LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 63

Search options

  1. Article ; Online: Phrenic-to-intercostal reflex activity in response to high frequency spinal cord stimulation (HF-SCS).

    Kowalski, Krzysztof E / DiMarco, Anthony F

    Respiratory physiology & neurobiology

    2022  Volume 306, Page(s) 103962

    Abstract: Objective: HF-SCS is a novel technique of inspiratory muscle activation which results in coincident activation of the diaphragm and inspiratory intercostal muscles via spinal cord pathways and has the potential to provide respiratory support in ... ...

    Abstract Objective: HF-SCS is a novel technique of inspiratory muscle activation which results in coincident activation of the diaphragm and inspiratory intercostal muscles via spinal cord pathways and has the potential to provide respiratory support in ventilator dependent persons with spinal cord injury. The purpose of the present study was to examine the phrenic-to-intercostal reflex during HF-SCS.
    Methods: In 5 anesthetized and C2 spinalized dogs, electrical stimulation was applied via a stimulating electrode located on the ventral surface of the upper thoracic spinal cord at the T2 level. Fine wire recording electrodes were used to assess single motor unit (SMU) activity of the left and right external intercostal muscles (EI) in the 3rd interspace before and after sequential left and right phrenicotomy.
    Results: Mean control peak firing frequency of the right EI and left EI was 11.4 ± 0.3 Hz and 10.6 ± 0.3 Hz respectively. Following unilateral right phrenic nerve section, mean SMU peak firing frequency of right EI (ipsilateral to the section) was significantly greater when compared to control (15.9 ± 0.5 Hz vs 11.4 ± 0.3 Hz; p = 0.01). Mean SMU peak firing frequency of the contralateral left EI remained unchanged (10.2 ± 0.3 Hz vs 10.6 ± 0.3 Hz, p = 0.40). Subsequent, section of the left phrenic nerve resulted in significantly higher mean SMU peak firing frequency of the left EI (16.2 ± 0.5 Hz vs 10.2 ± 0.3 Hz) when compared to before section p = 0.01). Contralateral, right EI peak firing frequency was not different if compared to before left phrenic nerve section (16.9 ± 0.4 Hz vs. 15.9 ± 0.5 Hz; p = 0.14).
    Conclusion: This study demonstrates that during HF-SCS: 1) unilateral diaphragmatic afferents reflexly inhibit motor activity to the ipsilateral EI muscles, 2) the neural circuitry mediating the phrenic-to-intercostal reflex is preserved at a spinal level and does not require supraspinal input and 3) unilateral compensatory increases were observed in EI muscle activation following ipsilateral diaphragm paralysis.
    MeSH term(s) Animals ; Diaphragm/physiology ; Dogs ; Electric Stimulation/methods ; Intercostal Muscles/physiology ; Phrenic Nerve/physiology ; Reflex ; Spinal Cord/physiology ; Spinal Cord Injuries/therapy ; Spinal Cord Stimulation/methods
    Language English
    Publishing date 2022-09-05
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2077867-3
    ISSN 1878-1519 ; 1569-9048
    ISSN (online) 1878-1519
    ISSN 1569-9048
    DOI 10.1016/j.resp.2022.103962
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Diaphragm Pacing.

    DiMarco, Anthony F

    Clinics in chest medicine

    2018  Volume 39, Issue 2, Page(s) 459–471

    Abstract: Diaphragm pacing (DP) is a useful and cost-effective alternative to mechanical ventilation in patients with ventilator-dependent spinal cord injury and central hypoventilation syndrome. Patients with SCI should be carefully screened to assess the ... ...

    Abstract Diaphragm pacing (DP) is a useful and cost-effective alternative to mechanical ventilation in patients with ventilator-dependent spinal cord injury and central hypoventilation syndrome. Patients with SCI should be carefully screened to assess the integrity of their phrenic nerves. In eligible patients, DP improves mobility, speech, olfaction, and quality of life. The stigma of being attached to a mechanical device and risk of ventilator disconnection are eliminated. There is also some evidence that DP results in a reduction in the rate of respiratory tract infections. DP is associated with infrequent side effects and complications, such as wire breakage, radiofrequency failure, and infection.
    MeSH term(s) Diaphragm/physiology ; Electric Stimulation Therapy ; Electrodes, Implanted ; Humans ; Spinal Cord Injuries/complications ; Spinal Cord Injuries/physiopathology
    Language English
    Publishing date 2018-05-21
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 447455-7
    ISSN 1557-8216 ; 0272-5231
    ISSN (online) 1557-8216
    ISSN 0272-5231
    DOI 10.1016/j.ccm.2018.01.008
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: Impact of the cough stimulation system on the care burden and life quality of caregivers of tetraplegics.

