18 results on '"Bowers SJ"'
Search Results
2. Professional issues. Issues surrounding professional portfolio development for nurses.
- Author
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Bowers SJ and Jinks AM
- Abstract
This article discusses issues that underpin professional portfolio development for registered nurses. The findings were informed by a review of the pertinent literature. The literature was obtained by undertaking searches of a number of electronic databases and hand searches of key journals. It was found that portfolio development has been a requirement for re-registration for a number of years. However, there appears to remain confusion and uncertainty among professionals regarding the meaning and implications of portfolio development for nurses. For example, in the review conducted, the terminology used was often found to be confusing and expectations of how a portfolio should look are unclear. Conclusions can be drawn that practitioners may be in a quandary of how to develop and present evidence in what is now a mandatory requirement for re-registration, the maintenance of a professional portfolio. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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- View/download PDF
3. A Prebiotic Diet Containing Galactooligosaccharides and Polydextrose Produces Dynamic and Reproducible Changes in the Gut Microbial Ecosystem in Male Rats.
- Author
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Thompson RS, Bowers SJ, Vargas F, Hopkins S, Kelley T, Gonzalez A, Lowry CA, Dorrestein PC, Vitaterna MH, Turek FW, Knight R, Wright KP Jr, and Fleshner M
- Subjects
- Animals, Male, Rats, Bile Acids and Salts metabolism, Feces microbiology, Bacteria classification, Bacteria metabolism, RNA, Ribosomal, 16S, Diet methods, Prebiotics, Gastrointestinal Microbiome drug effects, Rats, Sprague-Dawley, Oligosaccharides pharmacology, Oligosaccharides administration & dosage, Glucans
- Abstract
Despite substantial evidence supporting the efficacy of prebiotics for promoting host health and stress resilience, few experiments present evidence documenting the dynamic changes in microbial ecology and fecal microbially modified metabolites over time. Furthermore, the literature reports a lack of reproducible effects of prebiotics on specific bacteria and bacterial-modified metabolites. The current experiments examined whether consumption of diets enriched in prebiotics (galactooligosaccharides (GOS) and polydextrose (PDX)), compared to a control diet, would consistently impact the gut microbiome and microbially modified bile acids over time and between two research sites. Male Sprague Dawley rats were fed control or prebiotic diets for several weeks, and their gut microbiomes and metabolomes were examined using 16S rRNA gene sequencing and untargeted LC-MS/MS analysis. Dietary prebiotics altered the beta diversity, relative abundance of bacterial genera, and microbially modified bile acids over time. PICRUSt2 analyses identified four inferred functional metabolic pathways modified by the prebiotic diet. Correlational network analyses between inferred metabolic pathways and microbially modified bile acids revealed deoxycholic acid as a potential network hub. All these reported effects were consistent between the two research sites, supporting the conclusion that dietary prebiotics robustly changed the gut microbial ecosystem. Consistent with our previous work demonstrating that GOS/PDX reduces the negative impacts of stressor exposure, we propose that ingesting a diet enriched in prebiotics facilitates the development of a health-promoting gut microbial ecosystem.
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- 2024
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4. Protected areas reduce deforestation and degradation and enhance woody growth across African woodlands.
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McNicol IM, Keane A, Burgess ND, Bowers SJ, Mitchard ETA, and Ryan CM
- Abstract
Protected areas are increasingly promoted for their capacity to sequester carbon, alongside biodiversity benefits. However, we have limited understanding of whether they are effective at reducing deforestation and degradation, or promoting vegetation growth, and the impact that this has on changes to aboveground woody carbon stocks. Here we present a new satellite radar-based map of vegetation carbon change across southern Africa's woodlands and combine this with a matching approach to assess the effect of protected areas on carbon dynamics. We show that protection has a positive effect on aboveground carbon, with stocks increasing faster in protected areas (+0.53% per year) compared to comparable lands not under protection (+0.08% per year). The positive effect of protection reflects lower rates of deforestation (-39%) and degradation (-25%), as well as a greater prevalence of vegetation growth (+12%) inside protected lands. Areas under strict protection had similar outcomes to other types of protection after controlling for differences in location, with effect scores instead varying more by country, and the level of threat. These results highlight the potential for protected areas to sequester aboveground carbon, although we caution that in some areas this may have negative impacts on biodiversity, and human wellbeing., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2023.)
