69 results on '"Lyons DJ"'
Search Results
2. Prolactin Regulates Tuberoinfundibular Dopamine (TIDA) Neuron Discharge Pattern: Novel Feedback Control Mechanisms in the Lactotrophic Axis
- Author
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Lyons DJ, Hellysaz A, and Broberger C
- Published
- 2012
3. Petiole sap nitrate is better than total nitrogen in dried leaf for indicating nitrogen status and yield responsiveness of capsicum in subtropical Australia
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Olsen, JK, primary and Lyons, DJ, additional
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- 1994
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4. Irrigation frequency and nitrogen fertilizers modify cotton yield at Emerald, central Queensland
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Ockerby, SE, primary, Lyons, DJ, additional, Keefer, GD, additional, Blamey, FPC, additional, and Yule, DF, additional
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- 1993
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5. Lymphocyte macrophage interactions: peripolesis of human alveolar macrophages
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Lyons, DJ, primary, Gautam, A, additional, Clark, J, additional, Harries, MG, additional, Mitchell, EB, additional, Milledge, JS, additional, and Balfour, BM, additional
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- 1992
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6. Search for a retroviral cause for sarcoidosis: no evidence from peripheral blood studies
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Lyons, DJ, primary, Sinclair, A, additional, Smith, HG, additional, Mitchell, DN, additional, and Dalgleish, AG, additional
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- 1991
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7. Sarcoidosis: in search of Kveim reactivity in vitro
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Lyons, DJ, primary, Mitchell, EB, additional, and Mitchell, DN, additional
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- 1991
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8. Chronic anaemia in an Irish gastroenterology unit: one hundred consecutive cases
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Lyons, DJ, primary, Kavanagh, G, additional, and Fielding, JF, additional
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- 1990
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9. Scintigraphic imaging of lung tumours with a radiolabelled somatostatin analogue
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C. O Donnell, D. Luke, K. O Byrne, L. Clancy, M. Istarabadi, P. Freyne, Lyons Dj, E. McGovern, J. Ennis, N. O Hare, J. Prichard, and D. Carney
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Somatostatin Analogue ,business.industry ,Scintigraphic imaging ,Medicine ,Radiology, Nuclear Medicine and imaging ,General Medicine ,Lung tumours ,Nuclear medicine ,business - Published
- 1993
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10. Follow-up Study of Elementary School Children Exempted from Los Angeles City Schools during 1960–1961
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Lyons Dj and Powers
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medicine.medical_specialty ,Schools ,Statistics as Topic ,05 social sciences ,Follow up studies ,050301 education ,Child Behavior Disorders ,Los Angeles ,California ,Education ,Family medicine ,Developmental and Educational Psychology ,medicine ,Humans ,0501 psychology and cognitive sciences ,Child ,Psychology ,0503 education ,Follow-Up Studies ,050104 developmental & child psychology - Published
- 1963
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11. Percutaneous fine-needle aspiration biopsy of mediastinal lesions
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Weisbrod, GL, primary, Lyons, DJ, additional, Tao, LC, additional, and Chamberlain, DW, additional
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- 1984
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12. Recognizing and reporting vertebral fractures: reducing the risk of future osteoporotic fractures.
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Lentle BC, Brown JP, Khan A, Leslie WD, Levesque J, Lyons DJ, Siminoski K, Tarulli G, Josse RG, and Hodsman A
- Abstract
Objective: Given the increasing evidence that vertebral fractures are underdiagnosed and not acted on, Osteoporosis Canada and the Canadian Association of Radiologists initiated a project to develop and publish a set of recommendations to promote and facilitate the diagnosis and reporting of vertebral fractures. Options: The identification of spinal fractures is not uniform. More than 65% of vertebral fractures cause no symptoms. It is also apparent that vertebral fractures are inadequately recognized when the opportunity for diagnosis arises fortuitously. It is to patients' benefit that radiologists report vertebral fractures evident on a chest or other radiograph, no matter how incidental to the immediate clinical indication for the examination. Outcomes: The present recommendations can help to close the gap in care in recognizing and treating vertebral fractures, to prevent future fractures and thus reduce the burden of osteoporosis-related morbidity and mortality, as well as fracture-related costs to the health care system. Evidence: Several studies indicate that a gap exists in regard to the diagnosis of vertebral fractures and the clinical response following such diagnosis. All recommendations presented here are based on consensus. Values: These recommendations were developed by a multidisciplinary working group under the auspices of the Scientific Advisory Council of Osteoporosis Canada and the Canadian Association of Radiologists. Benefits, Harm, and Costs: Prevalent vertebral fractures have important clinical implications in terms of future fracture risk. Recognizing and reporting fractures incidental to radiologic examinations done for other reasons has the potential to reduce health care costs by initiating further steps in osteoporosis diagnosis and appropriate therapy. Recommendations: Physicians should be aware of the importance of vertebral fracture diagnosis in assessing future osteoporotic fracture risk. Vertebral fractures incidental to radiologic examinations done for other reasons should be identified and reported. Vertebral fractures should be assessed from lateral spinal or chest radiographs according to the semiquantitative method of Genant and colleagues. Grade II and Grade III fractures as classified by this method should be given the greatest emphasis. Semiquantitative fracture recognition should include the recognition of changes such as loss of vertebral end-plate parallelism, cortical interruptions, and quantitative changes in the anterior, midbody, and posterior heights of vertebral bodies. When spine radiographs are performed to assess the presence of vertebral fractures, anteroposterior examinations may assist in the initial evaluation. The standard follow-up need only consist of single lateral views of the thoracic and lumbar spine that include T4 to L4 vertebrae. The radiographic technique described in this paper, or a technique of comparable efficacy, should be used. Dual X-ray absorptiometry examinations that include lateral spinal morphological assessments (vertebral fracture assessment) may contribute to fracture recognition. Educational material about the clinical importance of vertebral fracture recognition as a potential indicator of future osteoporotic fracture risk with its associated morbidity and mortality should be directed to all physicians. [ABSTRACT FROM AUTHOR]
- Published
- 2007
13. Recommendations for bone mineral density reporting in Canada.
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Siminoski K, Leslie WD, Frame H, Hodsman A, Josse RG, Khan A, Lentle BC, Lévesque J, Lyons DJ, Tarulli G, and Brown JP
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OBJECTIVE: To propose a set of recommendations for optimal bone mineral density (BMD) reporting in postmenopausal women and older men and to provide clinicians with both a BMD diagnostic category and a useful tool to assess an individual's risk of osteoporotic fracture. OPTIONS: The current methods of BMD reporting were reviewed. In this document, we propose that an individual's 10-year absolute fracture risk, rather than BMD alone, be used for fracture risk categorization. Consequently, age, sex, BMD, fragility fracture history, and glucocorticoid use are the basis for the approach outlined in this document. OUTCOMES: An optimal BMD report as proposed in this document will provide clinicians with both a BMD diagnostic category and a useful tool to assess an individual's risk of osteoporotic fracture. A BMD report format, a checklist, and a patient questionnaire are meant to further encourage its use. EVIDENCE: All recommendations were developed using a consensus from clinicians and experts in the field of BMD testing and a standard method for the evaluation and citation of the supporting evidence. VALUES: These recommendations were developed by a multidisciplinary working group under the auspices of the Scientific Advisory Council of the Osteoporosis Society of Canada and the Canadian Association of Radiologists. BENEFITS, HARM, AND COSTS: Optimal BMD reports help the practitioner to assess an individual's risk for osteoporotic fracture and to decide whether medical therapy is warranted. RECOMMENDATIONS: The BMD report should include: patient identifiers. Dual-energy X-ray absorptiometry (DXA) scanner identifier. BMD results expressed in absolute values (g/cm2; 3 decimal places) and T-score (1 decimal place) for lumbar spine; proximal femur (total hip, femoral neck, and trochanter); and an alternate site (forearm BMD preferred: 1/3 radius, 33% radius or proximal radius) if either hip or spine is not valid. A statement about any limitations due to artifacts, if present. The fracture risk category (low, moderate, or high) as determined by using Tables 3 and 4 and by including major clinical factors that modify absolute fracture risk probability (with an indication of the corresponding absolute 10-year fracture risk of <10%, 10-20%, or >20%). A statement as to whether the change is statistically significant or not for serial measurements. The BMD centre's least significant change for each skeletal site (in g/cm2) should be included. VALIDATION: Recommendations were based on consensus opinion. Since these are the first Canadian recommendations integrating clinical risk factors in a quantitative fracture risk assessment, it is anticipated that these 'Recommendations for BMD Reporting in Canada' will be a work in progress and will be updated periodically to accommodate advances in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2005
