White Matter Changes Related to Subconcussive Impact Frequency during a Single Season of High School Football

BACKGROUND AND PURPOSE

The effect of exposing the developing brain of a high school football player to subconcussive impacts during a single season is unknown. The purpose of this pilot study was to use diffusion tensor imaging to assess white matter changes during a single high school football season, and to correlate these changes with impacts measured by helmet accelerometer data and neurocognitive test scores collected during the same period.

MATERIALS AND METHODS

Seventeen male athletes (mean age, 16 ± 0.73 years) underwent MR imaging before and after the season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis.

RESULTS

The mean number of impacts over a 10-g threshold sustained was 414 ± 291. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant (P < .05, corrected) decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The effects were strongest in the fornix-stria terminalis, where decreases in fractional anisotropy correlated with worsening visual memory.

CONCLUSIONS

Our findings suggest that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level.

Multidisciplinary retroperitoneal and pelvic soft-tissue sarcoma case conferences: the added value that radiologists can provide

Clinical Vignette: A 50-year-old woman presents to the emergency department with increasing abdominal pain. Abdominal computed tomography imaging reveals an expanded inferior vena cava-filling defect that is suspicious for a retroperitoneal sarcoma, possibly a primary leiomyosarcoma of the inferior vena cava. The surgery team discusses the case with the radiologist, and all agree that there are multiple challenges with obtaining a tissue diagnosis and determining resectability. Thus, it is decided that this patient should be discussed at a multidisciplinary case conference. In the present article, we feature a case-based scenario focusing on the role of the radiologist in this type of multidisciplinary team.

Population Genomics of the Euryhaline Teleost Poecilia latipinna

Global climate change and increases in sea levels will affect coastal marine communities. The conservation of these ecologically important areas will be a challenge because of their wide geographic distribution, ecological diversity and species richness. To address this problem, we need to better understand how the genetic variation of the species in these communities is distributed within local populations, among populations and between distant regions. In this study we apply genotyping by sequencing (GBS) and examine 955 SNPs to determine Sailfin molly (Poecilia latipinna) genetic diversity among three geographically close mangrove salt marsh flats in the Florida Keys compared to populations in southern and northern Florida. The questions we are asking are whether there is sufficient genetic variation among isolated estuarine fish within populations and whether there are significant divergences among populations. Additionally, we want to know if GBS approaches agree with previous studies using more traditional molecular approaches. We are able to identify large genetic diversity within each saltmarsh community (π ≈ 36%). Additionally, among the Florida Key populations and the mainland or between southern and northern Florida regions, there are significant differences in allele frequencies seen in population structure and evolutionary relationships among individuals. Surprisingly, even though the cumulative F_ST value using all 955 SNPs within the three Florida Key populations is small, there are 29 loci with significant F_ST values, and 11 of these were outliers suggestive of adaptive divergence. These data suggest that among the salt marsh flats surveyed here, there is significant genetic diversity within each population and small but significant differences among populations. Much of the genetic variation within and among populations found here with GBS is very similar to previous studies using allozymes and microsatellites. However, the meaningful difference between GBS and these previous measures of genetic diversity is the number of loci examined, which allows more precise delineations of population structure as well as facilitates identifying loci with excessive F_ST values that could indicate adaptive divergence.

Cannabis intoxication in three Green iguanas (Iguana iguana)

This report describes clinical signs and plasma biochemical changes associated with significant cannabis consumption in three Green iguanas (Iguana iguana) which resulted in seizures, cardiovascular and digestive tract aberrations, elevated hepatic enzymes and bile acid concentrations for a number of weeks post recovery. One case required extensive antiseizuring therapy to recover. All Green iguanas eventually made a full recovery.

Epidermolysis bullosa in calves in the United Kingdom

Epidermolysis bullosa (EB) was diagnosed in eight calves from four farms in the United Kingdom on the basis of clinical, histological and ultrastructural findings. In three affected herds, pedigree Simmental bulls had been mated with Simmental-cross cows. In a fourth herd two Holstein-Friesian calves were affected. Lesions included multifocal erosion and ulceration of the hard and soft palates, tongue, nares and gingiva, with onychomadesis (dysungulation). There was alopecia, erosion and crusting of the coronets, pasterns, fetlocks, carpi, hocks, flanks and axillae. Histopathological findings included segmental separation of full thickness epidermis from the dermis, with formation of large clefts containing eosinophilic fluid, extravasated red blood cells and small numbers of neutrophils. Follicular and interfollicular areas of skin were affected, with clefts extending around hair follicles and sometimes involving whole follicles. Ultrastructurally, there was evidence of vacuolar change within basal keratinocytes, corresponding to areas of histological clefting. Preliminary genetic screening of the candidate keratin genes (bKRT5 and bKRT14) has excluded mutations of these as the cause of this condition.

Examination of serum total IgG1 concentration in atopic and non-atopic dogs

In this study, serum immunoglobulin G1 (IgG1) concentrations were examined in atopic and non-atopic dogs receiving different levels of parasite control. Significantly lower serum total IgG1 concentrations were found in non-atopic dogs receiving stringent parasite control than in atopic dogs or non-atopic dogs receiving less stringent parasite control. Examination of serum total IgG1 concentrations of atopic dogs after six months of allergen specific immunotherapy (ASIT) showed a significant increase in serum total IgG1 concentrations. It is proposed that serum total IgG1 concentrations are affected by parasitism, atopic dermatitis and ASIT.

Studies of serum total immunoglobulin E concentrations in atopic and non-atopic dogs

The serum total immunoglobulin E (IgE) concentrations of two groups of atopic dogs and three groups of non-atopic dogs were compared. There was a wide range of concentrations with a high degree of overlap between the groups. The serum total IgE concentrations of a group of 15 non-atopic racing greyhounds were significantly higher than those of all the other groups. Atopic and non-atopic dogs receiving stringent parasite control treatments could not be differentiated on the basis of their serum total IgE concentrations. In the non-atopic dogs there was no correlation between their serum total IgE concentrations and the number of allergen-specific positive results obtained in an ELISA, or between their serum total IgE concentrations and their age.