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  1. Book ; Online: Recent developments in the epidemiology of diabetes in the Americas / Braxton D. Mitchell and Michael P. Stern ; Evolution récente de l' épidémiologie du diabète en Europe

    Mitchell, Braxton D / Stern, Michael P

    résumé

    1992  

    Keywords Diabetes mellitus ; Type 2 ; Americas ; Chronic Diseases and their Control ; epidemiology
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Journal ; Article ; Online: Recent developments in the epidemiology of diabetes in the Americas / Braxton D. Mitchell and Michael P. Stern ; Evolution récente de l' épidémiologie du diabète en Europe

    Mitchell, Braxton D / Stern, Michael P

    résumé

    1992  

    Keywords Diabetes Mellitus ; Type 2 ; Americas ; Chronic Diseases and their Control ; epidemiology
    Document type Journal ; Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Transcranial Magnetic Stimulation in Primary Care: Indications, Risks, and Outcomes.

    Razafsha, Mahdi / Barbour, Tracy A / Chopra, Amit / Kritzer, Michael D / Stern, Theodore A

    The primary care companion for CNS disorders

    2024  Volume 26, Issue 2

    MeSH term(s) Humans ; Transcranial Magnetic Stimulation ; Hospitals, General ; Inpatients ; Psychiatry ; Primary Health Care
    Language English
    Publishing date 2024-03-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2675414-9
    ISSN 2155-7780 ; 2155-7780
    ISSN (online) 2155-7780
    ISSN 2155-7780
    DOI 10.4088/PCC.23f03614
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Elementary intracellular Ca signals approximated as a transition of release channel system from a metastable state.

    Veron, Guillermo / Maltsev, Victor A / Stern, Michael D / Maltsev, Anna V

    Journal of applied physics

    2023  Volume 134, Issue 12, Page(s) 124701

    Abstract: Cardiac muscle contraction is initiated by an elementary Ca signal (called Ca spark) which is achieved by collective action of Ca release channels in a cluster. The mechanism of this synchronization remains uncertain. We approached Ca spark activation as ...

    Abstract Cardiac muscle contraction is initiated by an elementary Ca signal (called Ca spark) which is achieved by collective action of Ca release channels in a cluster. The mechanism of this synchronization remains uncertain. We approached Ca spark activation as an emergent phenomenon of an interactive system of release channels. We constructed a weakly lumped Markov chain that applies an Ising model formalism to such release channel clusters and probable open channel configurations and demonstrated that spark activation is described as a system transition from a metastable to an absorbing state, analogous to the pressure required to overcome surface tension in bubble formation. This yielded quantitative estimates of the spark generation probability as a function of various system parameters. We performed numerical simulations to find spark probabilities as a function of sarcoplasmic reticulum Ca concentration, obtaining similar values for spark activation threshold as our analytic model, as well as those reported in experimental studies. Our parametric sensitivity analyses also showed that the spark activation threshold decreased as Ca sensitivity of RyR activation and RyR cluster size increased.
    Language English
    Publishing date 2023-09-22
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3112-4
    ISSN 0021-8979
    ISSN 0021-8979
    DOI 10.1063/5.0151255
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: A novel conceptual model of heart rate autonomic modulation based on a small-world modular structure of the sinoatrial node.

    Maltsev, Alexander V / Stern, Michael D / Lakatta, Edward G / Maltsev, Victor A

    Frontiers in physiology

    2023  Volume 14, Page(s) 1276023

    Abstract: The present view on heartbeat initiation is that a primary pacemaker cell or a group of cells in the sinoatrial node (SAN) center paces the rest of the SAN and the atria. However, recent high-resolution imaging studies show a more complex paradigm of SAN ...

