Sideline coverage of youth football

Youth football is a popular sport in the United States and has been for some time. There are currently more than 3 million participants in youth football leagues according to USA Football. While the number of participants and overall injuries may be higher in other sports, football has a higher rate of injuries. Most youth sporting events do not have medical personnel on the sidelines in event of an injury or emergency. Therefore it is necessary for youth sports coaches to undergo basic medical training in order to effectively act in these situations. In addition, an argument could be made that appropriate medical personnel should be on the sideline for collision sports at all levels, from youth to professional. This article will discuss issues pertinent to sideline coverage of youth football, including coaching education, sideline personnel, emergency action plans, age and size divisions, tackle versus flag football, and injury prevention.

Neuroimaging features of neurodegeneration with brain iron accumulation

NBIA characterizes a class of neurodegenerative diseases that feature a prominent extrapyramidal movement disorder, intellectual deterioration, and a characteristic deposition of iron in the basal ganglia. The diagnosis of NBIA is made on the basis of the combination of representative clinical features along with MR imaging evidence of iron accumulation. In many cases, confirmatory molecular genetic testing is now available as well. A number of new subtypes of NBIA have recently been described, with distinct neuroradiologic and clinical features. This article outlines the known subtypes of NBIA, delineates their clinical and radiographic features, and suggests an algorithm for evaluation.

One-year surveillance of methicillin-resistant Staphylococcus aureus nasal colonization and skin and soft tissue infections in collegiate athletes

OBJECTIVE

To determine the frequency and clinical importance of methicillin-resistant Staphylococcus aureus (MRSA) colonization in student athletes.

DESIGN

Prospective observational cohort study.

SETTING

A major university in the southeastern United States.

PARTICIPANTS

Student athletes participating in the men's football and women's lacrosse programs (N = 126). Main Exposure Monthly assessment of S aureus nasal colonization.

MAIN OUTCOME MEASURES

Trends in S aureus colonization over time and the occurrence of skin and soft tissue infections.

RESULTS

Methicillin-resistant S aureus nasal colonization varied significantly through the athletic season (4%-23%), peaking during times of highest athletic activity. This increase in colonization was not associated with the development of an outbreak of skin and soft tissue infections, and no single MRSA clone emerged as a dominant isolate.

CONCLUSIONS

During the athletic season, there is a considerable burden of MRSA colonization in student athletes; however, colonization alone appears to be insufficient to trigger an outbreak of staphylococcal infections. A combination of distinct molecular characteristics in the organism and specific host factors may govern the development of staphylococcal disease.

An experimental investigation on aspects of infectious salmon anaemia virus (ISAV) infection dynamics in seawater Atlantic salmon, Salmo salar L

This study investigated infection dynamics of infectious salmon anaemia virus (ISAV) by conducting two experiments to examine minimum infective dose and viral shedding of ISAV. In terms of minimum infective dose, the high variability between replicate tanks and the relatively slow spread of infection through the population at 1 x 10(1) TCID(50) mL(-1) indicated this dose is approaching the minimum infective dose for ISAV in seawater salmon populations. A novel qPCR assay incorporating an influenza virus control standard with each seawater sample was developed that enabled the quantity of ISAV shed from infected populations to be estimated in values equivalent to viral titres. Viral shedding was first detected at 7 days post-challenge (5.8 x 10(-2) TCID(50) mL(-1)kg(-1)) and rose to levels above the minimum infective dose (4.2 x 10(1) TCID(50) mL(-1)kg(-1)) on day 11 post-challenge, 2 days before mortalities in ISAV inoculated fish started. These results clearly demonstrate that a large viral shedding event occurs before death. Viral titres peaked at 7.0 x 10(1) TCID(50) mL(-1)kg(-1) 15 days post-infection. These data provide important information relevant to the management of ISA.

DTI-based muscle fiber tracking of the quadriceps mechanism in lateral patellar dislocation

PURPOSE

To determine the feasibility of using diffusion tensor MRI (DT-MRI) -based muscle fiber tracking to create biomechanical models of the quadriceps mechanism in healthy subjects and those with chronic lateral patellar dislocation (LPD).

MATERIALS AND METHODS

Four healthy (average 14.5 years old; BMI 21.8) and four chronic LPD (average 17.3 years old; BMI 22.4) females underwent DT and axial T1W MRI of the thighs. The anatomical and physiologic cross-sectional areas (ACSA and PCSA, respectively) and pennation angle were calculated of the vastus lateralis oblique (VLO) and vastus medialis oblique (VMO) muscles. The predicted resultant force vector on the patella was calculated.

