Paralyzed hemidiaphragm

A C2 cervical spinal cord hemisection (SH) interrupts descending inspiratory-related drive to phrenic motoneurons located between C3 and C5 in rats, paralyzing the ipsilateral hemidiaphragm muscle. There is gradual recovery of rhythmic diaphragm muscle activity ipsilateral to cervical spinal cord injury over time, consistent with neuroplasticity and strengthening of spared, contralateral descending premotor input to phrenic motoneurons. Brain-derived neurotrophic factor (BDNF) signaling through the tropomyosin related kinase receptor subtype B (TrkB) plays an important role in neuroplasticity following spinal cord injury...

CONTEXT: Botulinum neurotoxins (BoNTs) are popularly used to treat various diseases and for cosmetic purposes. They act by blocking neurotransmission through specific cleavage of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Recently, several polyphenols were shown to interfere with SNARE complex formation by wedging into the hydrophobic core interface, thereby leading to reduced neuroexocytosis. OBJECTIVE: In order to find industrially-viable plant extract that functions like BoNT, 71 methanol extracts of flowers were screened and BoNT-like activity of selected extract was evaluated...

Botulinum neurotoxins (BoNTs) comprise a family of neurotoxic proteins synthesized by anaerobic bacteria of the genus Clostridium. Each neurotoxin consists of two polypeptide chains: a 100kDa heavy chain, responsible for binding and internalization into the nerve terminal of cholinergic motoneurons and a 50kDa light chain that mediates cleavage of specific synaptic proteins in the host nerve terminal. Exposure to BoNT leads to cessation of voltage- and Ca(2+)-dependent acetylcholine (ACh) release, resulting in flaccid paralysis which may be protracted and potentially fatal...

BACKGROUND: Partially paralyzed patients may be placed in the risk of pharyngeal dysfunction. Bupivacaine acts as acetylcholine receptor ion channel blocker and may synergistically interact with rocuronium to augment NM blockade. Thus, this study aims to elucidate whether or not, at a therapeutic concentration, bupivacaine by itself may cause NM blockade and reduce an effective concentration of rocuronium. METHODS: Twenty-two left phrenic nerve-hemidiaphragms (Male SD rats, 150-250 g) were hung in Krebs solution...

The ultrasound-guided interscalene brachial plexus is becoming increasingly popular for anesthesia in the management of upper-extremity injuries by emergency physicians. Traditional high-volume injections of local anesthesia will also affect the phrenic nerve, leading to temporary paralysis of the ipsilateral hemidiaphragm. With direct ultrasound guidance, more precise needle placement allows for lower-volume injections that reduce inadvertent spread of local anesthetic to the phrenic nerve without decreasing the efficacy of onset of time and quality of the block...

Recent studies proposed that mechanical inactivity of the human diaphragm during mechanical ventilation rapidly causes diaphragm atrophy and weakness. However, conclusive evidence for the notion that diaphragm weakness is a direct consequence of mechanical inactivity is lacking. To study the effect of hemidiaphragm paralysis on diaphragm muscle fiber function and structure in humans, biopsies were obtained from the paralyzed hemidiaphragm in eight patients with hemidiaphragm paralysis. All patients had unilateral paralysis of known duration, caused by en bloc resection of the phrenic nerve with a tumor...

BACKGROUND: Unilateral phrenic nerve injury often results in symptomatic hemidiaphragm paralysis, and currently few treatment options exist. Reported etiologies include cardiac surgery, neck surgery, chiropractic manipulation, and interscalene nerve blocks. Although diaphragmatic plication has been an option for treatment, the ideal treatment would be restoration of function to the paralyzed hemidiaphragm. The application of peripheral nerve surgery techniques for phrenic nerve injuries has not been adequately evaluated...

Consequences of spinal cord injury (SCI) depend on the level and extent of injury. Cervical SCI often results in a compromised respiratory system. Primary treatment of SCI patients with respiratory insufficiency continues to be with mechanical ventilatory support. In an animal model of SCI, an upper cervical spinal cord hemisection paralyzes the hemidiaphragm ipsilateral to the side of injury. However, a latent respiratory motor pathway can be activated to restore respiratory function after injury. In this review, restoration of respiratory activity following systemic administration of theophylline, a respiratory stimulant will be discussed...

The ability of galantamine hydrobromide (GAL HBr) treatment to antagonize O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX)-induced lethality, impairment of muscle tension, and electroencephalographic (EEG) changes was assessed in guinea pigs. Guinea pigs were challenged with 16.8 microg/kg VX (2LD50). One min after challenge, animals were administered 0.5 mg/kg atropine sulfate (ATR) and 25 mg/kg pyridine-2-aldoxime methochloride (2-PAM). In addition, guinea pigs were given 0, 1, 2, 4, 8 or 10 mg/kg GAL as a post-exposure treatment immediately prior to ATR and 2-PAM...

Cervical spinal cord hemisection at C2 leads to paralysis of the ipsilateral hemidiaphragm in rats. Respiratory function of the paralyzed hemidiaphragm can be restored by activating a latent respiratory motor pathway in adult rats. This pathway is called the crossed phrenic pathway and the restored activity in the paralyzed hemidiaphragm is referred to as crossed phrenic activity. The latent neural pathway is not latent in neonatal rats as shown by the spontaneous expression of crossed phrenic activity. However, the anatomy of the pathway in neonatal rats is still unknown...