    Abstract The present view on heartbeat initiation is that a primary pacemaker cell or a group of cells in the sinoatrial node (SAN) center paces the rest of the SAN and the atria. However, recent high-resolution imaging studies show a more complex paradigm of SAN function that emerges from heterogeneous signaling, mimicking brain cytoarchitecture and function. Here, we developed and tested a new conceptual numerical model of SAN organized similarly to brain networks featuring a modular structure with small-world topology. In our model, a lower rate module leads action potential (AP) firing in the basal state and during parasympathetic stimulation, whereas a higher rate module leads during β-adrenergic stimulation. Such a system reproduces the respective shift of the leading pacemaker site observed experimentally and a wide range of rate modulation and robust function while conserving energy. Since experimental studies found functional modules at different scales, from a few cells up to the highest scale of the superior and inferior SAN, the SAN appears to feature hierarchical modularity, i.e., within each module, there is a set of sub-modules, like in the brain, exhibiting greater robustness, adaptivity, and evolvability of network function. In this perspective, our model offers a new mainframe for interpreting new data on heterogeneous signaling in the SAN at different scales, providing new insights into cardiac pacemaker function and SAN-related cardiac arrhythmias in aging and disease.
    Language English
    Publishing date 2023-12-11
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564217-0
    ISSN 1664-042X
    ISSN 1664-042X
    DOI 10.3389/fphys.2023.1276023
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Disorder in Ca2+ release unit locations confers robustness but cuts flexibility of heart pacemaking.

    Maltsev, Anna V / Stern, Michael D / Maltsev, Victor A

    The Journal of general physiology

    2022  Volume 154, Issue 9

    Abstract: Excitation-contraction coupling kinetics is dictated by the action potential rate of sinoatrial-nodal cells. These cells generate local Ca releases (LCRs) that activate Na/Ca exchanger current, which accelerates diastolic depolarization and determines ... ...

    Abstract Excitation-contraction coupling kinetics is dictated by the action potential rate of sinoatrial-nodal cells. These cells generate local Ca releases (LCRs) that activate Na/Ca exchanger current, which accelerates diastolic depolarization and determines the pace. LCRs are generated by clusters of ryanodine receptors, Ca release units (CRUs), residing in the sarcoplasmic reticulum. While CRU distribution exhibits substantial heterogeneity, its functional importance remains unknown. Using numerical modeling, here we show that with a square lattice distribution of CRUs, Ca-induced-Ca-release propagation during diastolic depolarization is insufficient for pacemaking within a broad range of realistic ICaL densities. Allowing each CRU to deviate randomly from its lattice position allows sparks to propagate, as observed experimentally. As disorder increases, the CRU distribution exhibits larger empty spaces and simultaneously CRU clusters, as in Poisson clumping. Propagating within the clusters, Ca release becomes synchronized, increasing action potential rate and reviving pacemaker function of dormant/nonfiring cells. However, cells with fully disordered CRU positions could not reach low firing rates and their β-adrenergic-receptor stimulation effect was substantially decreased. Inclusion of Cav1.3, a low-voltage activation L-type Ca channel isoform into ICaL, strongly increases recruitment of CRUs to fire during diastolic depolarization, increasing robustness of pacemaking and complementing effects of CRU distribution. Thus, order/disorder in CRU locations along with Cav1.3 expression regulates pacemaker function via synchronization of CRU firing. Excessive CRU disorder and/or overexpression of Cav1.3 boosts pacemaker function in the basal state, but limits the rate range, which may contribute to heart rate range decline with age and disease.
    MeSH term(s) Action Potentials/physiology ; Calcium/metabolism ; Calcium Signaling/physiology ; Ryanodine Receptor Calcium Release Channel/metabolism ; Sarcoplasmic Reticulum/metabolism ; Sinoatrial Node/physiology
    Chemical Substances Ryanodine Receptor Calcium Release Channel ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2022-08-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Intramural
    ZDB-ID 3118-5
    ISSN 1540-7748 ; 0022-1295
    ISSN (online) 1540-7748
    ISSN 0022-1295
    DOI 10.1085/jgp.202113061
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Social heterogeneity drives complex patterns of the COVID-19 pandemic: insights from a novel Stochastic Heterogeneous Epidemic Model (SHEM).

