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  1. Article ; Online: Conversion of spikers to bursters in pituitary cell networks: Is it better to disperse for maximum exposure or circle the wagons?

    Fazli, Mehran / Bertram, Richard

    PLoS computational biology

    2024  Volume 20, Issue 1, Page(s) e1011811

    Abstract: The endocrine cells of the pituitary gland are electrically active, and in vivo they form small networks where the bidirectional cell-cell coupling is through gap junctions. Numerous studies of dispersed pituitary cells have shown that typical behaviors ... ...

    Abstract The endocrine cells of the pituitary gland are electrically active, and in vivo they form small networks where the bidirectional cell-cell coupling is through gap junctions. Numerous studies of dispersed pituitary cells have shown that typical behaviors are tonic spiking and bursting, the latter being more effective at evoking secretion. In this article, we use mathematical modeling to examine the dynamics of small networks of spiking and bursting pituitary cells. We demonstrate that intrinsic bursting cells are capable of converting intrinsic spikers into bursters, and perform a fast/slow analysis to show why this occurs. We then demonstrate the sensitivity of network dynamics to the placement of bursting cells within the network, and demonstrate strategies that are most effective at maximizing secretion from the population of cells. This study provides insights into the in vivo behavior of cells such as the stress-hormone-secreting pituitary corticotrophs that are switched from spiking to bursting by hypothalamic neurohormones. While much is known about the electrical properties of these cells when isolated from the pituitary, how they behave when part of an electrically coupled network has been largely unstudied.
    MeSH term(s) Pituitary Gland ; Models, Theoretical ; Endocrine Cells ; Action Potentials
    Language English
    Publishing date 2024-01-30
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2193340-6
    ISSN 1553-7358 ; 1553-734X
    ISSN (online) 1553-7358
    ISSN 1553-734X
    DOI 10.1371/journal.pcbi.1011811
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Network Properties of Electrically Coupled Bursting Pituitary Cells.

    Fazli, Mehran / Bertram, Richard

    Frontiers in endocrinology

    2022  Volume 13, Page(s) 936160

    Abstract: The endocrine cells of the anterior pituitary gland are electrically active when stimulated or, in some cases, when not inhibited. The activity pattern thought to be most effective in releasing hormones is bursting, which consists of depolarization with ... ...

    Abstract The endocrine cells of the anterior pituitary gland are electrically active when stimulated or, in some cases, when not inhibited. The activity pattern thought to be most effective in releasing hormones is bursting, which consists of depolarization with small spikes that are much longer than single spikes. Although a majority of the research on cellular activity patterns has been performed on dispersed cells, the environment
    MeSH term(s) Action Potentials ; Endocrine Cells ; Hormones ; Pituitary Gland
    Chemical Substances Hormones
    Language English
    Publishing date 2022-07-06
    Publishing country Switzerland
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2592084-4
    ISSN 1664-2392
    ISSN 1664-2392
    DOI 10.3389/fendo.2022.936160
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Chlorthalidone or Spironolactone for Patients With TRH and Advanced Chronic Kidney Disease?

    Pitt, Bertram / Auchus, Richard J

    Hypertension (Dallas, Tex. : 1979)

    2023  Volume 81, Issue 1, Page(s) 107–109

    MeSH term(s) Humans ; Chlorthalidone/therapeutic use ; Spironolactone/therapeutic use ; Hypertension/drug therapy ; Diuretics/therapeutic use ; Renal Insufficiency, Chronic/drug therapy
    Chemical Substances Chlorthalidone (Q0MQD1073Q) ; Spironolactone (27O7W4T232) ; Diuretics
    Language English
    Publishing date 2023-11-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 423736-5
    ISSN 1524-4563 ; 0194-911X ; 0362-4323
    ISSN (online) 1524-4563
    ISSN 0194-911X ; 0362-4323
    DOI 10.1161/HYPERTENSIONAHA.123.21962
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: A mathematical study of the efficacy of possible negative feedback pathways involved in neuronal polarization.

