93 results on '"Duggan KA"'
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2. 0203 THE EFFECT OF EXPERIMENTALLY MANIPULATING NAP FREQUENCY ON NIGHTTIME SLEEP QUALITY: AN ACTIGRAPHY STUDY
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Hernandez, LT, primary, McDevitt, EA, additional, Cellini, N, additional, Duggan, KA, additional, Granados, S, additional, and Mednick, SC, additional
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- 2017
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3. MECHANISMS UNDERLYING THE DECREASE IN CIRCULATING ANGIOTENSIN II CONCENTRATION AFTER SODIUM LOADING
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Duggan, KA, primary and Ye, VZC, additional
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- 1998
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4. EVIDENCE FOR DIRECT INTERACTION OF KETAMINE WITH α‐ AND β2‐ADRENOCEPTORS
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Bevan, RK, primary, Rose, MA, additional, and Duggan, KA, additional
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- 1997
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5. ACUTE BUT NOT CHRONIC ANGIOTENSIN‐CONVERTING ENZYME INHIBITION INDUCES ENZYME SYNTHESIS IN THE GLOMERULUS OF THE SPONTANEOUSLY HYPERTENSIVE RAT
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Hodge, G., primary, Makarious, MM, additional, Charlesworth, JA, additional, and Duggan, KA, additional
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- 1997
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6. STIMULATION OF GASTRIC OSMORECEPTORS BUT NOT THE SODIUM MONITOR INCREASES RENAL ANGIOTENSIN‐CONVERTING ENZYME ACTIVITY
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Ye, VZC, primary and Duggan, KA, additional
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- 1997
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7. STIMULATION OF THE GASTRIC SODIUM MONITOR REDUCES HEPATIC ANGIOTENSIN‐CONVERTING ENZYME ACTIVITY
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Duggan, KA, primary and Ye, VZC, additional
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- 1997
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8. DIFFERENTIAL EFFICACY OF PERINDOPRIL AND ENALAPRIL IN EXPERIMENTAL DIABETIC NEPHROPATHY
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Duggan, KA, primary, Hodge, G., additional, Makarious, MM, additional, and Charlesworth, JA, additional
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- 1996
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9. CHANGES IN ANGIOTENSIN II METABOLISM CONTRIBUTE TO THE INCREASED PRESSOR RESPONSE TO ANGIOTENSIN AFTER CHRONIC TREATMENT WITH l-NAME IN THE SPONTANEOUSLY HYPERTENSIVE RAT
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Yang, Y., primary, Macdonald, GJ, additional, and Duggan, KA, additional
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- 1996
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10. INCREASES IN THE MYOCARDIAL CONCENTRATION OF VASOACTIVE INTESTINAL PEPTIDE MAY EXPLAIN THE POSITIVE INOTROPIC EFFECT OF ANGIOTENSIN CONVERTING ENZYME INHIBITORS
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Ye, VZC, primary and Duggan, KA, additional
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- 1996
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11. A STUDY OF ANGIOTENSIN II RECEPTORS AFTER CHRONIC INHIBITION OF NITRIC OXIDE SYNTHASE IN THE SPONTANEOUSLY HYPERTENSIVE RAT
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Yang, Y., primary, Macdonald, GJ, additional, and Duggan, KA, additional
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- 1996
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12. Definition of ambulatory blood pressure targets for diagnosis and treatment of hypertension in relation to clinic blood pressure: prospective cohort study.
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Head GA, Mihailidou AS, Duggan KA, Beilin LJ, Berry N, Brown MA, Bune AJ, Cowley D, Chalmers JP, Howe PRC, Hodgson J, Ludbrook J, Mangoni AA, McGrath BP, Nelson MR, Sharman JE, Stowasser M, and Ambulatory Blood Pressure Working Group of the High Blood Pressure Research Council of Australia
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- 2010
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13. Is visual information use during facial emotion recognition related to eating disorder symptoms in college-aged men and women? An experimental study.
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Nudnou I, Duggan KA, Schaefer L, and Balas B
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Background: Previous studies of emotion recognition abilities of people with eating disorders used accuracy to identify performance deficits for these individuals. The current study examined eating disorder symptom severity as a function of emotion categorization abilities, using a visual cognition paradigm that offers insights into how emotional faces may be categorized, as opposed to just how well these faces are categorized., Methods: Undergraduate students (N = 87, 50 women, 34 men, 3 non-binary) completed the Bubbles task and a standard emotion categorization task, as well as a set of questionnaires assessing their eating disorder symptomology and comorbid disorders. We examined the relationship between visual information use (assessed via Bubbles) and eating disorder symptomology (EDDS) while controlling for anxiety (STAI), depression (BDI-II), alexithymia (TAS), and emotion regulation difficulties (DERS-sf)., Results: Overall visual information use (i.e. how well participants used facial features important for accurate emotion categorization) was not significantly related to eating disorder symptoms, despite producing interpretable patterns for each emotion category. Emotion categorization accuracy was also not related to eating disorder symptoms., Conclusions: Results from this study must be interpreted with caution, given the non-clinical sample. Future research may benefit from comparing visual information use in patients with an eating disorder and healthy controls, as well as employing designs focused on specific emotion categories, such as anger., (© 2024. The Author(s).)
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- 2024
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14. When and how perceived control buffers against cognitive declines: A moderated mediation analysis.
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Hamm JM, Lachman ME, Duggan KA, Mogle JA, McGrath R, Parker K, and Klepacz LM
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Although perceived control is a well-established predictor of cognitive aging, less is known about how and under what developmental circumstances these beliefs about personal influence may protect against cognitive declines. Our study examined light physical activity (LPA) as an unexplored mechanism that may link changes in two facets of perceived control (personal mastery, perceived constraints) to longitudinal trajectories of cognitive functioning. We also examined whether mediated pathways were moderated by age (i.e., differed across the adult lifespan). We analyzed two-wave, 9-year data from the national Midlife in the United States Study ( n = 2,456; M
age = 56 years, range = 30-84; 56% female) using autoregressive mediation and moderated mediation models. Mediation models showed that changes in personal mastery and perceived constraints predicted episodic memory and executive functioning via self-reported change in LPA. Only the mediated effects of constraints remained significant in a model that included both mastery and constraints as predictors. Moderated mediation models showed that, for episodic memory, the mediated pathways were strongest in old age and emerged only for constraints: For older but not younger adults, declines in constraints were associated with less decline in episodic memory, as mediated by increases in LPA. Results were consistent in sensitivity analyses that controlled for levels and change in moderate-to-vigorous physical activity. Findings inform lifespan theories of control and provide initial evidence that change in a largely overlooked health behavior (LPA) may underlie the link between perceived constraints and cognitive functioning, with this pathway becoming more pronounced in late life. (PsycInfo Database Record (c) 2024 APA, all rights reserved).- Published
- 2024
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15. Increased frequency of light physical activity during midlife and old age buffers against cognitive declines.
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Hamm JM, Parker K, Lachman ME, Mogle JA, Duggan KA, and McGrath R
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- Humans, Female, Male, Aged, Middle Aged, Aged, 80 and over, Adult, Memory, Episodic, Longitudinal Studies, Aging psychology, Aging physiology, Cognitive Dysfunction prevention & control, Cognitive Dysfunction psychology, United States, Cognition, Exercise psychology, Executive Function physiology
- Abstract
Although it is well established that moderate-to-vigorous physical activity (MVPA) buffers against declines in cognitive health, less is known about the benefits of light physical activity (LPA). Research on the role of LPA is crucial to advancing behavioral interventions to improve late life health outcomes, including cognitive functioning, because this form of physical activity remains more feasible and amenable to change in old age. Our study examined the extent to which increases in LPA frequency protected against longitudinal declines in cognitive functioning and whether such a relationship becomes pronounced in old age when opportunities for MVPA are typically reduced. We analyzed 9-year data from the national Midlife in the United States Study (n = 2,229; M
age = 56 years, range = 33-83; 56% female) using autoregressive models that assessed whether change in LPA frequency predicted corresponding changes in episodic memory and executive functioning in middle and later adulthood. Increases in LPA frequency predicted less decline in episodic memory (β = 0.06, p = .004) and executive functioning (β = 0.14, p < .001) over the 9-year follow-up period, even when controlling for moderate and vigorous physical activity. Effect sizes for moderate and vigorous physical activity were less than half that observed for LPA. Moderation models showed that, for episodic memory, the benefits of increases in LPA frequency were more pronounced at older ages. Findings suggest that increases in LPA over extended periods of time may help slow age-related cognitive declines, particularly in later life when opportunities for MVPA are often diminished., (© 2024. The Author(s).)- Published
- 2024
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16. Individual Differences in Patterns of Developmental Opportunity and Constraint During COVID-19: Implications for Longitudinal Well-Being.
