The T1-weighted/T2-weighted ratio as a biomarker of anti-NMDA receptor encephalitis.

BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis rarely causes visible lesions in conventional MRI, yet advanced imaging detects extensive white matter damage. To improve prognostic capabilities, we evaluate the T1-weighted/T2-weighted (T1w/T2w) ratio, a measure of white matter integrity computable from clinical MRI sequences, in NMDAR encephalitis and examine its associations with cognitive impairment. METHODS: T1-weighted and T2-weighted MRI were acquired cross-sectionally at 3 Tesla in 53 patients with NMDAR encephalitis (81% women, mean age 29 years) and 53 matched healthy controls. Quantitative and voxel-wise group differences in T1w/T2w ratios and associations with clinical and neuropsychological outcomes were assessed. P-values were false discovery rate (FDR) adjusted where multiple tests were conducted. RESULTS: Patients with NMDAR encephalitis had significantly lower T1w/T2w ratios across normal appearing white matter (p=0.009, Hedges' g=-0.51), which was associated with worse verbal episodic memory performance (r=0.39, p=0.005, p(FDR)=0.026). White matter integrity loss was observed in the corticospinal tract, superior longitudinal fascicle, optic radiation and callosal body with medium to large effects (Cohen's d=[0.42-1.17]). In addition, patients showed decreased T1w/T2w ratios in the hippocampus (p=0.002, p(FDR)=0.005, Hedges' g=-0.62), amygdala (p=0.002, p(FDR)=0.005, Hedges' g=-0.63) and thalamus (p=0.010, p(FDR)=0.019, Hedges' g=-0.51). CONCLUSIONS: The T1w/T2w ratio detects microstructural changes in grey and white matter of patients with NMDAR encephalitis that correlate with cognitive performance. Computable from conventional clinical MRI sequences, this measure shows promise in bridging the clinico-radiological dissociation in NMDAR encephalitis and could serve as an imaging outcome measure in clinical trials.

A temporospatial histomorphometric analysis of bone density adjacent to acid-etched self-tapping dental implants with an external hexagon connection in the female baboon.

OBJECTIVE: To characterize osseointegration as the percent of bone-implant contact (%BIC) along the surface (0.0 mm) as well as at surface profiles 0.5 mm and 1.0 mm lateral to the implant, determining any differences between early occlusally loaded and non-loaded implants. MATERIAL AND METHODS: In ten adult female baboons, 120 dental implants were randomly placed in opposing mandibular and maxillary locations. Eighty sites had two groups of healing (no load) of either 1 (n = 40) or 2 (n = 40) months leading to 3 months of functional loading. These sites received full acid-etched surface implants. The 40 control implants represented healing only periods (no load) for 1 (n = 10), 2 (n = 10), 4 (n = 10), and 5 (n = 10) months. These implants were of a vertically split surface texture design (acid-etched and machined). Block sections and photomicrographs were obtained. Blinded histometric analyses determined the %BIC via a superimposed template. RESULTS: The unloaded groups (1, 2, and 4 months) had higher %BIC compared to the 5-month group (p < 0.0001). The loaded groups exhibited mean bone densities of 59.2% and 55.5% (1-month healing at 0.5 mm and 1.0 mm, respectively) and 61.0% and 57.1% (2-month healing at 0.5 mm and 1.0 mm, respectively) with no significant difference between healing time (p = 0.4118). CONCLUSION: There was a lateral increase in %BIC in the loaded compared to unloaded groups. CLINICAL RELEVANCE: The decrease in bone densities at the 5-month unloaded group suggests that there is a critical earlier time period when dental implants should be placed into functional load.

Hospital admissions in the Hunter Region from trees and other falling objects, 2008-2012.

OBJECTIVE: To assess the impact on hospital admissions produced by trees and other falling objects, to examine these accidents' circumstances, and to investigate the degree of support provided by the data for tree-related accident prevention. METHODS: Admissions to emergency departments in the Hunter Region for the period 2008-2012 allocated the International Classification of Disease 10 code W20 (struck by falling object) were analysed. RESULTS: Of 620 admissions, 125 files were incorrectly coded leaving an eligible sample of 495 W20 admissions. Males made up 79.4% of admissions. Where recorded, the commonest accident locations were workplaces (63.2%) and homes (31.5%). Trees/branches caused only 24 (4.8%) of such accidents with an age-adjusted admission rate of 0.28 per 10,000 people compared with 6.84 per 10,000 for all falling objects combined. Most tree-related admissions (at least 62.5%) occurred to persons actively interacting with the tree. Being male (p=0.04) and living in an outer regional area (p=0.001) increased the incidence of tree injuries. CONCLUSIONS: Hospital admissions caused by falling objects especially trees are uncommon. Implications for public health: It is difficult to justify any major health promotion expenditure to reduce tree-related accidents, given their especial rarity. Any funds allocated should focus on preventing falling object injuries in workplaces and homes.