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High school athletes who had suffered mild concussion demonstrated significant declines in memory processes relative to a noninjured control group. Statistically significant differences between preseason and postinjury memory test results were still evident in the concussion group at 4 and 7 days postinjury. Self-reported neurological symptoms such as headache, dizziness, and nausea resolved by Day 4. Duration of on-field mental status changes such as retrograde amnesia and posttraumatic confusion was related to the presence of memory impairment at 36 hours and 4 and 7 days postinjury and was also related to slower resolution of self-reported symptoms. The results of this study suggest that caution should be exercised in returning high school athletes to the playing field following concussion. On-field mental status changes appear to have prognostic utility and should be taken into account when making return-to-play decisions following concussion. Athletes who exhibit on-field mental status changes for more than 5 minutes have longer-lasting postconcussion symptoms and memory decline.

Stereotactic brain biopsy was associated with a low likelihood of postbiopsy hemorrhage. The risk of hemorrhage increased steadily as the platelet count fell below 150,000/mm3. The authors found a small but definable risk of delayed hemorrhage, despite unremarkable findings on an immediate postbiopsy head CT scan. This risk justifies an overnight hospital observation stay for all patients after having undergone stereotactic brain biopsy.

Findings suggest that any degree of postconcussion headache in high school athletes 7 days after injury is likely associated with an incomplete recovery after concussion.

This study is the first to suggest a cumulative effect of concussion in high school athletes. A more severe on-field presentation of concussion markers is evidenced in high school athletes with a pronounced history of concussion. This study's findings highlight the need for more long-term outcome studies in high school athletes who sustain sports-related concussions.

The differences among these groups can be used as a basis to argue that PTM characteristics triggered by sports-related concussion are related to increased neurocognitive dysfunction following mild traumatic brain injury. Thus, athletes suffering a concussion accompanied by PTM should be examined in a setting that includes symptom status and neurocognitive testing to address their recovery more fully. Given the increased impairments observed in the PTM group, in this population clinicians should exercise increased caution in decisions about treatment and when the athlete should be allowed to return to play.

FP21 is a glycoprotein which, when tracked by radioactivity in its fucosyl moiety, was previously detected in the cytosol of Dictyostelium cells after cell fractionation. This compartmentalization is confirmed by SDS-polyacrylamide gel electrophoresis/Western blotting of cell fractions using three different antibodies. Although a substantial fraction of FP21 is also detected in the particulate fraction using these new antibodies, particulate FP21 is released by disrupting protein-protein interactions, but not membrane disruption. Since purified FP21 is susceptible to aggregation, and purified nuclei do not contain FP21, particulate FP21 is also part of the cytosol. Additional compositional and structural information provides strong evidence that FP21 does not at any time traverse the rough endoplasmic reticulum. First, cDNAs spanning the entire coding region of the FP21 gene predict no hydrophobic motifs expected to promote membrane insertion, but do predict an NH2-terminal coiled coil domain which could explain aggregation. Second, monosaccharide composition analysis of the predominant glycoform of FP21 yields 2 mol of galactose, 1 mol of xylose, and 1 mol of fucose/mol of polypeptide; FP21 from a fucosylation-defective mutant contains 1 additional mol of xylose in place of fucose. Thus the N-glycosylation sequon present in FP21 is not utilized by oligosaccharyl transferase, which resides in the rough endoplasmic reticulum. These findings indicate that nascent FP21 remains in the cytosol after synthesis and is therefore glycosylated by unusual cytosolic xylosyl-, galactosyl-, and fucosyltransferases.

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