Guillain-Barré syndrome (GBS), an immune-mediated disease of the peripheral nervous system, is mainly characterized by rapidly progressive ascending weakness of the limbs with reduced or absent deep tendon reflexes. The exact cause of GBS is unknown, but it often occurs after a gastrointestinal or respiratory infection. The present study represents a case of GBS in which multiple antecedent antigenic stimuli may have contributed to the development of GBS.
View Article and Find Full Text PDFBackground: Pancoast tumors represent a unique subset of lung cancers wherein a primary neoplasm arises in the lung's apex and invades the surrounding soft tissues. One of the main challenges in the diagnosis and treatment of these apical lung cancers is that they are usually not visualized on initial chest x-ray and, by the time the patient presents with symptoms, the tumor has almost always invaded nearby structures.
Case Presentation: Herein we report a case of a 58-year-old nonsmoking African American male who presented to the neurology clinic with a history of multiple chronic joint pains.
Cerebral sinus vein thrombosis (CVT) is a rare but serious complication associated with ulcerative colitis (UC), an idiopathic autoimmune inflammatory disease of the gastrointestinal tract. Management approaches for CVT remain unclear but may include anticoagulation and surgical thrombectomy. Herein, we report a case of a 23-year-old male who developed CVT with a history of UC.
View Article and Find Full Text PDFNicotine, the main addictive component of tobacco smoke, has both rewarding and aversive properties. Recent studies have suggested that GABAergic neurons, one of the main neurochemical components of the reward-addiction circuitry, may also play a role in the aversive responses to nicotine. In the present study of transgenic mice expressing Green Fluorescent Protein (GFP) in Glutamate Decarboxylase 67 (GAD67) neurons, we hypothesized that a subpopulation of GABAergic neurons in the Ventral Tegmental Area (VTA) are the targets of aversive doses of nicotine in the CNS.
View Article and Find Full Text PDFOrexin/hypocretin-containing neurons in lateral hypothalamus (LH) are implicated in the neurobiology of nicotine addiction. However, the neuroanatomical relationships between orexin-neurons/nerve fibers and nicotine-activated cells within the reward-addiction neurocircuitry is not known. In the present study in mice, we first used c-Fos immunohistochemistry to identify CNS cells stimulated by an acute single injection of nicotine (NIC, 2 mg/kg, IP).
View Article and Find Full Text PDFThe sensory experience of smoking is a key component of nicotine addiction known to result, in part, from stimulation of nicotinic acetylcholine receptors (nAChRs) at peripheral sensory nerve endings. Such stimulation of nAChRs is followed by activation of neurons at multiple sites in the mesocorticolimbic reward pathways. However, the neurochemical profiles of CNS cells that mediate the peripheral sensory impact of nicotine remain unknown.
View Article and Find Full Text PDFDirect actions of nicotine in the CNS appear to be essential for its reinforcing properties. However, activation of nicotinic acetylcholine receptors (nAChRs) on afferent sensory nerve fibers is an important component of addiction to, and withdrawal from, cigarette smoking. The aim of the present study was to identify the neuroanatomical substrates activated by the peripheral actions of nicotine and to determine whether these sites overlap brain structures stimulated by direct actions of nicotine.
View Article and Find Full Text PDFPrevious studies have shown that molecules of the taste transduction pathway may serve as biochemical markers for chemoreceptive cells in respiratory and gastrointestinal tracts. In this study, we tested the hypothesis that brainstem neurons contain signaling molecules similar to those in taste buds which may sense the chemical composition of brain extracellular fluids. We used the reverse transcription polymerase chain reaction (RT-PCR), Western blot and immunohistochemical techniques to evaluate presence of different bitter-responsive type 2 taste receptors (T2Rs), their associated G-protein α-gustducin, the downstream signaling molecules phospholipase C isoform β2 (PLC-β2) and transient receptor potential melastatin 5 (TRPM5) in the brainstem of rats.
