming growth factor beta and erythropoietin on the proliferation of normal erythroid progenitors and leukemic UT-7 cells: action of transforming growth factor beta on the erythropoietin receptor.

The actions of transforming growth factor beta (TGF beta) and erythropoietin (Epo) were studied using normal erythroid progenitors from fetal rat liver and spleen at 18, 19 and 20 days. rhTGF beta 1 inhibited the growth of late BFUe colonies significantly at each age and in both organs in methylcellulose cultures containing 2 U/ml rhEpo. There was no significant inhibition of CFUe proliferation, except for spleen CFUe at 18 days, suggesting different CFUe sensitivities to growth factors at a given fetal age, 18 days, in liver and spleen. The colorimetric MTT assay was used to examine the inhibition of the growth of human leukemic UT-7 cells by TGF beta 1. TGF beta 1 inhibited the proliferation of UT-7 cells in cultures without Epo at 24 h and in cultures with Epo at 24 and 72 h. The specific binding of [125I]Epo to UT-7 surface was decreased by TGF beta 1 without any change in non-specific binding. TGF beta 1 also inhibited the expression of Epo-receptors on UT-7 cells, without changing receptor affinity. The inhibition of hematopoietic progenitor cell growth by TGF beta could involve altering the cell surface expression of growth factor receptors.