Ulnar artery aneurysm causing palmar mass in 5-month-old girl

A 5-month-old previously healthy girl presented to the emergency department with a large palpable nontender mass in the hypothenar soft tissues of her left hand. US revealed a well-demarcated nonvascular soft tissue mass. Subsequent MR imaging showed a rim-enhancing mass with heterogeneous intrinsic signal characteristics. Abscess and necrotic tumor were the primary considerations. Surgery demonstrated a thrombosed aneurysm continuous with the ulnar artery system. The aneurysm was resected and the ulnar artery was ligated at the wrist.     

C-fiber (Remak) bundles contain both isolectin B4-binding and calcitonin gene-related peptide-positive axons

Unmyelinated nerve fibers (Remak bundles) in the rodent sciatic nerve typically contain multiple axons. This study asked whether C-fiber bundles contain axons arising from more than one type of neuron. Most small neurons of the lumbar dorsal root ganglion (DRG) are either glial cell line-derived neurotrophic factor dependent or nerve growth factor dependent, binding either isolectin B4 (IB4) or antibodies to calcitonin gene-related peptide (CGRP), respectively. Injection of IB4-conjugated horseradish peroxidase into a lumbar DRG resulted in intense labeling of IB4 axons, with very low background. Visualized by confocal fluorescence, IB4-binding and CGRP-positive nerve fibers originating from different DRG neurons came together and remained closely parallel over long distances, suggesting that these two types of axon occupy the same Remak bundle. With double-labeling immunogold electron microscopy (EM), we confirmed that IB4 and CGRP axons were distinct and were found together in single Remak bundles. Previous studies indicate that some DRG neurons express both CGRP and IB4 binding. To ensure that our immunogold results were not a consequence of coexpression, we studied large populations of unmyelinated axons by using quantitative single-label EM. Tetramethylbenzidine, a chromogen with strong intrinsic signal amplification of IB4-horseradish peroxidase, labeled as many as 52% of unmyelinated axons in the dorsal root. Concomitantly, 97% of the Remak bundles with more than one axon contained at least one IB4-labeled axon. Probabilistic modeling using binomial distribution functions rejected the hypothesis that IB4 axons segregate into IB4-specific bundles (P < 0.00001). We conclude that most Remak bundle Schwann cells simultaneously support diverse axon types with different growth factor dependences.     

C-fiber structure varies with location in peripheral nerve

Recent advances in regeneration and pain research have revealed gaps in the understanding of normal C-fiber anatomy. In the rat PNS, C-fiber axons assemble into Remak bundles, but beyond this, features of C-fiber organization are not defined. Systematic sampling and quantitation reveals that Remak bundles exiting from the L5 dorsal root ganglion (DRG) contain large numbers of axons, for example, 56% of unmyelinated axons were in bundles of >20 axons. This is different from distal nerve segments such as the hindpaw plantar nerve where the median number of axons per bundle is 3. The cross-sectional area of unmyelinated axons in dorsal root was homogeneous near the DRG but variability in axonal area increased near the spinal cord (p = 0.00001) and the mean axonal area was unchanged. Unmyelinated axons in peripheral nerve were almost always isolated from one another by Schwann cell processes; however, in dorsal root 7% to 9% of unmyelinated axons were immediately adjacent within pockets containing 2 or more axons. Remak bundles in the distal peripheral nerve clustered with other Remak bundles. We observe that multiple unmyelinated axons are juxtaposed within the C-fiber/Remak bundle and that the close association of afferent axons may have important functional implications.     