    DiMarco, Anthony F / Geertman, Robert T / Nemunaitis, Gregory A / Kowalski, Krzysztof E

    The journal of spinal cord medicine

    2023  Volume 46, Issue 5, Page(s) 778–788

    Abstract: Objectives: To determine caregiver burden and quality of life of primary family caregivers of participants with cervical SCI before and after use of the cough stimulation system (CSS).: Design: Prospective assessment at four timepoints via ... ...

    Abstract Objectives: To determine caregiver burden and quality of life of primary family caregivers of participants with cervical SCI before and after use of the cough stimulation system (CSS).
    Design: Prospective assessment at four timepoints via questionnaire responses.
    Setting: Out-patient hospital, United States.
    Participants: 15 primary family caregivers of participants with cervical SCI completed questionnaires including a respiratory care burden index (
    Results: SCI participants had significant clinical improvements in terms of restoration of an effective cough and ability to manage airway secretions with use of the CSS. Restoration of expiratory muscle function with use of the CSS also resulted in less caregivers (CG) stress, greater control of their participants' breathing problems, and improvement in quality of life. Results of the caregiver burden inventory demonstrated marked reductions in caregiver burden in development items, physical health and social relationship. Overall caregiver burden fell from 43.4 ± 13.8 pre-implant to 32.4 ± 7.9 (P = 0.06), 31.7 ± 10.5 (P = 0.05), and 26.5 ± 9.3 (P = 0.01) at the 6-month, 1-year and 2-year timepoints.
    Conclusion: Use of the CSS by cervical SCI participants results in restoration of an effective cough with significant clinical benefits. While caregiver burden is very high in primary family caregivers, they derive marked improvement in caregiver burden and quality of life with implementation of this device.
    MeSH term(s) Humans ; Quality of Life ; Caregivers ; Cough ; Caregiver Burden ; Spinal Cord Injuries ; Prospective Studies
    Language English
    Publishing date 2023-04-05
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 1223949-5
    ISSN 2045-7723 ; 1079-0268
    ISSN (online) 2045-7723
    ISSN 1079-0268
    DOI 10.1080/10790268.2022.2148845
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Comparison of wire and disc electrodes to electrically activate the inspiratory muscles in dogs.

    Kowalski, Krzysztof E / DiMarco, Anthony F

    Journal of neuroscience methods

    2021  Volume 357, Page(s) 109176

    Abstract: Objective: To compare the effectiveness of wire versus disc electrodes to activate the inspiratory muscles via high frequency spinal cord stimulation.: Design: Animal study.: Setting: Research laboratory.: Animals: Dogs (n = 5) INTERVENTIONS: ... ...

    Abstract Objective: To compare the effectiveness of wire versus disc electrodes to activate the inspiratory muscles via high frequency spinal cord stimulation.
    Design: Animal study.
    Setting: Research laboratory.
    Animals: Dogs (n = 5) INTERVENTIONS: In separate trials, spinal cord stimulation (SCS) was applied via disc (DE) and two parallel wire electrodes (WE) on the ventral epidural space at the T2-T3 spinal region.
    Main outcome measure(s): Airway pressure (P) and inspired volume (V) generation following stimulation with DE and WE were compared. Given our previous success with (DE), outcome variables with this electrode were used as our gold standard to which all comparisons were made.
    Results: Two configurations of WE using monopolar stimulation (MS) resulted in P and V that were similar to those generated with MS with DE. For example, MS with parallel WE connected together to function as a common cathode (Y-connection) and a 2-channel system (separate cathodes with a remote ground), resulted in P that were 91 ± 6 and 92 ± 4%, respectively, of those achieved with DE (NS for both). Bipolar stimulation with parallel WE using a Y-connection and with a 2-channel system, resulted in P that were 96 ± 4 and 94 ± 4%, of the P achieved with DE (NS for both).
    Conclusion(s): These results suggest that specific configurations of WE, which can be placed via minimally invasive techniques, provide comparable activation of the inspiratory muscles compared to DE and may be a useful technique to restore ventilatory support in persons with spinal cord injury.
    MeSH term(s) Animals ; Dogs ; Electric Stimulation ; Electrodes ; Electrodes, Implanted ; Respiratory Muscles ; Spinal Cord ; Spinal Cord Injuries ; Spinal Cord Stimulation
    Language English
    Publishing date 2021-04-02
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 282721-9
    ISSN 1872-678X ; 0165-0270
    ISSN (online) 1872-678X
    ISSN 0165-0270
    DOI 10.1016/j.jneumeth.2021.109176
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Activation of the expiratory muscles via lower thoracic high frequency spinal cord stimulation in awake animals.