14. Developing a Statewide Research Compendium: Key Points and Steps for Success.
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Embree JL, Lyons DJ, Adams C, Heinzman S, Oetting S, and Swenty C
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- Humans, Technology, Education, Nursing, Continuing, Nursing Research
- Abstract
Engaging clinical nurses in nursing research requires value for the nurses and a structured process. One way to involve nurses in research is through development of a research compendium. A professional development specialist can lead the creation of a research compendium. Identifying key stakeholders, developing a technologic infrastructure, piloting the compendium, gaining feedback, and identifying outcomes that will be evaluated are key. [ J Contin Educ Nurs . 2022;53(3):106-108.] .
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- 2022
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15. Non-human Primate Macaca mulatta as an Animal Model for Testing Efficacy of Amixicile as a Targeted Anti-periodontitis Therapy.
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Gui Q, Lyons DJ, Deeb JG, Belvin BR, Hoffman PS, and Lewis JP
- Abstract
Periodontitis is an inflammatory condition triggered by selected oral microbiota; thus treatment strategies should be aimed at reducing the abundance of the pathogenic bacteria. An obstacle to preclinical testing of such strategies is the availability of reliable animal models. Here, a non-human primate (NHP), Macaca mulatta , was used to examine the effectiveness of a novel antimicrobial, amixicile, which inhibits pyruvate-ferredoxin oxidoreductase (PFOR) present in anaerobic bacteria. Animals were assessed for their periodontal health, including radiography, clinical attachment loss (CAL), presence of plaque (PI), bleeding on probing (BOP) and pocket depth (PD), and sampled for saliva, gingival crevicular fluid (GCF), and subgingival plaque to determine their baseline clinical status. Amixicile was then administered for 2 weeks (40 mg/kg/day) and the animals were monitored for periodontal health immediately after the antibiotic treatment, then at 1 month-, 3 months-, and 6-months posttreatment. Microbial species present in plaque and saliva were determined through 16S rDNA sequencing. Baseline assessment of the microbiome has shown a significant proportion of bacteria belonging to the Streptococcus, Haemophilus, Porphyromonas, Gemella , and Fusobacterium genera. The abundance of Porphyromonas and Fusobacterium was reduced following treatment with amixicile, whereas that of Escherichia, Haemophilus , and Gemella were elevated. CAL, PD, and BOP were also significantly reduced following the treatment. In conclusion, the NHP model proves useful for preclinical studies of strategies targeting selected members of the oral microbiome. We show that amixicile reduces the levels of anaerobic bacteria under in vivo conditions, correlating with a reduction in CAL, PD, and BOP, thus validating its usefulness as an antimicrobial strategy., Competing Interests: The 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 © 2021 Gui, Lyons, Deeb, Belvin, Hoffman and Lewis.)
- Published
- 2021
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16. Instilling Hope and Resiliency: A Narrative Photo-Taking Intervention During an Intercultural Exchange Involving 9/11 Survivors in Post 3/11 Japan.
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Lurie JM, Lever H, Goodson L, Lyons DJ, Yanagisawa RT, and Katz CL
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- Cross-Cultural Comparison, Earthquakes, Humans, Japan, Natural Disasters, September 11 Terrorist Attacks, Surveys and Questionnaires, Travel, Tsunamis, United States, Hope, Photography, Posttraumatic Growth, Psychological, Resilience, Psychological, Survivors psychology
- Abstract
On March 11, 2011 ("3/11"), a magnitude 9.0 earthquake in Northeastern Japan triggered a tsunami and nuclear power plant meltdown that killed 16,000 people and displaced more than 470,000 people. Since 2012, a group of volunteer docents from the September 11th Families Association in New York City has traveled throughout Northeastern Japan and held organized meetings where 9/11 and 3/11 survivors share their experiences and stories of trauma as part of an intercultural exchange to promote posttraumatic recovery. We sought to elucidate whether participating 9/11 docents developed a sense of increased resiliency by participating in this international outreach. This study employed photo-taking as well as framing questions, which were developed by 9/11 docents from the August 2016 trip. These questions guided photo-taking and resulting photographs informed discussion in individual and group sharing sessions. This process helped identify codes that guided analysis. Participants acquired a deeper appreciation of their own ability to overcome adversity and experienced a gratifying desire to help 3/11 survivors better cope with their experiences. This narrative photo-taking and group sharing experience demonstrates that a cross-cultural exchange between survivors of different disasters can instill feelings of resilience among participants. It additionally provides early evidence of the efficacy of such an exchange in benefitting disaster survivors in the long term.
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- 2020
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17. Bone Mineral Densitometry Reporting and the CAR Technical Standards: Tips for the Radiologist.
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Hammond I and Lyons DJ
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- Humans, Middle Aged, Practice Guidelines as Topic, Absorptiometry, Photon methods, Absorptiometry, Photon standards, Bone and Bones diagnostic imaging, Bone Density
- Published
- 2020
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18. Fukushima Triple Disaster and the Road to Recovery: a Qualitative Exploration of Resilience in Internally Displaced Residents.
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Mann CL, Gillezeau CN, Massazza A, Lyons DJ, Tanaka K, Yonekura K, Sekine H, Yanagisawa R, and Katz CL
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- Aged, Disaster Victims rehabilitation, Female, Humans, Japan epidemiology, Male, Adaptation, Psychological physiology, Community Mental Health Services methods, Disaster Victims psychology, Fukushima Nuclear Accident, Mental Health, Resilience, Psychological
- Abstract
Six years after the March 2011 Triple Disaster, over 35,000 Japanese individuals remain in temporary housing. Evacuated residents, many of who are elderly, face mental health challenges. This study evaluates the well being of individuals living in temporary housing within Fukushima. Reactions to relocation were explored using Photovoice, a community-based participatory research method, in which a set of research questions are examined qualitatively through photographs and interviews. Seven participants (average age = 69.7) were provided cameras to answer a set of self-generated questions, a process that was repeated three times. An initial analysis found resilience among participants, which was explored using a theoretical framework of resiliency. Residents discussed how relocation has disrupted their lives and coping strategies they employ to ameliorate stressors. They were often optimistic and future-oriented, stating that they wanted to "live strong" after the disaster. These resilient mindsets were personified in action: all engaged in hobbies, critical for their emotional well being. Participants also emphasized the importance of community and familial support. The evidence of resilience in participants is encouraging, suggesting that these vulnerable elderly internally displaced residents are recovering from the disruption of relocation. These themes should be explored in larger temporary housing communities. Considering the number of relocated individuals today, understanding how to foster resilience could be used to inform the development of future temporary housing shelters.