- Published
- 2023
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5. A Prebiotic Diet Alters the Fecal Microbiome and Improves Sleep in Response to Sleep Disruption in Rats.
- Author
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Bowers SJ, Summa KC, Thompson RS, González A, Vargas F, Olker C, Jiang P, Lowry CA, Dorrestein PC, Knight R, Wright KP Jr, Fleshner M, Turek FW, and Vitaterna MH
- Abstract
Sleep disruption is a challenging and exceedingly common physiological state that contributes to a wide range of biochemical and molecular perturbations and has been linked to numerous adverse health outcomes. Modern society exerts significant pressure on the sleep/wake cycle via myriad factors, including exposure to electric light, psychological stressors, technological interconnection, jet travel, shift work, and widespread use of sleep-affecting compounds. Interestingly, recent research has identified a link between the microbiome and the regulation of sleep, suggesting that interventions targeting the microbiome may offer unique therapeutic approaches to challenges posed by sleep disruption. In this study, we test the hypothesis that administration of a prebiotic diet containing galactooligosaccharides (GOS) and polydextrose (PDX) in adult male rats improves sleep in response to repeated sleep disruption and during recovery sleep. We found that animals fed the GOS/PDX prebiotic diet for 4 weeks exhibit increased non-rapid eye movement (NREM) and rapid eye movement (REM) sleep during 5 days of sleep disruption and increased total sleep time during 24 h of recovery from sleep disruption compared to animals fed a control diet, despite similar baseline sleep characteristics. Further, the GOS/PDX prebiotic diet led to significant changes in the fecal microbiome. Consistent with previous reports, the prebiotic diet increased the relative abundance of the species Parabacteroides distasonis , which positively correlated with sleep parameters during recovery sleep. Taken together, these findings suggest that the GOS/PDX prebiotic diet may offer an approach to improve resilience to the physiologic challenge of sleep disruption, in part through impacts on the microbiome., Competing Interests: KW reports research support/donated materials from DuPont Nutrition & Biosciences; Grain Processing Corporation; and Friesland Campina Innovation Centre. Financial relationships: consulting with or without receiving fees and/or serving on the advisory boards for Circadian Therapeutics, Ltd., Circadian Biotherapies, Inc., Philips Respironics, and the United States Army Medical Research and Materiel Command – Walter Reed Army Institute of Research. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bowers, Summa, Thompson, González, Vargas, Olker, Jiang, Lowry, Dorrestein, Knight, Wright, Fleshner, Turek and Vitaterna.)
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- 2022
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6. Ruminiclostridium 5, Parabacteroides distasonis, and bile acid profile are modulated by prebiotic diet and associate with facilitated sleep/clock realignment after chronic disruption of rhythms.
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Thompson RS, Gaffney M, Hopkins S, Kelley T, Gonzalez A, Bowers SJ, Vitaterna MH, Turek FW, Foxx CL, Lowry CA, Vargas F, Dorrestein PC, Wright KP Jr, Knight R, and Fleshner M
- Subjects
- Animals, Bacteroidetes, Chromatography, Liquid, Circadian Rhythm, Diet, Male, RNA, Ribosomal, 16S genetics, Rats, Rats, Sprague-Dawley, Sleep, Tandem Mass Spectrometry, Bile Acids and Salts, Prebiotics
- Abstract
Chronic disruption of rhythms (CDR) impacts sleep and can result in circadian misalignment of physiological systems which, in turn, is associated with increased disease risk. Exposure to repeated or severe stressors also disturbs sleep and diurnal rhythms. Prebiotic nutrients produce favorable changes in gut microbial ecology, the gut metabolome, and reduce several negative impacts of acute severe stressor exposure, including disturbed sleep, core body temperature rhythmicity, and gut microbial dysbiosis. In light of previous compelling evidence that prebiotic diet broadly reduces negative impacts of acute, severe stressors, we hypothesize that prebiotic diet will also effectively mitigate the negative impacts of chronic disruption of circadian rhythms on physiology and sleep/wake behavior. Male, Sprague Dawley rats were fed diets enriched in prebiotic substrates or calorically matched control chow. After 5 weeks on diet, rats were exposed to CDR (12 h light/dark