Publications by authors named "Matthew A Walker"

Nicotinamide adenine dinucleotide provides the critical redox pair, NAD and NADH, for cellular energy metabolism. In addition, NAD is the precursor for de novo NADP synthesis as well as the co-substrates for CD38, poly(ADP-ribose) polymerase and sirtuins, thus, playing a central role in the regulation of oxidative stress and cell signaling. Declines of the NAD level and altered NAD/NADH redox states have been observed in cardiometabolic diseases of various etiologies.

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The tadpole-dwelling pinworm, Gyrinicola batrachiensis (Walton, 1929) Adamson, 1981 was recognized as the sole representative of the genus across Canada and the United States. However, evaluation of the morphology of these parasites across their range revealed considerable morphological variability that suggested diagnosable morphotypes. These morphotypes were associated with different species of anurans, several of which occurred in sympatry.

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Gyrinicola Yamaguti, 1938, includes 6 species of oxyurid found within the intestinal tract of numerous, larval, anuran species in Europe, Asia, South America, and North America. The systematic placement and hierarchical treatment of the genus has shifted at least 5 times since its discovery; the group was first considered as its own family (Gyrinicolidae), then treated as a subfamily (Gyrinicolinae) of Cosmocercidae, then as a member of the Pharyngodonidae, followed by movement back to the Cosmocercidae, and finally a recent proposal suggested the resurrection of the Gyrinicolidae. Species in the genus vary widely in the morphology of the uterine tract, a characteristic often used to indicate membership in the genus, as it is tied to the reproductive mode.

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Background: Strategies to increase cellular NAD (oxidized nicotinamide adenine dinucleotide) level have prevented cardiac dysfunction in multiple models of heart failure, but molecular mechanisms remain unclear. Little is known about the benefits of NAD-based therapies in failing hearts after the symptoms of heart failure have appeared. Most pretreatment regimens suggested mechanisms involving activation of sirtuin, especially Sirt3 (sirtuin 3), and mitochondrial protein acetylation.

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Advancements in cross-linking mass spectrometry (XL-MS) bridge the gap between purified systems and native tissue environments, allowing the detection of protein structural interactions in their native state. Here we use isobaric quantitative protein interaction reporter technology (iqPIR) to compare the mitochondria protein interactomes in healthy and hypertrophic murine hearts, 4 weeks post-transaortic constriction. The failing heart interactome includes 588 statistically significant cross-linked peptide pairs altered in the disease condition.

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A hallmark of impaired myocardial energetics in failing hearts is the downregulation of the creatine kinase (CK) system. In heart failure patients and animal models, myocardial phosphocreatine content and the flux of the CK reaction are negatively correlated with the outcome of heart failure. While decreased CK activity is highly reproducible in failing hearts, the underlying mechanisms remains elusive.

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Mitochondria are intracellular organelles that oxidize nutrients, make ATP, and fuel eukaryotic life. Their energy providing function is directly dependent on enzymes and coenzymes contained within the organelle. Perhaps, the most important coenzymes for energy yielding reactions are the pyridine nucleotides NAD(H) and NADP(H).

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Purpose: This study evaluated the American Speech-Language-Hearing Association's recommendation that audiometric testing for patients with tinnitus should use pulsed or warble tones. Using listeners with varied audiometric configurations and tinnitus statuses, we asked whether steady, pulsed, and warble tones yielded similar audiometric thresholds, and which tone type was preferred.

Method: Audiometric thresholds (octave frequencies from 0.

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Background: The relationship between severity of preoperative radiographic findings and surgical outcomes following decompression for lumbar degenerative spinal canal stenosis is unclear. Our aim in this paper was to gain insight into this relationship. We determined pre-operative radiographic severity on MRI scans using strict methodological controls and correlated such severity with post-operative outcomes using prospectively collected data.

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