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- 2018
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19. FRAX vs CAROC for the Canadian Imaging Physician: An Existential Dilemma.
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Hammond I, Burrell S, Lyons DJ, and Lentle BC
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- Absorptiometry, Photon, Bone Density, Canada, Humans, Practice Guidelines as Topic, Risk Factors, Osteoporosis diagnostic imaging, Osteoporotic Fractures diagnostic imaging, Risk Assessment methods
- Published
- 2017
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20. Community Effect of Alcoholism: A Photovoice Study in Saint Vincent and the Grenadines.
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Rosenthal AI, Mayott L, Lyons DJ, Providence K, Scott A, Smart Y, and Katz CL
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- Adult, Humans, Photography, Qualitative Research, Saint Vincent and the Grenadines, Alcoholics Anonymous, Alcoholism ethnology, Alcoholism rehabilitation, Community-Based Participatory Research
- Abstract
The Icahn School of Medicine at Mount Sinai and the Saint Vincent/Grenadines Ministry of Health, Wellness and the Environment have been collaborating since 2012 in addressing the plight of alcoholism in Saint Vincent and the Grenadines (SVG). SVG is a middle-income country with few resources available for those who suffer from alcohol use disorders, and these efforts have centered on establishing and monitoring alcohol self-help groups based on the "Alcoholics Anonymous model" (AA model) in several communities in Saint Vincent and the Grenadines. In the summer of 2014, the efforts evolved to include an in-depth investigation of the experience of members of self-help group members via the qualitative research method known as Photovoice. Photovoice is a community based participatory research method in which a set of research questions are explored qualitatively through photographs, interviews, and focus groups. In June 2014, a Photovoice project was established with the longest running self-help group on the island of Saint Vincent in the fishing community of Barrouallie. This project consisted of three rounds of photo-taking, individual interviews, and focus groups, and analysis of the data revealed a number of broad themes relevant to perceptions about the impact of problematic drinking and about drinkers themselves; about the applicability of the AA model in SVG; and about factors that may perpetuate or mitigate problem drinking. It was evident that current and recovering alcoholics believed that there were different types of drinkers who because of their gender, public drinking or tendency for violence could be labeled as "irresponsible." These findings suggest areas for future interventions and research in SVG.
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- 2017
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21. Activation of Ventral Tegmental Area 5-HT 2C Receptors Reduces Incentive Motivation.
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Valencia-Torres L, Olarte-Sánchez CM, Lyons DJ, Georgescu T, Greenwald-Yarnell M, Myers MG Jr, Bradshaw CM, and Heisler LK
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- Animals, Benzazepines pharmacology, Conditioning, Operant drug effects, Conditioning, Operant physiology, Eating drug effects, Eating psychology, Female, Male, Mice, Mice, Transgenic, Motivation drug effects, Ventral Tegmental Area drug effects, Eating physiology, Motivation physiology, Receptor, Serotonin, 5-HT2C metabolism, Serotonin 5-HT2 Receptor Agonists pharmacology, Ventral Tegmental Area metabolism
- Abstract
Obesity is primarily due to food intake in excess of the body's energetic requirements, intake that is not only associated with hunger but also the incentive value of food. The 5-hydroxytryptamine 2C receptor (5-HT
2C R) is a target for the treatment of human obesity. Mechanistically, 5-HT2C Rs are positioned to influence both homeostatic feeding circuits within the hypothalamus and reward circuits within the ventral tegmental area (VTA). Here we investigated the role of 5-HT2C Rs in incentive motivation using a mathematical model of progressive ratio (PR) responding in mice. We found that the 5-HT2C R agonist lorcaserin significantly reduced both ad libitum chow intake and PR responding for chocolate pellets and increased c-fos expression in VTA 5-HT2C R expressing γ-aminobutyric acid (GABA) neurons, but not 5-HT2C R expressing dopamine (DA) neurons. We next adopted a chemogenetic approach using a 5-HT2C RCRE line to clarify the function of subset of 5-HT2C receptor expressing VTA neurons in the modulation of appetite and food-motivated behavior. Activation of VTA 5-HT2C receptor expressing neurons significantly reduced ad libitum chow intake, operant responding for chocolate pellets, and the incentive value of food. In contrast, chemogenetic inhibition of VTA 5-HT2C receptor expressing neurons had no effect on the feeding behavior. These results indicate that activation of the subpopulation of 5-HT2C R neurons within the VTA is sufficient to significantly reduce homeostatic feeding and effort-based intake of palatable food, and that this subset has an inhibitory role in motivational processes. These findings are relevant to the treatment of obesity.- Published
- 2017
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22. Desynchronization of the Rat Cortical Network and Excitation of White Matter Neurons by Neurotensin.
- Author
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Case L, Lyons DJ, and Broberger C
- Subjects
- Animals, Fluorescent Antibody Technique, Male, Patch-Clamp Techniques, Rats, Rats, Sprague-Dawley, Cerebral Cortex physiology, Neurons physiology, Neurotensin metabolism, Wakefulness physiology, White Matter physiology
- Abstract
Cortical network activity correlates with vigilance state: Deep sleep is characterized by slow, synchronized oscillations, whereas desynchronized, stochastic discharge is typical of the waking state. Neuropeptides, such as orexin and substance P but also neurotensin (NT), promote arousal. Relatively little is known about if NT can directly affect the cortical network, and if so, through which mechanisms and cellular targets. Here, we addressed these issues using rat in vitro cortex preparations. Following NT application specifically to deeper layers, slow oscillation activity was attenuated with a significant reduction in UP state frequency. The cortical response to thalamic stimulation exhibited enhanced temporal precision in the presence of NT, consistent with the transition in vivo from sleep to wakefulness. These changes were associated with a relative shift toward inhibition in the excitation/inhibition balance. Whole-cell recordings from layer 6 revealed presynaptically driven NT-induced inhibition of pyramidal neurons and excitation of fast-spiking interneurons. Deeper in the cortex, neurons within the white matter (WM) were strongly depolarized by NT application. The colocalization of NT and tyrosine hydroxylase immunoreactivities in deep layer fibers throughout the cortical mantle indicates mediation via dopaminergic systems. These data suggest a cortical mechanism for NT-induced wakefulness and support a role for WM neurons in state control., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2017
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23. Promotion of Organic Reactions by Non-Benzenoid Carbocyclic Aromatic Ions.
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Lyons DJ, Crocker RD, Blümel M, and Nguyen TV
- Abstract
The first three primary members of the non-benzenoid carbocyclic aromatic ion family, namely cyclopropenium, cyclopentadienide, and cycloheptatrienium (tropylium) ions, have planar cyclic structures with (4n+2)π electrons in fully conjugated systems. They fulfill Hückel's rule for aromaticity and hence possess extraordinary stability. Since the historic discovery of tropylium bromide in the late 19th Century, these non-benzenoid aromatic ions have attracted a lot of attention because of their unique combination of stability and reactivity. The charge on the aromatic ions makes them more prone to nucleophilic/electrophilic reactions than the neutral benzenoid counterparts. Within the last seven years, there has been a large number of investigations in utilizing aromatic ions to mediate organic reactions. This Review highlights these recent developments and discusses the potential of aromatic ions in promoting synthetically useful organic transformations., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2017
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24. Hypocretin/Orexin Peptides Excite Rat Neuroendocrine Dopamine Neurons through Orexin 2 Receptor-Mediated Activation of a Mixed Cation Current.