reversal, weekly for 8 weeks) or remained on undisturbed normal light/dark cycles (NLD). Sleep EEG, core body temperature, and locomotor activity were recorded via biotelemetry in freely moving rats. Fecal samples were collected on experimental days -33, 0 (day of onset of CDR), and 42. Taxonomic identification and relative abundances of gut microbes were measured in fecal samples using 16S rRNA gene sequencing and shotgun metagenomics. Fecal primary, bacterially modified secondary, and conjugated bile acids were measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Prebiotic diet produced rapid and stable increases in the relative abundances of Parabacteroides distasonis and Ruminiclostridium 5. Shotgun metagenomics analyses confirmed reliable increases in relative abundances of Parabacteroides distasonis and Clostridium leptum, a member of the Ruminiclostridium genus. Prebiotic diet also modified fecal bile acid profiles; and based on correlational and step-wise regression analyses, Parabacteroides distasonis and Ruminiclostridium 5 were positively associated with each other and negatively associated with secondary and conjugated bile acids. Prebiotic diet, but not CDR, impacted beta diversity. Measures of alpha diversity evenness were decreased by CDR and prebiotic diet prevented that effect. Rats exposed to CDR while eating prebiotic, compared to control diet, more quickly realigned NREM sleep and core body temperature (ClockLab) diurnal rhythms to the altered light/dark cycle. Finally, both cholic acid and Ruminiclostridium 5 prior to CDR were associated with time to realign CBT rhythms to the new light/dark cycle after CDR; whereas both Ruminiclostridium 5 and taurocholic acid prior to CDR were associated with NREM sleep recovery after CDR. These results support our hypothesis and suggest that ingestion of prebiotic substrates is an effective strategy to increase the relative abundance of health promoting microbes, alter the fecal bile acid profile, and facilitate the recovery and realignment of sleep and diurnal rhythms after circadian disruption., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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7. Structural diversity and tree density drives variation in the biodiversity-ecosystem function relationship of woodlands and savannas.
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Godlee JL, Ryan CM, Bauman D, Bowers SJ, Carreiras JMB, Chisingui AV, Cromsigt JPGM, Druce DJ, Finckh M, Gonçalves FM, Holdo RM, Makungwa S, McNicol IM, Mitchard ETA, Muchawona A, Revermann R, Ribeiro NS, Siampale A, Syampungani S, Tchamba JJ, Tripathi HG, Wallenfang J, Te Beest M, Williams M, and Dexter KG
- Subjects
- Biodiversity, Forests, Grassland, Ecosystem, Trees
- Abstract
Positive biodiversity-ecosystem function relationships (BEFRs) have been widely documented, but it is unclear if BEFRs should be expected in disturbance-driven systems. Disturbance may limit competition and niche differentiation, which are frequently posited to underlie BEFRs. We provide the first exploration of the relationship between tree species diversity and biomass, one measure of ecosystem function, across southern African woodlands and savannas, an ecological system rife with disturbance from fire, herbivores and humans. We used > 1000 vegetation plots distributed across 10 southern African countries and structural equation modelling to determine the relationship between tree species diversity and above-ground woody biomass, accounting for interacting effects of resource availability, disturbance by fire, tree stem density and vegetation type. We found positive effects of tree species diversity on above-ground biomass, operating via increased structural diversity. The observed BEFR was highly dependent on organismal density, with a minimum threshold of c. 180 mature stems ha
-1 . We found that water availability mainly affects biomass indirectly, via increasing species diversity. The study underlines the close association between tree diversity, ecosystem structure, environment and function in highly disturbed savannas and woodlands. We suggest that tree diversity is an under-appreciated determinant of wooded ecosystem structure and function., (© 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation.)- Published
- 2021
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8. Immunization with a heat-killed bacterium, Mycobacterium vaccae NCTC 11659, prevents the development of cortical hyperarousal and a PTSD-like sleep phenotype after sleep disruption and acute stress in mice.
