Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Senegalese baboons (Papio papio), with a natural syndrome of photosensitive epilepsy, consistently show generalized myoclonic jerks if stimulated stroboscopically at hourly intervals, two to eight hours after the intravenous administration of allylglycine, 200 mg/kg. This provides a model for testing the acute antiepileptic effects of established or new drugs. The relationship between concentration of drug, antiepileptic action, and acute neurological toxic effects can be studied. Pnehobarbital (15 mg/kg) and diazepam (0;5 to 1.5 mg/kg) were highly effective in the absence of signs of toxic reaction (plasma levels: phenobarbital sodium, 0.7 to 1.7 mg/100 ml; diazepam, greater than 0.5 mug/ml). After administration of carbamazepine (30 to 40 mg/kg) and diphenylhydantoin sodium (40 to 50 mg/kg), antiepileptic action was seen, but was accompanied by severe toxic signs (nystagmus and ataxia). Sulthiame (20 to 125 mg/kg) and ethosuximide (50 to 100 mg/kg) had little antiepileptic activity and no acute toxic effects. This primate model may aid the identification of new drugs that are active against grand mal seizures and status epilepticus.
 ...
PMID:A primate model for testing anticonvulsant drugs. 23 98

Ten patients, suffering from affective disorders, were treated with carbamazepine for polyuria and polydipsia associated with long-term lithium therapy. Oral carbamazepine (300--600 mg daily for six weeks) was observed to have no beneficial effect in alleviating these symptoms when compared with placebo tablets in a double blind crossover study. Plasma and urinary osmolality were observed to be within normal range in these patients and there was no antidiuretic response following subcutaneous Pitressin injection. There was 50% drop-out due to severe side-effects like ataxia, dizziness, restlessness and confusional states. It appears that lithium exacerbates carbamazepine induced CNS side-effects or vice versa, the mechanism of which is not very clear. It may be due to their mutual effect on sodium metabolism or on nervous conduction velocity. Hence, simultaneous administration of these two drugs should preferably be avoided.
 ...
PMID:Effect of carbamazepine in polyuria associated with lithium therapy. 36 Feb 49

A family is described with three affected brothers, two of whom were examined, born to consanguineous parent, who in early adult life began to experience ataxia, intention myoclonus, and progressive visual failure. The brothers examined had cherry red spots at the maculae and cataracts. They were of normal intelligence. The intention myoclonus responded partially to treatment with clonazepam and pheneturide, but not to 5-hydroxytryptophan in combination with carbidopa or to sodium valproate. Studies in one patient showed the excretion of large quantities of sialylated oligosaccharides in the urine. Both patients showed deficient sialidase activity in their cultured fibroblasts. Further studies on cultured skin fibroblasts revealed increased electrophoretic mobility of six glycoprotein enzymes that was returned approximately to normal by treatment with sialidase. The clinical and biochemical findings indicate that these patients are further cases of the newly described condition sialidosis type 1.
 ...
PMID:Sialidosis type 1: cherry red spot-myoclonus syndrome with sialidase deficiency and altered electrophoretic mobilities of some enzymes known to be glycoproteins. 1. Clinical findings. 51 62

We have compared the sleep-producing effects of thalidomide and pentobarbital. In a dose range that did not produce ataxia, thalidomide increased slow wave sleep and rapid eye movement sleep in cats (2-8 mg/kg p.o.) and rats (16 mg/kg p.o.). Pentobarbital had hypnotic activity in the same dose range but produced ataxia also at these doses. Thalidomide reduced spontaneous activity of both mice and rats. This occurred over a dose range of 8 to 1000 mg/kg p.o., but plateaued at a level of activity well above the complete inactivity of anesthesia that occurred with pentobarbital at well above the complete inactivity of anesthesia that occurred with pentobarbital at doses (greater than or equal to 32 mg/kg p.o.) above the hypnotic range. Several simple screens for thalidomide-like activity have been described which, together, could facilitate the search for thalidomide-like hypnotics. Pentobarbital, at doses 3 to 10 times the hypnotic range, prevented audiogenic seizures in physically dependent rats withdrawn from sodium barbital but thalidomide did not substitute for barbiturates even at doses 30 times those that increased sleep. Thalidomide, but not pentobarbital, enhanced the sleep-producing effect of electrical stimulation of basal forebrain in cats. The latter two findings suggest that thalidomide probably has a mechanism of action different from that of pentobarbital and that this may involve the activation of a sleep center in the forebrain.
 ...
PMID:A comparison of thalidomide and pentobarbital - new methods for identifying novel hypnotic drugs. 56 42