- Author
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Lyons DJ, Hellysaz A, Ammari R, and Broberger C
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- Animals, Boron Compounds pharmacology, Excitatory Postsynaptic Potentials drug effects, Hypothalamus metabolism, Immunohistochemistry, Male, Melatonin metabolism, Melatonin pharmacology, Neurosecretory Systems drug effects, Neurosecretory Systems physiology, Pyramidal Cells drug effects, Pyramidal Cells physiology, Rats, Sodium metabolism, Transient Receptor Potential Channels antagonists & inhibitors, Cations metabolism, Dopaminergic Neurons drug effects, Dopaminergic Neurons physiology, Orexin Receptors metabolism, Orexins pharmacology, Synaptic Potentials drug effects
- Abstract
Hypocretin/Orexin (H/O) neurons of the lateral hypothalamus are compelling modulator candidates for the chronobiology of neuroendocrine output and, as a consequence, hormone release from the anterior pituitary. Here we investigate the effects of H/O peptides upon tuberoinfundibular dopamine (TIDA) neurons - cells which control, via inhibition, the pituitary secretion of prolactin. In whole cell recordings performed in male rat hypothalamic slices, application of H/O-A, as well as H/O-B, excited oscillating TIDA neurons, inducing a reversible depolarising switch from phasic to tonic discharge. The H/O-induced inward current underpinning this effect was post-synaptic (as it endured in the presence of tetrodotoxin), appeared to be carried by a Na
+ -dependent transient receptor potential-like channel (as it was blocked by 2-APB and was diminished by removal of extracellular Na+ ), and was a consequence of OX2R receptor activation (as it was blocked by the OX2R receptor antagonist TCS OX2 29, but not the OX1R receptor antagonist SB 334867). Application of the hormone, melatonin, failed to alter TIDA membrane potential or oscillatory activity. This first description of the electrophysiological effects of H/Os upon the TIDA network identifies cellular mechanisms that may contribute to the circadian rhythmicity of prolactin secretion., Competing Interests: The authors declare no competing financial interests.- Published
- 2017
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25. Serotonin and Antidepressant SSRIs Inhibit Rat Neuroendocrine Dopamine Neurons: Parallel Actions in the Lactotrophic Axis.
- Author
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Lyons DJ, Ammari R, Hellysaz A, and Broberger C
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- Action Potentials drug effects, Animals, Electric Stimulation, Excitatory Amino Acid Agents pharmacology, In Vitro Techniques, Male, Patch-Clamp Techniques, Rats, Rats, Sprague-Dawley, Receptors, Serotonin metabolism, Serotonin metabolism, Serotonin Antagonists pharmacology, Sodium Channel Blockers pharmacology, Tetrahydronaphthalenes pharmacology, Tetrodotoxin pharmacology, Tyrosine 3-Monooxygenase metabolism, Antidepressive Agents pharmacology, Arcuate Nucleus of Hypothalamus cytology, Dopaminergic Neurons drug effects, Lactotrophs drug effects, Serotonin pharmacology, Selective Serotonin Reuptake Inhibitors pharmacology
- Abstract
Unlabelled: Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for depression, but sexual side effects often compromise compliance. These reproductive dysfunctions are likely mediated by elevations of the hormone prolactin. Yet, how serotonin (5-HT) and SSRIs cause changes in prolactin secretion is not known. Here, using in vitro whole-cell patch-clamp recordings, we show that 5-HT hyperpolarizes and abolishes phasic discharge in rat neuroendocrine tuberoinfundibular dopamine (TIDA) neurons, the main inhibitor of prolactin secretion. This process is underpinned by 5-HT1A receptor-mediated activation of G-protein-coupled inwardly rectifying K(+)-like currents. We further demonstrate that the SSRIs, fluoxetine and sertraline, directly suppress TIDA neuron activity through parallel effects, independent of 5-HT transmission. This inhibition involves decreased intrinsic excitability and a slowing of TIDA network rhythms. These findings indicate that SSRIs may inhibit neuroendocrine dopamine release through both 5-HT-dependent and -independent actions, providing a mechanistic explanation for, and potential molecular targets for the amelioration of, the hyperprolactinemia and sexual dysfunction associated with these drugs., Significance Statement: Depression affects approximately one-tenth of the population and is commonly treated with selective serotonin reuptake inhibitors (SSRIs; e.g., Prozac). Yet, many patients withdraw from SSRI therapy due to sexual side effects (e.g., infertility, menstrual disturbances, and impotence). Although it is generally accepted that sexual side effects are due to the ability of these drugs to elevate blood levels of the hormone prolactin, the mechanism for this hormonal imbalance is not known. Here, we show that SSRIs can inhibit hypothalamic dopamine neurons that normally suppress the secretion of prolactin. Intriguingly this inhibition can be explained both by increased serotonin activity and also by parallel serotonin-independent actions., (Copyright © 2016 the authors 0270-6474/16/367392-15$15.00/0.)
- Published
- 2016
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26. Dopamine Autoreceptor Regulation of a Hypothalamic Dopaminergic Network.
- Author
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Stagkourakis S, Kim H, Lyons DJ, and Broberger C
- Abstract
How autoreceptors contribute to maintaining a stable output of rhythmically active neuronal circuits is poorly understood. Here, we examine this issue in a dopamine population, spontaneously oscillating hypothalamic rat (TIDA) neurons, that underlie neuroendocrine control of reproduction and neuroleptic side effects. Activation of dopamine receptors of the type 2 family (D2Rs) at the cell-body level slowed TIDA oscillations through two mechanisms. First, they prolonged the depolarizing phase through a combination of presynaptic increases in inhibition and postsynaptic hyperpolarization. Second, they extended the discharge phase through presynaptic attenuation of calcium currents and decreased synaptic inhibition. Dopamine reuptake blockade similarly reconfigured the oscillation, indicating that ambient somatodendritic transmitter concentration determines electrical behavior. In the absence of D2R feedback, however, discharge was abolished by depolarization block. These results indicate the existence of an ultra-short feedback loop whereby neuroendocrine dopamine neurons tune network behavior to echoes of their own activity, reflected in ambient somatodendritic dopamine, and also suggest a mechanism for antipsychotic side effects., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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27. Appetite controlled by a cholecystokinin nucleus of the solitary tract to hypothalamus neurocircuit.
- Author
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D'Agostino G, Lyons DJ, Cristiano C, Burke LK, Madara JC, Campbell JN, Garcia AP, Land BB, Lowell BB, Dileone RJ, and Heisler LK
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- Animals, Brain Mapping, Mice, Optogenetics, Appetite, Cholecystokinin metabolism, Neural Pathways anatomy & histology, Paraventricular Hypothalamic Nucleus physiology, Solitary Nucleus physiology
- Abstract
The nucleus of the solitary tract (NTS) is a key gateway for meal-related signals entering the brain from the periphery. However, the chemical mediators crucial to this process have not been fully elucidated. We reveal that a subset of NTS neurons containing cholecystokinin (CCK(NTS)) is responsive to nutritional state and that their activation reduces appetite and body weight in mice. Cell-specific anterograde tracing revealed that CCK(NTS) neurons provide a distinctive innervation of the paraventricular nucleus of the hypothalamus (PVH), with fibers and varicosities in close apposition to a subset of melanocortin-4 receptor (MC4R(PVH)) cells, which are also responsive to CCK. Optogenetic activation of CCK(NTS) axon terminals within the PVH reveal the satiating function of CCK(NTS) neurons to be mediated by a CCK(NTS)→PVH pathway that also encodes positive valence. These data identify the functional significance of CCK(NTS) neurons and reveal a sufficient and discrete NTS to hypothalamus circuit controlling appetite.
