Your search for: 'author:("Dhaliwal, Satvinder S.")' has returned 6 results. (0.011s) Save search

Authors: Wahjoepramono, Eka J. | Wijaya, Linda K. | Taddei, Kevin | Martins, Georgia | Howard, Matthew | de Ruyck, Karl | Bates, Kristyn | Dhaliwal, Satvinder S. | Verdile, Giuseppe | Carruthers, Malcolm | Martins, Ralph N.

Article Type: Research Article

Abstract: The effect of testosterone on the levels of the Alzheimer's disease amyloid-β peptide (Aβ) was investigated in guinea pigs. Castrated guinea pigs (GPX) were administered testosterone at two different dosages, following which plasma and cerebrospinal fluid (CSF) Aβ40 levels were measured. Plasma Aβ40 levels were reduced in GPX in the early stages of low-dose testosterone treatment, whereas CSF Aβ40 levels were only reduced by the time circulating testosterone had returned to untreated GPX levels. The supraphysiological testosterone dose did not reduce CSF Aβ40 levels significantly until circulating testosterone was back to uncastrated levels, whereas plasma Aβ40 levels significantly increased over …time in these animals. These results indicate that the extent of testosterone-induced changes to Aβ40 levels and their response rates depend on both the tissue examined and testosterone dosage. Show more

Keywords: Aging, Alzheimer's disease, amyloid-β, castration, cerebrospinal fluid, guinea pig, testosterone

DOI: 10.3233/JAD-2008-15111

Citation: Journal of Alzheimer's Disease, vol. 15, no. 1, pp. 129-137, 2008

Authors: Sohrabi, Hamid R. | Bates, Kristyn A. | Rodrigues, Mark | Taddei, Kevin | Martins, Georgia | Laws, Simon M. | Lautenschlager, Nicola T. | Dhaliwal, Satvinder S. | Foster, Jonathan K. | Martins, Ralph N.

Article Type: Research Article

Abstract: Apolipoprotein E ε4 (APOE-ε4) is a major genetic risk factor for Alzheimer's disease. In this study, we addressed the question of whether possession of the APOE-ε4 allele results in adverse effects on perceived health-related quality of life (HRQL) and on symptoms of depression and anxiety in people with subjective memory complaints (SMC). 138 healthy, community-dwelling elderly volunteers, aged 52 to 85, were assessed for HRQL, depression, and anxiety. The participants were classified as i) APOE-ε4 carriers or ii) non-carriers with a) SMC or b) without memory complaints. The possible interactions of APOE genotype, gender, and SMC on HRQL, depression, and …anxiety were investigated statistically. SMC was significantly associated with poorer outcomes on measures of depression, trait anxiety, and mental health. APOE-ε4 carriers did not significantly differ from non-carriers on HRQL, depression, and anxiety. However, significant interaction was found between APOE-ε4 genotype and SMC on depression. These findings are important from a health perspective and suggest that memory complaints are associated with markers of mental health and quality of life that are independent of possession of the APOE-ε4 allele, despite the importance of this polymorphism in the risk of AD and other health problems. Show more

Keywords: Alzheimer's disease, anxiety, APOE-ε4, depression, health-related quality of life (HRQL), subjective memory complaints

DOI: 10.3233/JAD-2009-1018

Citation: Journal of Alzheimer's Disease, vol. 17, no. 1, pp. 69-79, 2009

Authors: Brook, Emily S. | D’Alonzo, Zachary J. | Lam, Virginie | Chan, Dick C. | Dhaliwal, Satvinder S. | Watts, Geraldb F. | Mamo, John C.L. | Takechi, Ryusuke

Article Type: Research Article

Abstract: Background: Obesity is linked to a higher incidence of Alzheimer’s disease (AD). Studies show that plasma amyloid-β (Aβ) dyshomeostasis, particularly low 42/40 ratio indicates a heightened risk for developing AD. However, the relationship between body mass index (BMI) and circulating plasma Aβ has not been extensively studied. Objective: We hypothesized that people with a high BMI have altered plasma Aβ homeostasis compared with people with a lower BMI. We also tested whether reducing BMI by calorie-restriction could normalize plasma concentrations of Aβ. Methods: Plasma concentrations of Aβ40 , Aβ42 , and Aβ42/40 ratio were measured in 106 participants with BMIs …classified as lean, overweight, or obese. From this cohort, twelve participants with overweight or obese BMIs entered a 12-week calorie-restriction weight loss program. We then tested whether decreasing BMI affected plasma Aβ concentrations. Results: Plasma Aβ42/40 ratio was 17.54% lower in participants with an obese BMI compared to lean participants (p  < 0.0001), and 11.76% lower compared to participants with an overweight BMI (p  < 0.0001). The weight loss regimen decreased BMI by an average of 4.02% (p  = 0.0005) and was associated with a 6.5% decrease in plasma Aβ40 (p  = 0.0425). However, weight loss showed negligible correlations with plasma Aβ40 , Aβ42 , and Aβ42/40 ratio. Conclusion: Obesity is associated with aberrant plasma Aβ homeostasis which may be associated with an increased risk for AD. Weight loss appears to lower Aβ40 , but large-scale longitudinal studies in addition to molecular studies are required to elucidate the underlying mechanisms of how obesity and weight loss influence plasma Aβ homeostasis. Show more

Keywords: Alzheimer’s disease, amyloid-β, body mass index, obesity, weight loss

DOI: 10.3233/JAD-220529

Citation: Journal of Alzheimer's Disease, vol. 93, no. 2, pp. 653-664, 2023

Authors: Sohrabi, Hamid R. | Bates, Kristyn A. | Rodrigues, Mark | Taddei, Kevin | Laws, Simon M. | Lautenschlager, Nicola T. | Dhaliwal, Satvinder S. | Johnston, Amy N.B. | Mackay-Sim, Alan | Gandy, Samuel | Foster, Jonathan K. | Martins, Ralph N.