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Hamm JM, Shane J, Pierce MJ, and Duggan KA
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Individual differences in sociodemographic characteristics and trait-like perceptions of opportunities and constraints may shape responses to adversities such as the onset of the COVID-19 pandemic. However, little is known about how these factors combine to form multifaceted profiles of developmental opportunity and constraint or the implications of such profiles for longitudinal well-being following major life stressors. Using a national sample of U.S. adults ( n = 293), we used latent profile analysis to identify profiles based on relevant sociodemographic characteristics (age, SES, chronic conditions, functional status) and trait-like perceptions of opportunity and constraints (perceived mastery, perceived constraints). Results showed that three common profiles emerged at pandemic onset (veridical opportunity, perceived constraints, perceived opportunity). Subsequent latent growth models showed that, despite reporting more sociodemographic constraints, the perceived opportunity profile exhibited better 1-year emotional well-being (positive and negative affect) during the pandemic than the perceived constraints profile. Findings advance the literature by identifying multifaceted individual differences in profiles of developmental opportunity and constraint and by showing these profiles have consequences for longitudinal well-being following the pandemic onset., Competing Interests: The authors have no conflicts of interest to disclose.
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- 2023
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17. Context-Dependent Shifts in Self-Regulatory Personality Processes During COVID-19: Changes in Control Predict Dynamic Shifts in Goal Reengagement Capacity.
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Hamm JM, Barlow MA, Garcia OG, and Duggan KA
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The ability to reengage with new attainable goals after major setbacks is a core self-regulatory trait linked to health and well-being. Yet little is known about the extent to which such goal reengagement capacities may shift over time in response to changing contextual circumstances. Using a nationally-representative sample of U.S. adults aged 18-80 ( n = 293), the present 1-year study examined whether changes in opportunity to influence life circumstances (perceived control) were coupled with dynamic shifts in goal reengagement capacity for individuals who differed in their levels of control at pandemic onset. Results of multilevel models showed that within-person increases in perceived control during the pandemic predicted corresponding within-person increases in goal reengagement capacity. Moderation models showed that the positive within-person association between perceived control and goal reengagement was pronounced for individuals with lower levels of control at pandemic onset who may be particularly sensitive to periods of opportunity to pursue new attainable goals. Findings inform theories of personality and self-regulation in pointing to contextual circumstances under which goal reengagement capacity exhibits dynamic shifts in populations who differ in their perceived opportunities for control., Competing Interests: The authors have no conflicts of interest to disclose.
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- 2023
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18. Conscientiousness and Cardiometabolic Risk: A Test of the Health Behavior Model of Personality Using Structural Equation Modeling.
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Thomas MC, Duggan KA, Kamarck TW, Wright AGC, Muldoon MF, and Manuck SB
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- Adult, Cross-Sectional Studies, Female, Humans, Latent Class Analysis, Male, Middle Aged, Personality, Cardiovascular Diseases, Health Behavior
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Background: High trait conscientiousness is associated with lower cardiometabolic risk, and health behaviors are a putative but relatively untested pathway that may explain this association., Purpose: To explore the role of key health behaviors (diet, physical activity, substance use, and sleep) as links between conscientiousness and cardiometabolic risk., Methods: In a cross-sectional analysis of 494 healthy, middle-aged working adults (mean age = 42.7 years, 52.6% women, 81.0% White), participants provided self-reports of conscientiousness, physical activity, substance use, diet, and sleep, and wore monitors over a 7-day monitoring period to assess sleep (Actiwatch-16) and physical activity (SenseWear Pro3). Cardiometabolic risk was expressed as a second-order latent variable from a confirmatory factor analysis involving insulin resistance, dyslipidemia, obesity, and blood pressure. Direct, indirect, and specific indirect effect pathways linking conscientiousness to health behaviors and cardiometabolic risk were examined. Unstandardized indirect effects for each health behavior class were computed separately using bootstrapped samples., Results: After controlling for demographics (sex, age, race, and education), conscientiousness showed the predicted, inverse association with cardiometabolic risk. Among the examined health behaviors, objectively-assessed sleep midpoint variability (b = -0.003, p = .04), subjective sleep quality (b = -0.003, p = .025), and objectively-assessed physical activity (b = -0.11, p = .04) linked conscientiousness to cardiometabolic risk., Conclusions: Physical activity and sleep partially accounted for the relationship between conscientiousness and cardiometabolic risk., (© Society of Behavioral Medicine 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2022
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19. Goal adjustment capacities in uncontrollable life circumstances: Benefits for psychological well-being during COVID-19.
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Hamm JM, Tan JXY, Barlow MA, Delaney RL, and Duggan KA
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Goal adjustment capacities (i.e., goal disengagement and goal reengagement) are core self-regulatory resources theorized to buffer psychological well-being during intractable life circumstances. However, research has yet to examine whether these capacities protect well-being for individuals who encounter uncontrollable losses in their ability to pursue important life goals due to the COVID-19 pandemic. Using a nationally-representative sample of U.S. adults aged 18-80 ( n = 292), the present longitudinal study examined the extent to which goal disengagement and reengagement predicted levels and change in psychological well-being for individuals who differed in perceived control over their goals early in the pandemic. Results from multilevel growth models showed that goal reengagement, but not goal disengagement, capacities predicted higher levels of well-being during the pandemic (lower perceived stress, depressive symptoms; higher life satisfaction, meaning in life). Moderation models showed the benefits of goal reengagement for well-being were pronounced among individuals who perceived pandemic-induced declines in control over their goals. Findings inform theories of motivation and self-regulation and point to the adaptive value of goal reengagement capacities during uncontrollable life circumstances., (© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022.)
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- 2022
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20. Pathways connecting family socioeconomic status in adolescence and sleep continuity in adult Black and White men.
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Matthews KA, Lee L, Duggan KA, and Pardini DA
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- Actigraphy, Adolescent, Adult, Black or African American, Black People, Humans, Male, Sleep, Social Class
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Objective: To evaluate the roles of parenting and adolescent characteristics during ages 13 to 16 in connecting family socioeconomic status (SES) during adolescence with adult sleep in Black and White men., Design: Longitudinal school-based community study beginning in 1987-1988 when participants were enrolled in the first or seventh grade., Setting: Pittsburgh, PA., Participants: 291 men (54.4% Black, mean age = 33, SD = 2.5) participated in 2012-2014 in a week-long study of sleep measured by actigraphy and diary., Measures: In adolescence (ages 13-16), measures of family SES based on occupation, education, income and public assistance; parenting based on monitoring, positive expectations for future, warm parent-child relationship, and communication; and adolescent characteristics based on anxiety, hyperactivity/impulsivity, and peer rejection. In adulthood, participant SES, minutes awake after sleep onset (WASO), duration, and diary-assessed sleep quality., Results: Structural equation modeling confirmed significant indirect pathways: (1) low family SES in adolescence to negative parenting to low adult SES to greater WASO; (2) low family SES in adolescence to adolescent characteristics to low adult SES to greater WASO; (3) Black race to low family SES in adolescence to negative parenting to low adult SES to greater WASO; and (4) Black race to low family SES in adolescence to adolescent characteristics to adult SES to greater WASO. Similar models for duration and quality were not confirmed., Conclusions: Parenting and adolescent characteristics may have an indirect association with adult sleep continuity. Parenting and mental health interventions in adolescence may improve adult sleep., (Copyright © 2021 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.)
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- 2021
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21. Prospective Associations of Parenting and Childhood Maltreatment with Personality in Adolescent Males.
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Cundiff JM, Duggan KA, Xia M, and Matthews KA
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- Adolescent, Child, Extraversion, Psychological, Humans, Longitudinal Studies, Male, Personality, Child Abuse, Parenting
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This longitudinal study examines whether early experiences with caregivers between the ages of 10 and 12 are associated with later adolescent personality at age 16 using both parent and child reports. Lower positive parenting was prospectively associated with higher neuroticism and lower extraversion and conscientiousness for both parent and self-reports of personality, as well as lower openness and agreeableness by parent report. Substantiated maltreatment was prospectively associated with greater neuroticism and lower agreeableness and conscientiousness assessed by parent report. Prospective associations were similar across Black and White participants. Positive parenting and, to a lesser extent, a lack of maltreatment were associated with adaptive personality profiles in adolescents, and associations were stronger for parent reports of personality., (© 2021 Society for Research on Adolescence.)
