Publications by authors named "Gunasekaran T"

The Alzheimer's Disease Sequencing Project (ADSP) is a national initiative to understand the genetic architecture of Alzheimer's Disease and Related Dementias (AD/ADRD) by sequencing whole genomes of affected participants and age-matched cognitive controls from diverse populations. The Genome Center for Alzheimer's Disease (GCAD) processed whole-genome sequencing data from 36,361 ADSP participants, including 35,014 genetically unique participants of which 45% are from non-European ancestry, across 17 cohorts in 14 countries in this fourth release (R4). This sequencing effort identified 387 million bi-allelic variants, 42 million short insertions/deletions, and 2.

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Introduction/objectives: The primary objective was to compare the 24-h mean heart rate (HR) provided by a smart collar with 24-h ambulatory electrocardiography (Holter) in healthy dogs. The secondary objective was to compare the 2-min HR values between the two methods during periods of activity and rest.

Animals, Materials, And Methods: Twelve healthy dogs were fitted with both Holter monitors and smart collars.

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  • Genetic research on Alzheimer's disease (AD) has largely concentrated on amyloid-β (Aβ), while this study focuses on understanding the genetic basis of tau pathology to uncover new pathways related to AD.
  • A genome-wide association study (GWAS) was conducted using data from the A4 and ADNI studies to analyze genetic variants linked to tau pathology, finding two significant loci and pinpointing certain genes associated with tau deposition.
  • Mendelian randomization analyses suggest that the LRRFIP1 protein may have a causal relationship with tau pathology, while the polygenic risk scores showed strong associations with amyloid pathology but not with tau pathology.
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Background: Few rare variants have been identified in genetic loci from genome-wide association studies (GWAS) of Alzheimer's disease (AD), limiting understanding of mechanisms, risk assessment, and genetic counseling.

Methods: Using genome sequencing data from 197 families in the National Institute on Aging Alzheimer's Disease Family Based Study and 214 Caribbean Hispanic families, we searched for rare coding variants within known GWAS loci from the largest published study.

Results: Eighty-six rare missense or loss-of-function (LoF) variants completely segregated in 17.

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  • Genetic variants in the ABCA7 gene are linked to a higher risk of Alzheimer's disease (AD), but the exact function of ABCA7 in AD development remains uncertain.* -
  • Researchers created a zebrafish model lacking the abca7 gene, revealing that ABCA7 is essential for the expression of neuropeptide Y (NPY) and other neurotrophic factors vital for brain health.* -
  • Findings suggest that decreased NPY due to impaired ABCA7 function contributes to synaptic issues and a higher risk of AD, with clinical data showing a correlation between NPY levels and disease progression.*
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  • Objective: The study aims to evaluate how different body positions affect transesophageal atrial pacing (TEAP) in dogs.
  • Methods: Eight mixed-breed dogs underwent TEAP in various body positions (left lateral, right lateral, ventral, and dorsal) using a pacing catheter, measuring the minimum pacing threshold (MPT) and zone of capture (ZOC) at each increment.
  • Results: TEAP was successfully achieved in all positions, showing no significant differences in MPT or ZOC across body positions, indicating body position doesn’t impact TEAP effectiveness. Future research is needed to compare TEAP with drugs for managing bradycardia in dogs during anesthesia.
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The risk of developing Alzheimer's disease (AD) significantly increases in individuals carrying the APOEε4 allele. Elderly cognitively healthy individuals with APOEε4 also exist, suggesting the presence of cellular mechanisms that counteract the pathological effects of APOEε4; however, these mechanisms are unknown. We hypothesized that APOEε4 carriers without dementia might carry genetic variations that could protect them from developing APOEε4-mediated AD pathology.

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There is little research on how Virtual Reality (VR) applications can identify and respond meaningfully to users' emotional changes. In this paper, we investigate the impact of Context-Aware Empathic VR (CAEVR) on the emotional and cognitive aspects of user experience in VR. We developed a real-time emotion prediction model using electroencephalography (EEG), electrodermal activity (EDA), and heart rate variability (HRV) and used this in personalized and generalized models for emotion recognition.

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The risk of developing Alzheimer's disease (AD) significantly increases in individuals carrying the allele. Elderly cognitively healthy individuals with also exist, suggesting the presence of cellular mechanisms that counteract the pathological effects of ; however, these mechanisms are unknown. We hypothesized that carriers without dementia might carry genetic variations that could protect them from developing mediated AD pathology.

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Article Synopsis
  • Alzheimer's disease (AD) is a complicated condition linked to cognitive decline and memory loss, with genetic variations playing a significant role in its development, although the exact mechanisms are still unclear.
  • Researchers developed a knockout zebrafish model of an established AD-risk gene using CRISPR/Cas9, which exhibited decreased astroglial growth, synaptic density, and microglial levels when exposed to amyloid beta 42 (Aβ42).
  • Findings from single-cell transcriptomics indicated that neuropeptide Y (NPY) signaling is crucial for neuronal and glial interaction, while clinical data in humans showed a correlation between reduced gene expression and advanced AD stages, along with genetic variations linked to the disease.
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Background: Few rare variants have been identified in genetic loci from genome wide association studies of Alzheimer's disease (AD), limiting understanding of mechanisms and risk assessment, and genetic counseling.

Methods: Using genome sequencing data from 197 families in The NIA Alzheimer's Disease Family Based Study, and 214 Caribbean Hispanic families, we searched for rare coding variants within known GWAS loci from the largest published study.