    DiMarco, Anthony F / Kowalski, Krzysztof E

    Respiratory physiology & neurobiology

    2020  Volume 276, Page(s) 103360

    Abstract: Lower thoracic spinal cord stimulation is an effective method of restoring an effective cough in participants with complete spinal cord injury. The high voltage requirements however significantly limits this application in subjects with intact lower ... ...

    Abstract Lower thoracic spinal cord stimulation is an effective method of restoring an effective cough in participants with complete spinal cord injury. The high voltage requirements however significantly limits this application in subjects with intact lower chest wall sensation. In anesthetized animals, we have shown that the expiratory muscles can also be effectively activated with low stimulus currents (1 mA) but with high stimulus frequencies (HF-SCS -500 Hz). In 3 intact, awake pigs the responses to HF-SCS, were evaluated. HF-SCS was associated with marked expansion of the abdominal wall and external oblique EMG activity without any associated changes in heart rate or vocalization. During a terminal procedure under general anesthesia, responses to HF-SCS were re-assessed. Abdominal movement and EMG were similar to that observed in the awake state. HF-SCS (1.5 mA) resulted in an airway pressure of 65 ± 2cmH
    MeSH term(s) Abdominal Muscles/physiology ; Abdominal Wall ; Animals ; Cough ; Electromyography ; Exhalation/physiology ; Maximal Respiratory Pressures ; Muscle Strength ; Respiratory Muscles/physiology ; Spinal Cord Stimulation/methods ; Swine ; Thoracic Vertebrae ; Wakefulness
    Language English
    Publishing date 2020-02-08
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2077867-3
    ISSN 1878-1519 ; 1569-9048
    ISSN (online) 1878-1519
    ISSN 1569-9048
    DOI 10.1016/j.resp.2019.103360
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Model-Based Optimization of Spinal Cord Stimulation for Inspiratory Muscle Activation.

    Zander, Hans J / Kowalski, Krzysztof E / DiMarco, Anthony F / Lempka, Scott F

    Neuromodulation : journal of the International Neuromodulation Society

    2022  Volume 25, Issue 8, Page(s) 1317–1329

    Abstract: Objective: High-frequency spinal cord stimulation (HF-SCS) is a potential method to provide natural and effective inspiratory muscle pacing in patients with ventilator-dependent spinal cord injuries. Experimental data have demonstrated that HF-SCS ... ...

    Abstract Objective: High-frequency spinal cord stimulation (HF-SCS) is a potential method to provide natural and effective inspiratory muscle pacing in patients with ventilator-dependent spinal cord injuries. Experimental data have demonstrated that HF-SCS elicits physiological activation of the diaphragm and inspiratory intercostal muscles via spinal cord pathways. However, the activation thresholds, extent of activation, and optimal electrode configurations (i.e., lead separation, contact spacing, and contact length) to activate these neural elements remain unknown. Therefore, the goal of this study was to use a computational modeling approach to investigate the direct effects of HF-SCS on the spinal cord and to optimize electrode design and stimulation parameters.
    Materials and methods: We developed a computer model of HF-SCS that consisted of two main components: 1) finite element models of the electric field generated during HF-SCS, and 2) multicompartment cable models of axons and motoneurons within the spinal cord. We systematically evaluated the neural recruitment during HF-SCS for several unique electrode designs and stimulation configurations to optimize activation of these neural elements. We then evaluated our predictions by testing two of these lead designs with in vivo canine experiments.
    Results: Our model results suggested that within physiological stimulation amplitudes, HF-SCS activates both axons in the ventrolateral funiculi (VLF) and inspiratory intercostal motoneurons. We used our model to predict a lead design to maximize HF-SCS activation of these neural targets. We evaluated this lead design via in vivo experiments, and our computational model predictions demonstrated excellent agreement with our experimental testing.
    Conclusions: Our computational modeling and experimental results support the potential advantages of a lead design with longer contacts and larger edge-to-edge contact spacing to maximize inspiratory muscle activation during HF-SCS at the T2 spinal level. While these results need to be further validated in future studies, we believe that the results of this study will help improve the efficacy of HF-SCS technologies for inspiratory muscle pacing.
    Language English
    Publishing date 2022-06-14
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1500372-3
    ISSN 1525-1403 ; 1094-7159
    ISSN (online) 1525-1403
    ISSN 1094-7159
    DOI 10.1111/ner.13415
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article: Effects of restoration of cough via spinal cord stimulation on subject quality of life.