RESULTS

The VLO pennation angles in healthy and LPD subjects were 18.7 and 14.5 degrees, respectively (P=0.141). The VMO pennation angles in healthy and LPD subjects were 11.4 and 14.8 degrees, respectively (P=0.02). The ACSA and PCSA VLO:VMO ratios in healthy and LPD subjects were 1.9:1.6 and 2.1:1.6, respectively (P=0.025 and 0.202, respectively). Regardless of whether ACSA or PCSA was used to predict resultant lateral force vectors, the values differed between healthy and LPD subjects (approximately 2 and approximately 5.3 degrees, respectively; P<0.05).

CONCLUSION

Chronic LPD patients had more laterally directed predicted resultant force vectors than healthy subjects. Our preliminary results suggest that biomechanical models of the quadriceps mechanism in patients with chronic LPD and healthy subjects can be created in healthy subjects and patients with chronic LPD using DT-MRI.

Estimation of infectious dose and viral shedding rates for infectious pancreatic necrosis virus in Atlantic salmon, Salmo salar L., post-smolts

Infectious dose and shedding rates are important parameters to estimate in order to understand the transmission of infectious pancreatic necrosis virus (IPNV). Bath challenge of Atlantic salmon post-smolts was selected as the route of experimental infection as this mimics a major natural route of exposure to IPNV infection. Doses ranging from 10(2) to 10(-4) 50% end-point tissue culture infectious dose (TCID(50)) mL(-1) sea water were used to estimate the minimum infectious dose for a Scottish isolate of IPNV. The minimum dose required to induce infection in Atlantic salmon post-smolts was <10(-1) TCID(50) mL(-1) by bath immersion (4 h at 10 degrees C). The peak shedding rate for IPNV following intraperitoneal challenge using post-smolts was estimated to be 6.8 x 10(3) TCID(50) h(-1) kg(-1) and occurred 11 days post-challenge. This information may be incorporated into mathematical models to increase the understanding of the dispersal of IPNV from marine salmon sites.

Clinical and genetic delineation of neurodegeneration with brain iron accumulation

Neurodegeneration with brain iron accumulation (NBIA) describes a group of progressive neurodegenerative disorders characterised by high brain iron and the presence of axonal spheroids, usually limited to the central nervous system. Mutations in the PANK2 gene account for the majority of NBIA cases and cause an autosomal recessive inborn error of coenzyme A metabolism called pantothenate kinase associated neurodegeneration (PKAN). More recently, it was found that mutations in the PLA2G6 gene cause both infantile neuroaxonal dystrophy (INAD) and, more rarely, an atypical neuroaxonal dystrophy that overlaps clinically with other forms of NBIA. High brain iron is also present in a portion of these cases. Clinical assessment, neuroimaging, and molecular genetic testing all play a role in guiding the diagnostic evaluation and treatment of NBIA.

Neurodegeneration associated with genetic defects in phospholipase A(2)

OBJECTIVE

Mutations in the gene encoding phospholipase A(2) group VI (PLA2G6) are associated with two childhood neurologic disorders: infantile neuroaxonal dystrophy (INAD) and idiopathic neurodegeneration with brain iron accumulation (NBIA). INAD is a severe progressive psychomotor disorder in which axonal spheroids are found in brain, spinal cord, and peripheral nerves. High globus pallidus iron is an inconsistent feature of INAD; however, it is a diagnostic criterion of NBIA, which describes a clinically and genetically heterogeneous group of disorders that share this hallmark feature. We sought to delineate the clinical, radiographic, pathologic, and genetic features of disease resulting from defective phospholipase A(2).

METHODS

We identified 56 patients clinically diagnosed with INAD and 23 with idiopathic NBIA and screened their DNA for PLA2G6 mutations.

RESULTS

Eighty percent of patients with INAD had mutations in PLA2G6, whereas mutations were found in only 20% of those with idiopathic NBIA. All patients with two null mutations had a more severe phenotype. On MRI, nearly all mutation-positive patients had cerebellar atrophy, and half showed brain iron accumulation. We observed Lewy bodies and neurofibrillary tangles in association with PLA2G6 mutations.

CONCLUSION

Defects in phospholipase A(2) lead to a range of phenotypes. PLA2G6 mutations are associated with nearly all cases of classic infantile neuroaxonal dystrophy but a minority of cases of idiopathic neurodegeneration with brain iron accumulation, and genotype correlates with phenotype. Cerebellar atrophy predicts which patients are likely to be mutation-positive. The neuropathologic changes that are caused by defective phospholipase A(2) suggest a shared pathogenesis with both Parkinson and Alzheimer diseases.