BACKGROUND/OBJECTIVE: High cervical spinal cord hemisection interrupts descending respiratory drive from the rostral ventral respiratory group in the medulla to the ipsilateral phrenic motoneurons. Hemisection results in the paralysis of the ipsilateral hemidiaphragm. Chronic administration of rolipram, a specific phosphodiesterase-IV inhibitor, promotes synaptic plasticity and restores phrenic nerve function after a high cervical spinal cord lesion. Here, we test the hypothesis that an acute administration of rolipram will increase spinal and medullary levels of 3',5'-cyclic adenosine monophosphate (cAMP) and induce phrenic nerve recovery after cervical (C2) spinal cord hemisection...

OBJECTIVE: To describe a case of an anterior mediastinal mass (AMM) in a patient with Graves disease. METHODS: We report the clinical presentation, diagnosis, management, and outcome of a 34-year-old man with dyspnea on exertion. RESULTS: Initial evaluation of the patient's complaints revealed a large AMM on chest radiography and then chest computed tomography. After occurrence of additional symptoms, the patient was diagnosed as having Graves disease and treated with antithyroid medications...

Cervical spinal cord hemisection rostral to the phrenic nucleus leads to paralysis of the ipsilateral hemidiaphragm in adult rats. Respiratory function can be restored to the paralyzed hemidiaphragm by activating a latent respiratory motor pathway. The latent pathway is called the crossed phrenic pathway. In adult rats, the pathway can be activated by drug-induced upregulation of NMDA receptor NR2A subunit and AMPA receptor GluR1 subunit in the phrenic nucleus following hemisection. In neonatal rats, this pathway is not latent as shown by the spontaneous expression of activity in the ipsilateral hemidiaphragm following hemisection...

Spinal cord hemisection rostral to the phrenic nucleus leads to paralysis of the ipsilateral hemidiaphragm and respiratory insufficiency. Recovery of the paralyzed hemidiaphragm may be induced by activating a latent respiratory motor pathway in adult rats. Although the pathway is latent in adults, it may not be latent in neonatal rats as shown by the spontaneous expression of activity over this pathway in an earlier in vitro study. Activity mediated over the latent pathway is known as "crossed phrenic activity"...

PURPOSE: To investigate the complex breathing patterns in patients with hemidiaphragmatic paralysis due to malignant infiltration using four-dimensional magnetic resonance imaging (4D-MRI). PATIENTS AND METHODS: Seven patients with bronchial carcinoma infiltrating the phrenic nerve were examined using 1.5 T MRI. The motion of the tumor and of both hemi-diaphragms were measured on dynamic 2D TrueFISP and 4D FLASH MRI sequences. RESULTS: For each patient, 3-6 breathing cycles were recorded...

OBJECTIVE: This case report describes the anesthetic management of a patient with severe chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) who underwent elective sigmoid resection under combined spinal-epidural anesthesia and bilevel positive airway pressure (BiPAP). CASE REPORT: A 63-year-old man with diverticular disease presented for a sigmoid resection. His medical history included coronary artery bypass grafting, diabetes mellitus, gastroesophageal reflux, chronic renal failure, COPD, a paralyzed left hemidiaphragm, and OSA treated with nighttime BiPAP and oxygen...

Neuronal soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) proteins mediate membrane fusion between synaptic vesicle and presynaptic membrane, resulting in neurotransmitter release. SNARE proteins are specific substrates of botulinum neurotoxins (BoNT) which are now widely used for therapeutic and cosmetic purposes. While BoNT blocks neuroexocytosis by cleaving SNAREs, inhibiting SNARE assembly process might exert the same effect on neurotransmission. In the present study, some extracts of 100 plants reduced neurotransmitter release by inhibiting SNARE complex formation in neuronal cells...

BACKGROUND: The physiologic advantages of preserving phrenic nerve integrity and normal diaphragmatic motion (DM) during the course of pnemonectomy are incompletely understood. This study was conducted to investigate potential benefits of this strategy on postoperative lung function. METHODS: Among 523 consecutive patients who underwent pneumonectomy for lung cancer between January 1992 and September 2001, 117 were alive at the time of study (March to December 2006) and thus had 5 years' minimum follow-up...

Gymnodimines (GYMs) are phycotoxins exhibiting unusual structural features including a spirocyclic imine ring system and a trisubstituted tetrahydrofuran embedded within a 16-membered macrocycle. The toxic potential and the mechanism of action of GYM-A, highly purified from contaminated clams, have been assessed. GYM-A in isolated mouse phrenic hemidiaphragm preparations produced a concentration- and time-dependent block of twitch responses evoked by nerve stimulation, without affecting directly elicited muscle twitches, suggesting that it may block the muscle nicotinic acetylcholine (ACh) receptor (nAChR)...

High cervical spinal cord hemisection results in paralysis of the ipsilateral hemidiaphragm; however, functional recovery of the paralyzed hemidiaphragm can occur spontaneously. The mechanisms mediating this recovery are unknown. In chronic, experimental contusive spinal cord injury, an upregulation of the NMDA receptor 2A subunit and a downregulation of the AMPA receptor GluR2 subunit have been correlated with improved hind limb motor recovery. Therefore, we hypothesized that NR2A is upregulated, whereas GluR2 is down-regulated following chronic C2 hemisection to initiate synaptic strengthening in respiratory motor pathways...