    Bai, Fan / Bertram, Richard / Karamched, Bhargav R

    Journal of theoretical biology

    2023  Volume 571, Page(s) 111561

    Abstract: Neuronal polarization, a process wherein nascent neurons develop a single long axon and multiple short dendrites, can occur within in vitro cell cultures without environmental cues. This is an apparently random process in which one of several short ... ...

    Abstract Neuronal polarization, a process wherein nascent neurons develop a single long axon and multiple short dendrites, can occur within in vitro cell cultures without environmental cues. This is an apparently random process in which one of several short processes, called neurites, grows to become long, while the others remain short. In this study, we propose a minimum model for neurite growth, which involves bistability and random excitations reflecting actin waves. Positive feedback is needed to produce the bistability, while negative feedback is required to ensure that no more than one neurite wins the winner-takes-all contest. By applying the negative feedback to different aspects of the neurite growth process, we demonstrate that targeting the negative feedback to the excitation amplitude results in the most persistent polarization. Also, we demonstrate that there are optimal ranges of values for the neurite count, and for the excitation rate and amplitude that best maintain the polarization. Finally, we show that a previously published model for neuronal polarization based on competition for limited resources shares key features with our best-performing minimal model: bistability and negative feedback targeted to the size of random excitations.
    MeSH term(s) Feedback ; Neurons/metabolism ; Axons/physiology ; Neurites/physiology
    Language English
    Publishing date 2023-06-16
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2972-5
    ISSN 1095-8541 ; 0022-5193
    ISSN (online) 1095-8541
    ISSN 0022-5193
    DOI 10.1016/j.jtbi.2023.111561
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Book: "Dem Mensch nah ..."

    Bertram, Heinrich / Sautmann, Richard

    100 Jahre Albertinenkrankenhaus Dissen

    2004  

    Institution Albertinenkrankenhaus
    Author's details Heinrich Bertram. Bearb. von Richard Sautmann. [Hrsg.: Albertinenkrankenhaus Dissen a.T.W.]
    Keywords Albertinenkrankenhaus ; Geschichte
    Language German
    Size 84 S. : Ill., 23 cm
    Publisher Krützkamp
    Publishing place Glandorf
    Publishing country Germany
    Document type Book
    HBZ-ID HT014777629
    ISBN 3-9809633-0-6 ; 978-3-9809633-0-5
    Database Catalogue ZB MED Medicine, Health

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  6. Article ; Online: Mathematical modeling in neuroendocrinology.

    Bertram, Richard

    Comprehensive Physiology

    2015  Volume 5, Issue 2, Page(s) 911–927

    Abstract: Mathematical models are commonly used in neuroscience, both as tools for integrating data and as devices for designing new experiments that test model predictions. The wide range of relevant spatial and temporal scales in the neuroendocrine system makes ... ...

    Abstract Mathematical models are commonly used in neuroscience, both as tools for integrating data and as devices for designing new experiments that test model predictions. The wide range of relevant spatial and temporal scales in the neuroendocrine system makes neuroendocrinology a branch of neuroscience with great potential for modeling. This article provides an overview of concepts that are useful for understanding mathematical models of the neuroendocrine system, as well as design principles that have been illuminated through the use of mathematical models. These principles are found over and over again in cellular dynamics, and serve as building blocks for understanding some of the complex temporal dynamics that are exhibited throughout the neuroendocrine system.
    MeSH term(s) Action Potentials/physiology ; Animals ; Biological Clocks/physiology ; Computer Simulation ; Humans ; Models, Neurological ; Neuroendocrinology/methods ; Neurons/physiology ; Neurosecretory Systems/physiology
    Language English
    Publishing date 2015-04
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ISSN 2040-4603
    ISSN (online) 2040-4603
    DOI 10.1002/cphy.c140034
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Ca

    Fletcher, Patrick A / Thompson, Ben / Liu, Chanté / Bertram, Richard / Satin, Leslie S / Sherman, Arthur S

    American journal of physiology. Endocrinology and metabolism

    2023  Volume 324, Issue 6, Page(s) E477–E487

    Abstract: The standard model for ... ...