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Bowers SJ, Lambert S, He S, Lowry CA, Fleshner M, Wright KP, Turek FW, and Vitaterna MH
- Subjects
- Animals, Arousal, Electroencephalography, Hot Temperature, Immunization, Male, Mice, Mice, Inbred C57BL, Mycobacteriaceae, Phenotype, Sleep, Mycobacterium, Stress Disorders, Post-Traumatic
- Abstract
Study Objectives: Sleep deprivation induces systemic inflammation that may contribute to stress vulnerability and other pathologies. We tested the hypothesis that immunization with heat-killed Mycobacterium vaccae NCTC 11659 (MV), an environmental bacterium with immunoregulatory and anti-inflammatory properties, prevents the negative impacts of 5 days of sleep disruption on stress-induced changes in sleep, behavior, and physiology in mice., Methods: In a 2 × 2 × 2 experimental design, male C57BL/6N mice were given injections of either MV or vehicle on days -17, -10, and -3. On days 1-5, mice were exposed to intermittent sleep disruption, whereby sleep was disrupted for 20 h per day. Immediately following sleep disruption, mice were exposed to 1-h social defeat stress or novel cage (control) conditions. Object location memory (OLM) testing was conducted 24 h after social defeat, and tissues were collected 6 days later to measure inflammatory markers. Sleep was recorded using electroencephalography (EEG) and electromyography (EMG) throughout the experiment., Results: In vehicle-treated mice, only the combination of sleep disruption followed by social defeat (double hit): (1) increased brief arousals and NREM beta (15-30 Hz) EEG power in sleep immediately post-social defeat compared to baseline; (2) induced an increase in the proportion of rapid-eye-movement (REM) sleep and number of state shifts for at least 5 days post-social defeat; and (3) induced hyperlocomotion and lack of habituation in the OLM task. Immunization with MV prevented most of these sleep and behavioral changes., Conclusions: Immunization with MV ameliorates a stress-induced sleep and behavioral phenotype that shares features with human posttraumatic stress disorder., (© Sleep Research Society 2020. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.)
- Published
- 2021
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9. Sleep and Circadian Disruption and the Gut Microbiome-Possible Links to Dysregulated Metabolism.
- Author
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Withrow D, Bowers SJ, Depner CM, González A, Reynolds AC, and Wright KP Jr
- Abstract
Insufficient sleep and circadian misalignment are associated with adverse metabolic health outcomes. Alterations in gut microbial diversity occur with insufficient sleep and circadian misalignment, which can lead to modifications in microbial structure and function. Changes in microbially produced and modified metabolites such as short chain fatty acids and secondary bile acids may contribute to chronic inflammation, positive energy balance and endocrine changes, and represent potential mechanisms linking insufficient sleep and circadian misalignment with metabolic dysregulation. Literature primarily from the last two years is reviewed here, examining the impact of sleep and circadian rhythms and their disruption on the gut microbiome in human and non-human models, with an emphasis on the hypothesis that the altered gut microbiome may be one pathway by which insufficient sleep and circadian misalignment dysregulate metabolism.
- Published
- 2021
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10. Repeated sleep disruption in mice leads to persistent shifts in the fecal microbiome and metabolome.
- Author
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Bowers SJ, Vargas F, González A, He S, Jiang P, Dorrestein PC, Knight R, Wright KP Jr, Lowry CA, Fleshner M, Vitaterna MH, and Turek FW
- Subjects
- Animals, Male, Mice, Bacteria classification, Bacteria genetics, Bacteria growth & development, Feces microbiology, Gastrointestinal Microbiome, RNA, Bacterial genetics, RNA, Ribosomal, 16S genetics, Sleep Deprivation microbiology
- Abstract
It has been established in recent years that the gut microbiome plays a role in health and disease, potentially via alterations in metabolites that influence host physiology. Although sleep disruption and gut dysbiosis have been associated with many of the same diseases, studies investigating the gut microbiome in the context of sleep disruption have yielded inconsistent results, and have not assessed the fecal metabolome. We exposed mice to five days of sleep disruption followed by four days of ad libitum recovery sleep, and assessed the fecal microbiome and fecal metabolome at multiple timepoints using 16S rRNA gene amplicons and untargeted LC-MS/MS mass spectrometry. We found global shifts in both the microbiome and metabolome in the sleep-disrupted group on the second day of recovery sleep, when most sleep parameters had recovered to baseline levels. We observed an increase in the Firmicutes:Bacteroidetes ratio, along with decreases in the genus Lactobacillus, phylum Actinobacteria, and genus Bifidobacterium in sleep-disrupted mice compared to control mice. The latter two taxa remained low at the fourth day post-sleep disruption. We also identified multiple classes of fecal metabolites that were differentially abundant in sleep-disrupted mice, some of which are physiologically relevant and commonly influenced by the microbiome. This included bile acids, and inference of microbial functional gene content suggested reduced levels of the microbial bile salt hydrolase gene in sleep-disrupted mice. Overall, this study adds to the evidence base linking disrupted sleep to the gut microbiome and expands it to the fecal metabolome, identifying sleep disruption-sensitive bacterial taxa and classes of metabolites that may serve as therapeutic targets to improve health after poor sleep., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
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11. Chronic Alcohol Exposure and the Circadian Clock Mutation Exert Tissue-Specific Effects on Gene Expression in Mouse Hippocampus, Liver, and Proximal Colon.