The chromatographic separation and biochemical characterization of a beta-bungarotoxin is described. This toxin is isolated as the most basic eluting protein of Bungarus multicinctus venom when separated by column chromatography on CM-Sephadex C-25. The protein migrated as a single band on pH 4.3 and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The molecular weight of this toxin was estimated to be 10 000 +/- 1000 by analytical sedimentation analysis. This value was consistent with the electrophoretic mobility of the toxin in SDS-polyacrylamide gels. The amino acid composition of this 11 000-dalton beta-bungarotoxin was similar to that of the 22 000-dalton beta-bungarotoxin previously reported (Lee et al. (1972) J. Chromatogr. 72, 71--82; Kelly, R.B. and Brown, III, F.R. (1974) J. Neurobiol. 5, 135--150; Kondo et al. (1978) J. Biochem. Tokyo 83, 91--99), suggesting that the 11 000-dalton toxin may be one of the polypeptide chains of the larger toxin. The 11 000-dalton beta-bungarotoxin was toxic to mice when injected intravenously. Animals that received lethal doses exhibited hyperexcitability followed by ataxia, convulsions, and death. The minimum lethal dose was 0.12 microgram/g body weight. This beta-bungarotoxin exhibited Ca2+-dependent phospholipase A activity comparable to that of the 22 000-dalton beta-bungarotoxin. The enzyme exhibited phospholipid substrate specificity in the rank order of phosphatidyl-choline, phosphatidylserine, phosphatidylethanolamine, and phosphatidyl-inositol. The enzyme activity was destroyed by boiling for 3 min at pH 8.6. In addition, an enzymatically inactive quantity of the 11 000-dalton toxin, equivalent to five times the minimum lethal dose of enzymatically active toxin, was not lethal when injected into mice. To test whether phospholipase A activity is responsible for lethality, bee venom phospholipase A2 was injected into mice at similar and greater concentrations with no toxic effect. Thus, while phospholipase A activity may be required for the lethal effect of the 11 000-dalton beta-bungarotoxin, the specificity of action of the toxin is not determined by its enzyme activity.
 ...
PMID:Purification and biochemical characterization of an 11 000-dalton beta-bungarotoxin. 56

1 The effect of altering the ionic balance of the cerebrospinal fluid (CSF) on cloacal temperature of unanesthetized pigeons kept at room temperature (20-25 degrees C) was examined by injection or infusion of solutions of different ionic composition into a cannulated lateral cerebral ventricle. 2 An increase in the concentration of calcium ions caused a fall in temperature and behavioural sedation. The effects were the same whether the calcium was present as calcium chloride or as the calcium disodium salt of ethylenediamine tetra-acetic acid (CaNa2EDTA). 3 When the concentration of sodium ions in the CSF perfusate was increased by addition of NaCl or that of calcium ions was decreased by addition of Na2EDTA a rise in temperature was often produced but this was not consistent. NaCl sometimes had either no effect or lowered the temperature. Na2EDTA while producing a rise when first injected failed to do so when repeated a few hours, 24 h and often 72 h later. Prolonged infusion of either agent caused intense behavioural excitement leading to death. 4 Potassium ions, like sodium ions, caused a rise in temperature but only when infused continuously. Behavioural excitement was only rarely observed. 5 Magnesium produced a fall in temperature. The concentration required was much higher than that of calcium but the hypothermia was more prolonged suggesting a slower elimination of the magnesium ions from the CSF. Magnesium ions caused tremors, nystagmus and ataxia as opposed to sedation caused by calcium. 6 All these were central effects as they were not obtained when the substances were injected intravenously. 7 Since changes in body temperature of the pigeon produced by injection of calcium or sodium ions into the CSF were similar to those seen in various species of mammal, it is concluded that the relative concentration of these ions within the brain plays an important role in establishing the temperature setpoint in both birds and mammals.
 ...
PMID:Sodium and calcium ions in the control of temperature set-point in the pigeon. 81 41

In a double-blind crossover trial sodium valproate or placebo was added to the existing anticonvulsant treatment of 20 patients with chronic uncontrolled epilepsy. Sodium valproate 1200 mg/day significantly reduced the frequency of both tonic-clonic and minor seizures in these patients. Only mild and transient side effects occurred (drowsiness, ataxia, and nausea), and these may have been due to the effect of adding sodium valproate to existing phenobarbitone or phenytoin treatment. Further controlled trials are needed to assess more fully the efficacy of this drug in various types of epilepsy.
 ...
PMID:Controlled trial of sodium valproate in severe epilepsy. 110 59