T2* and FSE MRI distinguishes four subtypes of neurodegeneration with brain iron accumulation

BACKGROUND

Neurodegeneration with brain iron accumulation (NBIA) defines a group of genetic disorders characterized by brain iron deposition and associated with neuronal death. The known causes of NBIA include pantothenate kinase-associated neurodegeneration (PKAN), neuroferritinopathy, infantile neuroaxonal dystrophy (INAD), and aceruloplasminemia.

OBJECTIVE

To define the radiologic features of each NBIA subtype.

METHODS

Brain MRIs from patients with molecularly confirmed PKAN (26 cases), neuroferritinopathy (21 cases), INAD (four cases), and aceruloplasminemia (10 cases) were analyzed blindly to delineate patterns of iron deposition and neurodegeneration.

RESULTS

In most cases of PKAN, abnormalities were restricted to globus pallidus and substantia nigra, with 100% having an eye of the tiger sign. In a minority of PKAN cases there was hypointensity of the dentate nuclei (1/5 on T2* sequences, 2/26 on fast spin echo [FSE]). In INAD, globus pallidus and substantia nigra were involved on T2* and FSE scans, with dentate involvement only seen on T2*. By contrast, neuroferritinopathy had consistent involvement of the dentate nuclei, globus pallidus, and putamen, with confluent areas of hyperintensity due to probable cavitation, involving the pallida and putamen in 52%, and a subset having lesions in caudate nuclei and thalami. More uniform involvement of all basal ganglia and the thalami was typical in aceruloplasminemia, but without cavitation.

CONCLUSIONS

In the majority of cases, different subtypes of neurodegeneration associated with brain iron accumulation can be reliably distinguished with T2* and T2 fast spin echo brain MRI, leading to accurate clinical and subsequent molecular diagnosis.

Distribution of infectious pancreatic necrosis virus (IPNV) in wild marine fish from Scottish waters with respect to clinically infected aquaculture sites producing Atlantic salmon, Salmo salar L

This study represents the first large-scale investigation of IPNV in Scottish wild marine fish. Kidney samples were taken from 30 627 fish comprising 37 species and 45 isolations were made from nine different species, illustrating these as reservoirs of IPNV in Scottish waters. The estimated prevalence of IPNV in the Scottish marine environment was low at 0.15% (90% confidence intervals, (CI) of 0.11-0.19%). This was significantly greater in fish caught less than 5.0 km from IPN-positive fish farms in Shetland, at 0.58% (90% CI of 0.45-0.77%). This prevalence persisted and did not significantly decrease over the 16-month period of study. The estimated prevalence of IPNV for each positive species was less than 1% with the statistically non-significant exceptions of flounder, Platichthys flesus (L.), at 12.5% (90% CI of 0.64-47.06%) and saithe, Pollachius virens (L.), at 1.11% (90% CI of 0.49-2.19%). The 45 isolates were titrated and all but two were below the detection limit of the test (<55 PFU g(-1)). Titres of 3.8 x 10(2) PFU g(-1) and 2.8 x 10(1) PFU g(-1) were calculated from common dab, Limanda limanda (L.), and saithe, respectively. This study provides evidence that clinical outbreaks of IPN in farmed Atlantic salmon may cause a localized small increase in the prevalence of IPNV in wild marine fish.

Genetic analysis of infectious pancreatic necrosis virus from Scotland

Infectious pancreatic necrosis (IPN) is a highly contagious disease of young salmonid fish, and is one of the most serious economic diseases in aquaculture. In Scotland, an increase in IPN virus (IPNV) outbreaks in seawater Atlantic salmon, Salmo salar, has been reported in recent years. The aim of this study was to analyse the VP2 gene from recent IPNV isolates from Scotland, to determine whether there are epidemiological links between IPNV isolates from farms (13), wild fish (17) and the environment (6) in order to investigate potential wild and farmed fish interactions. Comparison of the nucleotide sequence of the VP2 gene revealed that 34 of 36 isolates were 97.1-100% similar and the deduced amino acid sequences showed 97-100% identity. Two isolates from wild fish exhibited the most divergence at 85-87.3% similarity to the other isolates at the nucleotide level and 88.2-90.8% identity at the deduced amino acid level. Phylogenetic analyses revealed that 34 of 36 of the isolates from Scotland were genetically closely related to the A2 (Sp) serotype of IPNV. The two wild isolates from seatrout, Salmo trutta, and flounder, Platichthys flesus, were most closely related to the European A5 (Te) serotype. This study represents a comprehensive IPNV phylogenetic study that indicates that there are closely related or identical isolates in circulation in the marine environment, which adds evidence that disease interactions between wild and farmed fish may occur. This type of analysis is a useful tool in the management and control of fish diseases because it can assist in the identification of epidemiological links and highlight potential risks to aquaculture.