Restoration of high-frequency glucose-entrained insulin oscillations in obese subjects with type 2 diabetes after biliopancreatic diversion.

Background: Minimal glucose infusions are known to entrain insulin oscillations in patients with normal glucose tolerance (NGT) but not in patients with type 2 diabetes (T2D).

Objectives: To investigate whether weight loss after a version of biliopancreatic diversion (BPD) can restore the glucose entrainment of high-frequency insulin oscillations in morbidly obese NGT or T2D patients.

Setting: University Hospital, Greece.

(99m)Tc-labeled aminosilane-coated iron oxide nanoparticles for molecular imaging of ανβ3-mediated tumor expression and feasibility for hyperthermia treatment.

Hypothesis: Dual-modality imaging agents, such as radiolabeled iron oxide nanoparticles (IO-NPs), are promising candidates for cancer diagnosis and therapy. We developed and evaluated aminosilane coated Fe3O4 (10±2nm) as a tumor imaging agent in nuclear medicine through 3-aminopropyltriethoxysilane (APTES) functionalization. We evaluated this multimeric system of targeted (99m)Tc-labeled nanoparticles (NPs) conjugated with a new RGD derivate (cRGDfK-Orn3-CGG), characterized as NPs-RGD as a potential thermal therapy delivery vehicle.

Real-time tumor ablation simulation based on the dynamic mode decomposition method.

Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation.

Methods: A meshless point collocation solver is used for the numerical solution of the governing equations.

Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: creation of an oncology database.

Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance restrictions and have limited spatial resolution. For those reasons, the measured intensity cannot be simply introduced in GATE simulations, to reproduce clinical data.

Automatic quantitative analysis of in-stent restenosis using FD-OCT in vivo intra-arterial imaging.

Purpose: A new segmentation technique is implemented for automatic lumen area extraction and stent strut detection in intravascular optical coherence tomography (OCT) images for the purpose of quantitative analysis of in-stent restenosis (ISR). In addition, a user-friendly graphical user interface (GUI) is developed based on the employed algorithm toward clinical use.

Methods: Four clinical datasets of frequency-domain OCT scans of the human femoral artery were analyzed.

Biological evaluation of an ornithine-modified (99m)Tc-labeled RGD peptide as an angiogenesis imaging agent.

Introduction: Radiolabeled RGD peptides that specifically target integrin α(ν)β(3) have great potential in early tumor detection through noninvasive monitoring of tumor angiogenesis. Based on previous findings of our group on radiopeptides containing positively charged aminoacids, we developed a new cyclic cRGDfK derivative, c(RGDfK)-(Orn)(3)-CGG. This new peptide availing the polar linker (Orn)(3) and the (99m)Tc-chelating moiety CGG (Cys-Gly-Gly) is appropriately designed for (99m)Tc-labeling, as well as consequent conjugation onto nanoparticles.

PDE5 inhibition against acute renal ischemia reperfusion injury in rats: does vardenafil offer protection?

Purpose: To evaluate the effect of vardenafil on renal function after renal ischemia-reperfusion (IR) injury (IRI) in a rat model.

Materials And Methods: Seventy-one Wistar rats were divided into 7 groups including (1) a vehicle-treated group, (2) a vehicle pretreated-IR group, (3-6) vardenafil pretreated-IR groups in doses of 0.02, 0.

Emerging technologies for image guidance and device navigation in interventional radiology.

Recent developments in image-guidance and device navigation, along with emerging robotic technologies, are rapidly transforming the landscape of interventional radiology (IR). Future state-of-the-art IR procedures may include real-time three-dimensional imaging that is capable of visualizing the target organ, interventional tools, and surrounding anatomy with high spatial and temporal resolution. Remote device actuation is becoming a reality with the introduction of novel magnetic-field enabled instruments and remote robotic steering systems.

A dose point kernel database using GATE Monte Carlo simulation toolkit for nuclear medicine applications: comparison with other Monte Carlo codes.

