Modelling human pathology of traumatic brain injury in animal models.

Traumatic brain injury (TBI) is caused by a head impact with a force exceeding regular exposure from normal body movement which the brain normally can accommodate. People affected include, but are not restricted to, sport athletes in American football, ice hockey, boxing as well as military personnel. Both single and repetitive exposures may affect the brain acutely and can lead to chronic neurodegenerative changes including chronic traumatic encephalopathy associated with the development of dementia. The changes in the brain following TBI include neuroinflammation, white matter lesions, and axonal damage as well as hyperphosphorylation and aggregation of tau protein. Even though the human brain gross anatomy is different from rodents implicating different energy transfer upon impact, especially rotational forces, animal models of TBI are important tools to investigate the changes that occur upon TBI at molecular and cellular levels. Importantly, such models may help to increase the knowledge of how the pathologies develop, including the spreading of tau pathologies, and how to diagnose the severity of the TBI in the clinic. In addition, animal models are helpful in the development of novel biomarkers and can also be used to test potential disease-modifying compounds in a preclinical setting.

A quantitative study of tau pathology in 11 cases of chronic traumatic encephalopathy.

AIMS: To quantify tau pathology of chronic traumatic encephalopathy (CTE) and investigate influence of dot-like lesions (DL), brain region, comorbidity and sporting career length. METHODS: Densities of neurofibrillary tangles (NFT), astrocytic tangles (AT), DL, oligodendroglial inclusions (GI), neuropil threads (NT), vacuoles, neurons and enlarged neurons (EN) were measured in tau-immunoreactive sections of upper cortical laminae of frontal and temporal lobes, hippocampus (HC), amygdala and substantia nigra (SN) in 11 cases of CTE. RESULTS: DL were a consistent finding in CTE. Densities of NFT, NT and DL were greatest in sectors CA1 and CA2 of the HC. Densities of AT were lower than NFT, small numbers of GI were recorded in temporal lobe and low densities of vacuoles and EN were consistently present. ß-Amyloid-containing neuritic plaques (NP) also occurred at low density. Densities of NFT, NT, DL and AT were greater in sulci than gyri, while vacuole density was greater in gyri. Principal components analysis (PCA) suggested that sporting career length and densities of NFT in entorhinal cortex, NT in CA2 and SN and vacuolation in the DG were significant sources of variation among cases. CONCLUSION: DL are frequent in CTE suggesting affinity with argyrophilic grain disease (AGD) and Parkinson's disease dementia (PD-Dem). Densities of AT in all regions and NT/DL in sectors CA2/4 were consistent features of CTE. The 11 cases are neuropathologically heterogeneous which may result from genetic diversity, and variation in anatomical pathways subjected to trauma.

Relapsing Guillain Barré Syndrome and nephrotic syndrome secondary to focal segmental glomerulosclerosis.

A 49-year-old man developed simultaneously a Guillain Barré Syndrome (GBS) and a nephrotic syndrome (NS). The patient relapsed twice, despite treatment with intravenous immunoglobulins (IVIg) after a full or partial recovery, and became resistant to IVIg. Renal biopsy revealed focal segmental glomerulosclerosis (FSGS). He responded to plasmapheresis and corticosteroids with simultaneous recovery of his GBS and NS, suggesting a common pathogenesis of the two conditions.

Effect of 6-fluoro-m-tyrosine on dopamine release and metabolism in rat striatum using in vivo microdialysis.

6-[(18)F]Fluoro-m-tyrosine (FMT) is a positron emission tomography (PET) imaging agent for the aromatic L-amino acid decarboxylase enzyme. Its parent compound, L-m-tyrosine (LMT) induces behavioral effects in rodents via dopamine release. To assess the potential pharmacologic effect of FMT, its role in dopamine release and metabolism in rat striatum was compared with LMT and L-DOPA using in vivo microdialysis. Results indicate that FMT will not have the same dopamine-induced behavioral effects as LMT.