Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The airway of the young infant is anatomically vulnerable at the oropharyngeal level between the soft palate and the base of the skull. Airway occlusion at this level might occur during the muscle relaxation which occurs during REM sleep, facilitated by a hypermobile mandible, by the hypotonia of infection, perhaps by an enlarged tongue with a strong backwards sucking action which might be the result of the artificial feeding of the infant. It is possible that "cot deaths" (SIDS) may be precipitated by such oropharyngeal airway occlusion, cardiac arrest following variable periods of partial or complete oxygen deprivation.
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PMID:Sudden infant death syndrome: hypothesis of causation. 16 52

Neurophysiological studies were performed on 8 patients with group A xeroderma pigmentosum during early childhood. EEG, ABR and NCV were normal during this period. In contrast, various sleep parameters detected by polysomnography showed abnormal findings even in the neurologically normal patient. Decreased % sleep REM was seen in a case, and decreased frequency of REMs were seen in another. Body movements were extremely high or low in frequency in 3 cases in whole night sleep. The distribution of body movements were abnormal; in control subjects, the frequency was higher in SREM and stage 1 than in slow wave sleep; in 7 cases, it was higher in slow wave sleep than in stage 1 or 2, or body movements were extremely frequent. Neurological examination revealed soft signs in various systems in early childhood. All cases except one showed hypotonia. Many cases were slow in learning to walk and the gait was unstable. Speech delay and decreased deep tendon reflexes, especially of patella, were seen in most cases. Since the neural deficits in XP may be related to the DNA repair defect, these findings indicate the possibility that some endogenous compounds distributing all over the nervous system might produce the DNA damages. Because the body movements during sleep are controlled by the nigrostriatal dopaminergic system, present data indicate that the basal ganglia might be one of the earliest degenerative systems in the CNS. Recently, some studies have suggested the possibility that oxygen radical mechanisms might be involved in the development of the dopamine neurodegenerative process in Parkinson's disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Neurophysiological studies on group A xeroderma pigmentosum in early childhood]. 217 31

We presented a 3-year-old boy, a product of consanguineous parents, with periodic apnea during waking and sleep states, severe psychomotor retardation and hypotonia. According to polysomnographical recordings, he exhibited frequent central apneas which decreased in frequency and regularity in the stage REM. He showed abnormal background EEG, undifferentiated sleep stage and very short duration of stage REM. The initiation of breathing after apnea was often accompanied with generalized muscles contraction like a startle response. In the waking state the apnea induced generalized muscular hypotonicity and the decline of wakefulness. Arterial CO2 and O2 saturation was within normal limits. It was suggested that the malfunction of the brain stem responsible for the control of breathing, sleep-wakefulness cycle and determination of sleep stages was closely connected with the pathogenesis of abnormal breathing patterns.
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PMID:[A case of three-year-old boy with periodic apnea during waking and sleep, severe psychomotor retardation and hypotonia]. 240 Jun 15

An all-night polygraphic study of sleep was carried out in 6 healthy volunteers acutely medicated with clonidine (225 micrograms), yohimbine (15 mg), a combination of both drugs or with placebo at random order under simple blind conditions. The conventional scoring of sleep stages was extended by an on-line analysis of the EEG according to Hjorth. Clonidine, an agonist at alpha2 receptors, induced increases of the stages 2 and 3 + 4 but a decrease of REM sleep; the reduction of the parameters mobility and complexity during non-REM sleep signified synchronization of the EEG. Yohimbine, an antagonist at the same receptor sites, enhancing noradrenaline release, increased stage 1 and REM sleep, but decreased the stages 2 and 3 + 4; increases of mobility during REM and non-REM sleep signified desynchronization. The combined treatment with clonidine + yohimbine reduced REM sleep, but not as extensively as clonidine alone; the Hjorth parameters were without significant alterations compared to placebo. The physiological hypotonia was enhanced by clonidine and the combined treatment with clonidine + yohimbine. These results favour the hypothesis of a noradrenergic facilitation of REM sleep.
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PMID:Effect of clonidine and yohimbine on sleep in man: polygraphic study and EEG analysis by normalized slope descriptors. 240 46