- Published
- 2016
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28. Physical experience enhances science learning.
- Author
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Kontra C, Lyons DJ, Fischer SM, and Beilock SL
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- Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Male, Sensation, Students, Universities, Comprehension, Feedback, Sensory, Learning
- Abstract
Three laboratory experiments involving students' behavior and brain imaging and one randomized field experiment in a college physics class explored the importance of physical experience in science learning. We reasoned that students' understanding of science concepts such as torque and angular momentum is aided by activation of sensorimotor brain systems that add kinetic detail and meaning to students' thinking. We tested whether physical experience with angular momentum increases involvement of sensorimotor brain systems during students' subsequent reasoning and whether this involvement aids their understanding. The physical experience, a brief exposure to forces associated with angular momentum, significantly improved quiz scores. Moreover, improved performance was explained by activation of sensorimotor brain regions when students later reasoned about angular momentum. This finding specifies a mechanism underlying the value of physical experience in science education and leads the way for classroom practices in which experience with the physical world is an integral part of learning., (© The Author(s) 2015.)
- Published
- 2015
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29. Peroxisome proliferator-activated receptor alpha plays a crucial role in behavioral repetition and cognitive flexibility in mice.
- Author
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D'Agostino G, Cristiano C, Lyons DJ, Citraro R, Russo E, Avagliano C, Russo R, Raso GM, Meli R, De Sarro G, Heisler LK, and Calignano A
- Abstract
Background/objectives: Nuclear peroxisome proliferator activated receptor-α (PPAR-α) plays a fundamental role in the regulation of lipid homeostasis and is the target of medications used to treat dyslipidemia. However, little is known about the role of PPAR-α in mouse behavior., Methods: To investigate the function of Ppar-α in cognitive functions, a behavioral phenotype analysis of mice with a targeted genetic disruption of Ppar-α was performed in combination with neuroanatomical, biochemical and pharmacological manipulations. The therapeutic exploitability of PPAR-α was probed in mice using a pharmacological model of psychosis and a genetic model (BTBR T + tf/J) exhibiting a high rate of repetitive behavior., Results: An unexpected role for brain Ppar-α in the regulation of cognitive behavior in mice was revealed. Specifically, we observed that Ppar-α genetic perturbation promotes rewiring of cortical and hippocampal regions and a behavioral phenotype of cognitive inflexibility, perseveration and blunted responses to psychomimetic drugs. Furthermore, we demonstrate that the antipsychotic and autism spectrum disorder (ASD) medication risperidone ameliorates the behavioral profile of Ppar-α deficient mice. Importantly, we reveal that pharmacological PPAR-α agonist treatment in mice improves behavior in a pharmacological model of ketamine-induced behavioral dysinhibition and repetitive behavior in BTBR T + tf/J mice., Conclusion: Our data indicate that Ppar-α is required for normal cognitive function and that pharmacological stimulation of PPAR-α improves cognitive function in pharmacological and genetic models of impaired cognitive function in mice. These results thereby reveal an unforeseen therapeutic application for a class of drugs currently in human use.
- Published
- 2015
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- View/download PDF
30. A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions.
- Author
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Nguyen TV and Lyons DJ
- Abstract
A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Published
- 2015
- Full Text
- View/download PDF
31. A role for solute carrier family 10 member 4, or vesicular aminergic-associated transporter, in structural remodelling and transmitter release at the mouse neuromuscular junction.
- Author
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Patra K, Lyons DJ, Bauer P, Hilscher MM, Sharma S, Leão RN, and Kullander K
- Subjects
- Animals, Blotting, Western, Female, Imaging, Three-Dimensional, Immunohistochemistry, Mice, 129 Strain, Mice, Inbred C57BL, Mice, Knockout, Microelectrodes, Microscopy, Confocal, Miniature Postsynaptic Potentials physiology, Motor Activity physiology, Muscle, Skeletal metabolism, Nerve Tissue Proteins genetics, RNA, Messenger metabolism, Receptors, Cholinergic metabolism, Spinal Cord metabolism, Symporters, Vesicular Transport Proteins genetics, Nerve Tissue Proteins metabolism, Neuromuscular Junction physiology, Neuronal Plasticity physiology, Synaptic Vesicles physiology, Vesicular Transport Proteins metabolism
- Abstract
The solute carrier and presynaptic vesicle protein solute carrier family 10 member 4, or vesicular aminergic-associated transporter (VAAT), was recently proven to have a modulatory role in central cholinergic signalling. It is currently unknown whether VAAT also affects peripheral cholinergic synapses. Here we demonstrated a regulatory role for the presynaptic vesicle protein VAAT in neuromuscular junction (NMJ) development and function. NMJs lacking VAAT had fewer branch points, whereas endplates showed an increased number of islands. Whereas the amplitude of spontaneous miniature endplate potentials in VAAT-deficient NMJs was decreased, the amplitude of evoked endplate potentials and the size of the readily releasable pool of vesicles were both increased. Moreover, VAAT-deficient NMJs displayed aberrant short-term synaptic plasticity with enhanced synaptic depression in response to high-frequency stimulation. Finally, the transcript levels of cholinergic receptor subunits in VAAT-deficient muscles were increased, indicating a compensatory postsynaptic sensitization. Our results suggested that VAAT modulates NMJ transmission efficiency and, as such, may represent a novel target for treatment of disorders affecting motor neurons., (© 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)
- Published
- 2015
- Full Text
- View/download PDF
32. TIDAL WAVES: Network mechanisms in the neuroendocrine control of prolactin release.
- Author
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Lyons DJ and Broberger C
- Subjects
- Animals, Humans, Pituitary Gland metabolism, Dopamine metabolism, Neurons metabolism, Neurosecretory Systems metabolism, Prolactin metabolism, Thyrotropin-Releasing Hormone metabolism
- Abstract
Neuroendocrine tuberoinfundibular dopamine (TIDA) neurons tonically inhibit pituitary release of the hormone, prolactin. Through the powerful actions of prolactin in promoting lactation and maternal behaviour while suppressing sexual drive and fertility, TIDA neurons play a key role in reproduction. We summarize insights from recent in vitro studies into the membrane properties and network behaviour of TIDA neurons including the observations that TIDA neurons exhibit a robust oscillation that is synchronized between cells and depends on intact gap junction communication. Comparisons are made with phasic firing patterns in other neuronal populations. Modulators involved in the control of lactation - including serotonin, thyrotropin-releasing hormone and prolactin itself - have been shown to change the electrical behaviour of TIDA cells. We propose that TIDA discharge mode may play a central role in tuning the amount of dopamine delivered to the pituitary and hence circulating prolactin concentrations in different reproductive states and pathological conditions., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
