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  1. Book ; Online: High-Intensity Exercise in Hypoxia - Beneficial Aspects and Potential Drawbacks

    Millet, Gregoire P. / McCrimmon, Donald R. / Girard, Olivier

    2018  

    Abstract: In the past, 'traditional' moderate-intensity continuous training (60-75% peak heart rate) was the type of physical activity most frequently recommended for both athletes and clinical populations (cf. American College of Sports Medicine guidelines). ... ...

    Abstract In the past, 'traditional' moderate-intensity continuous training (60-75% peak heart rate) was the type of physical activity most frequently recommended for both athletes and clinical populations (cf. American College of Sports Medicine guidelines). However, growing evidence indicates that high-intensity interval training (80-100% peak heart rate) could actually be associated with larger cardiorespiratory fitness and metabolic function benefits and, thereby, physical performance gains for athletes. Similarly, recent data in obese and hypertensive individuals indicate that various mechanisms - further improvement in endothelial function, reductions in sympathetic neural activity, or in arterial stiffness - might be involved in the larger cardiovascular protective effects associated with training at high exercise intensities.-

    Concerning hypoxic training, similar trends have been observed from 'traditional' prolonged altitude sojourns ('Live High Train High' or 'Live High Train Low'), which result in increased hemoglobin mass and blood carrying capacity. Recent innovative 'Live Low Train High' methods ('Resistance Training in Hypoxia' or 'Repeated Sprint Training in Hypoxia') have resulted in peripheral adaptations, such as hypertrophy or delay in muscle fatigue. Other interventions inducing peripheral hypoxia, such as vascular occlusion during endurance/resistance training or remote ischemic preconditioning (i.e. succession of ischemia/reperfusion episodes), have been proposed as methods for improving subsequent exercise performance or altitude tolerance (e.g. reduced severity of acute-mountain sickness symptoms).-

    Postulated mechanisms behind these metabolic, neuro-humoral, hemodynamics, and systemic adaptations include stimulation of nitric oxide synthase, increase in anti-oxidant enzymes, and down-regulation of pro-inflammatory cytokines, although the amount of evidence is not yet significant enough. Improved O2 delivery/utilization conferred by hypoxic training interventions might also be effective in preventing and treating cardiovascular diseases, as well as contributing to improve exercise tolerance and health status of patients. For example, in obese subjects, combining exercise with hypoxic exposure enhances the negative energy balance, which further reduces weight and improves cardio-metabolic health. In hypertensive patients, the larger lowering of blood pressure through the endothelial nitric oxide synthase pathway and the associated compensatory vasodilation is taken to reflect the superiority of exercising in hypoxia compared to normoxia.-
    Keywords Science (General) ; Physiology
    Size 1 electronic resource (169 p.)
    Publisher Frontiers Media SA
    Document type Book ; Online
    Note English ; Open Access
    HBZ-ID HT020099601
    ISBN 9782889454068 ; 2889454061
    Database ZB MED Catalogue: Medicine, Health, Nutrition, Environment, Agriculture

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  2. Article ; Online: Teaching an intuitive derivation of the clinical alveolar equations: mass balance as a fundamental physiological principle.

    Wang, Michael C / Corbridge, Thomas C / McCrimmon, Donald R / Walter, James M

    Advances in physiology education

    2020  Volume 44, Issue 2, Page(s) 145–152

    MeSH term(s) Humans ; Intuition ; Physiology/education ; Pulmonary Gas Exchange/physiology ; Respiratory Mechanics/physiology ; Teaching/education
    Language English
    Publishing date 2020-02-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1024917-5
    ISSN 1522-1229 ; 1043-4046
    ISSN (online) 1522-1229
    ISSN 1043-4046
    DOI 10.1152/advan.00064.2019
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: A Leptin-Mediated Neural Mechanism Linking Breathing to Metabolism.

    Do, Jeehaeh / Chang, Zheng / Sekerková, Gabriella / McCrimmon, Donald R / Martina, Marco

    Cell reports

    2020  Volume 33, Issue 6, Page(s) 108358

    Abstract: Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of ... ...

    Abstract Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of the solitary tract (NTS) mimics the respiratory stimulation after systemic leptin administration. We show that leptin activates the sodium leak channel (NALCN), thereby depolarizing a subset of glutamatergic (VGluT2) LepRb NTS neurons expressing galanin. Mice with selective deletion of NALCN in LepRb neurons have increased breathing irregularity and central apneas. On a high-fat diet, these mice gain weight with an associated depression of minute ventilation and tidal volume, which are not detected in control littermates. Anatomical mapping reveals LepRb NTS-originating glutamatergic axon terminals in a brainstem inspiratory premotor region (rVRG) and dorsomedial hypothalamus. These findings directly link a defined subset of NTS LepRb cells to the matching of ventilation to energy balance.
    MeSH term(s) Animals ; Energy Metabolism/physiology ; Humans ; Leptin/metabolism ; Metabolism/genetics ; Mice ; Respiration/genetics
    Chemical Substances Leptin
    Language English
    Publishing date 2020-11-11
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2649101-1
    ISSN 2211-1247 ; 2211-1247
    ISSN (online) 2211-1247
    ISSN 2211-1247
    DOI 10.1016/j.celrep.2020.108358
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Activation of astrocytic PAR1 receptors in the rat nucleus of the solitary tract regulates breathing through modulation of presynaptic TRPV1.

