Muscle Sympathetic Nerve Activity Is Associated with Liver Insulin Sensitivity in Obese Non-Diabetic Men.

Muscle sympathetic nerve activity (MSNA) may play a role in insulin resistance in obesity. However, the direction and nature of the relationship between MSNA and insulin resistance in obesity remain unclear. We hypothesized that resting MSNA would correlate inversely with both muscle and liver insulin sensitivity and that it would be higher in insulin-resistant vs.

Phenotypic Characterization of Insulin-Resistant and Insulin-Sensitive Obesity.

Context: Whereas insulin resistance and obesity coexist, some obese individuals remain insulin sensitive.

Objective: We examined phenotypic and metabolic factors associated with insulin sensitivity in both muscle and liver in obese individuals.

Design And Participants: Sixty-four nondiabetic obese adults (29 males) underwent hyperinsulinemic (15 and 80 mU/m(2) · min)-euglycemic clamps with deuterated glucose.

Noninvasive tumor hypoxia measurement using magnetic resonance imaging in murine U87 glioma xenografts and in patients with glioblastoma.

Purpose: There is a clinical need for noninvasive, nonionizing imaging biomarkers of tumor hypoxia and oxygenation. We evaluated the relationship of T1 -weighted oxygen-enhanced magnetic resonance imaging (OE-MRI) measurements to histopathology measurements of tumor hypoxia in a murine glioma xenograft and demonstrated technique translation in human glioblastoma multiforme.

Methods: Preclinical evaluation was performed in a subcutaneous murine human glioma xenograft (U87MG).

Physiological and performance responses to a preseason altitude-training camp in elite team-sport athletes.

Purpose: Little research has been done on the physiological and performance effects of altitude training on team-sport athletes. Therefore, this study examined changes in 2000-m time-trial running performance (TT), hemoglobin mass (Hbmass), and intramuscular carnosine content of elite Australian Football (AF) players after a preseason altitude camp.

Methods: Thirty elite AF players completed 19 days of living and training at either moderate altitude (~2130 m; ALT, n = 21) or sea level (CON, n = 9).

Resistance training improves cardiac output, exercise capacity and tolerance to positive airway pressure in Fontan physiology.

Background: Subjects with Fontan-type circulation have no sub-pulmonary ventricle and thus depend exquisitely on the respiratory bellows and peripheral muscle pump for cardiac filling. We hypothesised that resistance training to augment the peripheral muscle pump might improve cardiac filling, reduce inspiratory-dependence of IVC return to the heart and thus improve exercise capacity and cardiac output on constant positive airway pressure (CPAP).

Methods: Eleven Fontan subjects (32+/-2 years, mean+/-SEM) had cardiac magnetic resonance imaging (MRI) and exercise testing (CPET); six underwent 20 weeks of high-intensity resistance training; others were non-exercising controls.

A quantitative comparison of the influence of individual versus population-derived vascular input functions on dynamic contrast enhanced-MRI in small animals.

For quantitative analysis of dynamic contrast enhanced magnetic resonance imaging data, the time course of the concentration of the contrast agent in the blood plasma, or vascular input function (VIF), is required. We compared pharmacokinetic parameters derived using individual and population-based VIFs in mice for two different contrast agents, gadopentetate dimeglumine and P846. Eleven mice with subcutaneous 4T(1) breast cancer xenografts were imaged at 7 T.

Use of dynamic susceptibility-contrast MRI (DSC-MRI) to assess perfusion changes in the ipsilateral brain parenchyma from glioblastoma.

Introduction: We investigated the effect of increased tumor perfusion using dynamic susceptibility-contrast magnetic resonance imaging (DSC-MRI) in glioblastoma (GBM) patients on the surrounding ipsilateral brain tissue with respect to perfusion of the normal, unaffected contralateral brain and of the tumor.

Material And Methods: DSC-MRI was performed in 11 patients with glioblastoma using a multislice T2*-weighed EPI sequence (TR/TE = 2,000/62 ms; FOV 240 mm; matrix 128 x 128; slice thickness 6 mm) on a standard clinical 1.5 Tesla scanner during intravenous injection of 40 cc Gadolinium-DTPA at a flow rate of 5 cc/s.

Retinal folding in the term rabbit fetus-Developmental abnormality or fixation artifact?

Unlabelled: Preclinical reproductive toxicology studies must be performed to provide information on the risk of causing fetal harm in pregnant patients. These studies detect fetal malformations, which may or may not be drug-related adverse events. In the rabbit fetus, "slight retinal folding" is commonly observed; there is anecdotal evidence that these folds may be caused by routine (Bouin's fluid) fixation.

Vessel wall damage caused by cerebral protection devices: ex vivo evaluation in porcine carotid arteries.

Purpose: To determine the extent of vessel wall damage caused by cerebral protection devices designed for carotid angioplasty by using ex vivo porcine carotid arteries.