The anticonvulsive properties of orally administered cinnarizine [(E)-1-(diphenylmethyl)-4-(3-phenyl-2-propenyl)-piperazine], its difluoro derivative flunarizine [(E)-1-(bis-(4-fluorophenyl)methyl)-4-(3-phenyl-2-propenyl)-piperazine], diphenylhydantoin and phenobarbital, were studied against maximal metrazol seizures (MMS) in rats and maximal electroshock seizures (MES) in mice. In rats (MMS), the lowest ED50 for protection against tonic extension of hindpaws was 4.10 mg/kg (1 h 35 min after treatment) with sodium phenobarbital, 6.04 mg/kg (5 h 45 min) with flunarizine dihydrochloride, 9.84 mg/kg (2 h 34 min) with cinnarizine and 19.30 mg/kg (3 h 38 min) with diphenylhydantoin. In mice (MES), protection against tonic extension of hindpaws was (2 h after treatment) 7.0 mg/kg with diphenylhydantoin, 13.2 mg/kg with sodium phenobarbital, 20.9 mg/kg with flunarizine kihydrochloride and 49.0 mg/kg with cinnarizine. Except at subtoxic doses no side effects were observed in rats and mice given cinnarizine, flunarizine kihydrochloride or kiphenylhydantoin. Phenobarbital induced ataxia in rats and mice at 22 mg/kg and 42.7 mg/kg, respectively, and loss of righting reflex at 112.8 mg/kg and 160 mg/kg, respectively. Flunarizine is the longest-acting drug and has the slowest onset. At a dose of twice the minimal ED50 flunarizine affords protection against tonic extension of hindpaws in rats (MMS) for 23 h 30 min dephenylhydantoin for 11 h 38 min, phenobarbital for 8 h 22 min and cinnarizine for 8 h 16 min. Peak effect was reached with flunarizine at 5 h 45 min, with diphenylhydantoin at 3 h 38 min, with cinnarizine at 2 h 34 min and with phenobarbital at 1 h 35 min. The anti-MMS profiles of cinnarizine and flunarizine resemble that of dephenylhydantoin as all three compounds are selective blockers of tonic extension of hindpaws. Phenobarbital antagonized the whole MMS-pattern, i.e., tremors, clonic convulsions and tonic extension of fore- and hindpaws. However, the effects of phenobarbital against tremors, clonic convulsions and tonic extension of forepaws may reflect more a general CNS-depressant effect than a specific anticonvulsive activity since neurotoxic effects (ataxia and loss of righting reflex) appear at the same doses.
 ...
PMID:Anticonvulsive properties of cinnarizine and flunarizine in rats and mice. 124 63

A 51-year-old woman was admitted to our hospital because of gait disturbance and dysuria. Neurological examination revealed limb and truncal ataxia, orthostatic hypotension, cogwheel rigidity in all limbs, generalized hyperreflexia without pathological reflex, and horizontal gaze nystagmus. She became progressively worse and bedridden at age 52. Then she developed abnormal eye movements. Electrooculogram revealed vertical, horizontal or oblique macro square wave jerks and pendular nystagmus. Macro square wave jerks appeared during fixation and disappeared with eye closure or in the dark room. Macro square wave jerks were characterized by a duration of about 200 msec and an amplitude of 10 to 15 degrees. Pendular nystagmus with a duration of several seconds and amplitude of 5 to 15 degrees appeared when she changed her fixation or the point of fixation disappeared. Macro square wave jerks and pendular nystagmus were mildly suppressed after the intramuscular injection of 100 mg of phenobarbital, the oral intake of sodium valproate of 600 mg/day or baclofen of 60 mg/day. They were almost completely depressed after the intravenous injection of 3 mg of diazepam or the oral intake of clonazepam of 1.5 mg/day. We suggested that both macro square wave jerks and pendular nystagmus in this patient might be caused by the dysfunction of GABAergic system in the saccadic eye movement system.
 ...
PMID:[Multiple system atrophy with macro square wave jerks and pendular nystagmus]. 130 29

Ralitoline, a thiazolidinone derivative chemically distinct from known antiepileptic drugs, possesses remarkable anticonvulsant properties as demonstrated in various animal models of epilepsy. The efficacy of this compound seems to be comparable or even better than that of conventional antiepileptics. In the present study, the activity of ralitoline was investigated in four seizure models in rodents in order to characterize the anticonvulsant profile of action further. In the maximal electroshock seizure test (mice), this compound showed marked anticonvulsant effects (ED50 2.8 mg/kg i.p.). The efficacy of clinically established anti-epileptics was significantly increased when ralitoline was given as co-medication. In the strychnine seizure test (mice), ralitoline (5 and 10 mg/kg) prolonged the latency of tonic seizures as well as the survival time. On the other hand, in the subcutaneous pentylenetetrazol seizure threshold test (mice), this drug revealed limited protective actions at higher doses and increased the effectiveness of ethosuximide. In unrestrained rats with chronically implanted electrodes, ralitoline (5 mg/kg) significantly reduced the duration of electrically-evoked hippocampal discharges and raised the focal stimulation threshold (10 mg/kg). In the rotorod ataxia test (mice), a TD50 value of 14.5 mg/kg i.p. was determined for ralitoline (protective index TD50/MES-ED50 5.2). With regard to the possible mode of action, whole-cell voltage-clamp experiments on cultured neonatal rat cardiomyocytes showed that ralitoline may act specifically on voltage-sensitive sodium channels. The compound inhibited the fast sodium inward current in a frequency- and voltage-dependent manner. In conclusion, the findings confirm the potent anticonvulsant effects of ralitoline, especially against generalized tonic-clonic and complex partial seizures. Moreover, in combination with antiepileptics, an additive synergism can be found at lower concentrations. Regarding the mode of action, this drug was capable of depressing the fast sodium inward current in cultured heart ventricular cells, suggesting that the local anesthetic properties may be important for the anticonvulsant activity of ralitoline.
 ...
PMID:Anticonvulsant and sodium channel blocking effects of ralitoline in different screening models. 133 17


1 2 3 4 5 6 7 8 9 10 Next >>