- Author
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Summa KC, Jiang P, Fitzpatrick K, Voigt RM, Bowers SJ, Forsyth CB, Vitaterna MH, Keshavarzian A, and Turek FW
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- Animals, Colon drug effects, Ethanol administration & dosage, Liver drug effects, Male, Mice, Mutation, Organ Specificity drug effects, CLOCK Proteins genetics, Colon metabolism, Ethanol pharmacology, Gene Expression Regulation drug effects, Hippocampus drug effects, Hippocampus metabolism, Liver metabolism
- Abstract
Background: Chronic alcohol exposure exerts numerous adverse effects, although the specific mechanisms underlying these negative effects on different tissues are not completely understood. Alcohol also affects core properties of the circadian clock system, and it has been shown that disruption of circadian rhythms confers vulnerability to alcohol-induced pathology of the gastrointestinal barrier and liver. Despite these findings, little is known of the molecular interactions between alcohol and the circadian clock system, especially regarding implications for tissue-specific susceptibility to alcohol pathologies. The aim of this study was to identify changes in expression of genes relevant to alcohol pathologies and circadian clock function in different tissues in response to chronic alcohol intake., Methods: Wild-type and circadian Clock(Δ19) mutant mice were subjected to a 10-week chronic alcohol protocol, after which hippocampal, liver, and proximal colon tissues were harvested for gene expression analysis using a custom-designed multiplex magnetic bead hybridization assay that provided quantitative assessment of 80 mRNA targets of interest, including 5 housekeeping genes and a predetermined set of 75 genes relevant for alcohol pathology and circadian clock function., Results: Significant alterations in expression levels attributable to genotype, alcohol, and/or a genotype by alcohol interaction were observed in all 3 tissues, with distinct patterns of expression changes observed in each. Of particular interest was the finding that a high proportion of genes involved in inflammation and metabolism on the array was significantly affected by alcohol and the Clock(Δ19) mutation in the hippocampus, suggesting a suite of molecular changes that may contribute to pathological change., Conclusions: These results reveal the tissue-specific nature of gene expression responses to chronic alcohol exposure and the Clock(Δ19) mutation and identify specific expression profiles that may contribute to tissue-specific vulnerability to alcohol-induced injury in the brain, colon, and liver., (Copyright © 2015 by the Research Society on Alcoholism.)
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- 2015
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12. Preclinical assessment of the distribution of maraviroc to potential human immunodeficiency virus (HIV) sanctuary sites in the central nervous system (CNS) and gut-associated lymphoid tissue (GALT).
- Author
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Walker DK, Bowers SJ, Mitchell RJ, Potchoiba MJ, Schroeder CM, and Small HF
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- Animals, Cyclohexanes administration & dosage, Drug Evaluation, Preclinical, Feasibility Studies, HIV drug effects, HIV Fusion Inhibitors administration & dosage, Male, Maraviroc, Rats, Tissue Distribution, Triazoles administration & dosage, Brain metabolism, Cyclohexanes pharmacokinetics, HIV Fusion Inhibitors pharmacokinetics, Intestinal Mucosa metabolism, Lymphoid Tissue metabolism, Triazoles pharmacokinetics
- Abstract
1. Growing knowledge of the pathogenesis of human immunodeficiency virus (HIV)-1 infection has led to the identification of potential virus sanctuary sites within the central nervous system and gut-associated lymphoid tissue. 2. Maraviroc is a novel CCR5 antagonist for the treatment of HIV-1 infection. Disposition studies have been performed within the preclinical testing of maraviroc to determine its distribution to these anatomical sites. 3. Maraviroc, which is a substrate of the efflux transporter P-glycoprotein, shows limited distribution to the central nervous system as evidenced by cerebrospinal fluid concentrations that were 10% of the free plasma concentration following intravenous infusion to rats. Tissue distribution studies also indicated limited distribution of radioactivity into brain tissue of rats. 4. Radioactivity in gut-associated lymphoid tissue lymph nodes exceeded the concentrations in blood and concentrations in the contents of thoracic ducts of the lymphatic system were similar to blood levels following intravenous administration to rats.
