The Impact of Intracranial Tumor Proximity to White Matter Tracts on Morbidity and Mortality: A Retrospective Diffusion Tensor Imaging Study.

Background: Using diffusion tensor imaging (DTI) in neurosurgical planning allows identification of white matter tracts and has been associated with a reduction in postoperative functional deficits. Objective: This study explores the relationship between the lesion-to-tract distance (LTD) and postoperative morbidity and mortality in patients with brain tumors in order to evaluate the role of DTI in predicting postoperative outcomes. Methods: Adult patients with brain tumors (n = 60) underwent preoperative DTI. Three major white matter pathways (superior longitudinal fasciculi [SLF], cingulum, and corticospinal tract) were identified using DTI images, and the shortest LTD was measured for each tract. Postoperative morbidity and mortality information was collected from electronic medical records. Results: The ipsilesional corticospinal tract LTD and left SLF LTD were significantly associated with the occurrence rate of total postoperative motor (P = .018) and language (P < .001) deficits, respectively. The left SLF LTD was also significantly associated with the occurrence rate of new postoperative language deficits (P = .003), and the LTD threshold that best predicted this occurrence was 1 cm (P < .001). Kaplan­Meier log-rank survival analyses in patients having high-grade tumors demonstrated a significantly higher mortality for patients with a left SLF LTD <1 cm (P = .01). Conclusion: Measuring tumor proximity to major white matter tracts using DTI can inform clinicians of the likelihood of postoperative functional deficits. A distance of 1 cm or less from eloquent white matter structures most significantly predicts the occurrence of new deficits with current surgical and imaging techniques.

Drosophila TDP-43 dysfunction in glia and muscle cells cause cytological and behavioural phenotypes that characterize ALS and FTLD.

Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are neurodegenerative disorders that are characterized by cytoplasmic aggregates and nuclear clearance of TAR DNA-binding protein 43 (TDP-43). Studies in Drosophila, zebrafish and mouse demonstrate that the neuronal dysfunction of TDP-43 is causally related to disease formation. However, TDP-43 aggregates are also observed in glia and muscle cells, which are equally affected in ALS and FTLD; yet, it is unclear whether glia- or muscle-specific dysfunction of TDP-43 contributes to pathogenesis. Here, we show that similar to its human homologue, Drosophila TDP-43, Tar DNA-binding protein homologue (TBPH), is expressed in glia and muscle cells. Muscle-specific knockdown of TBPH causes age-related motor abnormalities, whereas muscle-specific gain of function leads to sarcoplasmic aggregates and nuclear TBPH depletion, which is accompanied by behavioural deficits and premature lethality. TBPH dysfunction in glia cells causes age-related motor deficits and premature lethality. In addition, both loss and gain of Drosophila TDP-43 alter mRNA expression levels of the glutamate transporters Excitatory amino acid transporter 1 (EAAT1) and EAAT2. Taken together, our results demonstrate that both loss and gain of TDP-43 function in muscle and glial cells can lead to cytological and behavioural phenotypes in Drosophila that also characterize ALS and FTLD and identify the glutamate transporters EAAT1/2 as potential direct targets of TDP-43 function. These findings suggest that together with neuronal pathology, glial- and muscle-specific TDP-43 dysfunction may directly contribute to the aetiology and progression of TDP-43-related ALS and FTLD.

Prevalence and characteristics of choroidal nevi: the multi-ethnic study of atherosclerosis.

OBJECTIVE: To describe the prevalence of choroidal nevi in 4 racial or ethnic groups (white, black, Hispanic, and Chinese) in the United States. DESIGN: Cross-sectional study. PARTICIPANTS: Participants of the second examination of the Multi-Ethnic Study of Atherosclerosis (MESA), involving 6176 persons 44 to 84 years of age without clinical cardiovascular disease at baseline selected from 6 United States communities. METHODS: Fundus images were taken using a 45° digital camera through dark-adapted pupils and were graded for choroidal nevi using the modified Wisconsin Age-Related Maculopathy Grading System and the Blue Mountains Eye Study protocol. MAIN OUTCOME MEASURES: Choroidal nevi. RESULTS: The overall prevalence of choroidal nevi in the whole cohort was 2.1%, with prevalences higher in whites (4.1%) than blacks (0.7%), Hispanics (1.2%), and Chinese (0.4%; P<0.001 for any differences among groups). The lowest prevalence of choroidal nevi occurred in those 75 to 84 years of age. The nevi were subfoveal in 4% of eyes with nevi and were not associated with a decrease in visual acuity. Characteristics of the nevi (size, shape, location, color, drusen on surface) did not differ among racial or ethnic groups. With the exception of associations with higher C-reactive protein levels (odds ratio [OR] per mg/dl on the logarithmic scale, 1.23; 95% confidence interval [CI], 1.06-1.43; P = 0.01) and lower systolic blood pressure (OR per 10 mmHg, 0.90; 95% CI, 0.82-0.99; P = 0.04), choroidal nevi were not associated with other potential risk factors (e.g., gender, smoking status, alcohol consumption, lipid levels, coagulation factors, or kidney disease). CONCLUSIONS: Low prevalences of choroidal nevi were found in the 4 groups participating in the MESA cohort, with whites having higher prevalence than the other racial or ethnic groups. The higher prevalence in whites than in other groups was not explained by any of the factors studied. When choroidal nevi were present, their characteristics did not differ among racial or ethnic groups. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.