Chronic traumatic encephalopathy (CTE) is reported at high prevalence in selected autopsy case series of former contact sports athletes. Nevertheless, the contribution of CTE pathology to clinical ...presentation and its interaction with co-morbid neurodegenerative pathologies remain unclear. To address these issues, we performed comprehensive neuropathology assessments on the brains of former athletes with dementia and considered these findings together with detailed clinical histories to derive an integrated clinicopathological diagnosis for each case. Consecutive, autopsy-acquired brains from former soccer and rugby players with dementia were assessed for neurodegenerative pathologies using established and preliminary consensus protocols. Thereafter, next of kin interviews were conducted to obtain detailed accounts of the patient’s clinical presentation and course of disease to inform a final, integrated clinicopathological diagnosis. Neuropathologic change consistent with CTE (CTE-NC) was confirmed in five of seven former soccer and three of four former rugby players’ brains, invariably in combination with mixed, often multiple neurodegenerative pathologies. However, in just three cases was the integrated dementia diagnosis consistent with CTE, the remainder having alternate diagnoses, with the most frequent integrated diagnosis Alzheimer’s disease (AD) (four cases; one as mixed AD and vascular dementia). This consecutive autopsy series identifies neuropathologic change consistent with preliminary diagnostic criteria for CTE (CTE-NC) in a high proportion of former soccer and rugby players dying with dementia. However, in the majority, CTE-NC appears as a co-morbidity rather than the primary, dementia causing pathology. As such, we suggest that while CTE-NC might be common in former athletes with dementia, in many cases its clinical significance remains uncertain.
The purpose of this study was twofold: (1) to determine the effect of increasing the duration of the workbout at each power output during the physical working capacity at fatigue threshold (PWC
FT
) ...test from 2 to 3 or 4 min, and (2) to examine the time to exhaustion during continuous workbouts at the PWC
FT
. Twelve adult males (χ¯± SD = 22.4 ± 3.0 years) volunteered to perform three PWC
FT
tests using workbout durations of 2, 3, and 4 min. Following the determination of the PWC
FT
values, nine of the subjects performed continuous workbouts at PWC
FT2
and PWC
FT4
for as long as possible. The mean PWC
FT
value using 4-min workbouts (PWC
FT4
= 168.8 ± 45.1 W) was significantly less (p<0.05, 19 1%) than that using 2-min workbouts (PWC
FT2
= 208.9 ± 59.0W). However, only two subjects were able to complete 60 min at PWC
FT4
and none of the subjects were able to complete 60min at PWC
FT2
. Therefore, although increasing the duration of the workbout at each power output resulted in a lower PWC
FT4
, these findings do not support a recommendation for a change in the PWC
FT
test protocol.
There have been few studies of abdominal imaging screening of individuals at high risk for pancreatic cancer (based on family history or genetic variants). We performed a meta-analysis of prospective ...cohort studies to determine the diagnostic yield and outcomes of abdominal imaging screening for asymptomatic individuals at high risk.
Through a systematic review of multiple electronic databases and conference proceedings through July 2017, we identified prospective cohort studies (>20 patients) of asymptomatic adults determined to be at high-risk of pancreatic cancer (lifetime risk >5%, including specific genetic-associated conditions) who were screened by endoscopic ultrasound (EUS) and/or magnetic resonance imaging (MRI) to detect pancreatic lesions. Our primary outcome was identification of high-risk pancreatic lesions (high-grade pancreatic intraepithelial neoplasia, high-grade dysplasia, or adenocarcinoma) at initial screening, and overall incidence during follow up. Summary estimates were reported as incidence rates per 100 patient-years.
We identified 19 studies comprising 7085 individuals at high risk for pancreatic cancer; of these, 1660 patients were evaluated by EUS and/or MRI. Fifty-nine high-risk lesions were identified (43 adenocarcinomas: 28 during the initial exam and 15 during follow-up surveillance) and 257 patients underwent pancreatic surgery. Based on our meta-analysis, the overall diagnostic yield screening for high-risk pancreatic lesions was 0.74 (95% CI, 0.33-1.14), with moderate heterogeneity among studies. The number needed to screen to identify 1 patient with a high-risk lesion was 135 (95% CI, 88-303). The diagnostic yield was similar for patients with different genetic features that increased risk, and whether patients were screened by EUS or MRI.
Based on meta-analysis, 135 patients at high-risk for pancreatic cancer must be screened to identify 1 patient with a high-risk pancreatic lesion. Further studies are needed to determine whether screening reduces mortality and is cost effectiveness for individuals at high-risk of pancreatic cancer.
The CABANA (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation) trial randomized 2,204 patients with atrial fibrillation (AF) to catheter ablation or drug therapy. Analysis ...by intention-to-treat showed a nonsignificant 14% relative reduction in the primary outcome of death, disabling stroke, serious bleeding, or cardiac arrest.
The purpose of this study was to assess recurrence of AF in the CABANA trial.