View Article and Find Full Text PDFNicotine in tobacco smoke is thought to stimulate sensory nerve fibers by receptors that are located on airway epithelial cells and on terminal branches of C-fiber afferents, but the exact neurochemical substrate that mediates the sensory effects of nicotine associated with cigarette smoking is not clear. ATP and nitric oxide (NO) have both been implicated in lung responsiveness to airborne chemicals such as nicotine. However, the neuroanatomical and functional relationships between nicotinic acetylcholine receptors (nAChRs), purinergic signaling, and NO are not known, and the main source of NO in the airways is not clear.
View Article and Find Full Text PDFPrevious studies have suggested that sensory mechanisms may be important components of addiction to, and withdrawal from, cigarette smoking. The sensory and respiratory responses to nicotine are mediated, in part, by bronchopulmonary C-fiber afferents. Nicotine has a direct stimulatory effect on pulmonary sensory neurons, and nicotinic cholinergic receptors (nAChRs) composed of various combinations of alpha and beta subunits are known to be present in pulmonary ganglia.
View Article and Find Full Text PDFRostral ventral medulla (RVM) contains significant numbers of local GABAergic neurons which may subserve respiratory chemosensory and baroreceptor reflexes. Nicotinic mechanisms stimulate release of GABA in certain brainstem neurons. Whether the GABAergic neurons at RVM express nicotinic cholinergic receptors (nAChRs) is not known.
View Article and Find Full Text PDFNicotine acting centrally increases bronchomotor tone and airway secretion, suggesting that airway-related vagal preganglionic neurons (AVPNs) within the rostral nucleus ambiguus (rNA) express nicotinic acetylcholine receptors (nAChRs). In the present study, we examined the three main functionally characterized subtypes of nAChRs in the CNS, the alpha7 homomeric and alpha4beta2 heteromeric receptors. First, we characterized the expression of these subunits at the message (mRNA) and protein levels in brain tissues taken from the rNA region, the site where AVPNs are located.
View Article and Find Full Text PDFIn the present study, immunohistochemistry combined with retrograde labeling techniques were used to determine if hypoglossal motoneurons (HMNs), retrogradely labeled after cholera toxin B subunit (CTB) injection to the genioglossus muscle in rats, show immunoreactivity for alpha-7 and alpha-4 subunits of nicotinic acetylcholine receptors (nAChRs). CTB-positive HMNs projecting to the genioglossus muscle were consistently labeled throughout the rostrocaudal extent of the hypoglossal nuclei with the greatest labeling at and caudal to area postrema. Alpha-7 subunit immunoreactivity was found in 39.
View Article and Find Full Text PDFIn the present study, we determined whether alpha-7 subunit containing nicotinic acetylcholine receptors (nAChRs) are expressed by neurons within the pre-Botzinger complex (pre-BotC), bulbospinal, and phrenic motor nuclei in the rat. alpha-7 Immunohistochemistry combined with cholera toxin B (CTB), a retrograde tracer was used to detect expression of alpha-7 nAChRs by phrenic motor and bulbospinal neurons. Neurokinin-1 receptor immunoreactivity was used as a marker for pre-BotC neurons.
View Article and Find Full Text PDFWe have previously reported that the anticholinergic properties of cocaine may be important in cocaine induced apneusis. We have studied the effects of the cholinergic muscarinic antagonist atropine (ATR) on cocaine induced apneusis at the caudal chemosensitive areas of the ventrolateral medulla oblongata (CVLM). Experiments were performed in urethane anesthetized and tracheotomized cats with the CVLM surgically exposed.