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- 2008
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13. Genomic instability during Myc-induced lymphomagenesis in the bursa of Fabricius.
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Neiman PE, Kimmel R, Icreverzi A, Elsaesser K, Bowers SJ, Burnside J, and Delrow J
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- Animals, Base Sequence, Chick Embryo, DNA, Complementary genetics, Female, Gene Amplification, Gene Dosage, Gene Expression Profiling, Genetic Vectors genetics, Inbreeding, Lymphoma, B-Cell etiology, Male, Nucleic Acid Hybridization, Oligonucleotide Array Sequence Analysis, Precancerous Conditions genetics, RNA, Messenger biosynthesis, RNA, Messenger genetics, RNA, Neoplasm biosynthesis, RNA, Neoplasm genetics, Repetitive Sequences, Nucleic Acid, Retroviridae genetics, Bursa of Fabricius pathology, Cell Transformation, Neoplastic genetics, Chickens genetics, Genes, myc, Genomic Instability, Lymphoma, B-Cell genetics
- Abstract
Retroviral vector-mediated overexpression of c-myc in embryonic bursal precursors induces multi-staged tumorigenesis beginning with preneoplastic-transformed follicles (TF) and progressing to clonal metastatic B-cell lymphomas. Using a 13K chicken cDNA microarray, specifically enriched for chicken immune system expressed sequence tagged (ESTs), we carried out array-based comparative genomic hybridization (array-CGH) and detected significant DNA copy number change at many loci on most or all chromosomes in both early TF and end-stage lymphomas. Formation of long palindromes, through breakage-fusion-bridge cycles, is thought to play an early role in gene amplification. Employing genome-wide analysis of palindrome formation (GAPF), we detected extensive palindrome formation in early TF and end-stage lymphomas. The population of loci showing amplification by array-CGH was enriched for palindromes detected by GAPF providing strong evidence for genetic instability early in Myc-induced tumorigenesis and further support for the role of palindromes in gene amplification. Comparing gene copy number change and RNA expression changes profiled on the same cDNA array, we detected very little consistent contribution of gene copy number change to RNA expression changes. Palindromic loci in TF and tumors, however, were expressed, many at high levels, suggesting an abundance of RNA species with long double-stranded segments generated during tumorigenesis.
- Published
- 2006
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14. Reduced Myc overexpression and normal B-cell differentiation mediate resistance to avian leukosis virus lymphomagenesis.
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Parghi SS, Brandvold KA, Bowers SJ, Neiman PE, and Ruddell A
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- Animals, Antigens, Differentiation, B-Lymphocyte physiology, Avian Leukosis Virus genetics, Bursa of Fabricius pathology, Cell Differentiation, Cell Transformation, Viral, Chick Embryo, Chickens, Enhancer Elements, Genetic, Gene Expression Regulation, Neoplastic, Gene Expression Regulation, Viral, Genetic Predisposition to Disease, Proviruses genetics, Terminal Repeat Sequences, Virus Integration, Avian Leukosis genetics, Avian Leukosis Virus physiology, B-Lymphocytes cytology, Genes, myc, Proto-Oncogene Proteins c-myc physiology
- Abstract
Avian leukosis virus (ALV) induces bursal lymphoma in tumor-susceptible chicken strains after proviral integration within the c-myc gene, and subsequent expansion of Myc-overexpressing lymphocytes within transformed follicles. Line 6(3) strain chickens are resistant to ALV tumorigenesis, largely failing to develop Myc-transformed follicles, although they show similar levels of ALV infection and integration as lymphoma-susceptible strains. Immunohistochemical analysis determined that the transformed follicles that do arise in lymphoma-resistant birds show much lower and more variable Myc overexpression than those of susceptible birds. This reduced Myc overexpression fails to block B-cell differentiation in resistant birds, while high Myc consistently blocks development at a late embryo stage in susceptible birds. This failure of Myc to block differentiation results in a normal pattern of posthatching bursal emigration in resistant transformed follicles, while transformed follicles of susceptible birds grow rapidly due to blocked emigration. Forced Myc overexpression produces transformed follicles in resistant birds, indicating that resistant lymphocytes can tolerate high Myc expression. The coding sequence and expression of the endogenous c-myc gene is the same in resistant and susceptible birds, suggesting that genetic resistance is instead mediated by reduced ALV LTR enhancer-driven transcription in the target lymphocytes of resistant birds.