A simultaneous liquid chromatography/mass spectrometric assay of glutathione,cysteine, homocysteine and their disulfides in biological samples

A liquid chromatography/mass spectrometric (LC/MS) method was developed for simultaneous detection and quantitation of glutathione (GSH), glutathione disulfide (GSSG), cysteine (CysSH), homocysteine (HCysSH) and homocystine in biological samples (rat brain, lung, liver, heart, kidneys, erythrocytes and plasma). Thiols were derivatized with a large excess of Ellman's reagent, a thiol-specific reagent, to ensure an instantaneous and complete derivatization. The derivatization blocked the oxidation of the thiols to disulfides, preventing errors caused by thiol oxidation. The samples were then analyzed by LC/MS. The method provides a highly selective and sensitive assay for these endogenous thiols and their corresponding disulfides. The detection limits for GSH, GSSG, CysSH, HCysSH and homocystine were 3.3, 3.3, 16.5, 29.6 and 14.9 pmol, respectively. An attempt for cystine analysis was unsuccessful due to earlier elution of the compound and strong interferences caused by other endogenous compounds. This method will be a useful tool in the investigation of the roles of these important thiol-containing compounds and their corresponding disulfides in physiological and pathological processes.     

Evaluating the “cushion effect” among children in frontal motor vehicle crashes

Background

The “Cushion Effect,” the phenomenon in which obesity protects against abdominal injury in adults in motor vehicle accidents, has not been evaluated among pediatric patients. This work evaluates the association between subcutaneous fat cross-sectional area, quantified using analytic morphomic techniques and abdominal injury.

Are resilience and perceived stress related to social support and housing stability among homeless adults with mental illness?

Perceived stress has been associated with adverse health outcomes. Although people experiencing homelessness often report multiple acute and chronic stressors, research on resilience and perceived stress on the general homeless population is limited. This longitudinal study examined homeless adults with mental illness who were part of a 24‐month trial of Housing First to explore: (a) changes in levels of resilience and perceived stress during the trial, and (b) the association between levels of resilience and perceived stress with measures of social support, social functioning and percentage of days stably housed over the study period. This longitudinal study (2009–2013) that used trial data included 575 participants in Toronto, Ontario. Of these individuals, 507 were included in this study. Connor‐Davidson Resilience Scale and Perceived Stress Scales (PSS) measured the two outcomes, resilience and perceived stress. Time (baseline, 12 and 24 months), housing stability and three measures of social support and social functioning were the main predictors. A longitudinal analysis was done with repeated measures analysis of resilience and perceived stress using linear mixed models with random intercepts. Mean resilience scores increased (baseline: 5.1 [95% CI: 4.9, 5.2], 12 months: 5.5 [95% CI: 5.3, 5.7], 24 months: 5.6 [95% CI: 5.4, 5.8]), and PSS scores decreased (baseline: 22.3 [95% CI: 21.5, 23.0], 24 months: 18.6 [95% CI: 17.9, 19.4]). In the multivariable analyses, increased resilience was associated with higher scores on the three social support and social functioning measures, (estimates = 0.12, 0.04, 0.02) but not percentage days stably housed. Lower PSS scores were associated with higher scores on all three social support and social functioning measures (?0.20, ?0.33, ?0.21) and higher percentages of days stably housed (?0.015). Strong social support and social functioning may minimise the harmful effects of stressful life events on homeless individuals by increasing resilience and reducing stress. Interventions to help homeless people build appropriate support networks should be delivered in parallel to efforts that increase housing stability.     

The relationship between young children’s language abilities,creativity, play,and storytelling

This study examined the connection between young children’s social play, creativity, storytelling, and language abilities. Participants were 56 primarily European American preschool children. First, to assess creativity we asked children to draw several pictures. Children created stories about their pictures during the creative process. Second, children created an original story with access to multiple ethnic family doll sets to use as props. We analysed all storytelling episodes for mean length of utterance and parts of speech. Third, we observed children’s social play behaviours over 10-minute intervals recording behaviour at 1-minute intervals. Finally, we administered the Test of Early Language Development 3 to assess children’s receptive and expressive language skills. Our findings revealed positive relationships between storytelling abilities and language abilities, relationships between type of play, storytelling, and language abilities, and connections between play and creativity and language and creativity. Our findings provide avenues for future research.