Identifying ureteropelvic junction obstruction by fluorescence imaging: a comparative study of imaging modalities to assess renal function and degree of obstruction in a mouse model.

Purpose: Radiological imaging is the mainstay of diagnosing ureteropelvic junction obstruction. Current established radiological modalities can potentially differentiate the varying degrees of obstruction but they are limited in functionality, applicability and/or comprehensiveness. Of particular concern is that some tests require radiation, which has long-term consequences, especially in children.

Development of an ovine model of pediatric complete heart block.

Background: Complete heart block is a significant clinical problem that can limit the quality of life in affected children. To understand the pathophysiology of this condition and provide for development of novel therapies, we sought to establish a large animal model of permanent, pacemaker-dependent atrioventricular block (AVB) that mimics the size and growth characteristics of pediatric patients.

Materials And Methods: We utilized nine immature lambs weighing 10.

Ultrasound diagnosis of mouse pregnancy and gestational staging.

Phenotypic analysis of mutant mice is limited by lack of accurate, simple, and nondestructive in utero imaging techniques. This study evaluated the usefulness of ultrasound imaging (US) to stage fetal mouse gestational age (GA) and depict morphologic development. We imaged 16 pregnant CD-1 mice and a total of 92 fetuses with a 15-MHz US transducer from 9.

Fetal sheep development on ultrasound and magnetic resonance imaging: a standard for the in utero assessment of models of congenital abnormalities.

Objective: To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR) imaging.

Methods: US and MR images of ten normal pregnant sheep, at 40, 65, 90, 115, and 140 gestational days (term = 145 days), were scored for organ conspicuity and imaging characteristics. Imaging biometry was correlated with specimens.

Radiation exposure reduction during voiding cystourethrography in a pediatric porcine model of vesicoureteral reflux.

Purpose: To compare grid-controlled variable-rate pulsed fluoroscopy (GCPFL) and continuous fluoroscopy (CFL) for the reduction of radiation exposure during voiding cystourethrography (VCUG) in a pediatric porcine model of vesicoureteral reflux.

Materials And Methods: Institutional animal care and use committee approval was obtained. Vesicoureteral reflux was simulated in four pigs, and 48 VCUG studies were performed (24 with GCPFL, 24 with CFL).

Epinephrine prevents muscle blood flow increases after perineural injection of tetrodotoxin.

Background: The local anesthetic properties of tetrodotoxin, a potent naturally occurring sodium channel blocker, have been recently reexamined. It was found that sciatic nerve block duration could be greatly increased and systemic toxicity greatly decreased if epinephrine was injected with tetrodotoxin. The mechanism that underlies epinephrine-mediated prolongation of tetrodotoxin nerve blocks is not known, but indirect evidence suggests that epinephrine may slow the clearance of tetrodotoxin from the site of injection.

Normal and ischemic epiphysis of the femur: diffusion MR imaging study in piglets.

Purpose: To evaluate normal diffusion characteristics in the femur in piglets and changes in diffusion with increasing duration of femoral head ischemia.

Materials And Methods: Normal epiphyses, physes, and metaphyses of piglets were evaluated with line-scan diffusion imaging (n = 12) and diffusion-tensor imaging (n = 4). Apparent diffusion coefficient (ADC) differences between normal proximal and distal femoral structures, epiphyseal and physeal cartilage, and epiphyseal and metaphyseal marrow were compared (Mann-Whitney test).

Correlation of contrast-enhanced power Doppler sonography and conventional angiography of abduction-induced hip ischemia in piglets.

Objective: The purpose of this study was to determine if enhanced power Doppler sonography can detect early ischemia of the capital femoral epiphysis induced by hip hyperabduction in piglets and to correlate these findings with angiography.

Materials And Methods: Proximal femoral perfusion was evaluated in 18 studies of 10 piglet hips with unenhanced power Doppler sonography, enhanced power Doppler sonography with IV contrast agent, and digital angiography, in neutral position, hyperabduction, and after release to neutral position. Enhancement ratios between pixel intensities of power Doppler sonography and enhanced power Doppler images in each position were calculated.

Activation of peripheral excitatory amino acid receptors decreases the duration of local anesthesia.

Background: Postsurgical wound infiltration with the -methyl-d-aspartate receptor antagonist ketamine and bupivacaine can significantly prolong the duration of local anesthesia. One possible mechanism for this effect is that increased glutamate concentrations, caused by tissue damage, sensitize nociceptive primary afferent fibers through activation of peripheral excitatory amino acid receptors.

Methods: The effect of intramuscular injection of hyper-tonic glutamate (1,000 mm), dextrose (1,400 mm), glutamate (1,000 mm) with the broad spectrum excitatory amino acid receptor antagonist kynurenate (100 mm), or isotonic saline (155 mm) on the duration of masseter muscle afferent fiber blockade after lidocaine (37 mm [1%], 10 microl) infiltration, on muscle edema formation and on muscle blood flow was examined.

The effects of lidocaine and adrenergic agonists on rat sciatic nerve and skeletal muscle blood flow in vivo.

Unlabelled: It has been proposed that epinephrine prolongs lidocaine nerve blockade duration by exerting a local vasoconstrictive effect on tissues at the injection site, slowing lidocaine's local clearance. However, previous studies have failed to demonstrate consistent effects of lidocaine and epinephrine, injected alone and in combination, on vascular tone or regional blood flow. To reinvestigate this idea, in this study we used the radiolabeled microsphere technique to measure in vivo tissue blood flow before and at several time points after perisciatic nerve and intramasseter muscle injection of lidocaine alone, epinephrine, the selective alpha(1)-adrenergic receptor agonist phenylephrine, or lidocaine combined with these adrenergic receptor agonists.