Pain control in the pediatric patient

PURPOSE: To investigate the ultrasonographic (US) characteristics of subdural empyema (SDE) and its differentiation from reactive subdural effusion (RSE) in infants with meningitis. MATERIALS AND METHODS: Images in 10 infants with SDE with or without RSE complicating meningitis were retrospectively reviewed and correlated with clinical findings and compared with US and magnetic resonance (MR) images in four infants with meningitis and RSE. RESULTS: At US, 15 of 16 SDEs in the 10 infants were seen as heterogeneous to hyperechoic convexity collections. Hyperechoic strands were seen in 12 SDEs. Other findings included a thick, echogenic inner membrane (n = 9), increased echogenicity of pia-arachnoid and exudates in the subarachnoid space (n = 16), mass effect (n = 16), and loculated extraaxial collections (n = 2). MR imaging findings correlated well with US and surgical results. At computed tomography, SDE was misinterpreted as RSE in one patient, due to the absence of inner membrane contrast material enhancement. Clinical outcome was related to the degree of brain damage consequent to meningitis and the chronicity of SDE. RSEs in seven infants (three with concurrent SDE) were anechoic; an inner membrane was seen in six, and increased pia-arachnoid echogenicity was seen in four. CONCLUSION: SDE has complex US features that are helpful for differentiation from anechoic RSE in infants with meningitis.     

Plasma leptin is directly related to body adiposity in subjects with spinal cord injury

We addressed the relationship between plasma leptin and body mass index in 48 able-bodied male controls and 34 male subjects with spinal cord injury, as well as the association between plasma leptin with body fat by dual energy x-ray absorptiometry in those with spinal cord injury. In subjects with spinal cord injury, the effect of an oral glucose tolerance test and the relationship of the serum lipid profile with plasma leptin levels were determined. Body mass index was not significantly different between the spinal cord injury and control groups. Plasma leptin was significantly higher in the group with spinal cord injury than in the control group (12.7 +/- 1.7 vs. 7.6 +/- 0.9 ng/ml, p < 0.005). A linear relationship was found between plasma leptin and body mass index in both groups separately (spinal cord injury: r = 0.59, p < 0.0002; control: r = 0.67, p < 0.0001). In those with SCI, a polynomial relationship was evident between plasma leptin and percent fat (r = 0.82, p < 0.0001). After an oral glucose load, plasma insulin levels and serum glucose concentrations were not related to plasma leptin levels. Serum triglycerides were found to be weakly correlated with plasma leptin levels (r = 0.35, p < 0.05). The higher plasma leptin levels in the group with spinal cord injury compared with the control group was probably due to a relatively increased percentage of adiposity in those with spinal cord injury.     

Second cancers after medulloblastoma: population-based results from the United States and Sweden

Medulloblastoma, one of the most common central nervous system (CNS) tumors in children, requires aggressive multimodality therapy including surgery, radiation therapy, and occasionally chemotherapy. Given its intensive treatment regimen and improved survival during the past 20 years, it is likely that a cohort of survivors will result who may incur consequences of therapy, including a second cancer. We used population-based data from the United States and Sweden to estimate risks of second neoplasms in patients with histologically confirmed medulloblastoma (n = 1,262). Overall, there was a 5.4-fold excess of second neoplasms (95 percent confidence interval = 3.3-8.4) based on 20 observed and 3.7 expected cancers. The second cancers occurred eight to 432 months after initial diagnosis (median, 73 months) with significantly elevated ratios for all intervals examined except for less than one year after initial diagnosis. Significantly elevated risks were seen for cancers of the salivary glands, cervix uteri, brain and CNS, thyroid gland, and acute lymphoblastic leukemia. Of the 15 second cancers with treatment data, seven occurred in the radiation field or within areas of scatter while two others may have been radiation-related. Although based on small numbers of second cancers, the results suggest that as survival increases, some patients with medulloblastoma will have an increased risk of a second cancer, particularly a radiation-related cancer. Thus, as survival improves, late-occurring consequences of diagnosis and treatment will need to be carefully assessed. Identification of patients hypersensitive to radiation therapy, such as those with Gorlin Syndrome, should also be attempted in order to reduce the sequelae from intensive radiation exposure.     

