Localized APP expression results in progressive network dysfunction by disorganizing spike timing.

Progressive cognitive decline in Alzheimer's disease could either be caused by a spreading molecular pathology or by an initially focal pathology that causes aberrant neuronal activity in a larger network. To distinguish between these possibilities, we generated a mouse model with expression of mutant human amyloid precursor protein (APP) in only hippocampal CA3 cells. We found that performance in a hippocampus-dependent memory task was impaired in young adult and aged mutant mice. In both age groups, we then recorded from the CA1 region, which receives inputs from APP-expressing CA3 cells. We observed that theta oscillation frequency in CA1 was reduced along with disrupted relative timing of principal cells. Highly localized pathology limited to the presynaptic CA3 cells is thus sufficient to cause aberrant firing patterns in postsynaptic neuronal networks, which indicates that disease progression is not only from spreading pathology but also mediated by progressively advancing physiological dysfunction.

Bleeding outcomes after routine transradial primary angioplasty for acute myocardial infarction using eptifibatide and unfractionated heparin: a single-center experience following the HORIZONS-AMI trial.

OBJECTIVES: We sought to (1) determine the bleeding rates after primary percutaneous coronary intervention (PPCI) in our institution, where the default strategy has been transradial (TR) access in combination with unfractionated heparin (UFH) plus eptifibatide, and (2) compare these with the outcomes of patients treated with bivalirudin in HORIZONS-AMI. BACKGROUND: HORIZONS-AMI demonstrated that in PPCI undertaken via the transfemoral route, routine use of bivalirudin was associated with lower bleeding rates and improved mortality compared to routine use of UFH plus glycoprotein IIb/IIIa inhibitor (GPI). METHODS: This was a single-center prospective registry of consecutive patients undergoing PPCI from January 2009 to August 2011 at the Queen Elizabeth Hospital Birmingham, UK. Thirty-day major bleeding was defined as per the HORIZONS-AMI criteria and also according to TIMI and GUSTO scales. RESULTS: Of the 432 consecutive patients, 350 fulfilled entry criteria for HORIZONS-AMI. In contrast with HORIZONS-AMI, these subjects were older (62.5 ± 13.7 yr vs. 59.8 ± 11.1 yr, P < 0.05) with a higher rate of cardiogenic shock (6.3% vs. 0.8%, P < 0.0001). Despite this higher risk population, the rate of major bleeding was favorable (3.7% [95% CI: 2.0-6.3%] vs. 4.9% [4.0-6.1%], P = 0.32). Similarly, TIMI major bleeding (2.0% [0.8-4.1%] vs. 3.1% [2.3-3.4%], P = 0.10) and GUSTO severe or life-threatening bleeding (0.6% [0.1-2.5%] vs. 0.4% [0.2-0.9%], P = 0.75) were comparable. CONCLUSIONS: Routine TR access for PPCI using UFH plus GPI is associated with a low 30-day rate of major bleeding equivalent to the bivalirudin arm of HORIZONS-AMI. Default transradial access for PPCI permits routine use of a GPI without the penalty of high bleeding rates.