Publications by authors named "Donna K Mahnke"

Cardiovascular calcification can occur in vascular and valvular structures and is commonly associated with calcium deposition and tissue mineralization leading to stiffness and dysfunction. Patients with chronic kidney disease and associated hyperphosphatemia have an elevated risk for coronary artery calcification (CAC) and calcific aortic valve disease (CAVD). However, there is mounting evidence to suggest that the susceptibility and pathobiology of calcification in these two cardiovascular structures may be different, yet clinically they are similarly treated.

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Background: Elevated total cell-free DNA (TCF) concentration has been associated with critical illness in adults and elevated donor fraction (DF), the ratio of donor specific cell-free DNA to total cell-free DNA present in the recipient's plasma, is associated with rejection following cardiac transplantation. This study investigates relationships between TCF and clinical outcomes after heart transplantation.

Methods: A prospective, blinded, observational study of 87 heart transplantation recipients was performed.

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Article Synopsis
  • Ebstein's anomaly (EA) is a rare heart condition associated with cardiac issues like left ventricular noncompaction (LVNC), with limited understanding of its genetic causes, yet a family study showed at least 10 affected members.* -
  • Using echocardiography and exome sequencing on family members, researchers discovered a significant variant in the KLHL26 gene, which only appeared in those affected by EA/LVNC.* -
  • The identified KLHL26 variant might disrupt critical protein interactions in the heart, suggesting a role in protein degradation during cardiac development, offering insight into the genetic basis of EA/LVNC.*
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Lifelong noninvasive rejection monitoring in heart transplant patients is a critical clinical need historically poorly met in adults and unavailable for children and infants. Cell-free DNA (cfDNA) donor-specific fraction (DF), a direct marker of selective donor organ injury, is a promising analytical target. Methodological differences in sample processing and DF determination profoundly affect quality and sensitivity of cfDNA analyses, requiring specialized optimization for low cfDNA levels typical of transplant patients.

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Article Synopsis
  • * Researchers conducted RNA sequencing on aortic tissue from CoA patients and found the downregulation of the natriuretic peptide receptor C (NPR-C) in areas affected by high blood pressure, which aligns with findings in a rabbit model of CoA.
  • * Their experiments revealed that decreased NPR-C activity disrupted normal blood vessel relaxation and calcium levels in the presence of certain peptides, and a specific gene variant was more common in CoA patients, potentially impacting hypertension treatment strategies.
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Hypoplastic left heart syndrome (HLHS) is a clinically and anatomically severe form of congenital heart disease (CHD). Although prior studies suggest that HLHS has a complex genetic inheritance, its etiology remains largely unknown. The goal of this study was to characterize a risk gene in HLHS and its effect on HLHS etiology and outcome.

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Background: Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD.

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The clinical significance of copy number variants (CNVs) in congenital heart disease (CHD) continues to be a challenge. Although CNVs including genes can confer disease risk, relationships between gene dosage and phenotype are still being defined. Our goal was to perform a quantitative analysis of CNVs involving 100 well-defined CHD risk genes identified through previously published human association studies in subjects with anatomically defined cardiac malformations.

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22q11.2 Deletion syndrome (22q11.2 DS) [DiGeorge syndrome type 1 (DGS1)] occurs in ∼1:3,000 live births; 75% of children with DGS1 have severe congenital heart disease requiring early intervention.

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Embryonic factor 1 (FAC1) is one of the earliest expressed plant genes and encodes an AMP deaminase (AMPD), which is also an identified herbicide target. This report identifies an N-terminal transmembrane domain in Arabidopsis FAC1, explores subcellular fractionation, and presents a 3.3-A globular catalytic domain x-ray crystal structure with a bound herbicide-based transition state inhibitor that provides the first glimpse of a complete AMPD active site.

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Adenosine 5'-monophosphate deaminase (AMPD) is a eukaryotic enzyme that converts adenosine 5'-monophosphate (AMP) to inosine 5'-monophosphate (IMP) and ammonia. AMPD from Arabidopsis thaliana (AtAMPD) was cloned into the baculoviral transfer vector p2Bac and co-transfected along with a modified baculoviral genome into Spodoptera frugiperda (Sf9) cells. The resulting recombinant baculovirus were plaque-purified, amplified and used to overexpress recombinant AtAMPD.

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Erythrocyte AMP deaminase [isoform E (AMPD3)] is activated in response to increased intracellular calcium levels in Tarui's disease, following exposure of ionophore-treated cells to extracellular calcium, and by the addition of calcium to freshly prepared hemolysates. However, the assumption that Ca(2+) is a positive effector of isoform E is inconsistent with the loss of sensitivity to this divalent cation following dilution of erythrocyte lysates or enzyme purification. Ca(2+) regulation of isoform E was studied by examining in vitro effects of calmodulin (CaM) on this enzyme and by monitoring the influence of CaM antagonists on purine catabolic flow in freshly prepared erythrocytes under various conditions of energy imbalance.

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