PubMed HealthSearch

Biomedical subjects

I Shoulson

Publications and source records attributed to I Shoulson.

At least 19 recordsLinked to original sources

Neuroprotective clinical strategies for Parkinson's disease.

Increasing knowledge of the role of brain iron in health and disease has prompted consideration of therapeutic strategies aimed at attenuating the effects of iron and its untoward oxidative consequences. The success of this approach is critically dependent on a better understanding of the pathogenesis of Parkinson's disease. The controlled trial "Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism" (DATATOP) represents a clinical strategy to detect neuroprotective effects of antioxidative interventions. Validation of reliable biological markers of nigral degeneration is central to development of therapies that exert genuine neuroprotective effects in slowing the progression and preventing the onset of Parkinson's disease.

Drug Therapy, Combination

An interim report of the effect of selegiline (L-deprenyl) on the progression of disability in early Parkinson's disease. The Parkinson Study Group.

The pathogenesis of Parkinson's disease (PD) has been linked to oxidative-mediated events including increased monoamine oxidase (MAO) and free-radical generation. We are investigating the ability of the MAO inhibitor, selegiline (deprenyl), and of the free-radical scavenger, tocopherol, to delay the onset of disability requiring levodopa therapy (primary end point) in patients with early PD. Eight hundred patients with early, untreated PD were enrolled in the multi-center placebo-controlled, double-blind clinical trial 'Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP)'. Subjects were assigned by 2 x 2 factorial design to receive selegiline (10 mg/day), tocopherol (2,000 IU/day), a combination of both drugs, or placebo, and followed to determine if and when disability occurred requiring levodopa therapy. After 12 +/- 5 months of observation, independent monitoring prompted a preliminary analysis indicating that selegiline 10 mg/day significantly extended the time to the primary end point. Selegiline therapy, alone or in combination with tocopherol, resulted in a 57% reduction in the rate of developing disability requiring levodopa therapy (p < 10(-10)) and a 50% reduction in the rate of loss of full-time employment (p = 0.01). Deterioration of motor and mental features was significantly less in selegiline-treated subjects. Adverse effects were minor and infrequent. We conclude from these preliminary results that selegiline (10 mg/day) delays the onset of disability associated with early, otherwise untreated PD. It remains unclear whether these benefits derive from mechanisms that are symptomatic (dopaminergic), protective (anti-neurotoxic), or both. The DATATOP study is ongoing to examine the long-term effects of selegiline and the independent and interactive effects of tocopherol.

Activities of Daily Living

Bromocriptine inhibits norepinephrine release.

Bromocriptine is a dopamine agonist that induces postural hypotension and can be used as an antihypertensive. The drug inhibits release of norepinephrine (NE) from an isolated artery by stimulating presynaptic receptors. In normotensive subjects it lowers both plasma and cerebrospinal fluid (CSF) levels of NE by 50% and lowers blood pressure moderately in standing subjects and slightly in recumbent subjects. Through central and peripheral mechanisms, bromocriptine inhibits sympathetic nervous discharge of NE.

Adult

Huntington's disease: treatment with muscimol, a GABA-mimetic drug.

Muscimol, a gamma-aminobutyric acid (GABA) analogue that exerts potent and specific agonist effects on GABA receptors, was administered orally to 10 patients with Huntington's disease. In this double-blind study, muscimol treatment did not result in improvement in these patients' motor or cognitive functions. However, muscimol administration did ameliorate chorea in the most severely hyperkinetic patient, and it was associated with the appearance of dystonic features, electroencephalographic changes, and behavioral alterations in some patients. These latter observations support a functional relationship between GABA-ergic activity and the genesis of both systonia and EEG abnormalities in humans. The therapeutic failure of muscimol indicates that the GABA disturbances in Huntington's disease does not alone account for the clinical features of this disorder.

Activities of Daily Living

Serotonergic functions in man.

Abundant preclinical evidence suggests that serotonin-containing neural systems may participate in the regulation of both extrapyramidal and neuroendocrine function. In an attempt to examine these possibilities in man, patients with various neurologic disorders received drugs believed to facilitate or inhibit serotonergic function. Extrapyramidal signs in patients with parkinsonism or Huntington's disease showed no consistent change with L-tryptophan or parachlorophenylalanine. Unexpectedly, L-5-hydroxytryptophan, given in combination with a peripheral decarboxylase inhibitor, caused a worsening of parkinsonian akinesia and rigidity. Fenfluramine, at doses which appeared to diminish central serotonin but not dopamine turnover, had no consistent effect on the severity of involuntary movements in patients with Huntington's chorea, but did produce a significant rise in plasma prolactin.

Animals

Huntington's disease: treatment with dipropylacetic acid and gamma-aminobutyric acid.

Dipropylacetic acid (DPA), and anticonvulsant known to raise brain gamma-aminobutyric acid (GABA), was administered orally to eight patients with Huntington's disease. Both alone and in combination with high oral doses of GAGA, DPA failed to ameliorate and motor signs of this disorder. At maximum dose levels, combined DPA and GABA treatment led to an apparent increase in the central turnover of both dopamine and serotonin, as estimated by the oral probenecid-loading test. These latter observations may indicate a close functional interrelation between monoaminergic and GABAnergic neural pathways in the central nervous system of man.

Adult

Studies with bromocriptine. Part 2. Double-blind comparison with levodopa in idiopathic parkinsonism.

A double-blind crossover study was performed in 12 patients with idiopathic parkinsonism to compare their response to bromocriptine with their response to previous optimal drug treatment, including levodopa. There was a 26 percent overall improvement with bromocriptine; rigidity, tremor, and facial expression showed the greatest response. Seven of eight patients who were taking levodopa at the beginning of the study was taken off the drug completely. Adverse reactions were transient and dose-dependent. Bromocriptine promises to be an effective new therapeutic agent in the treatment of idiopathic parkinsonism.

Aged

Studies with bromocriptine: III. Concomitant administration of caffeine to patients with idiopathic parkinsonism.

Caffeine was administered to six patients with idiopathic parkinsonism in an attempt to potentiate the therapeutic response of bromocriptine, a dopamine (DA) receptor agonist, by inhibition of phosphodiesterase. In a double-blind study at doses of 1,000 mg daily, caffeine failed to enhance the antiparkinsonian action of bromocriptine (40 mg daily) given concomitantly. Although effective in potentiating the action of levodopa and other agonists in animal models of parkinsonism, caffeine is inactive in parkinsonism in man.

Bromocriptine

Reversal of systemic manifestations of cryoglobulinemia. Treatment with melphalan and prednisone.

In a patient with essential cryoglobulinemia with systemic, cutaneous, and neurologic manifestations and a mixed IgG-IgM cryoprotein, elimination of systemic and cutaneous disease manifestations, as well as notable reversal of neurologic impairment, followed therapy with melphalan. Levels of circulating cryoprotein decreased, but protein structure was unchanged by chemotherapy. Experience to date with alkylating agents suggests that this mode of treatment is the most effective currently available.

Cryoglobulins