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- 2021
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22. Big 5 personality traits and intraindividual variability in sleep duration, continuity, and timing.
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Mead MP, Persich MR, Duggan KA, Veronda A, and Irish LA
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- Humans, Neuroticism, Self Report, Sleep, Young Adult, Extraversion, Psychological, Personality
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Objectives: The personality traits of conscientiousness and neuroticism have been consistently linked to mean-level, self-reported sleep duration and continuity. The present study expands this literature by using actigraphy sleep assessment to examine how personality is related to both mean-level and the intraindividual variability in sleep duration, continuity, and timing., Design: One-week ecological sleep assessment., Setting: The research was conducted at a mid-size Midwestern university. Actigraphy data were collected at participants' homes., Participant: The study had a sample size of 358 college-aged participants., Measurements: Sleep duration, continuity, and timing were assessed for 7 consecutive nights using actigraphy. Participants also completed a self-report assessment of personality., Results: Conscientiousness and extraversion emerged as the key personality predictors of sleep outcomes. Higher conscientiousness was associated with longer average sleep duration and earlier timing, as well as higher consistency in total sleep time. Higher extraversion was associated with later bedtimes, less total sleep time, and more variability in their sleep timing. Neuroticism, agreeableness, and openness to experience were not significantly related to sleep., Conclusion: The study's results highlight the importance of personality in sleep research, with implications for sleep health promotion efforts., (Copyright © 2020 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.)
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- 2021
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23. Vasoactive intestinal peptide infusion reverses existing renal interstitial fibrosis via a blood pressure independent mechanism in the rat.
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Duggan KA, Hodge G, Chen J, Trajanovska S, and Hunter T
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- Animals, Cyclic AMP pharmacology, Fibrosis, Gene Expression drug effects, Infusions, Intravenous, Kidney pathology, Macrophage Activation drug effects, Macrophages drug effects, Mice, Nephritis, Interstitial genetics, Nephritis, Interstitial pathology, RAW 264.7 Cells, Rats, Rats, Inbred SHR, Sodium, Dietary, Tumor Necrosis Factor-alpha biosynthesis, Vasoactive Intestinal Peptide administration & dosage, Blood Pressure drug effects, Nephritis, Interstitial drug therapy, Vasoactive Intestinal Peptide therapeutic use
- Abstract
Dialysis requiring renal failure is a silent epidemic. Despite an annual mortality of 24% the dialysis population has increased by 1-4% per annum. Regardless of the initial injury, tubulointerstitial fibrosis is a feature of the renal pathology and it inversely correlates with declining renal function. Current agents display little efficacy against tubulointerstitial fibrosis. Clearly, therapies effective against tubulointerstitial fibrosis and able to preserve kidney function are needed. Vasoactive intestinal peptide (VIP) has been shown to reverse pre-existing cardiac fibrosis. We sought to determine whether VIP is effective in tubulointerstitial fibrosis. Spontaneous hypertensive rats (SHR) on a 2.2% salt diet were randomised to zero time control, 4 week infusion of VIP (5 pmol/kg/min) or vehicle control infusion. A fourth group, to match the blood pressure reduction achieved in the VIP infused group was included. Fibrosis was quantitated by computerised histomorphometry, changes in pro-fibrotic mediators were measured by quantitative rt-PCR and macrophage activation assessed by cyclic adenosine monophosphate (c-AMP) response to incubation with VIP. Tubulointerstitial fibrosis in the VIP treated rats was significantly lower than the zero time control (P < 0.0005), the vehicle infused control (P < 0.0005) and the blood pressure matched group (P < 0.01). Although all six profibrotic mediators increased over the 4 week experimental period VIP infusion only decreased tumour necrosis alpha (TNFα) expression significantly (P < 0.001). Incubation of RAW264 macrophages with VIP significantly increased c-AMP (P < 0.01). We conclude that VIP infusion reversed existing tubulointerstitial fibrosis suggesting a possible therapeutic role for a VIP based therapy in chronic kidney disease., Competing Interests: Declaration of competing interest KD inventor, founder, shareholder Vectus Biosystems. TH, GH, JC, ST current or former employees and shareholders Vectus Biosystems., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2020
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24. Vasoactive intestinal peptide infusion reverses existing myocardial fibrosis in the rat.
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Duggan KA, Hodge G, Chen J, and Hunter T
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- Angiotensinogen analysis, Angiotensinogen metabolism, Animals, Biomarkers analysis, Biomarkers metabolism, Cardiomyopathies diagnosis, Cardiomyopathies etiology, Disease Models, Animal, Fibrosis, Humans, Infusions, Intravenous, Male, Myocardium metabolism, Rats, Rats, Inbred WKY, Receptor, Angiotensin, Type 1 analysis, Receptor, Angiotensin, Type 1 metabolism, Sodium, Dietary adverse effects, Vasoactive Intestinal Peptide analysis, Vasoactive Intestinal Peptide metabolism, Cardiomyopathies drug therapy, Myocardium pathology, Vasoactive Intestinal Peptide administration & dosage
- Abstract
Congestive cardiac failure has become one of the major health challenges of the 21st century and new therapies are needed to address this problem. The concentration of vasoactive intestinal peptide (VIP) in the heart has been shown to decrease as fibrosis (the pathology leading to heart failure) increases and to become undetectable in end stage cardiomyopathy. We sought to determine whether replenishment of myocardial VIP might treat myocardial fibrosis and therefore represent a new therapeutic target. Wistar Kyoto rats on a high (4.4%) salt diet were randomised to zero time control, 4 week infusion of VIP (5 pmol/kg/min) or vehicle control infusion. Myocardial VIP concentration was measured by radioimmunoassay, fibrosis was quantitated by computerised histomorphometry and changes in pro-fibrotic mediators were measured by quantitative rt-PCR. Myocardial VIP increased significantly in VIP treated rats compared with vehicle treated controls (P < 0.01) while fibrosis in the VIP treated rats was significantly lower than in both the zero time control (P < 0.05) and the vehicle infused control (P < 0.0005). Although all six profibrotic mediators which were measured increased over the 4 week experimental period VIP infusion only affected angiotensinogen (Agt) and angiotensin receptor type 1a (AT
1a ) expression. In both instances VIP caused a significant decrease in messenger rna expression (Agt P < 0.01 and At1a P < 0.01) compared with vehicle infused controls. We conclude that VIP infusion increased myocardial VIP concentration and was able to reverse existing myocardial fibrosis suggesting a possible therapeutic role for a VIP based therapy in cardiac failure., (Copyright © 2019 Vectus Biosystems. Published by Elsevier B.V. All rights reserved.)- Published
- 2019
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25. Prospective associations among objectively and subjectively assessed sleep and the metabolic syndrome.
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Bowman MA, Duggan KA, Brindle RC, Kline CE, Krafty RT, Thayer JF, and Hall MH
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- Aged, Blood Glucose analysis, Depressive Disorder, Major epidemiology, Fasting blood, Female, Follow-Up Studies, Humans, Male, Metabolic Syndrome epidemiology, Middle Aged, Prospective Studies, Risk Factors, Self Report, Sleep Wake Disorders physiopathology, Metabolic Syndrome etiology, Polysomnography methods, Sleep physiology, Sleep Wake Disorders complications
- Abstract
Objective: Subjective sleep disturbances have been associated with greater risk for concurrent and incident metabolic syndrome (MetS). Previous studies have not examined prospective associations among polysomnography-assessed sleep and the MetS, despite knowledge that self-reported sleep is subject to reporting bias, and that subjectively and objectively assessed sleep are weakly correlated., Method: In the current study, objectively-assessed (polysomnography) and subjectively-assessed (Pittsburgh Sleep Quality Index, PSQI) sleep was measured in 145 adults at two timepoints, separated by 12-30 years. A continuous measure of the MetS was assessed at the second time point. Statistical analyses were adjusted for age, sex, lifetime history of major depressive disorder, follow-up time, and apnea-hypopnea index., Results: Polysomnography-assessed sleep duration, latency, efficiency, and slow wave sleep were not significantly prospectively associated with the MetS (ps ≥ 0.16). Self-reported longer sleep latency was prospectively associated with higher MetS scores in unadjusted (β = 0.29, p = 0.002) and adjusted models (β = 0.25, p = 0.009). Longer sleep latency was associated with higher fasting glucose levels (β = 0.47, p < 0.001)., Conclusion: Our study provides evidence that subjective and objective measures of sleep may differ in their ability to prospectively predict MetS., (Copyright © 2019. Published by Elsevier B.V.)