    Abstract The standard model for Ca
    MeSH term(s) Insulin-Secreting Cells/metabolism ; Calcium/metabolism ; Insulin/metabolism ; Calcium Signaling ; Insulin Secretion
    Chemical Substances Calcium (SY7Q814VUP) ; Insulin
    Language English
    Publishing date 2023-04-19
    Publishing country United States
    Document type Journal Article ; Review ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, N.I.H., Extramural ; Research Support, N.I.H., Intramural
    ZDB-ID 603841-4
    ISSN 1522-1555 ; 0193-1849
    ISSN (online) 1522-1555
    ISSN 0193-1849
    DOI 10.1152/ajpendo.00030.2023
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: K

    Corradi, Jeremías / Thompson, Benjamin / Fletcher, Patrick A / Bertram, Richard / Sherman, Arthur S / Satin, Leslie S

    The Journal of physiology

    2023  Volume 601, Issue 24, Page(s) 5655–5667

    Abstract: Pancreatic beta cells secrete insulin in response to plasma glucose. The ATP-sensitive potassium channel ( ... ...

    Abstract Pancreatic beta cells secrete insulin in response to plasma glucose. The ATP-sensitive potassium channel (K
    MeSH term(s) Mice ; Animals ; Insulin-Secreting Cells/metabolism ; Islets of Langerhans ; Adenosine Triphosphate/pharmacology ; Adenosine Triphosphate/metabolism ; Phosphoenolpyruvate/metabolism ; Phosphoenolpyruvate/pharmacology ; Pyruvate Kinase/metabolism ; Pyruvate Kinase/pharmacology ; Adenosine Diphosphate/pharmacology ; Adenosine Diphosphate/metabolism ; Mitochondria/metabolism
    Chemical Substances Adenosine Triphosphate (8L70Q75FXE) ; Phosphoenolpyruvate (73-89-2) ; Pyruvate Kinase (EC 2.7.1.40) ; Adenosine Diphosphate (61D2G4IYVH)
    Language English
    Publishing date 2023-11-20
    Publishing country England
    Document type Journal Article
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/JP284982
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Deconstructing the integrated oscillator model for pancreatic β-cells.

    Bertram, Richard / Marinelli, Isabella / Fletcher, Patrick A / Satin, Leslie S / Sherman, Arthur S

    Mathematical biosciences

    2023  Volume 365, Page(s) 109085

    Abstract: Electrical bursting oscillations in the β-cells of pancreatic islets have been a focus of investigation for more than fifty years. This has been aided by mathematical models, which are descendants of the pioneering Chay-Keizer model. This article ... ...

    Abstract Electrical bursting oscillations in the β-cells of pancreatic islets have been a focus of investigation for more than fifty years. This has been aided by mathematical models, which are descendants of the pioneering Chay-Keizer model. This article describes the key biophysical and mathematical elements of this model, and then describes the path forward from there to the Integrated Oscillator Model (IOM). It is both a history and a deconstruction of the IOM that describes the various elements that have been added to the model over time, and the motivation for adding them. Finally, the article is a celebration of the 40th anniversary of the publication of the Chay-Keizer model.
    Language English
    Publishing date 2023-10-04
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1126-5
    ISSN 1879-3134 ; 0025-5564
    ISSN (online) 1879-3134
    ISSN 0025-5564
    DOI 10.1016/j.mbs.2023.109085
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Book: Mythos, Symbol, Idee in Richard Wagners Musik-Dramen

    Bertram, Johannes

    1957  

    Author's details Johannes Bertram
    Language German
    Size 336 S., 1 Taf., 1 Titelbild, 22 cm
    Publisher Hamburger Kulturverl
    Publishing place Hamburg
    Document type Book
    Database Former special subject collection: coastal and deep sea fishing

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