Publications by authors named "David Kagan"

The dim light melatonin onset (DLMO) is the current gold standard biomarker of the timing of the central circadian clock in humans and is often assessed from saliva samples. To date, only one commercially available salivary melatonin assay is considered accurate at the low daytime levels required to accurately detect the DLMO (Novolytix RIA RK-DSM2). The aim of this study was to conduct the first independent evaluation of a newly improved enzyme-linked immunosorbent assay (ELISA; Novolytix MLTN-96) and compare it with the recommended radioimmunoassay (RIA)-both in terms of melatonin concentrations and derived DLMOs.

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Background: Although patient-reported outcomes (PROs) have become important in the evaluation of spine surgery patients, the accuracy of patient recall of pre- or post-intervention  symptoms following epidural steroid injection remains unknown.

Objectives: The purpose of this study was to: 1) characterize the accuracy of patient recollection of back/leg pain following epidural steroid injection; 2) characterize the direction and magnitude of recall bias; and 3) characterize factors that impact patient recollection.

Study Design: A prospective cohort study.

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Sacubitril/valsartan (LCZ696) is the first angiotensin receptor neprilysin inhibitor approved to reduce cardiovascular mortality and hospitalization in patients with heart failure with reduced ejection fraction. As neprilysin (NEP) is one of several enzymes known to degrade amyloid-β (Aβ), there is a theoretical risk of Aβ accumulation following long-term NEP inhibition. The primary objective of this study was to evaluate the potential effects of sacubitril/valsartan on central nervous system clearance of Aβ isoforms in cynomolgus monkeys using the sensitive Stable Isotope Labeling Kinetics (SILK™)-Aβ methodology.

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Alport syndrome is a genetic disease of collagen IV (α3, 4, 5) resulting in renal failure. This study was designed to investigate sex-phenotype correlations and evaluate the contribution of macrophage infiltration to disease progression using Col4a3 knock out (Col4a3KO) mice, an established genetic model of autosomal recessive Alport syndrome. No sex differences in the evolution of body mass loss, renal pathology, biomarkers of tubular damage KIM-1 and NGAL, or deterioration of kidney function were observed during the life span of Col4a3KO mice.

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Background: Many types of glomerulonephritis (GN) undergo tandem connected phases: inflammation and fibrosis. Fibrosis in human GNs leads to irreversible end-stage disease. This study investigated how these 2 phases were controlled.

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Objective: To determine whether a random postoperative day-3 cortisol value of 10 μg/dL or greater is predictive of adrenal sufficiency 3 to 10 weeks after transsphenoidal surgery (TSS) and during long-term clinical follow-up.

Methods: We retrospectively reviewed the case records of patients who underwent TSS at our institution between 1991 and 2008. Inclusion criteria were as follows: random cortisol measured on the morning of postoperative day 3, adrenal dynamic testing performed 3 to 10 weeks after TSS, and clinical assessment of the hypothalamic-pituitary-adrenal (HPA) axis at least 6 months after TSS.

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Endometriosis is characterized by the presence of elevated proinflammatory cytokines such as tumor necrosis factor (TNF) alpha in the peritoneal cavity. Blocking interaction of TNFalpha with its receptor by the addition of excess TNFalpha-binding protein (TBP)-1 (a soluble form of TNF receptor-1) was effective in animal models of endometriosis. Recently, a novel, high-affinity inhibitor of TNFalpha, TNF-soluble high-affinity receptor complex (TNF-SHARC), was created by fusing TBP to both the alpha and beta subunits of inactive human chorionic gonadotropin.

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Tumor necrosis factor (TNF)-alpha is central to the endometriotic disease process. TNF-alpha receptor signaling regulates epithelial cell secretion of inflammation and invasion mediators. Because epithelial cells are a disease-inducing component of the endometriotic lesion, we explored the response of 12Z immortalized human epithelial endometriotic cells to TNF-alpha.

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Objective: To examine the role of leukemia inhibitory factor (LIF) during in vitro maturation (IVM) on human and mice cumulus expansion and mice oocyte competence by in vitro fertilization (IVF), culture, and embryo transfer (ET).

Design: Prospective animal and human study.

Setting: Serono laboratories and IVF clinic.

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Objective: To design a high-throughput cell assay to identify molecules modulating adhesion induced by tumor necrosis factor alpha (TNF-alpha) of endometrial cells to mesothelium.

Design: Prospective study.

Setting: Biotech company.

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Purpose: To investigate the prevalence and potential clinical significance of epigenetic aberrations in neuroblastoma (NB).

Experimental Design: The methylation status of 11 genes that are frequently epigenetically inactivated in adult cancers was assayed in 13 NB cell lines. The prevalence of RASSF1A and TSP-1 methylation was also analyzed in 56 NBs and 5 ganglioneuromas by methylation-specific PCR.

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Phosphodiesterases (PDEs) are a family of enzymes that hydrolyze cyclic nucleotides to render them biologically inactive. As such, these enzymes are critical regulators of signal transduction pathways that use cyclic nucleotides as second messengers. PDE4 is one such member that has been identified in ovarian tissue and purported to have a role in the regulation of gonadotropin action.

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