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- 2019
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26. Prospective Associations of Adolescent Conscientiousness With Psychological Resources and Metabolic Syndrome in Black and White Men.
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Duggan KA, Jennings JR, and Matthews KA
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- Adolescent, Adult, Black or African American statistics & numerical data, Emotional Adjustment, Humans, Longitudinal Studies, Male, Pennsylvania, Prospective Studies, Psychology, Self Concept, Surveys and Questionnaires, White People statistics & numerical data, Black or African American psychology, Metabolic Syndrome psychology, Personality, White People psychology
- Abstract
Objective: Conscientiousness predicts better psychological resources as well as lower cardiovascular mortality and lower metabolic syndrome (MetS) risk. However, the benefits of conscientiousness might be amplified, disabled, or reversed in disadvantaged groups. This study is the first to test these competing hypotheses for prospective associations between adolescent conscientiousness and adult psychological resources and MetS., Method: Participants were 220 men (54.6% black) from the Pittsburgh Youth Study. Adolescent conscientiousness (M [SD] age = 16 [1]) was rated by participants and their parents. Adult (M [SD] age = 32 [1]) socioeconomic status (SES; occupation and education), psychological resources (composite of positive affect, purpose in life, optimism, self-mastery, and self-esteem), and MetS scores (glucose, lipids, waist circumference, and blood pressure) were measured. Hierarchical regressions were used to evaluate the association of conscientiousness with adult psychological resources and MetS scores, with testing of moderation by race and SES., Results: Self- and parent-reported conscientiousness were associated with better psychological resources (βs = 0.23-0.29, ps ≤ .015), with no moderation by race or socioeconomic status. In the full sample, a three-way interaction of self-reported conscientiousness, race, and SES was obtained for MetS (β = 0.12, p = .093). Subgroup analysis indicated that self-reported conscientiousness was related to higher MetS scores in low SES black men (βint = -0.22, p = .022), but there was no comparable linear (βs ≤ 0.08, ps ≥ .50) or interaction (βs ≤ -0.13 ps ≥ .25) pattern in white men., Conclusions: Adolescent conscientiousness was beneficial for adult psychological resources, regardless of race or SES. However, there may be physiological costs of conscientiousness for black men from disadvantaged backgrounds.
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- 2019
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27. The impact of frequent napping and nap practice on sleep-dependent memory in humans.
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McDevitt EA, Sattari N, Duggan KA, Cellini N, Whitehurst LN, Perera C, Reihanabad N, Granados S, Hernandez L, and Mednick SC
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- Adolescent, Adult, Brain physiology, Humans, Task Performance and Analysis, Young Adult, Memory physiology, Sleep physiology
- Abstract
Napping benefits long-term memory formation and is a tool many individuals use to improve daytime functioning. Despite its potential advantages, approximately 47% of people in the United States eschew napping. The goal of this study was to determine whether people who endorse napping at least once a week (nap+) show differences in nap outcomes, including nap-dependent memory consolidation, compared with people who rarely or never nap (nap-). Additionally, we tested whether four weeks of nap practice or restriction would change sleep and performance profiles. Using a perceptual learning task, we found that napping enhanced performance to a greater degree in nap+ compared with nap- individuals (at baseline). Additionally, performance change was associated with different electrophysiological sleep features in each group. In the nap+ group, spindle density was positively correlated with performance improvement, an effect specific to spindles in the hemisphere contralateral to the trained visual field. In the nap- group, slow oscillatory power (0.5-1 Hz) was correlated with performance. Surprisingly, no changes to performance or brain activity during sleep emerged after four weeks of nap practice or restriction. These results suggest that individual differences may impact the potential benefits of napping on performance and the ability to become a better napper.
- Published
- 2018
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28. Cardiovascular Stress Reactivity and Carotid Intima-Media Thickness: The Buffering Role of Slow-Wave Sleep.
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Brindle RC, Duggan KA, Cribbet MR, Kline CE, Krafty RT, Thayer JF, Mulukutla SR, and Hall MH
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- Aged, Female, Humans, Male, Middle Aged, Blood Pressure physiology, Carotid Intima-Media Thickness, Heart Rate physiology, Sleep, Slow-Wave physiology, Stress, Psychological physiopathology
- Abstract
Objective: Exaggerated cardiovascular reactivity to acute psychological stress has been associated with increased carotid intima-media thickness (IMT). However, interstudy variability in this relationship suggests the presence of moderating factors. The current study aimed to test the hypothesis that poor nocturnal sleep, defined as short total sleep time or low slow-wave sleep, would moderate the relationship between cardiovascular reactivity and IMT., Methods: Participants (N = 99, 65.7% female, age = 59.3 ± 9.3 years) completed a two-night laboratory sleep study and cardiovascular examination where sleep and IMT were measured. The multisource interference task was used to induce acute psychological stress, while systolic and diastolic blood pressure and heart rate were monitored. Moderation was tested using the PROCESS framework in SPSS., Results: Slow-wave sleep significantly moderated the relationship between all cardiovascular stress reactivity variables and IMT (all pinteraction ≤ .048, all ΔRinteraction ≥ .027). Greater stress reactivity was associated with higher IMT values in the low slow-wave sleep group and lower IMT values in the high slow-wave sleep group. No moderating effects of total sleep time were observed., Conclusions: The results provide evidence that nocturnal slow-wave sleep moderates the relationship between cardiovascular stress reactivity and IMT and may buffer the effect of daytime stress-related disease processes.
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- 2018
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29. To Nap, Perchance to DREAM: A Factor Analysis of College Students' Self-Reported Reasons for Napping.
- Author
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Duggan KA, McDevitt EA, Whitehurst LN, and Mednick SC
- Subjects
- Adolescent, Adult, Female, Health, Humans, Male, Young Adult, Factor Analysis, Statistical, Self Report, Sleep physiology, Students psychology
- Abstract
Although napping has received attention because of its associations with health and use as a method to understand the function of sleep, to our knowledge no study has systematically and statistically assessed reasons for napping. Using factor analysis, we determined the underlying structure of reasons for napping in diverse undergraduates (N = 430, 59% female) and examined their relationships with self-reported sleep, psychological health, and physical health. The five reasons for napping can be summarized using the acronym DREAM (Dysregulative, Restorative, Emotional, Appetitive, and Mindful). Only Emotional reasons for napping were uniformly related to lower well-being. The use of factor analysis raises possibilities for future research, including examining the stability, structure, and psychological and physical health processes related to napping throughout the lifespan.
- Published
- 2018
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30. Perceived sleep quality: The interplay of neuroticism, affect, and hyperarousal.
- Author
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Cellini N, Duggan KA, and Sarlo M
- Subjects
- Adult, Female, Humans, Internet, Male, Neuropsychological Tests, Surveys and Questionnaires, Arousal physiology, Emotions physiology, Neuroticism, Sleep physiology
- Abstract
Introduction: Many adults experience poor sleep quality, and personality traits have emerged as important predictors of self-reported sleep. However, it is still unclear whether personality predicts sleep quality independent of other correlates, including mood, emotion regulation, and hyperarousal., Aims and Method: The aim of this study was twofold. First, using an online survey, we assessed the relationship between perceived sleep quality (defined here as the total score of the Pittsburgh Sleep Quality Index) and personality in 498 Italians (M age=26.6±7.4 years, 353 Female). Second, using multiple regressions, we investigated whether this association was independent of affect, emotion regulation strategies, and hyperarousal., Results: Results replicate previous findings, showing that neuroticism is the best personality predictor of sleep quality in Italians. When examined separately, hyperarousal explained the most variance in sleep quality (R
2 =.18), followed by personality traits (R2 =.12), affect (R2 =.12), and emotion regulation strategies (R2 =.01). However, when all predictors were entered into a single regression model (R2 =.20), only agreeableness, positive affect, and hyperarousal remained statistically significant., Conclusion: Overall, our data replicate the association between personality and perceived sleep quality in Italians, showing that neuroticism is the best predictor of worse sleep quality. Finally, we also demonstrate important roles for hyperarousal and positive affect, but not for emotion regulation strategies. Results have implications for applied research and interventions that may want to identify individuals at risk for poor sleep., (Copyright © 2017 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.)- Published
- 2017
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31. Hand Gesture and Mathematics Learning: Lessons From an Avatar.
