Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bilateral microinjections into the cerebellar flocculus of the rabbit of carbachol, a general cholinergic agonist, profoundly affect vestibuloocular (VOR) and optokinetic (OKR) reflexes. For sinusoidal stimuli (0.15 Hz, 5 deg peak to peak), the gain of the OKR was strongly increased, while the gain of the VOR was moderately increased. These effects were partially mimicked by floccular injection of the acetylcholinesterase inhibitor eserine. Floccular injection of the muscarinic blocker atropine significantly lowered the gain of the OKR. The effects of the nicotinic blocker mecamylamine were not significant. Optokinetic nystagmus (OKN) in response to constant stimulus velocities (1-30 deg/second) showed a markedly accelerated buildup and a shortened optokinetic after-nystagmus (OKAN) after floccular injections of carbachol. The steady-state gain of OKN remained unaffected. None of the described effects occurred after floccular injection of the solvent, saline. It is postulated that cholinergic cerebellar afferents, one probable source of which are the vestibular nuclei, enhance the optokinetic and vestibular modulation of floccular Purkinje cells.
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PMID:Enhancement of optokinetic and vestibuloocular responses in the rabbit by cholinergic stimulation of the flocculus. 159 69

Upbeat nystagmus is a vertical jerk nystagmus present in the primary position with a fast upward phase. It is to be distinguished from gaze-evoked upbeating nystagmus which is not present in the primary position, but is elicited only on upgaze. Drug toxicity commonly causes gaze-evoked upbeating nystagmus but rarely primary position upbeat nystagmus. A 21-month-old white girl swallowed Dermaton, an organophosphate pesticide, and developed primary position upbeat nystagmus, RBC and plasma cholinesterase levels were markedly depressed, confirming organophosphate poisoning. When the youngster was treated with intravenous atropine, the nystagmus quickly resolved.
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PMID:Primary position upbeat nystagmus with organophosphate poisoning. 715 25

A pathway from the pretectal region to the dorsal division of the lateral geniculate body has been studied by autoradiography in adult cats following injection of tritium-labeled amino acids into the meso-diencephalic border zone. The findings suggest that the pretecto-geniculate connection arises in the ipsilateral nucleus of the optic tract (NOT) and terminates in the principle dorsal layers of the geniculate body (A and A1), in lamina C and most massively in the medial interlaminar nucleus. In the A layers and lamina C, the pretectal fibers from a relatively even matting with partial interruptions occurring at the interlaminar leaflets. The ventral C layers do not appear to receive a substantial pretectal input as they were only weakly labeled, and partly in a perforant fiber pattern, after injections confined to the pretectum. Topographic ordering of the projection was evident at least along the medial to lateral axis of the NOT, fibers from the medial part terminating caudally, and those from the lateral part rostrally, within the lateral geniculate complex. The laminar pattern of termination correlates closely with the distribution of retinal Y-cell input and acetylcholinesterase activity in the geniculate body but contrasts sharply with the pattern of termination of tecto-geniculate fibers. Of potential importance in considering the functional significance of the pretecto-geniculate pathway is the fact that the NOT has been implicated in the mechanism of optokinetic nystagmus and the fact that the pathway terminates within the layers of the lateral geniculate body known to provide the main geniculo-cortical input to layer IV of the striate cortex.
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PMID:Autoradiographic evidence for a projection from the pretectal nucleus of the optic tract to the dorsal lateral geniculate complex in the cat. 739 90

