Paramagnetic nanoparticles to track and quantify in vivo immune human therapeutic cells.

This study aims to investigate gadolinium-based nanoparticles (Gd-HNP) for in vitro labeling of human plasmacytoid dendritic cells (HuPDC) to allow for in vivo tracking and HuPDC quantifying using magnetic resonance imaging (MRI) following parenteral injection. Human plasmacytoid DC were labeled (LabHuPDC) with fluorescent Gd-HNP (Gd-FITC-HNP) and injected via intraperitoneal and intravenous routes in 4-5 NOD-SCID β2m(-/-)mice (treated mice = TM). Control mice (CM) were similarly injected with unlabeled HuPDC.

Validation of renal oxidative metabolism measurement by positron-emission tomography.

Either in research or in clinical practice, the exploration of renal oxidative metabolism is limited by the lack of noninvasive measurement. Positron-emission tomography using carbon-11 acetate may estimate tissue oxidative metabolism by measuring acetate turnover in the Krebs cycle. Although extensively studied in cardiology, this method has never been validated for renal oxidative metabolism measurement.

Mechanisms leading to reversible mechanical dysfunction in severe CAD: alternatives to myocardial stunning.

Patients with severe chronic coronary artery disease (CAD) exhibit a highly altered myocardial pattern of perfusion, metabolism, and mechanical performance. In this context, the diagnosis of stunning remains elusive not only because of methodological and logistic considerations, but also because of the pathophysiological characteristics of the myocardium of these patients. In addition, a number of alternative pathophysiological mechanisms may act by mimicking the functional manifestations usually attributed to stunning.

T-cell homing to the pancreas in autoimmune mouse models of diabetes: in vivo MR imaging.

Purpose: To evaluate the efficiency of T-cell labeling with anionic magnetic nanoparticles (AMNPs) and in vivo magnetic resonance (MR) imaging monitoring of T-cell homing to the pancreas.

Materials And Methods: In vivo MR images of pancreas were obtained with a 7-T MR system in 12 NOD (nonobese diabetic) mice at 11 and 20 days after injection of AMNP-loaded or unloaded T cells. Homing of loaded T cells in pancreatic lymph nodes was detected by the presence of a focal dark spot with T2* effect in a caudal area of the pancreas.

Thyroid hormone receptor alpha is a molecular switch of cardiac function between fetal and postnatal life.

Thyroid hormones are involved in the regulation of many physiological processes and regulate gene transcription by binding to their nuclear receptors TRalpha and TRbeta. In the absence of triiodothyronine (T3), the unliganded receptors (aporeceptors) do bind DNA and repress the transcription of target genes. The role of thyroid hormone aporeceptors as repressors was observed in hypothyroid adult mice, but its physiological relevance in nonpathological hypothyroid conditions remained to be determined.

Tagged MRI and PET in severe CAD: discrepancy between preoperative inotropic reserve and intramyocardial functional outcome after revascularization.

In severe coronary artery disease (CAD), it has been shown that intramyocardial inotropic reserve as assessed with tagged magnetic resonance imaging (MRI) is uniformly distributed among positron emission tomography (PET) patterns reflecting normal or concomitant reductions in perfusion and glucose metabolism. This preliminary study aimed to delineate the relationship between preoperative values of intramyocardial inotropic reserve (in different PET patterns of perfusion and glucose uptake) and intramyocardial functional outcome after surgical revascularization in severe CAD. Twelve patients underwent preoperative tagged MRI (baseline, 10 microg.

Dobutamine-tagged MRI for inotropic reserve assessment in severe CAD: relationship with PET findings.

The impact of blood flow reductions on the intramyocardial inotropic reserve has not yet been established in coronary artery disease (CAD). We therefore evaluated in severe CAD the relationship between positron emission tomography (PET) patterns of perfusion and glucose uptake and the corresponding tagged magnetic resonance imaging (tagged MRI) values of midmyocardial strains under low-dose dobutamine. Eighteen patients underwent tagged MRI (at rest, with dobutamine) and H2(15)O/18F-fluorodeoxyglucose PET.

Myocardial perfusion and glucose uptake coupling in CAD patients.

Purpose: To evaluate coronary artery disease (CAD) patients regarding to their perfusion-glucose uptake relationship at rest for all myocardial regions and to determine whether this evaluation could typify patients with different positron emission tomography (PET)-pattern proportions and pathophysiological characteristics.

Methods: Rest/dipyridamole H(15)2O and 18FDG PET studies were performed in 23 patients with left ventricular dysfunction. Regional index (relative perfusion, %H(15)2O; relative glucose uptake, %18FDG) allowed to detect PERFUSION-metabolism mismatch (i.

Development and evaluation of a new apparatus for continuous perfusion of isolated perfused pig heart.

To develop a better model of isolated perfused heart, a new apparatus of coronary artery cannula- fixed-in-aortic tube was developed for continuous normothermic perfusion and compared to the Casalis apparatus with cold ischemia. Eight mongrel pigs with the body weight of 18 to 24 kg were divided half into two groups. All the continuous perfusion experimental hearts resumed a spontaneous heart beat and stabilized earlier than the control hearts without the need of defibrillator or pacemaker, indicating no reperfusion injury on the heart.

Dynamic renal blood flow measurement by positron emission tomography in patients with CRF.

Background: Positron emission tomography (PET) is a functional imaging device that allows dynamic regional blood flow measurements. We performed a study to test whether PET could detect acute changes in renal blood flow (RBF) in patients with chronic renal failure (CRF).

Methods: RBF was measured by means of PET (PET-RBF) using oxygen 15-labeled water (H2(15)O) in eight men with hypertension and moderate CRF before and 5, 40, 80, and 120 minutes after the injection of quinaprilat (10 mg intravenously).

Mapping myocardial perfusion with an intravascular MR contrast agent: robustness of deconvolution methods at various blood flows.

Evaluation of quantitative parameters such as regional myocardial blood flow (rMBF), blood volume (rMBV), and mean transit time (rMTT) by MRI is gaining acceptance for clinical applications, but still lacks robust postprocessing methods for map generation. Moreover, robustness should be preserved over the full range of myocardial flows and volumes. Using experimental data from an isolated pig heart preparation, synthetic MR kinetics were generated and four deconvolution approaches were evaluated.

Factor analysis of medical image sequences improves evaluation of first-pass MR imaging acquisitions for myocardial perfusion.

Rationale And Objectives: Factor analysis of medical image sequences (FAMIS) applied to gadolinium chelate-enhanced subsecond magnetic resonance (MR) imaging was evaluated as a postprocessing method for assessing myocardial perfusion in coronary artery disease (CAD).

Materials And Methods: To assess the accuracy of motion correction, five normal volunteers underwent MR imaging at rest. Thirteen patients with well-documented CAD and no myocardial infarction underwent MR imaging at rest and after dipyridamole administration.