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Cook SW, Friedman HS, Duggan KA, Cui J, and Popescu V
- Subjects
- Child, Female, Humans, Male, Problem Solving, Gestures, Learning, Mathematics, Teaching, Transfer, Psychology
- Abstract
A beneficial effect of gesture on learning has been demonstrated in multiple domains, including mathematics, science, and foreign language vocabulary. However, because gesture is known to co-vary with other non-verbal behaviors, including eye gaze and prosody along with face, lip, and body movements, it is possible the beneficial effect of gesture is instead attributable to these other behaviors. We used a computer-generated animated pedagogical agent to control both verbal and non-verbal behavior. Children viewed lessons on mathematical equivalence in which an avatar either gestured or did not gesture, while eye gaze, head position, and lip movements remained identical across gesture conditions. Children who observed the gesturing avatar learned more, and they solved problems more quickly. Moreover, those children who learned were more likely to transfer and generalize their knowledge. These findings provide converging evidence that gesture facilitates math learning, and they reveal the potential for using technology to study non-verbal behavior in controlled experiments., (Copyright © 2016 Cognitive Science Society, Inc.)
- Published
- 2017
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32. Animation Stimuli System for Research on Instructor Gestures in Education.
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Cui J, Popescu V, Adamo-Villani N, Wagner Cook S, Duggan KA, and Friedman HS
- Abstract
Education research has shown that instructor gestures can help capture, maintain, and direct the student's attention during a lecture as well as enhance learning and retention. Traditional education research on instructor gestures relies on video stimuli, which are time consuming to produce, especially when gesture precision and consistency across conditions are strictly enforced. The proposed system allows users to efficiently create accurate and effective stimuli for complex studies on gesture, without the need for computer animation expertise or artist talent.
- Published
- 2017
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33. Autonomic activity during sleep predicts memory consolidation in humans.
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Whitehurst LN, Cellini N, McDevitt EA, Duggan KA, and Mednick SC
- Subjects
- Adolescent, Adult, Female, Heart Rate physiology, Humans, Male, Young Adult, Autonomic Nervous System physiology, Memory Consolidation, Sleep physiology
- Abstract
Throughout history, psychologists and philosophers have proposed that good sleep benefits memory, yet current studies focusing on the relationship between traditionally reported sleep features (e.g., minutes in sleep stages) and changes in memory performance show contradictory findings. This discrepancy suggests that there are events occurring during sleep that have not yet been considered. The autonomic nervous system (ANS) shows strong variation across sleep stages. Also, increases in ANS activity during waking, as measured by heart rate variability (HRV), have been correlated with memory improvement. However, the role of ANS in sleep-dependent memory consolidation has never been examined. Here, we examined whether changes in cardiac ANS activity (HRV) during a daytime nap were related to performance on two memory conditions (Primed and Repeated) and a nonmemory control condition on the Remote Associates Test. In line with prior studies, we found sleep-dependent improvement in the Primed condition compared with the Quiet Wake control condition. Using regression analyses, we compared the proportion of variance in performance associated with traditionally reported sleep features (model 1) vs. sleep features and HRV during sleep (model 2). For both the Primed and Repeated conditions, model 2 (sleep + HRV) predicted performance significantly better (73% and 58% of variance explained, respectively) compared with model 1 (sleep only, 46% and 26% of variance explained, respectively). These findings present the first evidence, to our knowledge, that ANS activity may be one potential mechanism driving sleep-dependent plasticity.
- Published
- 2016
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34. Automatic detection of rapid eye movements (REMs): A machine learning approach.
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Yetton BD, Niknazar M, Duggan KA, McDevitt EA, Whitehurst LN, Sattari N, and Mednick SC
- Subjects
- Adolescent, Adult, Female, Humans, Male, Young Adult, Electrooculography methods, Eye Movements physiology, Machine Learning, Polysomnography methods, Sleep, REM physiology
- Abstract
Background: Rapid eye movements (REMs) are a defining feature of REM sleep. The number of discrete REMs over time, or REM density, has been investigated as a marker of clinical psychopathology and memory consolidation. However, human detection of REMs is a time-consuming and subjective process. Therefore, reliable, automated REM detection software is a valuable research tool., New Method: We developed an automatic REM detection algorithm combining a novel set of extracted features and the 'AdaBoost' classification algorithm to detect the presence of REMs in Electrooculogram data collected from the right and left outer canthi (ROC/LOC). Algorithm performance measures of Recall (percentage of REMs detected) and Precision (percentage of REMs detected that are true REMs) were calculated and compared to the gold standard of human detection by three expert sleep scorers. REM detection by four non-experts were also investigated and compared to expert raters and the algorithm., Results: The algorithm performance (78.1% Recall, 82.6% Precision) surpassed that of the average (expert & non-expert) single human detection performance (76% Recall, 83% Precision). Agreement between non-experts (Cronbach Alpha=0.65) is markedly lower than experts (Cronbach Alpha=0.80)., Comparison With Existing Method(s): By following reported methods, we implemented all previously published LOC and ROC based detection algorithms on our dataset. Our algorithm performance exceeded all others., Conclusions: The automatic detection algorithm presented is a viable and efficient method of REM detection as it reliably matches the performance of human scorers and outperforms all other known LOC- and ROC-based detection algorithms., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2016
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35. REM sleep rescues learning from interference.
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McDevitt EA, Duggan KA, and Mednick SC
- Subjects
- Adolescent, Adult, Humans, Visual Perception, Young Adult, Learning physiology, Memory Consolidation physiology, Sleep, REM
- Abstract
Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2015
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36. Childhood sleep duration and lifelong mortality risk.
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Duggan KA, Reynolds CA, Kern ML, and Friedman HS
- Subjects
- Adolescent, California, Cause of Death, Child, Child, Preschool, Female, Humans, Male, Proportional Hazards Models, Prospective Studies, Risk Factors, Sex Distribution, Time Factors, United States, Young Adult, Longevity, Sleep physiology, Sleep Deprivation mortality
- Abstract
Objective: Sleep duration is known to significantly affect health in adults and children, but little is understood about long-term associations. This prospective cohort study is the first to examine whether childhood sleep duration is associated with lifelong mortality risk., Method: Data from childhood were refined and mortality data collected for 1,145 participants from the Terman Life Cycle Study. Participants were born between 1904 and 1915, lived to at least 1940, and had complete age, bedtime, and waketime data at initial data collection (1917-1926). Homogeneity of the cohort sample (intelligent, mostly White) limits generality but provides natural control of common confounds. Through 2009, 1,039 participants had confirmed deaths. Sleep duration was calculated as the difference between each child's bed and wake times. Age-adjusted sleep (deviation from that predicted by age) was computed. Cox proportional hazards survival models evaluated childhood sleep duration as a predictor of mortality separately by sex, controlling for baseline age., Results: For males, a quadratic relation emerged: Male children who underslept or overslept compared with peers were at increased risk of lifelong all-cause mortality (HR = 1.15, CIs [1.05, 1.27]). Effect sizes were smaller and nonsignificant in females (HR = 1.02, CIs [0.91, 1.14])., Conclusions: Male children with shorter or longer sleep durations than expected for their age were at increased risk of death at any given age in adulthood. The findings suggest that sleep may be a core biobehavioral trait, with implications for new models of sleep and health throughout the entire life span.
- Published
- 2014
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37. The benefit of offline sleep and wake for novel object recognition.
- Author
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McDevitt EA, Rowe KM, Brady M, Duggan KA, and Mednick SC
- Subjects
- Adolescent, Adult, Analysis of Variance, Female, Humans, Male, Photic Stimulation, Polysomnography, Time Factors, Young Adult, Pattern Recognition, Visual physiology, Recognition, Psychology physiology, Sleep physiology, Wakefulness physiology
- Abstract
How do we segment and recognize novel objects? When explicit cues from motion and color are available, object boundary detection is relatively easy. However, under conditions of deep camouflage, in which objects share the same image cues as their background, the visual system must reassign new functional roles to existing image statistics in order to group continuities for detection and segmentation of object boundaries. This bootstrapped learning process is stimulus dependent and requires extensive task-specific training. Using a between-subject design, we tested participants on their ability to segment and recognize novel objects after a consolidation period of sleep or wake. We found a specific role for rapid eye movement (REM, n = 43) sleep in context-invariant novel object learning, and that REM sleep as well as a period of active wake (AW, n = 35) increased segmentation of context-specific object learning compared to a period of quiet wake (QW, n = 38; p = .007 and p = .017, respectively). Performance in the non-REM nap group (n = 32) was not different from the other groups. The REM sleep enhancement effect was especially robust for the top performing quartile of subjects, or "super learners" (p = .037). Together, these results suggest that the construction and generalization of novel representations through bootstrapped learning may benefit from REM sleep, and more specific object learning may also benefit from AW. We discuss these results in the context of shared electrophysiological and neurochemical features of AW and REM sleep, which are distinct from QW and non-REM sleep.