    DiMarco, Anthony F / Geertman, Robert T / Nemunaitis, Gregory A / Kowalski, Krzysztof E

    Journal of clinical orthopaedics and trauma

    2022  Volume 34, Page(s) 102027

    Abstract: Objectives: To determine participant quality of life before and after use of the cough stimulation system (Cough System).: Design: Prospective assessment of life quality at 4 timepoints via questionnaire responses.: Setting: Out-patient hospital, ... ...

    Abstract Objectives: To determine participant quality of life before and after use of the cough stimulation system (Cough System).
    Design: Prospective assessment of life quality at 4 timepoints via questionnaire responses.
    Setting: Out-patient hospital, United States.
    Participants: 28 subjects with spinal cord injury (SCI) completed life quality assessment questionnaires before and at the 28- 40- and 52-week timepoints following use of the Cough System.
    Results: Each subject demonstrated significant clinical improvements in terms of restoration of an effective cough and ability to manage airway secretions with use of the Cough System. Positive airway pressures and peak expiratory airflows approached values associated with a normal cough. Related to cough/secretion management, use of this system also resulted less interference with family life and daily activities, less financial difficulties, less requirement for caregiver assistance, less stress, less embarrassment and greater control of their breathing problems (p < 0.01), for each comparison). There also significant improvements in that their overall health and quality of life (p < 0.01, for each comparison). Subjects also reported greater ease in breathing, restored ability to sneeze and enhanced mobility. The incidence of acute respiratory tract infections fell from 1.3 ± 0.3 to 0.2 ± 0.1 events/subject year (p < 0.01). Ten subjects developed mild hemodynamic effects consistent with autonomic dysreflexia that abated completely with continued use of the Cough System. Some subjects experienced mild leg jerks during SCS, which were well tolerated and abated completely with reduction in stimulus amplitude, No subjects reported bowel or bladder leakage.
    Conclusion: Use of the Cough System by SCI subjects is a safe and efficacious method which significantly improves life quality and has the potential to reduce the mortality and morbidity associated with SCI.
    Language English
    Publishing date 2022-09-27
    Publishing country India
    Document type Journal Article
    ZDB-ID 2596956-0
    ISSN 2213-3445 ; 0976-5662
    ISSN (online) 2213-3445
    ISSN 0976-5662
    DOI 10.1016/j.jcot.2022.102027
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: High-frequency spinal cord stimulation in a subacute animal model of spinal cord injury.

    DiMarco, Anthony F / Kowalski, Krzysztof E

    Journal of applied physiology (Bethesda, Md. : 1985)

    2019  Volume 127, Issue 1, Page(s) 98–102

    Abstract: High-frequency spinal cord stimulation (HF-SCS) applied at the T2 spinal level results in physiologic activation of the inspiratory muscles in C2 spinal-sectioned dogs. Although the bulbo-spinal fibers were cut, they likely survived the duration of acute ...