33. Phosphorus as a limiting factor on sustainable greywater irrigation.
- Author
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Turner RD, Will GD, Dawes LA, Gardner EA, and Lyons DJ
- Subjects
- Agricultural Irrigation standards, Australia, Conservation of Natural Resources, Environmental Monitoring, Wastewater chemistry, Water Pollutants, Chemical chemistry, Agricultural Irrigation methods, Phosphorus analysis, Soil chemistry, Soil standards, Soil Pollutants analysis, Wastewater analysis, Water Pollutants, Chemical analysis
- Abstract
Water reuse through greywater irrigation has been adopted worldwide and has been proposed as a potential sustainable solution to increased water demands. Despite widespread adoption, there is limited domestic knowledge of greywater reuse. There is no pressure to produce low-level phosphorus products and current guidelines and legislation, such as those in Australia, may be inadequate due to the lack of long-term data to provide a sound scientific basis. Research has clearly identified phosphorus as a potential environmental risk to waterways from many forms of irrigation. To assess the sustainability of greywater irrigation, this study compared four residential lots that had been irrigated with greywater for four years and adjacent non-irrigated lots that acted as controls. Each lot was monitored for the volume of greywater applied and selected physic-chemical water quality parameters and soil chemistry profiles were analysed. The non-irrigated soil profiles showed low levels of phosphorus and were used as controls. The Mechlich3 Phosphorus ratio (M3PSR) and Phosphate Environmental Risk Index (PERI) were used to determine the environmental risk of phosphorus leaching from the irrigated soils. Soil phosphorus concentrations were compared to theoretical greywater irrigation loadings. The measured phosphorus soil concentrations and the estimated greywater loadings were of similar magnitude. Sustainable greywater reuse is possible; however incorrect use and/or lack of understanding of how household products affect greywater can result in phosphorus posing a significant risk to the environment., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
34. Thyroid hormone is required for hypothalamic neurons regulating cardiovascular functions.
- Author
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Mittag J, Lyons DJ, Sällström J, Vujovic M, Dudazy-Gralla S, Warner A, Wallis K, Alkemade A, Nordström K, Monyer H, Broberger C, Arner A, and Vennström B
- Subjects
- Animals, Blood Pressure genetics, Heart Rate genetics, Hypertension genetics, Hypertension pathology, Hypothalamus, Anterior pathology, Hypothyroidism genetics, Hypothyroidism metabolism, Hypothyroidism pathology, Mice, Mice, Transgenic, Mutation, Neurons pathology, Risk Factors, Tachycardia genetics, Tachycardia pathology, Thyroid Hormone Receptors alpha genetics, Thyroid Hormones genetics, Hypertension metabolism, Hypothalamus, Anterior metabolism, Neurons metabolism, Tachycardia metabolism, Thyroid Hormone Receptors alpha metabolism, Thyroid Hormones metabolism
- Abstract
Thyroid hormone is well known for its profound direct effects on cardiovascular function and metabolism. Recent evidence, however, suggests that the hormone also regulates these systems indirectly through the central nervous system. While some of the molecular mechanisms underlying the hormone's central control of metabolism have been identified, its actions in the central cardiovascular control have remained enigmatic. Here, we describe a previously unknown population of parvalbuminergic neurons in the anterior hypothalamus that requires thyroid hormone receptor signaling for proper development. Specific stereotaxic ablation of these cells in the mouse resulted in hypertension and temperature-dependent tachycardia, indicating a role in the central autonomic control of blood pressure and heart rate. Moreover, the neurons exhibited intrinsic temperature sensitivity in patch-clamping experiments, providing a new connection between cardiovascular function and core temperature. Thus, the data identify what we believe to be a novel hypothalamic cell population potentially important for understanding hypertension and indicate developmental hypothyroidism as an epigenetic risk factor for cardiovascular disorders. Furthermore, the findings may be beneficial for treatment of the recently identified patients that have a mutation in thyroid hormone receptor α1.
- Published
- 2013
- Full Text
- View/download PDF
35. Prolactin regulates tuberoinfundibular dopamine neuron discharge pattern: novel feedback control mechanisms in the lactotrophic axis.
- Author
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Lyons DJ, Hellysaz A, and Broberger C
- Subjects
- Action Potentials drug effects, Animals, Arcuate Nucleus of Hypothalamus cytology, Arcuate Nucleus of Hypothalamus drug effects, Boron Compounds pharmacology, Calcium pharmacology, Data Interpretation, Statistical, Electrophysiological Phenomena, Feedback, Physiological drug effects, Female, Indicators and Reagents, Ion Channels physiology, Lactation drug effects, Large-Conductance Calcium-Activated Potassium Channels drug effects, Large-Conductance Calcium-Activated Potassium Channels metabolism, Membrane Potentials physiology, Neurons drug effects, Patch-Clamp Techniques, Phosphatidylinositol 3-Kinases metabolism, Phosphoinositide-3 Kinase Inhibitors, Prolactin pharmacology, Rats, Rats, Sprague-Dawley, Arcuate Nucleus of Hypothalamus physiology, Dopamine physiology, Feedback, Physiological physiology, Lactation physiology, Neurons physiology, Prolactin physiology
- Abstract
Balance in the body's hormonal axes depends on feedback onto neuroendocrine hypothalamic neurons. This phenomenon involves transcriptional and biosynthetic effects, yet less is known about the potential rapid modulation of electrical properties. Here, we investigated this issue in the lactotrophic axis, in which the pituitary hormone prolactin is tonically inhibited by tuberoinfundibular dopamine (TIDA) neurons located in the hypothalamic arcuate nucleus. Whole-cell recordings were performed on slices of the rat hypothalamus. In the presence of prolactin, spontaneously oscillating TIDA cells depolarized, switched from phasic to tonic discharge, and exhibited broadened action potentials. The underlying prolactin-induced current is composed of separate low- and high-voltage components that include the activation of a transient receptor potential-like current and the inhibition of a Ca(2+)-dependent BK-type K(+) current, respectively, as revealed by ion substitution experiments and pharmacological manipulation. The two components of the prolactin-induced current appear to be mediated through distinct signaling pathways as the high-voltage component is abolished by the phosphoinositide 3-kinase blocker wortmannin, whereas the low-voltage component is not. This first description of the central electrophysiological actions of prolactin suggests a novel feedback mechanism. By simultaneously enhancing the discharge and spike duration of TIDA cells, increased serum prolactin can promote dopamine release to limit its own secretion with implications for the control of lactation, sexual libido, fertility, and body weight.
- Published
- 2012
- Full Text
- View/download PDF
36. Appropriate maximum holding times for analysis of total suspended solids concentration in water samples taken from open-channel waterways.
- Author
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Oudyn FW, Lyons DJ, and Pringle MJ
- Subjects
- Queensland, Time Factors, Environmental Monitoring methods, Particulate Matter, Water chemistry, Water Pollutants analysis
- Abstract
Many scientific laboratories follow, as standard practice, a relatively short maximum holding time (within 7 days) for the analysis of total suspended solids (TSS) in environmental water samples. In this study we have subsampled from bulk water samples stored at ∼4 °C in the dark, then analysed for TSS at time intervals up to 105 days after collection. The nonsignificant differences in TSS results observed over time demonstrates that storage at ∼4 °C in the dark is an effective method of preserving samples for TSS analysis, far past the 7-day standard practice. Extending the maximum holding time will ease the pressure on sample collectors and laboratory staff who until now have had to determine TSS within an impractically short period.
- Published
- 2012
- Full Text
- View/download PDF
37. Synchronized network oscillations in rat tuberoinfundibular dopamine neurons: switch to tonic discharge by thyrotropin-releasing hormone.