Snoring usually is trivial and unimportant, but it can turn into a social or medical problem. Obesity, hypertension and heart disease are more frequent among snorers than among nonsnorers, and especially snorers with hypersomnia during the day are at risk. Hypersomnia in association with snoring usually signifies obstructive sleep apnea. Increased resistance in the upper airways, together with negative inspiratory pharyngeal pressure and muscular hypotonia during deep non-REM and REM sleep, lead to collapse of the pharynx, hypoxia and hypercapnia. Only after arousal from sleep does muscle tone return, pharyngeal obstruction reopen and airflow resume. Since this process can occur 300 or 400 times a night, repetitive alveolar hypoventilation leads to pulmonary-arterial hypertension and cor pulmonale, and the repetitive sympathetic activations can cause systemic hypertension or serious cardiac arrhythmias. The countless arousals deprive the sufferer of deep non-REM and REM sleep and their consequence is sleep fragmentation. The symptoms are excessive daytime sleepiness, intellectual deterioration and personality and behavioral changes. Oronasomaxillofacial, endocrine and neuromuscular anomalies and diseases predispose to sleep apnea, and alcohol or CNS-depressant drugs can favour its occurrence. Diagnosis is made by nighttime oxymetry, and if this is abnormal, by polysomnography. After polysomnography it is possible to distinguish between obstructive and nonobstructive sleep apnea, and the decisions for an adequate treatment can be made.
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PMID:[Dangerous snoring. Sleep-apnea syndrome]. 331 92

We report 11 patients with the locked in syndrome (LIS). The functional outcome was good in four patients with notable motor recovery, but motor deficit remained seriously disturbed in seven patients. All of the patients regained some distal control of finger and toe movements, often allowing functional use of a digital switch. The independence thereby gained is worthwhile, in some patients allowing environment control, communication by means of a computer, and electric wheelchair ambulation. When motor recovery occurs, the progression is disto-proximal with dramatic axial hypotonia. In five patients clinical insomnia was noted and polysomnography showed a reduction of REM sleep. The implications of systems other than the pyramidal tracts in the physiopathology of LIS are discussed.
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PMID:Persistence of distal motor control in the locked in syndrome. Review of 11 patients. 858 98

Some aspects of the evolution of mechanisms for enhancement and maintenance of synaptic efficacy are treated. After the origin of use-dependent synaptic plasticity, frequent synaptic activation (dynamic stabilization, DS) probably prolonged transient efficacy enhancements induced by single activations. In many "primitive" invertebrates inhabiting essentially unvarying aqueous environments, DS of synapses occurs primarily in the course of frequent functional use. In advanced locomoting ectotherms encountering highly varied environments, DS is thought to occur both through frequent functional use and by spontaneous "non-utilitarian" activations that occur primarily during rest. Non-utilitarian activations are induced by endogenous oscillatory neuronal activity, the need for which might have been one of the sources of selective pressure for the evolution of neurons with oscillatory firing capacities. As non-sleeping animals evolved increasingly complex brains, ever greater amounts of circuitry encoding inherited and experiential information (memories) required maintenance. The selective pressure for the evolution of sleep may have been the need to depress perception and processing of sensory inputs to minimize interference with DS of this circuitry. As the higher body temperatures and metabolic rates of endothermy evolved, mere skeletal muscle hypotonia evidently did not suffice to prevent sleep-disrupting skeletal muscle contractions during DS of motor circuitry. Selection against sleep disruption may have led to the evolution of further decreases in muscle tone, paralleling the increase in metabolic rate, and culminating in the postural atonia of REM (rapid eye movement) sleep. Phasic variations in heart and respiratory rates during REM sleep may result from superposition of activations accomplishing non-utilitarian DS of redundant and modulatory motor circuitry on the rhythmic autonomic control mechanisms. Accompanying non-utilitarian DS of circuitry during sleep, authentic and variously modified information encoded in the circuitry achieves the level of unconscious awareness as dreams and other sleep mentation.
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PMID:Memory, sleep, and dynamic stabilization of neural circuitry: evolutionary perspectives. 881 18