    Huda, Rafiq / Chang, Zheng / Do, Jeehaeh / McCrimmon, Donald R / Martina, Marco

    The Journal of physiology

    2018  Volume 596, Issue 3, Page(s) 497–513

    Abstract: Key points: In the rat nucleus of the solitary tract (NTS), activation of astrocytic proteinase-activated receptor 1 (PAR1) receptors leads to potentiation of neuronal synaptic activity by two mechanisms, one TRPV1-dependent and one TRPV1-independent. ... ...

    Abstract Key points: In the rat nucleus of the solitary tract (NTS), activation of astrocytic proteinase-activated receptor 1 (PAR1) receptors leads to potentiation of neuronal synaptic activity by two mechanisms, one TRPV1-dependent and one TRPV1-independent. PAR1-dependent activation of presynaptic TRPV1 receptors facilitates glutamate release onto NTS neurons. The TRPV1-dependent mechanism appears to rely on astrocytic release of endovanilloid-like molecules. A subset of NTS neurons excited by PAR1 directly project to the rostral ventral respiratory group. The PAR1 initiated, TRPV1-dependent modulation of synaptic transmission in the NTS contributes to regulation of breathing.
    Abstract: Many of the cellular and molecular mechanisms underlying astrocytic modulation of synaptic function remain poorly understood. Recent studies show that G-protein coupled receptor-mediated astrocyte activation modulates synaptic transmission in the nucleus of the solitary tract (NTS), a brainstem nucleus that regulates crucial physiological processes including cardiorespiratory activity. By using calcium imaging and patch clamp recordings in acute brain slices of wild-type and TRPV1
    MeSH term(s) Action Potentials ; Animals ; Astrocytes/cytology ; Astrocytes/physiology ; Excitatory Postsynaptic Potentials ; Male ; Neurons/cytology ; Neurons/physiology ; Rats ; Rats, Sprague-Dawley ; Receptor, PAR-1/metabolism ; Respiration ; Solitary Nucleus/cytology ; Solitary Nucleus/physiology ; Synaptic Transmission ; TRPV Cation Channels/metabolism
    Chemical Substances Receptor, PAR-1 ; TRPV Cation Channels ; Trpv1 protein, rat
    Language English
    Publishing date 2018-01-15
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/JP275127
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: pH modulation of glial glutamate transporters regulates synaptic transmission in the nucleus of the solitary tract.

    Huda, Rafiq / McCrimmon, Donald R / Martina, Marco

    Journal of neurophysiology

    2013  Volume 110, Issue 2, Page(s) 368–377

    Abstract: The nucleus of the solitary tract (NTS) is the major site for termination of visceral sensory afferents contributing to homeostatic regulation of, for example, arterial pressure, gastric motility, and breathing. Whereas much is known about how different ... ...

    Abstract The nucleus of the solitary tract (NTS) is the major site for termination of visceral sensory afferents contributing to homeostatic regulation of, for example, arterial pressure, gastric motility, and breathing. Whereas much is known about how different neuronal populations influence these functions, information about the role of glia remains scant. In this article, we propose that glia may contribute to NTS functions by modulating excitatory neurotransmission. We found that acidification (pH 7.0) depolarizes NTS glia by inhibiting K(+)-selective membrane currents. NTS glia also showed functional expression of voltage-sensitive glutamate transporters, suggesting that extracellular acidification regulates synaptic transmission by compromising glial glutamate uptake. To test this hypothesis, we evoked glutamatergic slow excitatory potentials (SEPs) in NTS neurons with repetitive stimulation (20 pulses at 10 Hz) of the solitary tract. This SEP depends on accumulation of glutamate following repetitive stimulation, since it was potentiated by blocking glutamate uptake with dl-threo-β-benzyloxyaspartic acid (TBOA) or a glia-specific glutamate transport blocker, dihydrokainate (DHK). Importantly, extracellular acidification (pH 7.0) also potentiated the SEP. This effect appeared to be mediated through a depolarization-induced inhibition of glial transporter activity, because it was occluded by TBOA and DHK. In agreement, pH 7.0 did not directly alter d-aspartate-induced responses in NTS glia or properties of presynaptic glutamate release. Thus acidification-dependent regulation of glial function affects synaptic transmission within the NTS. These results suggest that glia play a modulatory role in the NTS by integrating local tissue signals (such as pH) with synaptic inputs from peripheral afferents.
    MeSH term(s) Amino Acid Transport System X-AG/physiology ; Animals ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Male ; Neuroglia/physiology ; Protons ; Rats ; Rats, Sprague-Dawley ; Solitary Nucleus/physiology ; Synaptic Transmission/physiology
    Chemical Substances Amino Acid Transport System X-AG ; Protons
    Language English
    Publishing date 2013-04-24
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 80161-6
    ISSN 1522-1598 ; 0022-3077
    ISSN (online) 1522-1598
    ISSN 0022-3077
    DOI 10.1152/jn.01074.2012
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Headed in the Wrong Direction: Chronic and Acute Derangements in Pulmonary Blood Flow Distribution in a Patient with Severe Pulmonary Vein Stenosis.