    Maltsev, Alexander V / Stern, Michael D

    medRxiv : the preprint server for health sciences

    2020  

    Abstract: In todays absence of a vaccine and impactful treatments, the most effective way to combat the virus is to find and implement mitigation strategies. An invaluable resource in this task is numerical modeling that can reveal key factors in COVID-19 pandemic ...

    Abstract In todays absence of a vaccine and impactful treatments, the most effective way to combat the virus is to find and implement mitigation strategies. An invaluable resource in this task is numerical modeling that can reveal key factors in COVID-19 pandemic development. On the other hand, it has become evident that regional infection curves of COVID-19 exhibit complex patterns which often differ from curves predicted by forecasting models. The wide variations in attack rate observed among different social strata suggest that this may be due to social heterogeneity not accounted for by regional models. We investigated this hypothesis by developing and using a new Stochastic Heterogeneous Epidemic Model (SHEM) that focuses on subpopulations that are vulnerable in the sense of having an increased likelihood of spreading infection among themselves. We found that the isolation or embedding of vulnerable sub-clusters in a major population hub generated complex stochastic infection patterns which included multiple peaks and growth periods, an extended plateau, a prolonged tail, or a delayed second wave of infection. Embedded vulnerable groups became hotspots that drove infection despite efforts of the main population to socially distance, while isolated groups suffered delayed but intense infection. Amplification of infection by these hotspots facilitated transmission from one urban area to another, causing the epidemic to hopscotch in a stochastic manner to places it would not otherwise reach, resembling a microcosm of the situation worldwide as of September 2020. Our results suggest that social heterogeneity is a key factor in the formation of complex infection propagation patterns. Thus, the mitigation of vulnerable groups is essential to control the COVID-19 pandemic worldwide. The design of our new model allows it to be applied in future studies of real-world scenarios on any scale, limited only by computing memory and the ability to determine the underlying topology and parameters.
    Keywords covid19
    Language English
    Publishing date 2020-11-30
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2020.07.10.20150813
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Functional Heterogeneity of Cell Populations Increases Robustness of Pacemaker Function in a Numerical Model of the Sinoatrial Node Tissue.

    Maltsev, Alexander V / Stern, Michael D / Lakatta, Edward G / Maltsev, Victor A

    Frontiers in physiology

    2022  Volume 13, Page(s) 845634

    Abstract: Each heartbeat is initiated by specialized pacemaker cells operating within the sinoatrial node (SAN). While individual cells within SAN tissue exhibit substantial heterogeneity of their electrophysiological parameters and Ca cycling, the role of this ... ...

    Abstract Each heartbeat is initiated by specialized pacemaker cells operating within the sinoatrial node (SAN). While individual cells within SAN tissue exhibit substantial heterogeneity of their electrophysiological parameters and Ca cycling, the role of this heterogeneity for cardiac pacemaker function remains mainly unknown. Here we investigated the problem numerically in a 25 × 25 square grid of connected coupled-clock Maltsev-Lakatta cell models. The tissue models were populated by cells with different degree of heterogeneity of the two key model parameters, maximum L-type Ca current conductance (
    Language English
    Publishing date 2022-04-27
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564217-0
    ISSN 1664-042X
    ISSN 1664-042X
    DOI 10.3389/fphys.2022.845634
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Airway Involvement and Intervention in Non-ACE-Inhibitor-Induced Angioedema.

    Bacak, Bartholomew J / Castle, Michael S / Barbot, Chantal / Srikantha, Luxman / Stern, Noah A / Vandjelovic, Nathan D

    The Laryngoscope

    2023  Volume 134, Issue 5, Page(s) 2282–2287

    Abstract: Objectives: Characterize the presentation of patients with non-angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema and determine risk factors associated with patient disposition and possible need for airway intervention.: Methods: The ... ...