- Published
- 2014
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38. Personality and healthy sleep: the importance of conscientiousness and neuroticism.
- Author
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Duggan KA, Friedman HS, McDevitt EA, and Mednick SC
- Subjects
- Demography, Female, Humans, Male, Neuroticism, Personality Inventory, Principal Component Analysis, Regression Analysis, Young Adult, Anxiety Disorders physiopathology, Personality, Sleep
- Abstract
Although previous research has shown personality and sleep are each substantial predictors of health throughout the lifespan, little is known about links between personality and healthy sleep patterns. This study examined Big Five personality traits and a range of factors related to sleep health in 436 university students (M(age) = 19.88, SD = 1.50, 50% Male). Valid self-report measures of personality, chronotype, sleep hygiene, sleep quality, and sleepiness were analyzed. To remove multicollinearity between personality factors, each sleep domain was regressed on relevant demographic and principal component-derived personality factors in multiple linear regressions. Results showed that low conscientiousness and high neuroticism were the best predictors of poor sleep (poor sleep hygiene, low sleep quality, and increased sleepiness), consistent with other research on predictors of poor health and mortality risk. In this first comprehensive study of the topic, the findings suggest that personality has a significant association with sleep health, and researchers could profitably examine both personality and sleep in models of health and well-being.
- Published
- 2014
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39. The 2010 Royal Australasian College of Physicians' policy statement 'Circumcision of infant males' is not evidence based.
- Author
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Morris BJ, Wodak AD, Mindel A, Schrieber L, Duggan KA, Dilley A, Willcourt RJ, Lowy M, and Cooper DA
- Subjects
- Australasia epidemiology, Circumcision, Male adverse effects, Foreskin physiology, HIV Infections epidemiology, HIV Infections prevention & control, Humans, Infant, Male, Penile Neoplasms epidemiology, Penile Neoplasms prevention & control, Randomized Controlled Trials as Topic standards, Sexually Transmitted Diseases epidemiology, Sexually Transmitted Diseases prevention & control, Urinary Tract Infections epidemiology, Urinary Tract Infections prevention & control, Circumcision, Male standards, Evidence-Based Medicine standards, Health Policy, Physicians standards
- Abstract
Infant male circumcision (MC) is an important issue guided by Royal Australasian College of Physicians (RACP) policy. Here we analytically review the RACP's 2010 policy statement 'Circumcision of infant males'. Comprehensive evaluation in the context of published research was used. We find that the Statement is not a fair and balanced representation of the literature on MC. It ignores, downplays, obfuscates or misrepresents the considerable evidence attesting to the strong protection MC affords against childhood urinary tract infections, sexually transmitted infections (human immunodeficiency virus, human papilloma virus, herpes simplex virus type 2, trichomonas and genital ulcer disease), thrush, inferior penile hygiene, phimosis, balanoposthitis and penile cancer, and in women protection against human papilloma virus, herpes simplex virus type 2, bacterial vaginosis and cervical cancer. The Statement exaggerates the complication rate. Assertions that 'the foreskin has a functional role' and 'is a primary sensory part of the penis' are not supported by research, including randomised controlled trials. Instead of citing these and meta-analyses, the Statement selectively cites poor quality studies. Its claim, without support from a literature-based risk-benefit analysis, that the currently available evidence does 'not warrant routine infant circumcision in Australia and New Zealand' is misleading. The Statement fails to explain that performing MC in the neonatal period using local anaesthesia maximises benefits, safety, convenience and cost savings. Because the RACP's policy statement is not a fair and balanced representation of the current literature, it should not be used to guide policy. In the interests of public health and individual well-being, an extensive, comprehensive, balanced review of the scientific literature and a risk-benefit analysis should be conducted to formulate policy., (© 2012 The Authors. Internal Medicine Journal © 2012 Royal Australasian College of Physicians.)
- Published
- 2012
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40. Vasopeptidase inhibition reverses myocardial vasoactive intestinal peptide depletion and decreases fibrosis in salt sensitive hypertension.
- Author
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Ye VZ, Hodge G, Yong JL, and Duggan KA
- Subjects
- Animals, Enalapril pharmacology, Enalapril therapeutic use, Fibrosis, Hypertension drug therapy, Hypertension pathology, Male, Myocardium pathology, Protease Inhibitors pharmacology, Protease Inhibitors therapeutic use, Pyridines pharmacology, Pyridines therapeutic use, Rats, Rats, Inbred WKY, Thiazepines pharmacology, Thiazepines therapeutic use, Hypertension enzymology, Myocardium enzymology, Peptide Hydrolases metabolism, Vasoactive Intestinal Peptide metabolism
- Abstract
We have shown previously that the concentration of Vasoactive Intestinal Peptide (VIP) in the heart is inversely correlated with the degree of fibrosis in a number of experimental models of early myocardial fibrosis. Vasopeptidase inhibition and angiotensin converting enzyme inhibition both decrease myocardial fibrosis. In this study, we sought to determine whether this myocardial protective effect might reflect increased VIP concentrations in the heart. We compared the effects of 4 weeks treatment of the vasopeptidase inhibitor omapatrilat and the angiotensin converting enzyme inhibitor enalapril on the degree of fibrosis and the concentration of VIP in the heart in salt sensitive hypertension induced by treatment with L-nitro-omega-methylarginine (L-NAME). Systolic blood pressure decreased in both treatment groups compared with control (omapatrilat P<0.005; enalapril P<0.001). Myocardial fibrosis was less for omapatrilat than control (P<0.0005) and enalapril (P<0.0005) groups. Myocardial VIP was greater in omapatrilat than in controls (P<0.005) and enalapril-treated rats (P<0.05). We conclude that vasopeptidase inhibition exerts a greater myocardial protective effect than angiotensin converting enzyme inhibition. Further, this myocardial protective effect is associated with increased VIP in the heart suggesting a pathogenetic role for VIP depletion in the development of fibrosis in the heart.
- Published
- 2004
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41. Myocardial vasoactive intestinal peptide and fibrosis induced by nitric oxide synthase inhibition in the rat.
- Author
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Ye VZ, Hodge G, Yong JL, and Duggan KA
- Subjects
- Animals, Blood Pressure physiology, Dose-Response Relationship, Drug, Fibrosis, Male, Metabolic Clearance Rate, NG-Nitroarginine Methyl Ester administration & dosage, Nitric Oxide Synthase antagonists & inhibitors, Organ Size, Random Allocation, Rats, Rats, Inbred SHR, Rats, Wistar, Sodium, Dietary administration & dosage, Vasoactive Intestinal Peptide blood, Enzyme Inhibitors pharmacology, Heart drug effects, Myocardium pathology, NG-Nitroarginine Methyl Ester pharmacology, Vasoactive Intestinal Peptide analysis
- Abstract
Aims: In both normotensive and hypertensive rats, the degree of myocardial fibrosis is inversely correlated with the concentration of vasoactive intestinal peptide (VIP) in the myocardium. Treatment with nitric oxide (NO) synthase inhibitors also causes myocardial fibrosis. In this study, we sought to determine whether the myocardial fibrosis induced by treatment with the NO synthase inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME) was also associated with depletion of VIP in the myocardium., Methods: Male Wistar Kyoto (WKY) and spontaneous hypertensive rats (SHR) rats treated with l-NAME were randomized to low, intermediate or high salt content diets. After 4 weeks, the hearts were harvested, the degree of fibrosis quantified and VIP concentration measured., Results: In WKY, systolic blood pressure increased with increasing dietary sodium (P < 0.05). Myocardial fibrosis also increased with increasing dietary sodium (P < 0.005). Myocardial VIP concentration decreased with increasing dietary sodium (P < 0.025). In contrast, in the SHR treated with l-NAME, systolic blood pressure increased but the increase was not affected by sodium intake. Further, myocardial fibrosis and myocardial VIP were unchanged by increased dietary sodium. Higher doses of l-NAME in the SHR did not increase the systolic blood pressure, increase the degree of myocardial fibrosis or decrease the myocardial concentration of VIP. These differences in myocardial VIP concentration may reflect differing effects of l-NAME on VIP metabolism, as l-NAME increased VIP metabolism in the WKY (P < 0.05) but did not change VIP metabolism in the SHR., Conclusions: We conclude that depletion of VIP in the myocardium is associated with increasing myocardial fibrosis in l-NAME treated WKY. As VIP depletion occurs in other models of myocardial fibrosis, it appears to be a common mechanism. Myocardial VIP depletion may therefore be a new and important factor in the pathogenesis of cardiac fibrosis.
