Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030552 (paresis)
 5,831 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four patients without symptoms of episodic hyperkalemic weakness from two families with paramyotonia congenita (Eulenburg) are described. 1. Maximum voluntary muscle contraction of the upper and lower arm was studied under isometric conditions at different temperatures. If the temperature was lowered stepwise, distinct paresis occured at 32--31 degrees C which increased with the amount of muscular effort. The upper arm muscles, however, developed weakness gradually after cooling. 2. During cooling of the resting muscle, the EMG showed dense spontaneous activity of the fibrillary type, which decreased again at about 30 degrees C. It can be assumed that in paramyotonia congenita cooling produces muscle cell membrane depolarization which at a critical level causes the firing of action potentials and finally muscular paresis. 3. Increasing muscular stiffness can be interpreted as abnormally slow muscular relaxation after isometric contraction. In the forearm muscles the time to 3/4 relaxation after cooling was about six times normal, in the upper arm muscles only two times normal. As an additional parameter the mechanical resistance to passive stretching of a muscle has been studied. This passive muscular tension increased simultaneously with the onset of weakness. 4. The close relation between weakness and stiffness suggest that both symptoms are caused by the same basic defect which is probably located in the sarcolemma. It is suggested that a defect of the sodium channel causes a cooling-dependent increase in sodium conductance. Raised intracellular sodium causes in the first place membrane depolarization, and in the second place depression of calcium reuptake through competition by sodium for calcium binding sites. This would explain muscle stiffness and delayed relaxation as well.
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PMID:Influence of temperature on isometric contraction and passive muscular tension in paramyotonia congenita (Eulenburg). 9 68

Fomocaine (CAS 56583-43-8) is a basic ether-type local anaesthetic used in dermatological practice for surface anaesthesia. For many years, modifications of the fomocaine molecule have been pursued, e.g. to improve its affinity to the sodium channel and also in view of possible new (systemic) applications. In the present study fomocaine and eight fomocaine derivatives with an additional alkyl chain in 2- or 3-position of different length (C1 up to C4), or with a branched C3 chain in 3-position, respectively, at the morpholine ring were evaluated in vitro for possible structure-activity relationships with respect to the interactions with cytochrome P450 (CYP) mediated monooxygenase and oxidase functions using rat liver 9000 g supernatants or microsomes. Results were compared to in vivo data from rats on toxicity (LD50), paresis of the N. ischiadicus and surface and conduction anaesthesia (cornea, N. ischiadicus). In general, the influence of the derivatives on the CYP system was less than that of fomocaine, showing a further decline with enlarging chain length. Toxicity of the derivatives was comparable to that of fomocaine and lower only with the compound with a C4 alkyl chain in 2-position. The derivatives caused a stronger surface anaesthesia than fomocaine, exhibiting an additional increase with enlarging chain length. No clear-cut structure-activity relationships were observed with respect to paresis of the N. ischiadicus and to conduction anaesthesia. Especially the derivatives having a C2 or C4 chain in 2- or a C3 chain in 3-position, respectively, may be of interest for further investigations. In comparison to fomocaine they caused a stronger surface anaesthesia combined with a lower interaction capacity with the CYP system.
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PMID:In vitro interactions with the Cytochrome P450 system, toxicity, and local anaesthetic effects of Fomocaine Alkylmorpholine derivatives in rats. 1647 99

Paramyotonia congenita (PC), first described in 1886 by Eulenberg, is characterized by cold and exercise-induced muscle stiffness and intermittent flaccid paresis not necessarily related to cold or myotonia. Several authors segregated a pure form of PC, which has no periodic paralysis, even after cold exposure. The existence of this phenotype has been debated in the literature. We describe electrophysiological and molecular genetic features of a patient with PC who had no history of periodic paralysis. Immersion in cold water or potassium load could not induce clinical paralysis. However, repetitive nerve stimulation and exercise test demonstrated a drop in compound muscle action potential amplitude. Genetic analysis revealed the substitution of valine for glycine on the human skeletal muscle sodium channel (SCN4A) gene. The G1306V mutation is rare in the classic form of PC, and moreover might be the first in pure paramyotonia.
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PMID:A case of paramyotonia congenita without periodic paralysis: electrophysiological and molecular genetic studies. 2044 32

Mutations of the skeletal muscle voltage-gated sodium channel (NaV1.4) are an established cause of several clinically distinct forms of periodic paralysis and myotonia. Focal paresis has sometimes already been described. We report a case with atypical clinical manifestation comprising paramyotonia and cold-induced persistent and focal paralysis. A 27-year-old woman presented with paramyotonia congenita since her childhood. She experienced during her childhood one brief episode of generalised weakness. At the age of 27, she experienced a focal paresis lasting for several months. The known mutation p.Val1293Ile was found in the muscle sodium channel gene (SCN4A). Channel inactivation is involved in most Na(+) channelopathies. Fast inactivation is known to be responsible for the myotonia phenotype. We hypothesise that the V1293I mutation may also alter the slow inactivation in specific conditions, for example, prolonged cold exposure or prolonged and intensive exercise. This observation broadens the spectrum of clinical manifestations of this sodium channel mutation.
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PMID:Focal and abnormally persistent paralysis associated with congenital paramyotonia. 2493 54