A 42-year-old housewife with myasthenia gravis (MG) for 22 years, who was initially treated by radiation to the hyperplastic thymus and anti-cholinesterase therapy, developed bilateral ptosis, paresthesia of her right face and decreased taste sensation after house work at the age of 42 years. Neurological examinations revealed lateral and vertical gaze palsy, upward nystagmus, decreased taste sensation, peripheral facial palsy on the left side. She also had hypalgesia on the right face, arm and chest up to Th7 level, and urinary retention. She had hyperreflexia on the right side but no extensor toe signs. CSF study revealed 5 cells/microliters and protein of 23 mg/dl. Serum IgG anticardiolipin antibody was positive. Magnetic resonance imaging studies revealed high intensity areas in the brainstem tegmentum and periventricular white matter. Diagnosis of multiple sclerosis (MS) was made. This is the first case in which MG, MS and serum anticardiolipin antibody were present simultaneously, which may be all due to some immunological abnormality. Steroid therapy made anti-cardiolipin antibody negative, but new MS plaque developed in 7 months, which favors diagnosis of MS rather than infarction, since the activities of ACLA were not correlating to clinical symptoms. MRI was helpful in detecting MS plaques in MG patients.
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PMID:[A case of myasthenia gravis associated with multiple sclerosis and positive anticardiolipin antibodies]. 836 70

Ocular symptoms of 17 myasthenia gravis (MG) patients were examined by electronystagmographic registration of optokinetic nystagmus. The aim of this study was to replace the subjective methods used previously with a more reliable quantitative technique and thus assess ophthalmoplegia and diplopia, important initial symptoms in MG. Slow phase angular speed values of foveolar type optokinetic nystagmus in the horizontal plane at 10, 20 and 30 degrees/s target speed were determined. Measurements were performed before and after administration of Mestinon, a reversible cholinesterase inhibitor. Twelve healthy volunteers were examined as controls under standard conditions. Results showed significant differences between MG patients and control group. Slow-phase angular speed was significantly larger after Mestinon administration (p < 0.001). It is concluded, that the exhaustion of external ocular muscles in MG can be well characterized by the determination of the slow phase angular speed values of optokinetic nystagmus (OKN). The examination of OKN was also recommended for the evaluation of ocular symptoms in other neurological disorders.
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PMID:Electronystagmographic analysis of optokinetic nystagmus for the evaluation of ocular symptoms in myasthenia gravis. 1058 93

Optokinetic nystagmus (OKN) eye movements of myasthenia gravis (MG) and nonmyasthenic ocular palsies, and normal subjects were examined under closed-loop and open-loop conditions. The open-loop OKN condition was achieved by adding the signal of eye-movement velocity of OKN to the computer-generated signal controlling the stimulus grating moving. The OKN was recorded by means of electromagnetic search scleral coil technique. In MG patients, the open-loop gains of OKN increased significantly after the intramuscular injection of an acetylcholinesterase inhibitor, neostigmine, while the closed-loop OKN gains were not significantly changed. Both the closed-loop and open-loop OKN gains of normal subjects and nonmyasthenic patients were not increased for the administration of neostigmine. The experimental results indicated that the open-loop OKN gain could be sensitive to reflect the changes of the function of neuromuscular junction in MG patients.
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PMID:Open-loop and closed-loop optokinetic nystagmus (OKN) in myasthenia gravis and nonmyasthenic subjects. 1103 Oct 92

We describe a 52-year-old man with a history of increasing fatigability and gait disturbances that were first attributed to hypothyroidism. On examination, he had bilateral pseudo-internuclear ophthalmoplegia with weakness of adduction and abducting nystagmus. Convergence was also impaired and he showed proximal weakness of the limb. Intravenous edrophonium almost completely abolished the nystagmus and adducting muscle weakness, and improved the strength of proximal muscles groups. The clinical response to the administration of edrophonium, the presence of AChR binding antibodes and the repetitive nerve stimulation test findings indicated that the patient had pseudo-internuclear ophthalmoplegia as a manifestation of generalized myasthenia gravis. Whereas hypothyroidism was effectively controlled with levothyroxine, his subsequent response to thymectomy, prednisolone and cholinesterase inhibitors confirmed the diagnosis of generalized myasthenia gravis.
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PMID:Pseudo-internuclear ophthalmoplegia as a sign of overlapping myasthenia gravis in a patient with 'intractable' hypothyroidism. 2004 5