The respiratory dysfunction in Duchenne muscular dystrophy (DMD) patients increases with age. We have attempted various methods of artificial respiration for them. Recently, a non-invasive positive pressure ventilation (NIPPV) became the first choice of respiration, but the chest respirator (CR) was still one of the choices. In our hospital, DMD patients with tracheostomy wearing a CR were alive for longer period, despite of respiratory dysfunction and complications. We studied 6 DMD patients with CR to evaluate nocturnal hypoxia index (NHI) by examining nocturnal periodic hypoxia, and measured oxygen saturation after 20 mg of clomipramine hydrochloride administration before sleep. Three patients had periodic nocturnal hypoxia which was prevented by the clomipramine administration. Two patients with tracheostomy did not exhibit hypoxia. We speculated that pharyngeal hypotonia during REM sleep induces periodic nocturnal hypoxia, therefore the tracheostomy would prevent hypoxia. Next, we examined the pharyngeal MRI on one DMD patient at the same disease stage who also had night NIPPV. We found that his soft palate and tongue shifted downward, which narrowed his pharynx during REM sleep. Consequently we have concluded that noctunnal periodic hypoxia is mainly caured by obstructive sleep apnea. For DMD patients with CR, the tracheostomy may be effective to prevent hypoxia during sleep.
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PMID:[The usefulness of tracheostomy in Duchenne muscular dystrophy ventilated by a chest respirator]. 1050 82

During REM sleep, a powerful postsynaptic inhibition of spinal motoneurons induces a generalized muscle hypotonia. Despite this inhibition, it has been shown that by transcranial magnetic stimulation of the brain (TMS), muscle responses of normal amplitude can be evoked in small hand muscles of humans. Tonic innervation during sleep is different in postural vs. limb muscles, and the spinal inhibition differs during tonic vs. phasic REM episodes, Both phenomena may affect muscle responses to TMS. In this study, muscle responses of 14 healthy subjects were compared to TMS in abductor digiti minimi, lumbar erector spinae, trapezius, and diaphragm during phasic and tonic REM sleep. In all four muscles, the amplitudes of the muscle responses were extremely variable, ranging for example in trapezius from -100% to +473% as compared to wakefulness. There was no systematic difference between the muscles. Moreover, no differences were found for TMS during phasic REM events compared to tonic REM sleep. Thus, responses to TMS during REM sleep may be preserved, with a decreased or increased amplitude. As a likely explanation, the cortical excitability and/or the spinal inhibition fluctuates during REM sleep in humans.
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PMID:Magnetic stimulation of the human brain during phasic and tonic REM sleep: recordings from distal and proximal muscles. 1060 43

Assessment of the development of motor function of Rett syndrome (RTT) revealed hypotonia with failure of crawling and disturbance in skillful hand manipulation are shown as early motor signs. Clinical evaluation has revealed the former as postural hypotonia with failure in locomotion and neurophysiological examinations have showed this to be due to hypofunction of the aminergic neurons of the brainstem. The latter signs are considered to indicate dysfunction of the corticospinal tract at higher levels. As the signs appear along with deceleration of head growth, dysfunction of the noradrenergic neuron, which is involved in synaptogenesis in the cerebral cortex, is postulated as the cause. The characteristic stereotyped hand movements appear in early childhood after loss of purposeful hand use and are underlain by rigid hypertonus. Neurophysiological examinations have indicated that these are due to hypofunction of the nigrostriatal (NS) dopamine (DA) neuron. By comparison with animal experimental work the neurohistochemical changes in the substantia nigra of the autopsied brain of RTT suggest a lesion caused by the dysfunction of the pedunculopontine nucleus, induced by dysfunction of the brainstem aminergic neurons which modulate postural tone and locomotion. Hypofunction of the aminergic neurons also cause 'leakage' of atonia into non-REM stages which lead to disturbances in the autonomic nervous system through inhibition of the reflex system. The grade of disturbance of locomotion closely matches the grade in abnormalities of higher cortical function as indicated by the development of meaningful words. The loci of missense mutation of methyl CPG binding domain of MECP 2gene which affect locomotion severely also markedly impaired their effects on the formation of the heterochromatin. Thus, dysfunction of the aminergic neurons of the brainstem which regulate postural tone and locomotion is proposed as the primary lesion.
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PMID:Early motor disturbances in Rett syndrome and its pathophysiological importance. 1618 86


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