- Published
- 2003
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42. Early myocardial fibrosis is associated with depletion of vasoactive intestinal peptide in rat heart.
- Author
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Ye VZ, Hodge G, Yong JL, and Duggan KA
- Subjects
- Animals, Blood Pressure, Fibrosis, Heart Diseases etiology, Male, Rats, Rats, Inbred SHR, Rats, Inbred WKY, Sodium, Dietary pharmacology, Heart Diseases metabolism, Heart Diseases pathology, Myocardium metabolism, Myocardium pathology, Vasoactive Intestinal Peptide blood
- Abstract
In this study we sought to determine whether early myocardial fibrosis is associated with depletion of vasoactive intestinal peptide (VIP) in the heart, thereby suggesting a possible pathogenetic role for depletion of myocardial VIP levels in the development of fibrosis in the heart. Spontaneously hypertensive rats (SHRs) and normotensive control Wistar-Kyoto rats (WKYs) were assigned randomly to low, intermediate or high sodium diets and their blood pressure was recorded twice weekly for 4 weeks. At the end of this period the rats were anaesthetised, blood was sampled for plasma VIP concentration and the hearts were harvested for histology and determination of the concentration of VIP in the heart. The degree of myocardial fibrosis increased with increasing dietary sodium intake in both the WKYs (P < 0.001) and the SHRs (P < 0.01). Myocardial VIP concentration decreased with increasing dietary sodium intake in the WKYs (P < 0.01) and in the SHRs (P < 0.01). There was a negative correlation between myocardial VIP concentration and the degree of myocardial fibrosis in both the WKYs (P < 0.0005) and the SHRs (P < 0.005). Dietary sodium intake induces myocardial fibrosis in a dose-dependent manner. Further, in early myocardial fibrosis resulting from increasing dietary sodium intake in both normotensive and hypertensive rats the concentration of VIP in the heart was negatively correlated with the degree of fibrosis. This suggests a possible role for depletion of VIP in the myocardium in the pathogenesis of myocardial fibrosis.
- Published
- 2002
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43. Dysregulation of angiotensin II synthesis is associated with salt sensitivity in the spontaneous hypertensive rat.
- Author
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Hodge G, Ye VZ, and Duggan KA
- Subjects
- Aldosterone blood, Angiotensin I blood, Angiotensin II blood, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors pharmacology, Angiotensinogen blood, Animals, Blood Pressure drug effects, Hypertension enzymology, Losartan pharmacology, Male, Peptidyl-Dipeptidase A blood, Peptidyl-Dipeptidase A metabolism, Rats, Rats, Inbred SHR, Receptors, Angiotensin metabolism, Renin blood, Sodium Chloride, Dietary administration & dosage, Angiotensin II biosynthesis, Hypertension physiopathology, Sodium Chloride, Dietary pharmacology
- Abstract
(1) Salt sensitive hypertension, which occurs as a result of treatment with nitric oxide synthase inhibitors, is associated with a loss of the usual down-regulatory effect of dietary sodium on angiotensin II (Ang II) synthesis. In the spontaneous hypertensive rat (SHR), which suffers a relative NO deficiency, the hypertension is in part salt sensitive. We sought to determine therefore whether the salt sensitive component to the hypertension was associated with a loss of the regulatory effect of dietary sodium on Ang II synthesis. (2) Male SHR were placed on low, intermediate or high salt diets for 4 weeks and their blood pressure recorded. After 4 weeks, blood was collected for determination of renin, angiotensinogen, Ang I, Ang II and aldosterone concentrations, as well as ACE activity. (3) The increase in systolic blood pressure in rats on the high salt diet was significantly greater than in those on the low (P < 0.005) and intermediate salt diets (P < 0.0005). Plasma renin and aldosterone concentrations and ACE activity decreased with increasing dietary sodium. However, the concentrations of Ang II and angiotensinogen both increased in the rats on the high salt diet (Ang II: P < 0.05; angiotensinogen: P < 0.05). (4) We conclude that the hypertension in the SHR is in part salt sensitive and that this salt sensitive component is associated with a loss of the normal down-regulatory effect of dietary sodium on Ang II and angiotensinogen synthesis.
- Published
- 2002
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44. Salt-sensitive hypertension resulting from nitric oxide synthase inhibition is associated with loss of regulation of angiotensin II in the rat.
- Author
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Hodge G, Ye VZ, and Duggan KA
- Subjects
- Aldosterone blood, Angiotensin I blood, Angiotensinogen blood, Animals, Blood Pressure physiology, Enzyme Inhibitors pharmacology, Male, NG-Nitroarginine Methyl Ester pharmacology, Nitric Oxide Synthase metabolism, Peptidyl-Dipeptidase A blood, Rats, Rats, Inbred WKY, Renin blood, Renin-Angiotensin System drug effects, Renin-Angiotensin System physiology, Angiotensin II blood, Hypertension metabolism, Nitric Oxide Synthase antagonists & inhibitors, Sodium Chloride, Dietary pharmacology
- Abstract
In the Dahl salt-sensitive hypertensive rat, a diet containing L-arginine, the natural substrate for nitric oxide synthase, abrogates the hypertension. We postulated that nitric oxide synthase inhibition might induce a salt-sensitive form of hypertension and that this salt sensitivity might be linked to a loss of the regulatory effect of sodium ingestion on angiotensin II (Ang II) and angiotensinogen. Male Wistar-Kyoto rats were randomised to a diet containing 0.008 %, 2.2 % or 4.4 % sodium chloride and to treatment with the NO synthase inhibitor L-NAME (10 mg kg(-1) day(-1)) in the drinking water, or drinking water alone (Controls) for 4 weeks. Blood pressure was measured by tail cuff plethysmography twice weekly. After 4 weeks, the rats were anaesthetised and truncal blood collected for determination of angiotensinogen, renin, angiotensin I (Ang I), Ang II and aldosterone concentrations as well as angiotensin-converting enzyme (ACE) activity. Systolic blood pressure increased with increasing dietary sodium intake in the L-NAME-treated rats (P < 0.05). Plasma renin and aldosterone concentrations decreased with increasing dietary sodium intake in both Control and L-NAME-treated rats. Ang I and ACE activity were unchanged by increasing dietary sodium intake. In contrast, the plasma concentration of Ang II and angiotensinogen increased with increasing dietary sodium (P < 0.05 and P < 0.005, respectively). Treatment with the Ang II receptor blocker, losartan, reversed the blood pressure increase. We conclude that treatment with L-NAME induces an increase in blood pressure that is at least in part salt sensitive. Further, the salt-sensitive component appears to be Ang II-dependent, as it was associated with increasing plasma Ang II levels and could be reversed by treatment with an Ang II receptor antagonist.
- Published
- 2002
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45. Effects of nitric oxide synthase inhibition on angiotensin receptors and metabolism in the pregnant hypertensive rat.