Factor structure of a measure of anxiety sensitivity in children

Anxiety sensitivity (i.e., the disposition to react to autonomic arousal with fear) has taken a central role in recent conceptualizations of anxiety. However, questions regarding the dimensional nature of anxiety sensitivity remain. In particular, the factor structure of anxiety sensitivity is unexplored in nonadult populations. The factor structure of the Anxiety Sensitivity Index for Children (ASIC) was examined in three studies. Study 1 (N = 95) used a sample of school children in Grades 4-8 to investigate the reliability of items and factor structure. Items with weak psychometric properties were eliminated, and subsequent analyses revealed that the ASIC was best viewed as a hierarchical scale with a higher order factor (Anxiety Sensitivity) and two first-order factors (Fear of Physiological Arousal and Fear of Mental Catastrophe). Study 2 (N = 112) and Study 3 (N = 144) used more distressed samples of youngsters, and they also found the ASIC to be a hierarchical scale. These findings add a developmental perspective to the Anxiety Sensitivity Index factor analytic discussion and are highly consistent with emergent thinking in the adult anxiety sensitivity literature.     

Vectorially oriented monolayers of the cytochrome c/cytochrome oxidase bimolecular complex

Vectorially oriented monolayers of yeast cytochrome c and its bimolecular complex with bovine heart cytochrome c oxidase have been formed by self-assembly from solution. Both quartz and Ge/Si multilayer substrates were chemical vapor deposited with an amine-terminated alkylsiloxane monolayer that was then reacted with a hetero-bifunctional cross-linking reagent, and the resulting maleimide endgroup surface then provided for covalent interactions with the naturally occurring single surface cysteine 102 of the yeast cytochrome c. The bimolecular complex was formed by further incubating these cytochrome c monolayers in detergent-solubilized cytochrome oxidase. The sequential formation of such monolayers and the vectorially oriented nature of the cytochrome oxidase was studied via meridional x-ray diffraction, which directly provided electron density profiles of the protein(s) along the axis normal to the substrate plane. The nature of these profiles is consistent with previous work performed on vectorially oriented monolayers of either cytochrome c or cytochrome oxidase alone. Furthermore, optical spectroscopy has indicated that the rate of binding of cytochrome oxidase to the cytochrome c monolayer is an order of magnitude faster than the binding of cytochrome oxidase to an amine-terminated surface that was meant to mimic the ring of lysine residues around the heme edge of cytochrome c, which are known to be involved in the binding of this protein to cytochrome oxidase.     

In vitro mutagenesis of the mitochondrial leucyl tRNA synthetase of Saccharomyces cerevisiae shows that the suppressor activity of the mutant proteins is related to the splicing function of the wild-type protein

The NAM2 gene of Saccharomyces cerevisiae encodes the mitochondrial leucyl tRNA synthetase (mLRS), which is necessary for the excision of the fourth intron of the mitochondrial cytb gene (bI4) and the fourth intron of the mitochondrial coxI gene (aI4), as well as for mitochondrial protein synthesis. Some dominant mutant alleles of the gene are able to suppress mutations that inactivate the bI4 maturase, which is essential for the excision of the introns aI4 and bI4. Here we report mutagenesis studies which focus on the splicing and suppressor functions of the protein. Small deletions in the C-terminal region of the protein preferentially reduce the splicing, but not the synthetase activity; and all the C-terminal deletions tested abolish the suppressor activity. Mutations which increase the volume of the residue at position 240 in the wild-type mLRS without introducing a charge, lead to a suppressor activity. The mutant 238C, which is located in the suppressor region, has a reduced synthetase activity and no detectable splicing activity. These data show that the splicing and suppressor functions are linked and that the suppressor activity of the mutant alleles results from a modification of the wild-type splicing activity.