- Published
- 2004
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15. Role of Mtd/Bok in normal and neoplastic B-cell development in the bursa of Fabricius.
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Brown CY, Bowers SJ, Loring G, Heberden C, Lee RM, and Neiman PE
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- Amino Acid Sequence, Animals, B-Lymphocytes immunology, Bursa of Fabricius embryology, Cell Fractionation, Cell Line, Tumor, Cell Transformation, Neoplastic immunology, Chick Embryo embryology, Immunoblotting veterinary, Lymphoma, B-Cell embryology, Lymphoma, B-Cell immunology, Mitochondria immunology, Molecular Sequence Data, Protein Isoforms immunology, Proto-Oncogene Proteins c-bcl-2 genetics, RNA blood, RNA genetics, Sequence Alignment, Transfection veterinary, Apoptosis immunology, B-Lymphocytes cytology, Bursa of Fabricius immunology, Cell Transformation, Neoplastic pathology, Chick Embryo immunology, Lymphoma, B-Cell pathology, Proto-Oncogene Proteins c-bcl-2 immunology
- Abstract
B-cell development in the bursa of Fabricius is accompanied by extensive apoptotic cell death. Apoptosis, however, is suppressed during c-myc-induced neoplasia. The experiments described here suggest that Mtd/Bok may drive apoptosis during normal development, and that this activity is blocked during myc-induced tumorigenesis. Bursal Mtd/Bok expression increases during development, correlating with the onset of intense, spontaneous apoptosis after hatching. Two isoforms of Mtd/Bok were characterized: WT-chMtd/Bok, found predominantly in the mitochondria and a less abundant form, lacking the presumptive transmembrane domain, Mtd/Bok deltaTM, found predominantly in the cytosol. Over-expression of Mtd/Bok deltaTM in a bursal lymphoma-derived cell line, DT40, reduced mitochondrial function and sensitized DT40 cells to apoptotic stimuli, while WT-chMtd/Bok had a diminished phenotype in these cells. In contrast, retroviral transduction of bursal stem cells with WT-chMtd/Bok ablated normal stem cell function in transplantation experiments, and produced extensive apoptosis in myc-induced pre-neoplastic bursal populations, but not in tumor cells., (Copyright 2003 Elsevier Ltd.)
- Published
- 2004
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16. Issues surrounding professional portfolio development for nurses.
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Bowers SJ and Jinks AM
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- Career Mobility, Clinical Competence, Employee Performance Appraisal, Humans, Licensure, Nursing, Documentation, Education, Nursing, Continuing, Job Application, Nursing Staff education, Staff Development
- Abstract
This article discusses issues that underpin professional portfolio development for registered nurses. The findings were informed by a review of the pertinent literature. The literature was obtained by undertaking searches of a number of electronic databases and hand searches of key journals. It was found that portfolio development has been a requirement for re-registration for a number of years. However, there appears to remain confusion and uncertainty among professionals regarding the meaning and implications of portfolio development for nurses. For example, in the review conducted, the terminology used was often found to be confusing and expectations of how a portfolio should look are unclear. Conclusions can be drawn that practitioners may be in a quandary of how to develop and present evidence in what is now a mandatory requirement for re-registration, the maintenance of a professional portfolio.
- Published
- 2004
- Full Text
- View/download PDF
17. Silent point mutation in an avian retrovirus RNA processing element promotes c-myb-associated short-latency lymphomas.