    Abstract High-frequency spinal cord stimulation (HF-SCS) applied at the T2 spinal level results in physiologic activation of the inspiratory muscles in C2 spinal-sectioned dogs. Although the bulbo-spinal fibers were cut, they likely survived the duration of acute experiments, and inspiratory muscle activation may have involved stimulation of these fibers. In two anesthetized, C2 paralyzed, intubated, and mechanically ventilated dogs, HF-SCS (300 Hz) was applied at the T2 level. The effectiveness of HF-SCS in generating inspired volume (V) and negative airway pressures (P) was evaluated over a period of 5 days during which time the bulbo-spinal fibers would have degenerated. Because the effectiveness of HF-SCS may be adversely affected by deterioration of these fibers and/or the condition of the animal, low-frequency (50 Hz) SCS (LF-SCS) was also performed and served as a control. All vital signs, oxygen saturation, and end-tidal Pco
    MeSH term(s) Animals ; Carbon Dioxide/metabolism ; Diaphragm/metabolism ; Diaphragm/physiopathology ; Disease Models, Animal ; Dogs ; Electric Stimulation/methods ; Intercostal Muscles/metabolism ; Intercostal Muscles/physiopathology ; Motor Neurons/metabolism ; Motor Neurons/physiology ; Musculoskeletal Physiological Phenomena ; Oxygen/metabolism ; Respiration ; Respiration, Artificial/methods ; Spinal Cord/metabolism ; Spinal Cord/physiopathology ; Spinal Cord Injuries/metabolism ; Spinal Cord Injuries/physiopathology ; Spinal Cord Stimulation/methods
    Chemical Substances Carbon Dioxide (142M471B3J) ; Oxygen (S88TT14065)
    Language English
    Publishing date 2019-05-16
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 219139-8
    ISSN 1522-1601 ; 0021-8987 ; 0161-7567 ; 8750-7587
    ISSN (online) 1522-1601
    ISSN 0021-8987 ; 0161-7567 ; 8750-7587
    DOI 10.1152/japplphysiol.00006.2019
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Book ; Online: The effects of Hurricane Harvey on Texas coastal-zone chemistry

    Chapman, Piers / DiMarco, Steven F. / Knap, Anthony H. / Quigg, Antonietta / Walker, Nan D.

    eISSN: 1812-0792

    2023  

    Abstract: Hurricane Harvey deposited over 90×10 9 m 3 of rainwater over central Texas, USA, during late August/early September 2017. During four cruises (June, August, September and November 2017) we observed changes in hydrography and nutrient and oxygen ... ...

    Abstract Hurricane Harvey deposited over 90×10 9 m 3 of rainwater over central Texas, USA, during late August/early September 2017. During four cruises (June, August, September and November 2017) we observed changes in hydrography and nutrient and oxygen concentrations in Texas coastal waters. Despite intense terrestrial runoff, nutrient supply to the coastal ocean was transient, with little phytoplankton growth observed and no hypoxia. Observations suggest this was probably related to the retention of nutrients in the coastal bays and rapid uptake by phytoplankton of nutrients washed out of the bays, as well as dilution by the sheer volume of rainwater and the lack of significant carbon reserves in the sediments, despite the imposition of a strong pycnocline. By the November cruise conditions had apparently returned to normal, and no long-term effects were observed.
    Subject code 333
    Language English
    Publishing date 2023-03-01
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  10. Book ; Online: The effects of Hurricane Harvey on Texas coastal zone chemistry

    Chapman, Piers / DiMarco, Steven F. / Knap, Anthony H. / Quigg, Antonietta / Walker, Nan D.

    eISSN:

    2023  

    Abstract: Hurricane Harvey deposited over 90×10 9 m 3 of rainwater over central Texas, USA, during late August/early September 2017. During four cruises (June, August, September and November 2017) we observed changes in hydrography and nutrient and oxygen ... ...

    Abstract Hurricane Harvey deposited over 90×10 9 m 3 of rainwater over central Texas, USA, during late August/early September 2017. During four cruises (June, August, September and November 2017) we observed changes in hydrography and nutrient and oxygen concentrations in Texas coastal waters. Despite intense terrestrial runoff, nutrient supply to the coastal ocean was transient, with little phytoplankton growth observed and no hypoxia. Observations suggest this was probably related to the retention of nutrients in the coastal bays and rapid uptake by phytoplankton of nutrients washed out of the bays, as well as dilution by the sheer volume of rainwater and the lack of significant carbon reserves in the sediments, despite the imposition of a strong pycnocline. By the November cruise conditions had apparently returned to normal, and no long-term effects were observed.
    Subject code 333
    Language English
    Publishing date 2023-03-01
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

To top