- Author
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Yang Y, Macdonald GJ, and Duggan KA
- Subjects
- Analysis of Variance, Animals, Blood Pressure drug effects, Female, Hypertension enzymology, Metabolic Clearance Rate, Nitric Oxide Synthase physiology, Pregnancy, Pregnancy Complications, Cardiovascular enzymology, Proteinuria chemically induced, Random Allocation, Rats, Rats, Inbred SHR, Angiotensin II metabolism, NG-Nitroarginine Methyl Ester pharmacology, Nitric Oxide Synthase antagonists & inhibitors, Receptors, Angiotensin physiology
- Abstract
Endothelial dysfunction and a consequent decrease in nitric oxide production have been implicated in the pathogenesis of pre-eclampsia. A prominent feature of the pre-eclamptic syndrome is a loss of the pregnancy-induced refractoriness to infused pressor agents, such as angiotensin. In this study, we sought to determine whether a decrease in nitric oxide production might be linked via changes in angiotensin II receptors and angiotensin II metabolism to changes in pressor sensitivity to infused angiotensin II. Pregnant and non-pregnant spontaneously hypertensive rats (SHRs) were randomly allocated to receive 5 mg x kg(-1) x day(-1) N(G)-nitro-L-arginine methyl ester (L-NAME) in the drinking water or drinking water alone from days 7 to 14 of gestation. Steady-state metabolic clearance studies of angiotensin II were then performed, or tissues were harvested for angiotensin II receptor studies. Treatment with L-NAME caused an increase in systolic pressure (P<0.001) in both pregnant and non-pregnant rats, while urinary protein excretion increased only in the pregnant SHRs (P<0.001). Plasma angiotensin II levels were significantly increased in the L-NAME-treated SHRs compared with controls (non-pregnant, P<0.0005; pregnant, P<0.01). The metabolic clearance rate of angiotensin II was decreased by L-NAME treatment in non-pregnant SHRs (P<0.05), but was increased by L-NAME treatment in the pregnant rats (P<0.01). In the aorta, the angiotensin II receptor number increased after treatment with L-NAME in both non-pregnant (P<0.0005) and pregnant (P<0.05) SHRs, and the dissociation constant increased in the non-pregnant SHRs (P<0.005). Thus treatment of SHRs with L-NAME increased blood pressure, as well as the circulating angiotensin II concentration and vascular angiotensin II receptor expression. However, treatment with L-NAME did not affect pressor sensitivity to infused angiotensin II. We conclude, therefore, that although a decrease in nitric oxide production is associated with changes in angiotensin II concentrations and receptor numbers, it does not induce changes in pressor sensitivity to infused angiotensin II in the SHR.
- Published
- 2001
46. Vasoactive intestinal peptide down-regulates the intrahepatic renin-angiotensin system in the anaesthetized rat.
- Author
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Ye VZ and Duggan KA
- Subjects
- Angiotensin I metabolism, Angiotensin II blood, Angiotensinogen metabolism, Animals, Male, Peptidyl-Dipeptidase A metabolism, Rats, Rats, Sprague-Dawley, Renin blood, Renin-Angiotensin System physiology, Down-Regulation drug effects, Gastrointestinal Agents pharmacology, Liver metabolism, Renin-Angiotensin System drug effects, Vasoactive Intestinal Peptide pharmacology
- Abstract
Gastric sodium loading results in an increase in the portal venous concentration of vasoactive intestinal peptide (VIP) and down-regulation of both the intrahepatic and circulating renin-angiotensin systems. In the present study we sought to determine whether an increase in the concentration of VIP in the portal circulation might act to down-regulate the intrahepatic and/or circulating renin-angiotensin systems. Male Sprague-Dawley rats were infused intraportally with haemaccel vehicle or VIP in haemaccel for 60 min. Livers were harvested and blood was sampled. Angiotensin-converting enzyme (ACE) activity and angiotensinogen, angiotensin I, angiotensin II and renin concentrations were measured. VIP infusion decreased hepatic ACE activity (P < 0.05), the hepatic angiotensinogen concentration (P < 0.001) and the hepatic angiotensin I concentration (P < 0.05). The plasma angiotensinogen concentration and serum ACE activity were also decreased by intraportal VIP infusion (P < 0.05 for each). Plasma renin, angiotensin I and angiotensin II concentrations were unchanged by VIP infusion. We conclude that an increase in the portal venous VIP concentration down-regulates the intrahepatic renin-angiotensin system. These changes are similar to those reported after gastric sodium loading, and we suggest, therefore, that the increase in portal venous VIP that occurs after gastric sodium is the means by which the gastric sodium sensor signals the liver to effect these changes in the renin-angiotensin system.
- Published
- 2000
47. Factors regulating renal angiotensin-converting enzyme activity in the rat.
- Author
-
Ye VZ and Duggan KA
- Subjects
- Animals, Denervation, Gastric Mucosa metabolism, Injections, Intravenous, Intestinal Absorption physiology, Kidney innervation, Male, Osmolar Concentration, Peripheral Nerves physiology, Rats, Rats, Sprague-Dawley, Sodium, Dietary blood, Urea pharmacology, Kidney enzymology, Natriuresis physiology, Peptidyl-Dipeptidase A metabolism, Sodium, Dietary pharmacokinetics
- Abstract
Changes in angiotensin-converting enzyme (ACE) activity appear to be important in mediating the natriuresis which ensues after administration of an oral or gastric sodium load. In this study, we sought to determine the time course of the changes in ACE activity in the kidney which occur after sodium ingestion. In addition, we sought to investigate mechanisms which might underlie these changes. Angiotensin-converting enzyme activity was measured by generation of histidyl-leucine in homogenates of kidneys harvested at varying time-points after gastric sodium administration. The effects of intravenous sodium loading, solution osmolality and of changes in renal nerve activity were also investigated. Intragastric instillation of both the sodium-containing solution and its iso-osmotic urea control solution resulted in significant increases in renal ACE activity (NaCl: P < 0.0005; Urea: P < 0.01). The increase in renal ACE activity after gastric sodium loading was more prolonged than after the urea control (P < 0.025, NaCl vs. urea at 90 min). This prolonged increase in renal ACE activity appeared to reflect a response to absorbed sodium as intravenous sodium administration caused a significant increase in renal ACE activity at 90 min (P < 0.0005). In contrast to these stimuli which increased renal ACE activity, renal denervation caused a significant decrease in ACE activity in the kidney (P < 0.05). We conclude that gastric sodium loading increases renal ACE activity. This effect appears to be due initially to a response to an increase in gastric lumenal osmolality and later to absorbed sodium. These changes in renal ACE activity are not mediated by a decrease in renal nerve activity.
- Published
- 2000
- Full Text
- View/download PDF
48. VIP regulates angiotensinogen synthesis in the liver.
- Author
-
Duggan KA and Ye VZ
- Subjects
- Angiotensinogen blood, Animals, Male, Portal Vein, Rats, Rats, Sprague-Dawley, Signal Transduction, Sodium administration & dosage, Angiotensinogen biosynthesis, Liver drug effects, Liver metabolism, Vasoactive Intestinal Peptide pharmacology
- Published
- 2000
- Full Text
- View/download PDF
49. Modulation of the intrahepatic renin-angiotensin system after stimulation of the gastric sodium monitor in the rat.
- Author
-
Ye VZ and Duggan KA
- Subjects
- Angiotensin I blood, Angiotensin II blood, Angiotensinogen blood, Animals, Lung enzymology, Male, Rats, Rats, Sprague-Dawley, Renin blood, Renin metabolism, Time Factors, Angiotensinogen metabolism, Gastric Mucosa metabolism, Liver enzymology, Peptidyl-Dipeptidase A metabolism, Sodium pharmacology
- Abstract
Changes in the rate of formation of angiotensin II (ANG II) participate in mediating the natriuresis that occurs in direct response to a gastric sodium stimulus (upper-gut sodium monitor). As this natriuresis is also dependent on intrahepatic events, we investigated whether changes in hepatic and plasma angiotensinogen levels and hepatic angiotensin-converting enzyme (ACE) activity might explain the decrease in ANG II synthesis. Male Sprague-Dawley rats, equilibrated on a low-sodium diet, were anaesthetized and received a sodium load of 1.5 mmol/kg (using 3 x normal saline) either intragastrically or intravenously. Blood and livers were sampled before and at various times after sodium administration. ACE activity in serum and tissues was determined by generation of histidyl-leucine. Angiotensinogen was determined by radioimmunoassay of angiotensin I generated by incubation in the presence of exogenous renin. Plasma angiotensinogen had decreased significantly by 15 min after sodium administration (P<0.005), while hepatic angiotensinogen was also decreased significantly from 30 min after the sodium load (P<0.01). Hepatic ACE activity decreased in response to sodium (P<0.005) from 30 min. We conclude that stimulation of the gastric sodium monitor regulates angiotensinogen synthesis and secretion by the liver, as well as hepatic ACE activity.
- Published
- 2000
50. Effect of sodium depletion by frusemide on tissue concentrations and metabolism of VIP.
- Author
-
Duggan KA and Ye VZ
- Subjects
- Animals, Heart drug effects, Kidney drug effects, Kidney metabolism, Lung drug effects, Lung metabolism, Male, Metabolic Clearance Rate, Myocardium metabolism, Rats, Rats, Sprague-Dawley, Sodium deficiency, Vasoactive Intestinal Peptide blood, Furosemide pharmacology, Sodium physiology, Vasoactive Intestinal Peptide metabolism
- Published
- 1998
- Full Text
- View/download PDF
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