Article Type: Research Article

Abstract: Olfactory dysfunction has been reported in clinical and preclinical phases of Alzheimer's disease. Subjective memory complaints have been proposed as a potential early indicator for increased risk of Alzheimer's disease, but have also been associated with depression, personality characteristics, and health problems. In this study, we aimed to determine which of these putative markers can predict memory complaints in community-dwelling elderly individuals, focusing on olfactory symptoms. A cohort of 144 elderly volunteers (42 males and 102 females), aged 50 to 86, was recruited from an ongoing longitudinal study. Participants were assessed for olfactory capacities (threshold, discrimination, and identification), subjective memory …complaints, depression, and cognitive functions. Subjective memory complaints were significantly associated with olfactory discrimination and identification but not with threshold. Olfactory functions and depressive symptoms were both significantly associated with subjective memory complaints. In addition, memory complainers were significantly worse than non-complainers with respect to olfactory discrimination, identification, and overall olfactory functioning. The findings suggest that olfactory capacity may be a potentially significant biomarker for identifying community-dwelling elderly with memory complaints who are at increased risk for age-related cognitive decline and Alzheimer's disease. Show more

Keywords: Alzheimer's disease, cognitive decline, depression symptoms, olfactory dysfunction, smell identification, Sniffin' Sticks, subjective memory complaints

DOI: 10.3233/JAD-2009-1020

Citation: Journal of Alzheimer's Disease, vol. 17, no. 1, pp. 135-142, 2009

Authors: Rimajova, Mira | Lenzo, Nat P. | Wu, Jing-Shan | Bates, Kristyn A. | Campbell, Andrew | Dhaliwal, Satvinder S. | McCarthy, Michael | Rodrigues, Mark | Paton, Athena | Rowe, Christopher | Foster, Jonathan K. | Martins, Ralph N.

Article Type: Research Article

Abstract: Apolipoprotein E-ϵ4 (APOEε4) has been associated with increased risk of developing Alzheimer's disease (AD) and regional cerebral glucose hypometabolism, as measured by fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET). We report here preliminary data from studies that aim to determine whether cerebral glucose hypometabolism is observed in APOEε4 positive, cognitively intact individuals between the ages of 50 and 80, and whether there is an additional impact of subjective memory complainer (SMC) status on glucose metabolism determined by NeuroStat analysis. FDG-PET was conducted in 30 community dwelling, APOE-ε4 carriers without clinical evidence of dementia and objective cognitive impairment as assessed using a neuropsychological battery. …Neurological soft-signs (NSS) were also assessed. Glucose hypometabolism was demonstrated in the anterior and posterior cingulate cortex and in the temporal association cortices in APOEε4 carriers compared to the normative NeuroStat database. This pattern was particularly evident in APOEε4 heterozygous individuals. SMC showed hypometabolism in the aforementioned brain regions, whereas non-SMC showed no significant pattern of glucose hypometabolism. FDG-PET with NeuroStat analysis showed that APOEε4 carriers have mild glucose hypometabolism in areas associated with AD. SMC may be associated with AD-related differences in regional cerebral glucose metabolism. These findings are currently being investigated in a larger group of APOEε4 carriers. Show more

Keywords: Alzheimer's disease, apolipoprotein E, cognitive aging, FDG-PET, memory

DOI: 10.3233/JAD-2008-13203

Citation: Journal of Alzheimer's Disease, vol. 13, no. 2, pp. 137-146, 2008

Authors: Bates, Kristyn A. | Sohrabi, Hamid R. | Rodrigues, Mark | Beilby, John | Dhaliwal, Satvinder S. | Taddei, Kevin | Criddle, Arthur | Wraith, Megan | Howard, Matthew | Martins, Georgia | Paton, Athena | Mehta, Pankaj | Foster, Jonathan K. | Martins, Ian J. | Lautenschlager, Nicola T. | Mastaglia, Frank L. | Laws, Simon M. | Gandy, Samuel E. | Martins, Ralph N.

Article Type: Research Article

Abstract: A strong link is indicated between cardiovascular disease (CVD) and risk for developing Alzheimer's disease (AD), which may be exacerbated by the major AD genetic risk factor apolipoprotein Eε4 (APOEε4). Since subjective memory complaint (SMC) may potentially be an early indicator for cognitive decline, we examined CVD risk factors in a cohort of SMC. As amyloid-ε (Aβ) is considered to play a central role in AD, we hypothesized that the CVD risk profile (increased LDL, reduced HDL, and increased body fat) would be associated with plasma Aβ levels. We explored this in 198 individuals with and without SMC (average age …= 63 years). Correlations between Aβ40 and HDL were observed, which were stronger in non-APOEε4 carriers (rho = −0.315, p < 0.001) and in SMC (rho = −0.322, p = 0.01). There was no relationship between percentage body fat and Aβ40 in this cohort. Age and HDL remained predictive for plasma Aβ40 using multivariate regression analysis. We report a novel negative association between HDL and Aβ, which if demonstrated to be causal has implications for the development of lifestyle interventions and/or novel therapeutics. The relationship between HDL and Aβ and the potential significance of such an association needs to be validated in a larger longitudinal study. Show more

Keywords: Aging, amyloid-β, apolipoprotein E, cholesterol, dementia, high density lipoprotein

DOI: 10.3233/JAD-2009-1050

Citation: Journal of Alzheimer's Disease, vol. 17, no. 2, pp. 305-318, 2009