Materials And Methods: The local animal experimentation committee did not require its approval for this study. With a benchtop vascular model (flow rate, 470 mL/min; dicrotic pulsatile flow, 76 pulses per minute; pressure, 115/67 mm Hg [mean pressure, 91 mm Hg]) into which 85 porcine internal carotid arteries (ICAs) were inserted, five different protection devices (Angioguard [Cordis/Johnson & Johnson, Miami, Fla], Filterwire EX [Boston Scientific, Natick, Mass], Trap [Microvena, White Bear Lake, Minn], Neuroshield [Abbott Laboratories, Redwood City, Calif], and Percusurge [Abbott Laboratories]) were evaluated.

Volumetric interpolated contrast-enhanced MRA for the diagnosis of pulmonary embolism in an ex vivo system.

Purpose: To implement a three-dimensional gradient-recalled echo (GRE) volumetric interpolated breath-hold examination (VIBE) sequence for pulmonary contrast-enhanced MRA (CE-MRA) in an experimental setup.

Materials And Methods: Eight porcine lungs were intubated, inflated inside a chest phantom, and examined at 1.5 T during slow perfusion (2-300 mL/minute).

Comparison of 4 cerebral protection filters for carotid angioplasty: an in vitro experiment focusing on carotid anatomy.

Purpose: To assess the influence of internal carotid artery (ICA) tortuosity on the effectiveness of 4 cerebral protection filters in an in vitro bench-top model.

Methods: To simulate the anatomical arterial variants, 3 open flow models were constructed: one with normal carotid anatomy, 1 representing a mildly tortuous ICA, and a third imitating a severely tortuous ICA. Polyvinyl alcohol particles (150-1000 microm) served as the embolic material; the emboli were divided into 3 groups according to size: small (150-250 microm), medium (355-500 microm), and large (710-1000 microm).

Comparison of various cerebral protection devices used for carotid artery stent placement: an in vitro experiment.

Purpose: To compare the effectiveness of five basic cerebral protection devices designed for carotid angioplasty in an in-vitro bench-top model.

Materials And Methods: Simulation of embolization from carotid angioplasty (n = 180) was performed with polyvinyl alcohol (PVA) particles (Contour; 150-1,000- micro m) in an open flow model simulating the aortic arch with a carotid bifurcation made from elastic silicone tubes. Particles (150-250 micro m [small], 355-500 micro m [medium], 710-1,000 micro m [large]; 5 mg each) were injected separately into the internal carotid artery (ICA) proximal to the placed protection device.

In vitro comparison of four cerebral protection filters for preventing human plaque embolization during carotid interventions.

Purpose: To evaluate in an in vitro bench-top model the efficacy of 4 filtration devices designed for cerebral protection during carotid angioplasty.

Methods: Embolization during carotid angioplasty was simulated with human plaque material (8 to 12 particles weighing 6.02 +/- 0.

Lung morphology: fast MR imaging assessment with a volumetric interpolated breath-hold technique: initial experience with patients.

Purpose: To prospectively evaluate the clinical feasibility of magnetic resonance (MR) imaging of the lungs with fast volumetric interpolated three-dimensional (3D) gradient-recalled-echo (GRE) sequences and to compare this examination with standard computed tomography (CT) in patients with lung abnormalities.

Materials And Methods: Twenty-five patients with different lung abnormalities were examined with 3D GRE MR imaging. The small pulmonary nodules in seven, TNM stage of large intrapulmonary tumors in eight, and benign bronchial disease in five patients were evaluated.

Characterization of the integrity of three-dimensional trabecular bone microstructure by connectivity and shape analysis using high-resolution magnetic resonance imaging in vivo.

Bone mineral density and bone structure are the main determinants of bone strength in osteoporosis. In this study we used high-resolution magnetic resonance imaging to visualize the bone microstructure in the finger phalanges in vivo and to assess the topological three-dimensional connectivity of the trabecular network and the shape of the trabeculae as measures of bone quality. We visualized the phalanges of young and elderly healthy volunteers in vivo with a spatial resolution of 152 microm x 152 microm x 280 microm.

Detection of changes in cartilage water content using MRI T2-mapping in vivo.

Objectives: Osteoarthritis (OA) is the most prevalent chronic disease in the elderly, and it is generally diagnosed at an advanced state when treatment is difficult if not impossible. The early form of OA is characterized by an elevated water content in the cartilage tissue. The purpose of this study was to verify in vivo if changes in the water content of patellar cartilage typically occurring in early OA can be detected using T(2) mapping MRI methods.

Comparison and modification of two cerebral protection devices used for carotid angioplasty: in vitro experiment.

The effectiveness of two basic cerebral protection devices designed for carotid angioplasty with and without additional aspiration techniques was compared in an in vitro model. During carotid angioplasty, embolization was simulated by injecting polyvinyl alcohol particles of different sizes into the model system. None of the tested devices, all of which were positioned in the internal carotid artery, was able to completely prevent embolization.

Metabolite and water apparent diffusion coefficients in the isolated rat heart: effects of ischemia.

A decrease in the apparent diffusion coefficient (ADC) of water is important in the detection of acute brain disorders, yet it is unknown whether changes in myocardial ADCs hold similar potential. Consequently, in this study a STEAM pulse sequence was modified in order to measure the ADCs of water and the (1)H-NMR detectable metabolites, taurine (an inert marker) and creatine, during perfusion, ischemia, and reperfusion in the isolated rat heart. At the short diffusion time of 50 ms, myocardial ADCs were (1.