    Morales-Nebreda, Luisa / Chung, Christopher S / Agrawal, Rishi / Yeldandi, Anjana V / Singer, Benjamin D / Bharat, Ankit / McCrimmon, Donald R / Walter, James M

    Annals of the American Thoracic Society

    2019  Volume 16, Issue 10, Page(s) 1321–1326

    MeSH term(s) Atrial Fibrillation/therapy ; Catheter Ablation/adverse effects ; Humans ; Magnetic Resonance Angiography ; Male ; Middle Aged ; Positive-Pressure Respiration ; Pulmonary Veno-Occlusive Disease/diagnosis ; Pulmonary Veno-Occlusive Disease/etiology ; Pulmonary Veno-Occlusive Disease/therapy ; Stenosis, Pulmonary Vein/diagnosis ; Stenosis, Pulmonary Vein/etiology ; Stenosis, Pulmonary Vein/therapy
    Language English
    Publishing date 2019-10-01
    Publishing country United States
    Document type Case Reports ; Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2717461-X
    ISSN 2325-6621 ; 1943-5665 ; 2325-6621
    ISSN (online) 2325-6621 ; 1943-5665
    ISSN 2325-6621
    DOI 10.1513/AnnalsATS.201905-402CC
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Changes in the Migration Phenology of Massachusetts Birds 1940–2013 in Relation to Temperatures along the Atlantic Flyway

    Cunningham, Caitlin M / Luscier, Jason D / Mackey, Erica A / Palmer, Corey A / Bolster, Daniel R / Valentine, Anna L / McCrimmon, Donald A

    Northeastern naturalist. 2020 Aug. 20, v. 27, no. 3

    2020  

    Abstract: Climate variables affect the phenology of bird migration, and anthropogenic climate change has likely resulted in shifts in these phenological patterns. Warmer springtime temperatures could lead to birds arriving earlier to northerly latitudes in North ... ...

    Abstract Climate variables affect the phenology of bird migration, and anthropogenic climate change has likely resulted in shifts in these phenological patterns. Warmer springtime temperatures could lead to birds arriving earlier to northerly latitudes in North America. We modeled the effect of temperature with 74 years of data on first arrival for 84 bird species in Worcester County, MA. We found migratory bird species have shifted their arrival to Worcester County an average of 0.11 days per year earlier, with short-distance migrants having stronger shifts (an average of 0.18 days earlier per year) than long-distance migrants (an average of 0.06 days earlier per year). Our results add to a body of literature regarding the potential impacts of climate change on bird migration phenology. We supply support for the notion that some species are temporally shifting their migration in response to warming springtime temperatures. These shifts may be mismatched with resource availability and thus could negatively affect populations and communities. Consequently, it is important to understand patterns in bird migration phenology in order to inform adequate conservation strategies.
    Keywords climate change ; climatic factors ; latitude ; lead ; literature ; migratory behavior ; migratory birds ; phenology ; population ; spring ; supply ; temperature ; Massachusetts
    Language English
    Dates of publication 2020-0820
    Size p. 448-468.
    Publishing place Humboldt Field Research Institute
    Document type Article
    Note NAL-light
    ZDB-ID 2117206-7
    ISSN 1938-5307 ; 1092-6194
    ISSN (online) 1938-5307
    ISSN 1092-6194
    DOI 10.1656/045.027.0312
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Cardiovascular Safety in Type 2 Diabetes With Sulfonylureas as Second-line Drugs: A Nationwide Population-Based Comparative Safety Study.