    Abstract Objectives: Characterize the presentation of patients with non-angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema and determine risk factors associated with patient disposition and possible need for airway intervention.
    Methods: The medical records of adult patients in the Emergency Department (ED) and diagnosed with non-ACEI-induced angioedema over 4.5 years were included. Demographics, vital signs, etiology, timeline, presenting symptoms, physical exam including flexible laryngoscopy, medical management, and disposition were examined. Statistical analyses were conducted using SPSS V 23.0 software calculating and comparing means, standard deviations, medians, and correlation of categorical and ordinate variables.
    Results: A total of 181 patients with non-ACEI-induced angioedema were evaluated with flexible laryngoscopy by otolaryngology. Notably, 11 patients (6.1%) required airway intervention and were successfully intubated. Statistically significant factors (p ≤ 0.05) associated with airway intervention included the diastolic blood pressure (DBP) and mean arterial pressure (MAP) (p = 0.006 and 0.01 respectively), symptoms of dysphonia (p = 0.018), the presence of oropharyngeal, supraglottic, and hypopharyngeal edema (p ≤ 0.001 for each site), and the number of edematous anatomic subsites documented on physical exam (p < 0.001). Other patient demographics, prior history of angioedema, heart rate, systolic blood pressure, symptom onset, number of symptoms at presentation, and medication administered in the ED did not correlate with airway intervention.
    Conclusion: Dysphonia, DBP, MAP, anatomic location of edema and edema in multiple sites are associated with airway intervention and a higher level of care in non-ACEI-induced angioedema and can be useful in risk assessment in patient management.
    Level of evidence: 4 Laryngoscope, 134:2282-2287, 2024.
    MeSH term(s) Adult ; Humans ; Dysphonia/complications ; Respiratory System ; Laryngoscopy ; Angioedema/chemically induced ; Angioedema/therapy ; Edema
    Language English
    Publishing date 2023-10-30
    Publishing country United States
    Document type Journal Article
    ZDB-ID 80180-x
    ISSN 1531-4995 ; 0023-852X
    ISSN (online) 1531-4995
    ISSN 0023-852X
    DOI 10.1002/lary.31127
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Atl (atlastin) regulates mTor signaling and autophagy in Drosophila muscle through alteration of the lysosomal network.

    Srivastav, Saurabh / van der Graaf, Kevin / Singh, Pratibha / Utama, Alloysius Budi / Meyer, Matthew D / McNew, James A / Stern, Michael

    Autophagy

    2023  Volume 20, Issue 1, Page(s) 131–150

    Abstract: Abbreviations: atl atlastin; ALR autophagic lysosome reformation; ER endoplasmic reticulum; GFP green fluorescent protein; HSP hereditary spastic paraplegia; Lamp1 lysosomal associated membrane protein 1 PolyUB polyubiquitin; RFP red fluorescent protein; ...

    Abstract Abbreviations: atl atlastin; ALR autophagic lysosome reformation; ER endoplasmic reticulum; GFP green fluorescent protein; HSP hereditary spastic paraplegia; Lamp1 lysosomal associated membrane protein 1 PolyUB polyubiquitin; RFP red fluorescent protein; spin spinster; mTor mechanistic Target of rapamycin; VCP valosin containing protein.
    MeSH term(s) Animals ; Autophagy/physiology ; Drosophila ; Lysosomes/metabolism ; Muscles ; TOR Serine-Threonine Kinases/metabolism
    Chemical Substances TOR Serine-Threonine Kinases (EC 2.7.11.1) ; Mtor protein, Drosophila
    Language English
    Publishing date 2023-08-30
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2454135-7
    ISSN 1554-8635 ; 1554-8627
    ISSN (online) 1554-8635
    ISSN 1554-8627
    DOI 10.1080/15548627.2023.2249794
    Database MEDical Literature Analysis and Retrieval System OnLINE

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