The authors prospectively studied CABANA patients using a proprietary electrocardiogram recording monitor for symptom-activated and 24-h AF auto detection. The AF recurrence endpoint was any post–90-day blanking atrial tachyarrhythmias lasting 30 s or longer. Biannual 96-h Holter monitoring was used to assess AF burden. Patients who used the CABANA monitors and provided 90-day post-blanking recordings qualified for this analysis (n = 1,240; 56% of CABANA population). Treatment comparisons were performed using a modified intention-to-treat approach.
Median age of the 1,240 patients was 68 years, 34.4% were women, and AF was paroxysmal in 43.0%. Over 60 months of follow-up, first recurrence of any symptomatic or asymptomatic AF (hazard ratio: 0.52; 95% confidence interval: 0.45 to 0.60; p < 0.001) or first symptomatic-only AF (hazard ratio: 0.49; 95% confidence interval: 0.39 to 0.61; p < 0.001) were both significantly reduced in the catheter ablation group. Baseline Holter AF burden in both treatment groups was 48%. At 12 months, AF burden in ablation patients averaged 6.3%, and in drug-therapy patients, 14.4%. AF burden was significantly less in catheter ablation compared with drug-therapy patients across the 5-year follow-up (p < 0.001). These findings were not sensitive to the baseline pattern of AF.
Catheter ablation was effective in reducing recurrence of any AF by 48% and symptomatic AF by 51% compared with drug therapy over 5 years of follow-up. Furthermore, AF burden was also significantly reduced in catheter ablation patients, regardless of their baseline AF type. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial CABANA; NCT00911508)
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Abstract
In Alzheimer’s disease (AD), neurodegenerative processes are ongoing for years prior to the time that cortical atrophy can be reliably detected using conventional neuroimaging techniques. ...Recent advances in diffusion-weighted imaging have provided new techniques to study neural microstructure, which may provide additional information regarding neurodegeneration. In this study, we used neurite orientation dispersion and density imaging (NODDI), a multi-compartment diffusion model, in order to investigate cortical microstructure along the clinical continuum of mild cognitive impairment (MCI) and AD dementia. Using gray matter-based spatial statistics (GBSS), we demonstrated that neurite density index (NDI) was significantly lower throughout temporal and parietal cortical regions in MCI, while both NDI and orientation dispersion index (ODI) were lower throughout parietal, temporal, and frontal regions in AD dementia. In follow-up ROI analyses comparing microstructure and cortical thickness (derived from T1-weighted MRI) within the same brain regions, differences in NODDI metrics remained, even after controlling for cortical thickness. Moreover, for participants with MCI, gray matter NDI—but not cortical thickness—was lower in temporal, parietal, and posterior cingulate regions. Taken together, our results highlight the utility of NODDI metrics in detecting cortical microstructural degeneration that occurs prior to measurable macrostructural changes and overt clinical dementia.
IMPORTANCE: The accumulation of aggregated β-amyloid and tau proteins into plaques and tangles is a central feature of Alzheimer disease (AD). While plaque and tangle accumulation likely contributes ...to neuron and synapse loss, disease-related changes to oligodendrocytes and myelin are also suspected of playing a role in development of AD dementia. Still, to our knowledge, little is known about AD-related myelin changes, and even when present, they are often regarded as secondary to concomitant arteriosclerosis or related to aging. OBJECTIVE: To assess associations between hallmark AD pathology and novel quantitative neuroimaging markers while being sensitive to white matter myelin content. DESIGN, SETTING, AND PARTICIPANTS: Magnetic resonance imaging was performed at an academic research neuroimaging center on a cohort of 71 cognitively asymptomatic adults enriched for AD risk. Lumbar punctures were performed and assayed for cerebrospinal fluid (CSF) biomarkers of AD pathology, including β-amyloid 42, total tau protein, phosphorylated tau 181, and soluble amyloid precursor protein. We measured whole-brain longitudinal and transverse relaxation rates as well as the myelin water fraction from each of these individuals. MAIN OUTCOMES AND MEASURES: Automated brain mapping algorithms and statistical models were used to evaluate the relationships between age, CSF biomarkers of AD pathology, and quantitative magnetic resonance imaging relaxometry measures, including the longitudinal and transverse relaxation rates and the myelin water fraction. RESULTS: The mean (SD) age for the 19 male participants and 52 female participants in the study was 61.6 (6.4) years. Widespread age-related changes to myelin were observed across the brain, particularly in late myelinating brain regions such as frontal white matter and the genu of the corpus callosum. Quantitative relaxometry measures were negatively associated with levels of CSF biomarkers across brain white matter and in areas preferentially affected in AD. Furthermore, significant age-by-biomarker interactions were observed between myelin water fraction and phosphorylated tau 181/β-amyloid 42, suggesting that phosphorylated tau 181/β-amyloid 42 levels modulate age-related changes in myelin water fraction. CONCLUSIONS AND RELEVANCE: These findings suggest amyloid pathologies significantly influence white matter and that these abnormalities may signify an early feature of the disease process. We expect that clarifying the nature of myelin damage in preclinical AD may be informative on the disease’s course and lead to new markers of efficacy for prevention and treatment trials.
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