    Wang, Huan / Cordiner, Ruth L M / Huang, Yu / Donnelly, Louise / Hapca, Simona / Collier, Andrew / McKnight, John / Kennon, Brian / Gibb, Fraser / McKeigue, Paul / Wild, Sarah H / Colhoun, Helen / Chalmers, John / Petrie, John / Sattar, Naveed / MacDonald, Thomas / McCrimmon, Rory J / Morales, Daniel R / Pearson, Ewan R

    Diabetes care

    2023  Volume 46, Issue 5, Page(s) 967–977

    Abstract: Objective: To assess the real-world cardiovascular (CV) safety for sulfonylureas (SU), in comparison with dipeptidyl peptidase 4 inhibitors (DPP4i) and thiazolidinediones (TZD), through development of robust methodology for causal inference in a whole ... ...

    Abstract Objective: To assess the real-world cardiovascular (CV) safety for sulfonylureas (SU), in comparison with dipeptidyl peptidase 4 inhibitors (DPP4i) and thiazolidinediones (TZD), through development of robust methodology for causal inference in a whole nation study.
    Research design and methods: A cohort study was performed including people with type 2 diabetes diagnosed in Scotland before 31 December 2017, who failed to reach HbA1c 48 mmol/mol despite metformin monotherapy and initiated second-line pharmacotherapy (SU/DPP4i/TZD) on or after 1 January 2010. The primary outcome was composite major adverse cardiovascular events (MACE), including hospitalization for myocardial infarction, ischemic stroke, heart failure, and CV death. Secondary outcomes were each individual end point and all-cause death. Multivariable Cox proportional hazards regression and an instrumental variable (IV) approach were used to control confounding in a similar way to the randomization process in a randomized control trial.
    Results: Comparing SU to non-SU (DPP4i/TZD), the hazard ratio (HR) for MACE was 1.00 (95% CI: 0.91-1.09) from the multivariable Cox regression and 1.02 (0.91-1.13) and 1.03 (0.91-1.16) using two different IVs. For all-cause death, the HR from Cox regression and the two IV analyses was 1.03 (0.94-1.13), 1.04 (0.93-1.17), and 1.03 (0.90-1.17).
    Conclusions: Our findings contribute to the understanding that second-line SU for glucose lowering are unlikely to increase CV risk or all-cause mortality. Given their potent efficacy, microvascular benefits, cost effectiveness, and widespread use, this study supports that SU should remain a part of the global diabetes treatment portfolio.
    MeSH term(s) Humans ; Diabetes Mellitus, Type 2/complications ; Hypoglycemic Agents/adverse effects ; Cohort Studies ; Treatment Outcome ; Sulfonylurea Compounds/adverse effects ; Metformin/adverse effects ; Dipeptidyl-Peptidase IV Inhibitors/adverse effects
    Chemical Substances Hypoglycemic Agents ; Sulfonylurea Compounds ; Metformin (9100L32L2N) ; Dipeptidyl-Peptidase IV Inhibitors
    Language English
    Publishing date 2023-03-21
    Publishing country United States
    Document type Randomized Controlled Trial ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 441231-x
    ISSN 1935-5548 ; 0149-5992
    ISSN (online) 1935-5548
    ISSN 0149-5992
    DOI 10.2337/dc22-1238
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Reflexively inhibiting respiratory drive.

    McCrimmon, Donald R / Alheid, George F

    The Journal of physiology

    2007  Volume 580, Issue Pt 1, Page(s) 3

    MeSH term(s) Animals ; Drive ; Humans ; Lung/physiology ; Mechanoreceptors/physiology ; Respiratory Physiological Phenomena
    Language English
    Publishing date 2007-04-01
    Publishing country England
    Document type Comment ; Journal Article
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/jphysiol.2007.130500
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: The chemical neuroanatomy of breathing.

    Alheid, George F / McCrimmon, Donald R

    Respiratory physiology & neurobiology

    2008  Volume 164, Issue 1-2, Page(s) 3–11

    Abstract: The chemical neuroanatomy of breathing must ultimately encompass all the various neuronal elements physiologically identified in brainstem respiratory circuits and their apparent aggregation into "compartments" within the medulla and pons. These ... ...

    Abstract The chemical neuroanatomy of breathing must ultimately encompass all the various neuronal elements physiologically identified in brainstem respiratory circuits and their apparent aggregation into "compartments" within the medulla and pons. These functionally defined respiratory compartments in the brainstem provide the major source of input to cranial motoneurons controlling the airways, and to spinal motoneurons activating inspiratory and expiratory pump muscles. This review provides an overview of the neuroanatomy of the major compartments comprising brainstem respiratory circuits, and a synopsis of the transmitters used by their constituent respiratory neurons.
    MeSH term(s) Animals ; Humans ; Respiration ; Respiratory Center/anatomy & histology ; Respiratory Center/metabolism
    Language English
    Publishing date 2008-07-25
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 2077867-3
    ISSN 1878-1519 ; 1569-9048
    ISSN (online) 1878-1519
    ISSN 1569-9048
    DOI 10.1016/j.resp.2008.07.014
    Database MEDical Literature Analysis and Retrieval System OnLINE

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