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Polony TS, Bowers SJ, Neiman PE, and Beemon KL
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- Animals, Avian Leukosis genetics, Avian Leukosis virology, Avian Leukosis Virus physiology, Base Sequence, Chick Embryo, DNA, Viral genetics, Genes, env, Lymphoma, B-Cell genetics, Lymphoma, B-Cell virology, Oncogene Proteins v-myb genetics, Oncogene Proteins v-myb physiology, Point Mutation, RNA Processing, Post-Transcriptional genetics, RNA Splicing genetics, RNA, Messenger genetics, RNA, Messenger metabolism, RNA, Viral genetics, RNA, Viral metabolism, Sequence Deletion, Viral Matrix Proteins genetics, Viral Matrix Proteins physiology, Virus Integration genetics, Virus Replication genetics, Avian Leukosis etiology, Avian Leukosis Virus genetics, Avian Leukosis Virus pathogenicity, Genes, myb, Lymphoma, B-Cell etiology
- Abstract
The avian leukosis virus DeltaLR-9 causes a high frequency of B-cell lymphomas within weeks after injection into 10-day-old chicken embryos. These lymphomas result from proviral integrations into the oncogene c-myb. In contrast, LR-9, which lacks the 42-nucleotide gag gene deletion of DeltaLR-9, does not cause a high frequency of c-myb-associated short-latency lymphomas. Although viral replication rates and spliced env mRNA levels were found to be similar for both viruses, DeltaLR-9 exhibited an increase in readthrough transcription compared to LR-9. The DeltaLR-9 deletion is located in the region of the gag gene corresponding to the matrix (MA) protein as well as in the negative regulator of splicing (NRS) element. To test whether disruption of the NRS or of the MA protein was responsible for inducing short-latency lymphomas, we generated viruses with NRS point mutations that maintained the wild-type Gag amino acid sequence. One of the mutant viruses induced an even higher incidence than DeltaLR-9 of short-latency lymphomas with viral integrations into c-myb. Thus, we propose that disruption of the NRS sequence promotes readthrough transcription and splicing to the downstream myb gene, causing overexpression of a slightly truncated Myb protein, which induces short-latency tumors.
- Published
- 2003
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18. Functional genomic analysis reveals distinct neoplastic phenotypes associated with c-myb mutation in the bursa of Fabricius.
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Neiman PE, Grbiç JJ, Polony TS, Kimmel R, Bowers SJ, Delrow J, and Beemon KL
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- Animals, Avian Leukosis Virus genetics, B-Lymphocytes metabolism, B-Lymphocytes pathology, Bursa of Fabricius metabolism, Cell Cycle Proteins biosynthesis, Cell Cycle Proteins genetics, Cell Division genetics, Chick Embryo, Defective Viruses genetics, Gene Expression Profiling, Genes, myc, Genes, rel, Lymphoma metabolism, Lymphoma pathology, Neoplasm Metastasis, Neoplasm Proteins biosynthesis, Neoplasm Proteins genetics, Oligonucleotide Array Sequence Analysis, Phenotype, Proto-Oncogene Proteins c-myc biosynthesis, Proto-Oncogene Proteins c-myc genetics, Signal Transduction genetics, Time Factors, Bursa of Fabricius pathology, Chickens genetics, Gene Expression Regulation, Neoplastic genetics, Genes, myb, Lymphoma genetics
- Abstract
Avian retroviral integration into the c-myb locus is casually associated with the development of lymphomas in the bursa of Farbricius of chickens; these arise with a shorter latency than bursal lymphomas caused by deregulation of c-myc. This study indicates that c-myb mutation in embryonic bursal precursors leads to an oligoclonal population of developing bursal follicles, showing a variable propensity to form a novel lesion, the neoplastic follicle (NF). About half of such bursas rapidly developed lymphomas. Detection of changes in gene expression, during the development of neoplasms, was carried out by cDNA microarray analysis. The transcriptional signature of lymphomas with mutant c-myb was more limited than, and only partially shared with, those of bursal lymphomas caused by Myc or Rel oncogenes. The c-myb-associated lymphomas frequently showed overexpression of c-myc and altered expression of other genes involved in cell cycle control and proliferation-related signal transduction. Oligoclonal, NF-containing bursas lacked detectable c-myc overexpression and demonstrated a pattern of gene expression distinct from that of normal bursa and partially shared with the short-latency lymphomas. This functional genomic analysis uncovered several different pathways of lymphomagenesis by oncogenic transcription factors acting in a B-cell lineage.
- Published
- 2003
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