Purpose: GATE is a Monte Carlo simulation toolkit based on the Geant4 package, widely used for many medical physics applications, including SPECT and PET image simulation and more recently CT image simulation and patient dosimetry. The purpose of the current study was to calculate dose point kernels (DPKs) using GATE, compare them against reference data, and finally produce a complete dataset of the total DPKs for the most commonly used radionuclides in nuclear medicine.

Methods: Patient-specific absorbed dose calculations can be carried out using Monte Carlo simulations.

Hysterosalpingography using a flat panel unit: evaluation and optimization of ovarian radiation dose.

Purpose: The aim of the present study was the evaluation and optimization of radiation dose to the ovaries (D) in hysterosalpingography (HSG).

Methods: The study included a phantom study and a clinical one. In the phantom study, we evaluated imaging results for different geometrical setups and irradiation conditions.

Automatic vessel lumen segmentation and stent strut detection in intravascular optical coherence tomography.

Purpose: Optical coherence tomography (OCT) is a catheter-based imaging method that employs near-infrared light to produce high-resolution cross-sectional intravascular images. The authors propose a segmentation technique for automatic lumen area extraction and stent strut detection in intravascular OCT images for the purpose of quantitative analysis of neointimal hyperplasia (NIH).

Methods: A clinical dataset of frequency-domain OCT scans of the human femoral artery was analyzed.

Tacrolimus and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors: An interaction study in CYP3A5 non-expressors, renal transplant recipients.

Objectives: Atherosclerosis is a significant factor affecting long-term outcome in renal transplant recipients. Studies have been conducted to determine the pharmacogenomic pathways involved in statin efficacy, efficiency, and adverse effect likelihood. However, little is known about the influence of statins on tacrolimus kinetics.

In vivo small animal imaging: current status and future prospects.

The use of small animal models in basic and preclinical sciences constitutes an integral part of testing new pharmaceutical agents prior to commercial translation to clinical practice. Whole-body small animal imaging is a particularly elegant and cost-effective experimental platform for the timely validation and commercialization of novel agents from the bench to the bedside. Biomedical imaging is now listed along with genomics, proteomics, and metabolomics as an integral part of biological and medical sciences.

Investigation of clinical interaction between omeprazole and tacrolimus in CYP3A5 non-expressors, renal transplant recipients.

Background: As proton pump inhibitors share CYP3A4 enzyme with tacrolimus for their hepatic elimination, they potentially affect its pharmacokinetics, most prominently in patients with CYP2C19 or CYP3A5 gene mutations. Our aim was to investigate the impact of omeprazole on tacrolimus pharmacokinetics in CYP3A5 non-expressors, kidney transplant recipients.

Methods: Twelve patients (five males/seven females) were observed for 175 +/- 92.

Factors affecting the long-term response to tacrolimus in renal transplant patients: pharmacokinetic and pharmacogenetic approach.

Background: The aim of our study was to determine the impact of CYP3A5*1 and CYP3A5*3 on the kinetics of tacrolimus in renal transplant recipients.

Material And Methods: Forty kidney recipients were selected to participate. Maintenance scheme consisted of tacrolimus, a purine inhibitor and a steroid.

Background adjustment of cDNA microarray images by Maximum Entropy distributions.

Many empirical studies have demonstrated the exquisite sensitivity of both traditional and novel statistical and machine intelligence algorithms to the method of background adjustment used to analyze microarray datasets. In this paper we develop a statistical framework that approaches background adjustment as a classic stochastic inverse problem, whose noise characteristics are given in terms of Maximum Entropy distributions. We derive analytic closed form approximations to the combined problem of estimating the magnitude of the background in microarray images and adjusting for its presence.

Segmentation of complementary DNA microarray images by wavelet-based Markov random field model.

A wavelet-based modification of the Markov random field (WMRF) model is proposed for segmenting complementary DNA (cDNA) microarray images. For evaluation purposes, five simulated and a set of five real microarray images were used. The one-level stationary wavelet transform (SWT) of each microarray image was used to form two images, a denoised image, using hard thresholding filter, and a magnitude image, from the amplitudes of the horizontal and vertical components of SWT.

