Publications by authors named "Omar Nelson"

Epidemiological and observational studies suggest that vitamin D has potential for the chemoprevention of ovarian cancer. The anticancer effect of vitamin D in the fallopian tube epithelium (FTE), which is now thought to harbor the precursor cells for high grade ovarian cancer, is not known. The purpose of this study was to investigate whether vitamin D can inhibit carcinogenesis in the mogp-TAg fallopian tube (FT) ovarian cancer mouse model and examine underlying mechanisms.

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Objective: Recent evidence suggests that the fimbriated end of the fallopian tube harbors the precursor cells for many high-grade ovarian cancers, opening the door for development of better screening methods that directly assess the fallopian tube in women at risk for malignancy. Previously we have shown that the karyometric signature is abnormal in the fallopian tube epithelium in women at hereditary risk of ovarian cancer. In this study, we sought to determine whether the karyometric signature in serous tubal intraepithelial carcinoma (STIC) is significantly different from normal, and whether an abnormal karyometric signature can be detected in histologically normal tubal epithelial cells adjacent to STIC lesions.

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Recent studies suggest that the fallopian tube epithelium (FTE) harbors the precursor for high-grade ovarian cancer, creating opportunities for targeting the FTE for ovarian cancer prevention. Preclinical evidence supports progestins as ovarian cancer preventives, but the effect of progestins on the FTE is not well characterized. The murine oviduct-specific glycoprotein promotor-driven simian virus 40 large T-Antigen (mogp-TAg) transgenic mouse model develops neoplastic lesions in the fallopian tube in a manner similar to that described in human fallopian tube and ovarian cancers.

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Significance: Most cases of high-grade serous ovarian carcinoma originate as serous tubal intraepithelial carcinoma (STIC) lesions in the fallopian tube epithelium (FTE), enabling early endoscopic detection.

Aim: The cell-acquiring fallopian endoscope (CAFE) was built to meet requirements for locating potentially pathological tissue indicated by an alteration in autofluorescence or presence of a targeted fluorophore. A channel was included for directed scrape biopsy of cells from regions of interest.

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Epithelial ovarian cancer represents a group of heterogeneous diseases with high grade serous cancer (HGSC) representing the most common histotype. Molecular profiles of precancerous lesions found in the fallopian tube have implicated this tissue as the presumptive site of origin of HGSC. Precancerous lesions are primarily found in the distal fallopian tube (fimbria), near the ovary relative to the proximal tissue (ampulla), nearer to the uterus.

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Background: Post-surgery adjuvant radiotherapy (RT) significantly improves clinical outcomes in breast cancer patients; however, some patients develop cancer or treatment-related pain that negatively impacts quality of life. This study examined an inflammatory biomarker, C-reactive protein (CRP), in RT-related pain in breast cancer.

Methods: During 2008 and 2014, breast cancer patients who underwent RT were prospectively evaluated for pre- and post-RT pain.

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The intramembrane proteolytic activities of presenilins (PSEN1/PS1 and PSEN2/PS2) underlie production of β-amyloid, the key process in Alzheimer's disease (AD). Dysregulation of presenilin-mediated signaling is linked to cancers. Inhibition of the γ-cleavage activities of PSENs that produce Aβ, but not the ε-like cleavage activity that release physiologically essential transcription activators, is a potential approach for the development of rational therapies for AD.

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Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and minorities have the worst survival. However, the molecular mechanisms underlying survival disparities have not been elucidated.

Methods: In a retrospective study, we assessed association between HNSCC early death (<2 years) and 208 somatic mutations of 10 cancer-related genes in 214 patients: 98 non-Hispanic whites (46%), 72 Hispanic whites (34%), and 44 African Americans (20%).

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Pain related to cancer or treatment is a critical quality of life issue for breast cancer survivors. In a prospective study of 375 patients with breast cancer (enrolled during 2008-2014), we characterized the risk factors for adjuvant radiotherapy (RT)-associated pain. Pain score was assessed at pre-RT and post-RT as the mean of 4 pain severity items (ie, pain at its worst, least, average, and now) from the Brief Pain Inventory with 11-point numeric rating scale (0-10).

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We evaluated predictors of radiation-induced skin toxicity in a prospective study of a tri-racial/ethnic breast cancer population. We evaluated patient demographics, tumor characteristics, and treatment variables in the first 392 patients in a prospective study assessing radiation-induced skin toxicity. Logistic regression analyses were conducted to evaluate potential predictors of skin toxicity.

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Missense mutations in presenilin 1 (PS1) and presenilin 2 (PS2) proteins are a major cause of familial Alzheimer disease. Presenilins are proteins with nine transmembrane (TM) domains that function as catalytic subunits of the γ-secretase complex responsible for the cleavage of the amyloid precursor protein and other type I transmembrane proteins. The water-filled cavity within presenilin is necessary to mediate the intramembrane proteolysis reaction.

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Mutations in presenilins 1 and 2 (PS1 and PS2) are responsible for approximately 40% of all early onset familial Alzheimer's disease (FAD) monogenic cases. Presenilins (PSs) function as the catalytic subunit of γ-secretase and support cleavage of the amyloid-β protein precursor (AβPP). We previously discovered that PSs also function as passive endoplasmic reticulum (ER) calcium (Ca2+) leak channels and that most FAD mutations in PSs affected their ER Ca2+ leak function.

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Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited, neurodegenerative disease caused by an expansion of polyglutamine tracts in the cytosolic protein ataxin-2 (Atx2). Cerebellar Purkinje cells (PCs) are predominantly affected in SCA2. The cause of PC degeneration in SCA2 is unknown.

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Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is an autosomal-dominant neurodegenerative disorder caused by a polyglutamine expansion in ataxin-3 (ATX3; MJD1) protein. In biochemical experiments, we demonstrate that mutant ATX3(exp) specifically associated with the type 1 inositol 1,4,5-trisphosphate receptor (InsP(3)R1), an intracellular calcium (Ca(2+)) release channel. In electrophysiological and Ca(2+) imaging experiments, we show that InsP(3)R1 was sensitized to activation by InsP(3) in the presence of mutant ATX3(exp).

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Mutations in presenilins are responsible for approximately 40% of all early-onset familial Alzheimer disease (FAD) cases in which a genetic cause has been identified. In addition, a number of mutations in presenilin-1 (PS1) have been suggested to be associated with the occurrence of frontal temporal dementia (FTD). Presenilins are highly conserved transmembrane proteins that support cleavage of the amyloid precursor protein by gamma-secretase.

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Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder. Mutations in presenilins 1 and 2 (PS1 and PS2) account for approximately 40% of familial AD (FAD) cases. FAD mutations and genetic deletions of presenilins have been associated with calcium (Ca(2+)) signaling abnormalities.

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Alzheimer's disease is characterized by neuronal degeneration in the cerebral cortex and hippocampus and subcortical neuronal degeneration in such nuclei as the locus coeruleus (LC). Transgenic mice overexpressing mutant human amyloid precursor protein V717F, PDAPP mice, develop several Alzheimer's disease-like lesions. The present study sought to determine whether there is also loss of LC noradrenergic neurons or evidence of degenerative changes in these animals.

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The dopaminergic neurons in the ventral substantia nigra (SN) are significantly more vulnerable to degeneration in Parkinson's disease (PD) than the dopaminergic neurons in the ventral tegmental area (VTA). The ventral SN neurons also contain significantly more neuromelanin pigment than the dopaminergic neurons in the VTA. In vitro data indicate that neuromelanin pigment is formed from the excess cytosolic catecholamine that is not accumulated into synaptic vesicles by the vesicular monoamine transporter-2 (VMAT2).

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