- Author
-
Lyons DJ, Horjales-Araujo E, and Broberger C
- Subjects
- Animals, Male, Rats, Rats, Sprague-Dawley, Arcuate Nucleus of Hypothalamus physiology, Biological Clocks physiology, Dopamine physiology, Nerve Net physiology, Neurons physiology, Thyrotropin-Releasing Hormone physiology
- Abstract
The pituitary hormone, prolactin, triggers lactation in nursing mothers. Under nonlactating conditions, prolactin secretion is suppressed by powerful inhibition from hypothalamic tuberoinfundibular dopamine (TIDA) neurons. Although firing pattern has been suggested as integral to neuroendocrine control, the electrical behavior of TIDA cells remains unknown. We demonstrate that rat TIDA neurons discharge rhythmically in a robust 0.05 Hz oscillation. The oscillation is phase locked between neurons, and while it persists during chemical synaptic transmission blockade, it is abolished by gap junction antagonists. Thyrotropin-releasing hormone (TRH) potently stimulates prolactin release, an effect assumed to take place in the pituitary. In TIDA cells, TRH caused a transition from phasic to tonic firing through combined pre- and postsynaptic effects. These findings suggest a model for prolactin regulation where a TIDA network switch from oscillations to sustained discharge converts dopamine from an antagonist at high concentrations to a functional agonist as dopamine output from the network decreases., (Copyright 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
38. Recommendations for bone mineral density reporting in Canada: a shift to absolute fracture risk assessment.
- Author
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Siminoski K, Leslie WD, Frame H, Hodsman A, Josse RG, Khan A, Lentle BC, Levesque J, Lyons DJ, Tarulli G, and Brown JP
- Subjects
- Absorptiometry, Photon, Canada epidemiology, Humans, Incidence, Risk Factors, Bone Density physiology, Fractures, Bone diagnostic imaging, Fractures, Bone epidemiology, Fractures, Bone prevention & control, Practice Guidelines as Topic, Registries
- Abstract
In June 2005, new Canadian recommendations for bone mineral density (BMD) reporting in postmenopausal women and older men were published by Osteoporosis Canada (formerly the Osteoporosis Society of Canada) and the Canadian Association of Radiologists. The recommendations were developed by a multidisciplinary working group that included the Canadian Panel of the International Society for Clinical Densitometry and were reviewed and endorsed by multiple stakeholders. Previous Canadian osteoporosis guidelines advised intervention based on an individual's World Health Organization category (normal, osteopenia, or osteoporosis) as a marker of relative fracture risk. In the new approach, an individual's 10-yr absolute fracture risk, rather than BMD alone, is used for fracture risk categorization. Absolute fracture risk is determined using not only BMD results, but also age, sex, fragility fracture history, and glucocorticoid use. A procedure is presented for estimating absolute 10-yr fracture risk in untreated individuals, leading to assigning an individual to 1 of 3 absolute fracture risk categories: low risk (<10% 10-yr fracture risk), moderate risk (10-20%), and high risk (>20%). We propose that an individual's absolute fracture risk category should be the basis for deciding on treatment and frequency of BMD monitoring.
- Published
- 2007
- Full Text
- View/download PDF
39. Pharmacological and molecular characterization of ATP-sensitive K(+) conductances in CART and NPY/AgRP expressing neurons of the hypothalamic arcuate nucleus.
- Author
-
van den Top M, Lyons DJ, Lee K, Coderre E, Renaud LP, and Spanswick D
- Subjects
- ATP-Binding Cassette Transporters genetics, Adenosine Triphosphate metabolism, Adenosine Triphosphate pharmacology, Agouti-Related Protein, Animals, Arcuate Nucleus of Hypothalamus cytology, Arcuate Nucleus of Hypothalamus drug effects, Ghrelin, Glucose metabolism, Glucose pharmacology, Male, Membrane Potentials drug effects, Membrane Potentials physiology, Multidrug Resistance-Associated Proteins genetics, Neurons drug effects, Organ Culture Techniques, Patch-Clamp Techniques, Peptide Hormones metabolism, Potassium metabolism, Potassium Channel Blockers pharmacology, Potassium Channels, Inwardly Rectifying drug effects, RNA, Messenger drug effects, RNA, Messenger metabolism, Rats, Rats, Wistar, Receptors, Drug, Sulfonylurea Receptors, Cocaine- and Amphetamine-Regulated Transcript Protein, Arcuate Nucleus of Hypothalamus metabolism, Intercellular Signaling Peptides and Proteins metabolism, Nerve Tissue Proteins metabolism, Neurons metabolism, Neuropeptide Y metabolism, Potassium Channels, Inwardly Rectifying metabolism
- Abstract
The role of hypothalamic ATP-sensitive potassium channels in the maintenance of energy homeostasis has been extensively explored. However, how these channels are incorporated into the neuronal networks of the arcuate nucleus remains unclear. Whole-cell patch-clamp recordings from rat arcuate nucleus neurons in hypothalamic slice preparations revealed widespread expression of functional ATP-sensitive potassium channels within the nucleus. ATP-sensitive potassium channels were expressed in orexigenic neuropeptide Y/agouti-related protein (NPY/AgRP) and ghrelin-sensitive neurons and in anorexigenic cocaine-and-amphetamine regulated transcript (CART) neurons. In 70% of the arcuate nucleus neurons recorded, exposure to glucose-free bathing medium induced inhibition of electrical excitability, the response being characterized by membrane hyperpolarization, a reduction in neuronal input resistance and a reversal potential consistent with opening of potassium channels. These effects were reversible upon re-introduction of glucose to the bathing medium or upon exposure to the ATP-sensitive potassium channel blockers tolbutamide or glibenclamide. The potassium channel opener diazoxide, but not pinacidil, also induced a tolbutamide and glibenclamide-sensitive inhibition of electrical excitability. Single-cell reverse transcription-polymerase chain reaction revealed expression of mRNA for sulfonylurea receptor 1 but not sulfonylurea receptor 2 subunits of ATP-sensitive potassium channels. Thus, rat arcuate nucleus neurons, including those involved in functionally antagonistic orexigenic and anorexigenic pathways express functional ATP-sensitive potassium channels which include sulfonylurea receptor 1 subunits. These data indicate a crucial role for these ion channels in central sensing of metabolic and energy status. However, further studies are needed to clarify the differential roles of these channels, the organization of signaling pathways that regulate them and how they operate in functionally opposing cell types.
- Published
- 2007
- Full Text
- View/download PDF
40. Thyrotoxicosis induced by choriocarcinoma a report of two cases.
- Author
-
O'Reilly S, Lyons DJ, Harrison M, Gaffney E, Cullen M, and Clancy L
- Subjects
- Adult, Choriocarcinoma pathology, Choriocarcinoma secondary, Dysgerminoma complications, Dysgerminoma pathology, Female, Humans, Middle Aged, Neoplasms, Germ Cell and Embryonal complications, Neoplasms, Germ Cell and Embryonal pathology, Neoplasms, Multiple Primary pathology, Ovarian Neoplasms pathology, Pregnancy, Uterine Neoplasms pathology, Choriocarcinoma complications, Ovarian Neoplasms complications, Thyrotoxicosis etiology, Uterine Neoplasms complications
- Abstract
We report two cases of choriocarcinoma, one uterine, the other a component of an ovarian germ cell tumour, in both instances clinically overt thyrotoxicosis was a feature of their initial presentation. These cases highlight a rare clinical association which is due a thyrotropic action of Human Chorionic Gonadotrophin.
- Published
- 1993
41. Very long term retention of bronchial foreign bodies two new cases and a review of the literature.
- Author
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Lyons DJ, McCleod D, Prichard J, Dowd D, and Clancy L
- Subjects
- Adult, Female, Humans, Time Factors, Bronchi, Foreign Bodies diagnosis, Foreign Bodies therapy
- Abstract
We report two cases in which foreign bodies were retrieved from the bronchus after intervals of 25 years or more. Both occurred in women in their 30s, in neither case was there a history of aspiration, and both patients were asymptomatic for many years. The literature on protracted retention of bronchial foreign bodies is reviewed using a Medline search and relevant bibliography.
