Hepatoblastoma: radiologic-pathologic correlation in 50 cases

Fifty cases of hepatoblastoma were reviewed. Virtually all patients were infants or young children with hepatomegaly or a mass. Calcification seen on 11 of 20 radiographs was often in a pattern of small chunks, and eight of these correlated with osteoid formation in histologically mixed hepatoblastomas. Angiography generally showed tumor vascularity, sometimes with a spoke-wheel pattern. Suggestion of tumor nodularity or lobulation on sonography or computed tomography (CT) correlated with the gross appearance. The tumor was usually echogenic and occasionally had small hypoechoic or anechoic areas representing necrosis or hemorrhage. On CT it was usually hypodense, with minimal if any enhancement. The calcification pattern and demonstration of tumor lobulation with septation may help differentiate hepatoblastoma from other liver neoplasms in infants and children under 5 years of age.     

Experimental studies of bone remodeling in total hip arthroplasty.

Experimental studies of bone remodeling after total hip arthroplasty are reviewed. Most of the studies have been motivated by the introduction of cementless hip replacements in which porous coatings are used to provide fixation by bone ingrowth. Stress shielding is thought to be the main factor responsible for bone loss after hip replacement. Experimentally, design features related to (1) the nature of the bone-implant interface and (2) stem stiffness have been tested to determine if the effects of stress shielding can be decreased. The dominant long-term design feature controlling bone remodeling in hip replacement appears to be stem stiffness.     

Survival motor neuron protein in motor neurons determines synaptic integrity in spinal muscular atrophy

The inherited motor neuron disease spinal muscular atrophy (SMA) is caused by deficient expression of survival motor neuron (SMN) protein and results in severe muscle weakness. In SMA mice, synaptic dysfunction of both neuromuscular junctions (NMJs) and central sensorimotor synapses precedes motor neuron cell death. To address whether this synaptic dysfunction is due to SMN deficiency in motor neurons, muscle, or both, we generated three lines of conditional SMA mice with tissue-specific increases in SMN expression. All three lines of mice showed increased survival, weights, and improved motor behavior. While increased SMN expression in motor neurons prevented synaptic dysfunction at the NMJ and restored motor neuron somal synapses, increased SMN expression in muscle did not affect synaptic function although it did improve myofiber size. Together these data indicate that both peripheral and central synaptic integrity are dependent on motor neurons in SMA, but SMN may have variable roles in the maintenance of these different synapses. At the NMJ, it functions at the presynaptic terminal in a cell-autonomous fashion, but may be necessary for retrograde trophic signaling to presynaptic inputs onto motor neurons. Importantly, SMN also appears to function in muscle growth and/or maintenance independent of motor neurons. Our data suggest that SMN plays distinct roles in muscle, NMJs, and motor neuron somal synapses and that restored function of SMN at all three sites will be necessary for full recovery of muscle power.     

Metabolomics in the assessment of chemical‐induced reproductive and developmental outcomes using non‐invasive biological fluids: application to the study of butylbenzyl phthalate

This study was conducted to evaluate the use of metabolomics for improving our ability to draw correlations between early life exposures and reproductive and/or developmental outcomes. Pregnant CD rats were exposed by gavage daily during gestation to vehicle or to butylbenzyl phthalate (BBP) in vehicle at a level known to induce effects in the offspring and at a level previously not shown to induce effects. Urine was collected for 24 h (on dry ice using all glass metabolism chambers) from dams on gestational day 18 (during exposure) and on post natal day (pnd) 21, and from pnd 25 pups. Traditional phenotypic anchors were measured in pups (between pnd 0 and pnd 26). Metabolomics of urine collected from dams exposed to vehicle or BBP exhibited different patterns for endogenous metabolites. Even three weeks after gestational exposure, metabolic profiles of endogenous compounds in urine could differentiate dams that received the vehicle, low dose or high dose of BBP. Metabolic profiles could differentiate male from female pups, pups born to dams receiving the vehicle, low or high BBP dose, and pups with observable adverse reproductive effects from pups with no observed effects. Metabolites significant to the separation of dose groups and their relationship with effects measured in the study were mapped to biochemical pathways for determining mechanistic relevance. The application of metabolomics to understanding the mechanistic link between low levels of environmental exposure and disease/dysfunction holds huge promise, because this technology is ideal for the analysis of biological fluids in human populations. Copyright © 2009 John Wiley & Sons, Ltd.