View Article and Find Full Text PDFJ Appl Physiol (1985)
February 2001
Physiological evidence has indicated that central respiratory chemosensitivity may be ascribed to neurons located at the ventral medullary surface (VMS); however, in recent years, multiple sites have been proposed. Because c-Fos immunoreactivity is presumed to identify primary cells as well as second- and third-order cells that are activated by a particular stimulus, we hypothesized that activation of VMS cells using a known adequate respiratory stimulus, H(+), would induce production of c-Fos in cells that participate in the central pH-sensitive respiratory chemoreflex loop. In this study, stimulation of rostral and caudal VMS respiratory chemosensitive sites in chloralose-urethane-anesthetized rats with acidic (pH 7.
View Article and Find Full Text PDFThe present study was designed to determine the relationship between neurological testing, anatomical imaging, and electrophysiological monitoring for assessing outcome of cervical spinal cord decompression. We prospectively studied 28 consecutive patients (age 39-76 yr) who were subjected to presurgical-(1-3 wk) and postsurgical (3-4 mo) neurological examination and recording of the median nerve somatosensory evoked potential (SEP). In 13 patients, magnetic resonance imaging (MRI) was also performed.
View Article and Find Full Text PDFThis study was performed to determine whether variations in analgesic responses to intrathecal morphine could be explained by cerebrospinal fluid (CSF) concentrations of morphine metabolites. Twenty-four CSF samples were collected at the beginning, middle and end of treatment periods in seven cancer patients with pain of malignant origin. CSF concentrations of morphine-3,beta-glucuronide (M3G) and morphine-6,beta-glucuronide (M6G) metabolites were measured by gas chromatography/mass spectrometry.
View Article and Find Full Text PDFPrevious studies have shown that alteration of the dietary arginine-methionine balance by use of synthetic L-amino acids inhibits tumor growth of a subcutaneously transplanted Morris hepatoma at the expense of maintaining body weight. However, L-methionine is susceptible to degradation and, therefore, may contribute to a deficiency state. The present studies were performed to determine whether growth of subcutaneous hepatoma transplants is inhibited, and body growth maintained, when rats are fed diets containing L-methionine in replacement of N-acetyl-L-methionine (NALM) for 28 days.
View Article and Find Full Text PDFJ Clin Neurophysiol
January 1996
We evaluated the intraoperative utility of monitoring median nerve somatosensory evoked potentials (SEPs) in 31 consecutively hospitalized neurosurgical patients (mean age 55.3 +/- 2.1 years) who underwent spinal cord decompression for cervical herniated disc, spondylosis, or tumor.
View Article and Find Full Text PDFNeurotoxicology
January 1997
The caudal ventrolateral medulla (CVLM) is an area of the brainstem, in the vicinity of the hypoglossal nerve roots, where cholinergic and adrenergic neurons participate in respiratory and vasomotor control. Cardiorespiratory depression has been produced by topical application of cocaine to the CVLM. In the present studies, the effects of topical pretreatments of the CVLM with alpha-adrenergic blockers (prazosin 4.
View Article and Find Full Text PDFExperimental perfusions of isolated rat kidneys were performed with flow rates adjusted to produce comparable glomerular filtration rates (GFR) in control and experimental groups. The experimental perfusate, consisting of Krebs-Ringer bicarbonate (KRB) containing 3.5% (uncrosslinked) stroma-free hemoglobin (SFH) plus 3.
View Article and Find Full Text PDFThe current study was undertaken to evaluate the effects of cholinomimetic drugs on cocaine-induced central cardiorespiratory depression. Cats anesthetized by urethane (2.0 g/kg) were subjected to topical application at the caudal ventrolateral medullary surface (cVMS) of cocaine and two cholinomimetic pretreatment drugs.
View Article and Find Full Text PDFIn a timed study over 75 min, divided into 5 15-min periods, experimental perfusions of isolated rat kidneys using Krebs-Ringer bicarbonate (KRB) containing 3.5% (uncrosslinked) stroma-free hemoglobin (SFH) plus 3.5% of the perfluorochemical Fluosol-DA were found to excrete only 13% as much total hemoglobin (Hb) as control perfusions using KRB containing 7% SFH alone (controls).
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