An MRI-Derived Definition of MCI-to-AD Conversion for Long-Term, Automati c Prognosis of MCI Patients

Alzheimer's disease (AD) and mild cognitive impairment (MCI), continue to be widely studied. While there is no consensus on whether MCIs actually "convert" to AD, the more important question is not whether MCIs convert, but what is the best such definition. We focus on automatic prognostication, nominally using only a baseline image brain scan, of whether an MCI individual will convert to AD within a multi-year period following the initial clinical visit. This is in fact not a traditional supervised learning problem since, in ADNI, there are no definitive labeled examples of MCI conversion. Prior works have defined MCI subclasses based on whether or not clinical/cognitive scores such as CDR significantly change from baseline. There are concerns with these definitions, however, since e.g. most MCIs (and ADs) do not change from a baseline CDR=0.5, even while physiological changes may be occurring. These works ignore rich phenotypical information in an MCI patient's brain scan and labeled AD and Control examples, in defining conversion. We propose an innovative conversion definition, wherein an MCI patient is declared to be a converter if any of the patient's brain scans (at follow-up visits) are classified "AD" by an (accurately-designed) Control-AD classifier. This novel definition bootstraps the design of a second classifier, specifically trained to predict whether or not MCIs will convert. This second classifier thus predicts whether an AD-Control classifier will predict that a patient has AD. Our results demonstrate this new definition leads not only to much higher prognostic accuracy than by-CDR conversion, but also to subpopulations much more consistent with known AD brain region biomarkers. We also identify key prognostic region biomarkers, essential for accurately discriminating the converter and nonconverter groups

Fine Mapping of Genetic Variants in BIN1, CLU, CR1 and PICALM for Association with Cerebrospinal Fluid Biomarkers for Alzheimer's Disease

Recent genome-wide association studies of Alzheimer's disease (AD) have identified variants in BIN1, CLU, CR1 and PICALM that show replicable association with risk for disease. We have thoroughly sampled common variation in these genes, genotyping 355 variants in over 600 individuals for whom measurements of two AD biomarkers, cerebrospinal fluid (CSF) 42 amino acid amyloid beta fragments (Aβ42) and tau phosphorylated at threonine 181 (ptau181), have been obtained. Association analyses were performed to determine whether variants in BIN1, CLU, CR1 or PICALM are associated with changes in the CSF levels of these biomarkers. Despite adequate power to detect effects as small as a 1.05 fold difference, we have failed to detect evidence for association between SNPs in these genes and CSF Aβ42 or ptau181 levels in our sample. Our results suggest that these variants do not affect risk via a mechanism that results in a strong additive effect on CSF levels of Aβ42 or ptau181

Thickness of Palatal Masticatory Mucosa and Its Relationship with Different Parameters in Turkish Subjects

Background: The aim of the study was to clinically investigate the mucosal variations in different parts of hard palate subject to soft tissue harvesting and its relationship with selected parameters in patients with gingival recessions

SYNTHESIS, CHARACTERIZATION AND SPECTROSCOPIC STUDIES ON TAUTOMERISM AND ACIDITY CONSTANTS OF CERTAIN 4- (PHENYLDIAZENYL) BENZENE-1,3-DIOL DERIVATIVES

Bu çalışmada, benzen-1,3-triol ve bazı sübstitüe amino benzen ile monoazo boyar maddeleri sentezlendi. Kimyasal yapıları spektroskopik teknikler ile aydınlatıldı. 4-(fenildiazenil)benzen-1,3-diol türevi bileşiklerinin tautomerik özellikleri saf polar ve apolar çözücülerde (dimetil sülfoksit, etanol, kloroform, benzen ve siklohekzan) asidik ve bazik ortamlarda 25±1 °C, 35±1 °C ve 45±1 °C UV-Vis. Spektrometresinde ölçüldü. Sentezlenen bileşiklerin azo-hidrazon tautomerleri hesaplandı. Bütün azo boyar madde bileşiklerinde azo tautomer formunun baskın olduğu belirlendi. Aynı bileşiklerin asitlik sabitleri 25 °C (0,1 °C) UV-Vis. Spektroskopik teknik ile belirlend