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Biomedical subjects

S Fahn

Publications and source records attributed to S Fahn.

At least 271 records · Page 15Linked to original sources
PubMed1986

Dyskinesias while awake and periodic movements in sleep in restless legs syndrome: treatment with opioids.

In five unrelated patients with the restless legs syndrome, opioid drugs relieved restlessness, dysesthesias, dyskinesias while awake, periodic movements of sleep, and sleep disturbances. When naloxone was given parenterally to two treated patients, the signs and symptoms of the restless legs syndrome reappeared. Naloxone placebo had no effect. Opioid medications may offer a useful therapy for the restless legs syndrome. The endogenous opiate system may be involved in the pathogenesis of the syndrome.

Drug Evaluation↗
PubMed1986

Torsion dystonia: a double-blind, prospective trial of high-dosage trihexyphenidyl.

We studied trihexyphenidyl in the treatment of torsion dystonia in a prospective, double-blind crossover protocol. Thirty-one patients completed the protocol. Twenty-two (71%) had a clinically significant response. After a mean follow-up of 2.4 years, 68% of patients continued to take trihexyphenidyl, and 42% continued to show a considerable or dramatic benefit. The 30-mg dose used was generally well tolerated. High-dosage trihexyphenidyl therapy is effective in the management of torsion dystonia.

Adolescent↗
PubMed1986

Spontaneous remissions in spasmodic torticollis.

We reviewed the frequency of spontaneous remissions in spasmodic torticollis (ST). One hundred sixteen patients with idiopathic ST (72 F, 44 M) were examined. The age at onset ranged from 9 to 69 (mean, 38.1 +/- 1.3). Twenty-one patients (18%) were Jewish. Eleven patients (9%) had a history of familial dystonia. Remissions longer than 1 year unrelated to treatment were observed in 14 patients (12%) (9 F, 5 M). They occurred in the first year of ST in 13 patients (93%) and in the eighth year in 1. Duration of remissions ranged from 1 to 20 years (mean, 6.5 +/- 1.6). Two patients had three remissions, and another had two. The mean age at the onset of ST in patients with remission was 26.4 +/- 3.3 (SEM) and ranged from 9 to 49. The age at the onset in the patients without remissions was 39.7 +/- 1.4, ranging from 10 to 69 (p less than 0.01). In the remission group, 3 patients were Jewish (21%); in the non-remission group, 18 (18%) were Jewish. There was a familial history in 1 case with remission (7%) and in 10 cases (10%) without remission. Spontaneous remissions in the course of ST seem to be more frequent in patients with early onset, and they occur usually during the first year.

Adolescent↗
PubMed1986

Clonazepam-induced up-regulation of serotonin1 and serotonin2 binding sites in rat frontal cortex.

Chronic administration of the benzodiazepine clonazepam increased the number of [3H]5-HT (5-HT1) and [3H]SPIP (5-HT2) binding sites in rat frontal cortex. In each instance, binding changes reflected increases in the maximum densities of binding sites (Bmax) with no change in ligand affinities (KD). Increases in binding required continued clonazepam exposure (10 days) at high doses. [3H]5-HT binding was significantly elevated at daily dose levels (i.p.) of 5.0 mg/kg but not 2.5 mg/kg. [3H]SPIP binding was significantly increased at drug doses of 2.5 mg/kg but not 1.0 mg/kg. Binding changes were regional in that they occurred in membranes from frontal cortex but not brainstem. A second benzodiazepine, diazepam, did not affect either binding site at daily doses of 30 mg/kg. These data suggest that serotonin receptor changes seen after chronic clonazepam may occur as a compensatory response to decreases in the presynaptic release of serotonin.

Animals↗
PubMed1986

Essential myoclonus.

The clinical characteristics of 15 patients with essential myoclonus are evaluated. The course of illness was one of initial worsening followed by a stable or improved state. Only two patients had positive family histories of involuntary movements. Nine patients had segmental distribution despite a careful search for etiology; in two of these patients, myoclonus was rhythmic. The trunk and proximal limbs were the most frequently affected body regions. Clonazepam improved myoclonus in 10 of 13 patients, two of whom had complete resolution of symptoms. On review of the salient features of the myoclonus, we discerned four phenomenological subcategories: (a) oscillatory myoclonus, (b) rhythmic segmental myoclonus, (c) nonrhythmic segmental myoclonus, and (d) nonrhythmic multifocal myoclonus.

Adolescent↗
PubMed1986

Biotin-responsive encephalopathy with myoclonus, ataxia, and seizures.

Prominent neurological abnormalities, including myoclonus, seizures, ataxia, and hearing loss, have been noted in juvenile-onset biotin-responsive MCD. The underlying defect in many of these patients, who generally present in the first year of life, appears to be a deficiency of biotinidase. We have presented a young woman with adult-onset myoclonus, ataxia, hearing loss, seizures, hemianopia, and hemiparesis who responded to pharmacologic dosages of biotin. Although she displayed many of the clinical and biochemical features of juvenile-onset MCD, she did not have a biotinidase deficiency, and the underlying defect remains to be determined. Because of her response to biotin, we have advocated that other patients with unexplained myoclonus syndromes be evaluated for biotin-dependent carboxylase deficiencies and undergo a therapeutic trial with biotin.

Adult↗
PubMed1986

Dominantly inherited restless legs with myoclonus and periodic movements of sleep: a syndrome related to the endogenous opiates?