- Published
- 1993
42. Chemical inactivation of the Kveim reagent.
- Author
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Lyons DJ, Donald S, Mitchell DN, and Asherson GL
- Subjects
- Chemical Fractionation, Humans, Indicators and Reagents, Mercaptoethanol pharmacology, Urea pharmacology, Kveim Test, Lung Diseases diagnosis, Sarcoidosis diagnosis
- Abstract
In an attempt to identify the nature of the active principle, Kveim reagent was exposed to chemical fractionating agents. Thirty-one patients with sarcoidosis underwent simultaneous intradermal injection with fractionated and unfractionated Kveim material. Kveim reagent was stable in the presence of DNAse, RNAse, pronase, 95% phenol, neutral detergent, and to lipid extraction with chloroform-methanol. Kveim reagent was also stable in the presence of both 8 M urea (8MU) and 2-mercaptoethanol (2ME) when used alone. When both these agents were used together, Kveim reagent was inactivated. Fourteen patients had a positive test to unfractionated Kveim reagent; of these, only 2 gave a positive response to material fractionated by exposure to 8MU and 2ME. Simultaneous exposure to 8MU and 2ME was more likely to inactivate Kveim reagent (10/10 tests) than sequential exposure to 8MU and 2ME (2/4 tests). Chemical analysis of the fractionated material showed that it retained granuloma-generating activity despite the lack of carbohydrates. Protein loss in terms of total and relative amino acid composition was progressive and non-specific throughout processing. These results are consistent with a protein-active principle which is dependent on three-dimensional structure.
- Published
- 1992
- Full Text
- View/download PDF
43. Ulcerative jejunitis: are we missing cases?
- Author
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Costello RW, Lyons DJ, and Fielding JF
- Subjects
- Adult, Enteritis blood, Enteritis pathology, Female, Humans, Jejunal Diseases blood, Jejunal Diseases pathology, Middle Aged, Ulcer, Enteritis diagnosis, Jejunal Diseases diagnosis
- Abstract
We present two cases of ulcerative jejunitis unassociated with coeliac disease. The condition is probably being underdiagnosed especially since the reduction in the investigative laparotomy.
- Published
- 1991
- Full Text
- View/download PDF
44. Severe haemolysis associated with hepatitis A and normal glucose-6-phosphate dehydrogenase status.
- Author
-
Lyons DJ, Gilvarry JM, and Fielding JF
- Subjects
- Adult, Female, Hepatitis A enzymology, Humans, Glucosephosphate Dehydrogenase metabolism, Hemolysis, Hepatitis A blood
- Abstract
We report massive acute haemolysis associated with hepatitis A in a 36 year old Irish woman. Although mild anaemia is not uncommon during viral hepatitis, haemolysis of the severity observed in this patient has previously been reported only in patients with glucose-6-phosphate dehydrogenase deficiency.
- Published
- 1990
- Full Text
- View/download PDF
45. What's in a relationship? Sarcoidosis and tuberculosis.
- Author
-
Lyons DJ and Fielding JF
- Subjects
- Humans, Mycobacterium Infections complications, Mycobacterium Infections immunology, Opportunistic Infections etiology, Opportunistic Infections immunology, Prevalence, Sarcoidosis etiology, Sarcoidosis immunology, Tuberculosis complications, Tuberculosis immunology, Mycobacterium Infections epidemiology, Opportunistic Infections epidemiology, Sarcoidosis epidemiology, Tuberculosis epidemiology
- Abstract
The relationship between the two granulomatous diseases sarcoidosis and tuberculosis is reviewed. Data from 14 published case series are presented in the form of a figure which indicates that case series collected earlier in time and with a high proportion of non-white patients show a higher prevalence of tuberculosis. This high prevalence was also found in other chronic diseases such as diabetes and rheumatoid arthritis. The more frequent presence of mycobacteria in sarcoid than in control tissue, the parallel changes in the prevalence of sarcoidosis and tuberculosis in a community and the presence of myocbacteria on culture if pursued with sufficient aggression, are consistant with a mycobacterial aetiology. Recent developments in the immunology of the two diseases are reviewed.
- Published
- 1990
46. Determination of total calcium, zinc, manganese, iron, magnesium and phosphorus in animal feeds and plant material using inductively coupled plasma emission spectrometry.
- Author
-
Lyons DJ, Spann KP, and Roofayel RL
- Subjects
- Calcium analysis, Iron analysis, Manganese analysis, Spectrophotometry, Zinc analysis, Animal Feed analysis, Metals analysis, Phosphorus analysis, Plants, Edible analysis
- Published
- 1985
- Full Text
- View/download PDF
47. Effect of ethanol on transfer factor: the importance of posture.
- Author
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Lyons DJ, Moszoro H, Peters TJ, and Milledge JS
- Subjects
- Adult, Blood Volume drug effects, Capillaries, Carbon Monoxide, Humans, Lung blood supply, Male, Middle Aged, Supination, Ethanol adverse effects, Pulmonary Diffusing Capacity drug effects
- Published
- 1987
- Full Text
- View/download PDF
48. A case of Graves' disease associated with autoimmune haemolytic anaemia.
- Author
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O'Brien D, Lyons DJ, and Fielding JF
- Subjects
- Adolescent, Anemia, Hemolytic, Autoimmune epidemiology, Anemia, Hemolytic, Autoimmune immunology, Graves Disease epidemiology, Graves Disease immunology, Humans, Ireland, Male, Anemia, Hemolytic, Autoimmune complications, Graves Disease complications
- Abstract
This report describes simultaneous autoimmune thyrotoxicosis and autoimmune haemolytic anaemia. Autoimmune haematological abnormalities should be excluded in patients with Graves' disease and thyroid function and thyroid antibody status should be evaluated in patients with autoimmune haemolytic anaemia.
- Published
- 1989
- Full Text
- View/download PDF
49. The Department of Justice: dealing with a constellation of problems.
- Author
-
Lyons DJ
- Subjects
- Delaware, Hazardous Waste legislation & jurisprudence, Humans, United States, AIDS Serodiagnosis, Criminal Law, Insurance, Insurance Selection Bias, Jurisprudence, Public Health legislation & jurisprudence
- Published
- 1988
50. Contribution of ethanol and cigarette smoking to pulmonary dysfunction in chronic alcoholics.
- Author
-
Lyons DJ, Howard SV, Milledge JS, and Peters TJ
- Subjects
- Adult, Female, Humans, Lung physiopathology, Lung Diseases physiopathology, Male, Middle Aged, Respiratory Function Tests, Alcoholism physiopathology, Ethanol adverse effects, Lung Diseases etiology, Smoking
- Abstract
Ethanol is claimed to have a specific damaging effect on the lung and to be at least partially responsible for pulmonary dysfunction in alcoholics. Adequate allowance for the damaging effects of cigarette smoking has not, however, been made hitherto. Pulmonary function studies were undertaken in 27 alcoholic subjects. Although there was a high prevalence of symptoms and abnormalities of pulmonary function, these were largely confined to current smokers: most of those who had never smoked and the ex-smokers who were symptom free and had normal pulmonary function. A case controlled study of alcoholics and matched controls showed no significant difference in pulmonary function between the two groups. It is concluded that the high prevalence of respiratory disease in alcoholics is largely attributable to their smoking habits: no evidence of a specific pulmonary toxic effect of ethanol was identified in the study.
- Published
- 1986
- Full Text
- View/download PDF
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