Results: Eighty-six rare missense or loss of function (LoF) variants completely segregated in 17.

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A 9-month-old intact male Ragdoll cat was presented for evaluation of a left-sided systolic murmur that was first auscultated during examination for a newly developed cough. Transthoracic echocardiography revealed a narrowed left pulmonary artery and an increase in flow velocities at the level of the narrowing, consistent with left pulmonary artery branch stenosis. The right pulmonary artery appeared normal.

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Objective: To describe the clinical presentation and outcome in dogs diagnosed with Trypanosoma cruzi infection in nonendemic areas and to survey veterinary cardiologists in North America for Chagas disease awareness.

Animals: 12 client-owned dogs; 83 respondents from a veterinary cardiology listserv.

Procedures: A retrospective, multicenter medical records review to identify dogs diagnosed with American trypanosomiasis between December 2010 and December 2020.

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Hippocampal subfield atrophy is a prime structural change in the brain, associated with cognitive aging and neurodegenerative diseases such as Alzheimer's disease. Recent developments in genome-wide association studies (GWAS) have identified genetic loci that characterize the risk of hippocampal volume loss based on the processes of normal and abnormal aging. Polygenic risk scores are the genetic proxies mimicking the genetic role of the pre-existing vulnerabilities of the underlying mechanisms influencing these changes.

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In human patients with hypoadrenocorticism, a secondary dilated cardiomyopathy is noted that has been reported to resolve with replacement steroid therapy. A similar secondary dilated cardiomyopathy in dogs with hypoadrenocorticism has not been previously described. We present three dogs concurrently diagnosed with hypoadrenocorticism and ventricular dilation with systolic dysfunction.

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Diabetic retinopathy (DR) is among the leading causes of blindness at the global level. A review of studies between 2015 and 2018 found that about 1.7% of the general population with any type of diabetes mellitus suffered from proliferative diabetic retinopathy (PDR).

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Measurement of N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels has been shown to have clinical significance for diagnosis and management of heart disease in dogs. Evaluation of current reference limits for specific breeds is necessary to ensure the test can accurately distinguish between healthy and diseased animals. The objective of this study is to evaluate the adequacy of currently established NT-proBNP reference limits for clinical use in healthy Salukis.

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  • * The study focused on the relationship between plasma NFL/Aβ levels and brain neurodegeneration in Alzheimer's, finding they are strongly correlated and provide better diagnostic accuracy in early stages compared to individual biomarkers.
  • * Results showed that as Alzheimer's disease progresses, NFL increases and Aβ decreases, with plasma NFL/Aβ being a promising non-invasive biomarker for early detection and monitoring of the disease.
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We report a case of a 43-year-old woman with an underlying right sphenoid wing meningioma (SWM) who complained of increased right eye swelling, proptosis, redness and severe pain for two weeks. Her symptoms started one week after completing radiotherapy. She seeked treatment after a worsening of symptoms.

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  • This study aimed to identify new genetic factors related to Alzheimer's disease (AD) by analyzing brain imaging data from 2,643 Koreans with varying cognitive conditions.
  • A specific genetic variant (rs77359862) in the SHARPIN gene was found to negatively impact brain areas linked to memory and cognition, suggesting it increases AD risk.
  • The research also noted that this variant affects important protein interactions involved in cellular signaling pathways, highlighting SHARPIN's potential role in the development of AD.
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  • The study identifies two new significant genetic loci linked to late-onset Alzheimer's disease in East Asian individuals who do not carry the APOE ε4 gene variant.
  • Researchers conducted a genome-wide association study among 2,291 Korean seniors and validated their findings in a separate group of 1,956 Japanese individuals.
  • The results suggest that it is possible to discover Alzheimer's-related genetic variations in non-European populations, benefiting from a more homogeneous genetic background even with smaller sample sizes.
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Introduction: The primary objective of this study was to describe the immediate post-procedural outcomes in dogs with severe pulmonary stenosis that were treated with low-pressure balloon valvuloplasty (BV) at a single institution.

Animals, Materials And Methods: Retrospective case series; medical records of dogs that underwent BV performed with a balloon dilation catheter >20 mm in diameter and a burst pressure of less than 4 atm (atm) were retrospectively reviewed. Twenty animals were identified fitting the criteria.

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A 6-month-old, neutered male, Vietnamese potbellied pig presented for evaluation of exercise intolerance and intermittent episodes of exertional cyanosis. Initial diagnostic evaluation revealed arterial hypoxemia. Transthoracic echocardiogram revealed double-outlet right ventricle (DORV) and a subaortic ventricular septal defect.

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The objective of this study was to evaluate the accuracy of short duration electrocardiographic (ECG) recordings extracted from ambulatory continuous ECG (Holter) to assess 24-hour mean heart rate in dogs with atrial fibrillation. In this retrospective study, Holter recordings obtained from 20 dogs with atrial fibrillation were selected for analysis. Ten out of 20 dogs were receiving drugs to control heart rate at the time of Holter evaluation.

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Background: The primary objective of this study is to evaluate the peri-procedural major and minor complications associated with percutaneous femoral arterial access using modified Seldinger's technique in dogs that underwent cardiac catheterization.

Methods: Medical records of 62 client owned dogs that underwent percutaneous femoral arterial access for interventional cardiac procedures were retrospectively evaluated. Post-procedural manual compression was used for hemostasis.

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