The restless legs syndrome is a sensory and motor disorder of evening, repose, and sleep. The cardinal features include (a) restlessness, which is frequently associated with (b) dysesthesias, (c) myoclonic jerks and other dyskinesias while awake, (d) periodic movements of sleep, and (e) sleep disturbances. We have recently had the opportunity to study two patients severely affected by this syndrome whose family histories are consistent with dominant inheritance. Both patients serendipitously discovered that their symptoms responded uniquely well to opiate medication. Both patients were studied extensively with electrophysiological and videotape monitoring, and their movements were characterized. In both patients, all elements of the syndrome responded to opiates, with marked relief of symptoms and without any significant side effects. The specific opiate antagonist naloxone blocked the therapeutic benefit of the opiates. Our findings support the involvement of the endogenous opiate system in the pathogenesis of restless legs and related dyskinesias and suggest that opiate therapy may be a potentially valuable treatment for this sometimes disabling syndrome.

Aged↗
PubMed1985

The effect of selective lesions on vestibular nuclear complex choline acetyltransferase activity in the rat.

Biochemical, physiological and behavioral evidence suggests that acetylcholine (ACh) may play a neurotransmitter role in central vestibular function. However, the anatomic basis for a possible cholinergic influence on the vestibular nuclear complex (VNC) is unknown. To investigate vestibular cholinergic anatomy, we have made selective lesions of neurons intrinsic to the VNC, and of most known afferents to the VNC, and we have measured the activity of choline acetyltransferase (ChAT), a specific marker for cholinergic neurons, following such lesions. We found that a kainic acid lesion of the VNC, and lesions of vestibular afferents, including the VIIth cranial nerve, cerebellum, spinal cord, vestibular commissure and the interstitial nucleus of Cajal, did not affect VNC ChAT activity. We conclude that there are no cholinergic neurons intrinsic to the VNC, and that these lesioned afferents are not cholinergic. It is likely, therefore, that a cholinergic projection to the VNC arises from a region other than those lesioned; possibilities include the nuclei of the reticular formation, the upper cervical cord and local pontomedullary nuclei.

Animals↗
PubMed1985

The effects of chronic bromocriptine treatment on behaviour and dopamine receptor binding in the rat striatum.

Agonist-induced rotation and striatal binding of [3H]spiperone ([3H]SPIP) were assessed in rats with unilateral lesions of the substantia nigra during and after a period of chronic bromocriptine administration. Agonist-induced rotation significantly increased over a three week period of daily administration of bromocriptine (10 mg/kg i.p.); control animals were tested for agonist-induced rotation at one week intervals, which remained constant. Rotation was increased by chronic bromocriptine administration in response to either of two DA agonists, apomorphine (APO) and bromocriptine, suggesting that increased agonist sensitivity did not reflect a reduction in the metabolism of bromocriptine. Striatal binding of the dopamine D2 radioligand, [3H]SPIP, was significantly increased in the denervated striata of nigra-lesioned rats. Chronic bromocriptine administration decreased binding in denervated striata to levels not significantly different from control values. [3H]SPIP binding in intact striata was significantly reduced by bromocriptine to below control values. Differences in receptor levels reflected changes in the maximum density of binding sites with no change in affinities. Paradoxical behavioural hypersensitivity developing during chronic bromocriptine levels is not apparently mediated by changes in striatal D2 binding sites.

Animals↗
PubMed1985

Presynaptic inhibition of dopamine synthesis in rat striatum: effects of chronic dopamine depletion and receptor blockade.

These studies assessed the effects of dopamine (DA) depletion and receptor blockade on presynaptic inhibition of DA synthesis in the rat striatum. Chronic reserpine administration significantly decreased striatal DA levels but did not affect in vivo tyrosine hydroxylase activity, as determined by following dihydroxyphenylalanine (DOPA) accumulations. Both reserpine and haloperidol increased the sensitivity of presynaptic striatal DA response as determined by the ability of apomorphine (APO) to inhibit DOPA accumulation in NSD-1015-treated rats. The effect of concurrent administration of reserpine plus haloperidol on presynaptic response was additive. Additivity occurred at doses of reserpine and haloperidol which induced maximum sensitivity when administered singularly. The data suggest that increases in sensitivity of presynaptic DA response following DA depletion and receptor blockade are mediated by separate regulatory mechanisms.

Animals↗
PubMed1985

Serotonin depletion induced by reserpine is attenuated by prophylactic administration of lithium.

Prophylactic administration of lithium significantly attenuated the serotonin depleting effects of reserpine. In rat brain, lithium did not change the capacity of the storage protein, serotonin binding protein to bind the amine either in vivo or in vitro nor did it change its sensitivity to reserpine. However, the chronic administration of lithium significantly decreased reserpine levels in plasma and brain tissue of treated rats compared with rats which were treated only with reserpine. It is concluded that the antagonism between reserpine and lithium does not involve the serotonin binding protein but may be due to the lithium-induced reduction of reserpine levels.

Animals↗
PubMed1985

Choline acetyltransferase activity of the principal vestibular nuclei of rat, studied by micropunch technique.

We have assayed choline acetyltransferase (CAT) activity, as a specific marker for cholinergic neurons, in the vestibular nuclear complex (VNC) as a whole, and in the 4 individual principal vestibular nuclei, dissected by a micropunch technique. The VNC contains a significant amount of CAT activity, comparable to that of hippocampus and frontal cortex. CAT activity is relatively concentrated in the medial vestibular nucleus (MVN), which agrees with studies by others showing a greater concentration of muscarinic receptors in MVN. We conclude that cholinergic systems may play a role in central vestibular function, particularly within the MVN.

Animals↗