Your search for: 'author:("Perez, Keyla A.")' has returned 3 results. (0.025s) Save search

Authors: Watt, Andrew D. | Perez, Keyla A. | Rembach, Alan R. | Masters, Colin L. | Villemagne, Victor L. | Barnham, Kevin J.

Article Type: Research Article

Abstract: Effective therapeutic interventions for Alzheimer's disease (AD) will require treatment regimes to move toward the earliest stages of the disease. For this to occur the field has to identify biomarkers that are able to accurately identify individuals at risk for progression toward AD in the presymptomatic stage. One very significant implication is that some form of population-based screening will need to be undertaken in order to identify those at risk. To date, efforts in neuroimaging brain amyloid-β (Aβ) and changes in cerebrospinal fluid Aβ and tau levels shows promise, however, it is questionable as to whether these methods are applicable …for screening the general population. The Aβ peptide is also found in blood which is the most economical and efficient biological fluid to analyze. Unfortunately, investigations into blood-based diagnostic markers have produced mixed results. This variability is likely to be the result of differences in the preanalytical processing of samples and as such is delaying progress in the field. Reported preanalytical processing techniques from 87 recent articles focusing on the measurement of Aβ in blood were compared, to investigate whether basic sample-handling techniques were comparable between studies. This comparison revealed that not only is it likely that some of the variability in blood-based results is attributable to discrepancies in preanalytical methodologies but also that the field is failing to adequately report sample processing techniques. This review highlights the current shortcomings in methodological reporting and recommends a standardized blood collection methodology based on the limited consensus of the reviewed articles. Show more

Keywords: Alzheimer's disease, amyloid-β, biomarkers, blood, plasma, protocol, standardized

DOI: 10.3233/JAD-2012-120058

Citation: Journal of Alzheimer's Disease, vol. 30, no. 2, pp. 323-336, 2012

Authors: Watt, Andrew D. | Perez, Keyla A. | Faux, Noel G. | Pike, Kerryn E. | Rowe, Christopher C. | Bourgeat, Pierrick | Salvado, Olivier | Masters, Colin L. | Villemagne, Victor L. | Barnham, Kevin J.

Article Type: Research Article

Abstract: Diagnostic measures for Alzheimer's disease (AD) commonly rely on evaluating the levels of amyloid-β (Aβ) peptides within the cerebrospinal fluid (CSF) of affected individuals. These levels are often combined with levels of an additional non-Aβ marker to increase predictive accuracy. Recent efforts to overcome the invasive nature of CSF collection led to the observation of Aβ species within the blood cellular fraction, however, little is known of what additional biomarkers may be found in this membranous fraction. The current study aimed to undertake a discovery-based proteomic investigation of the blood cellular fraction from AD patients (n = 18) and healthy …controls (HC; n = 15) using copper immobilized metal affinity capture and Surface Enhanced Laser Desorption/Ionisation Time-Of-Flight Mass Spectrometry. Three candidate biomarkers were observed which could differentiate AD patients from HC (ROC AUC > 0.8). Bivariate pairwise comparisons revealed significant correlations between these markers and measures of AD severity including; MMSE, composite memory, brain amyloid burden, and hippocampal volume. A partial least squares regression model was generated using the three candidate markers along with blood levels of Aβ. This model was able to distinguish AD from HC with high specificity (90%) and sensitivity (77%) and was able to separate individuals with mild cognitive impairment (MCI) who converted to AD from MCI non-converters. While requiring further characterization, these candidate biomarkers reaffirm the potential efficacy of blood-based investigations into neurodegenerative conditions. Furthermore, the findings indicate that the incorporation of non-amyloid markers into predictive models, function to increase the accuracy of the diagnostic potential of Aβ. Show more

Keywords: Amyloid-β, biomarkers, blood, copper, diagnostics, SELDI-TOF-MS

DOI: 10.3233/JAD-2010-101722

Citation: Journal of Alzheimer's Disease, vol. 24, no. 1, pp. 47-59, 2011

Authors: Watt, Andrew D. | Perez, Keyla A. | Ang, Ching-Seng | O'Donnell, Paul | Rembach, Alan | Pertile, Kelly K. | Rumble, Rebecca L. | Trounson, Brett O. | Fowler, Christopher J. | Faux, Noel G. | Masters, Colin L. | Villemagne, Victor L. | Barnham, Kevin J.

Article Type: Research Article

Abstract: Biomarkers enabling the preclinical identification of Alzheimer's disease (AD) remain one of the major unmet challenges in the field. The blood cellular fractions offer a viable alternative to current cerebrospinal fluid and neuroimaging modalities. The current study aimed to replicate our earlier reports of altered binding within the AD-affected blood cellular fraction to copper-loaded immobilized metal affinity capture (IMAC) arrays. IMAC and anti-amyloid-β (Aβ) antibody arrays coupled with mass spectrometry were used to analyze blood samples collected from 218 participants from within the AIBL Study of Aging. Peripheral Aβ was fragile and prone to degradation in the AIBL samples, even …when stored at −80°C. IMAC analysis of the AIBL samples lead to the isolation and identification of alpha-defensins 1 and 2 at elevated levels in the AD periphery, validating earlier findings. Alpha-defensins 1 and 2 were elevated in AD patients indicating that an inflammatory phenotype is present in the AD periphery; however, peripheral Aβ levels are required to supplement their prognostic power. Show more

Keywords: α-defensins, Alzheimer's disease, amyloid-β, biomarkers, blood, inflammation, mass spectrometry

DOI: 10.3233/JAD-142286

Citation: Journal of Alzheimer's Disease, vol. 44, no. 4, pp. 1131-1143, 2015