Complementary DNA microarray image processing based on the fuzzy gaussian mixture model.

The objective of this paper was to investigate the segmentation ability of the fuzzy Gaussian mixture model (FGMM) clustering algorithm, applied on complementary DNA (cDNA) images. Following a standard established procedure, a simulated microarray image of 1600 cells, each containing one spot, was produced. For further evaluation of the algorithm, three real microarray images were also used, each containing 6400 spots.

Thrombin promotes arteriogenesis and hemodynamic recovery in a rabbit hindlimb ischemia model.

Background: Compared with angiogenesis, arteriogenesis is a distinct process based on the remodeling and maturation of pre-existing arterioles into large conductance arteries. Therapeutic angiogenesis has been proposed as a potential treatment for ischemic atherosclerotic diseases. Since a variety of angiogenic factors have been tested with inconsistent so far clinical results, the challenge remains in identifying the factor(s) that will stimulate functional neovascularization.

Bayesian clustering of flow cytometry data for the diagnosis of B-chronic lymphocytic leukemia.

In the rapidly advancing field of flow cytometry, methodologies facilitating automated clinical decision support are increasingly needed. In the case of B-chronic lymphocytic leukemia (B-CLL), discrimination of the various subpopulations of blood cells is an important task. In this work, our objective is to provide a useful paradigm of computer-based assistance in the domain of flow-cytometric data analysis by proposing a Bayesian methodology for flow cytometry clustering.

Molecular imaging and the unification of multilevel mechanisms and data in medical physics.

Molecular imaging (MI) constitutes a recently developed approach of imaging, where modalities and agents have been reinvented and used in novel combinations in order to expose and measure biologic processes occurring at molecular and cellular levels. It is an approach that bridges the gap between modalities acquiring data from high (e.g.

A perspective for biomedical data integration: design of databases for flow cytometry.

Background: The integration of biomedical information is essential for tackling medical problems. We describe a data model in the domain of flow cytometry (FC) allowing for massive management, analysis and integration with other laboratory and clinical information. The paper is concerned with the proper translation of the Flow Cytometry Standard (FCS) into a relational database schema, in a way that facilitates end users at either doing research on FC or studying specific cases of patients undergone FC analysis

Results: The proposed database schema provides integration of data originating from diverse acquisition settings, organized in a way that allows syntactically simple queries that provide results significantly faster than the conventional implementations of the FCS standard.

Application of paclitaxel-eluting metal stents in renal artery of pig model.

Background And Purpose: Recent reports concerning coronary, carotid, and femoral vasculature have proposed the use of drug-eluting metal stents (MS) to improve clinical and angiographic outcomes. Based on these reports, we used paclitaxel-eluting MS within an animal renal artery lumen and compared the results with those using a bare-metal stent.

Materials And Methods: The experimental model in this study was the female pig renal artery.

Transcranial cerebral oximetry and transcranial doppler sonography in patients with ruptured cerebral aneurysms and delayed cerebral vasospasm.

Background: Vasospasm is a major cause of ischemic neurological deficits developing after subarachnoid hemorrhage. The goal was to identify hemodynamic changes and the presence of clinical vasospasm in patients suffering from subarachnoid hemorrhage secondary to ruptured intracranial aneurysms.

Material/methods: Pre- and postoperative serial transcranial cerebral oximetry and transcranial doppler sonography (TCD) examinations were performed in 75 patients operated for aneurysmal subarachnoid hemorrhage.

Computational representation and hemodynamic characterization of in vivo acquired severe stenotic renal artery geometries using turbulence modeling.

The present study reports on computational fluid dynamics in the case of severe renal artery stenosis (RAS). An anatomically realistic model of a renal artery was reconstructed from CT scans, and used to conduct CFD simulations of blood flow across RAS. The recently developed shear stress transport (SST) turbulence model was pivotally applied in the simulation of blood flow in the region of interest.