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Discover 23,284 clinical trials near Maryland. Find research studies in your area.
Showing 17061-17080 of 23,284 trials
NCT01046526
Background: * Individuals who have schizophrenia are significantly more likely to smoke than the general population, which leads to increased smoking-related illnesses and high rates of nicotine dependence. Research suggests that high rates of smoking and nicotine addiction in people with schizophrenia are related to the fact that nicotine temporally improves performance in several cognitive tasks, including sensory gating, long-term memory, and visual tracking-all of which are affected by schizophrenia. * Smoking among schizophrenia patients may be a form of self-medication, since nicotine may temporarily treat and improve cognitive deficits caused by schizophrenia. Researchers are interested in studying the effects of nicotine on the brain activity of individuals with schizophrenia to better understand how nicotine affects the brain regions connected to memory, visual tracking, and attention. Objectives: * To identify specific brain regions involved in the anticipatory learning deficits found in schizophrenia patients who smoke. * To determine whether and how nicotine enhances performance in these regions. Eligibility: \- Smokers (at least 10 cigarettes per day) between 18 and 50 years of age who either are healthy volunteers or have been diagnosed with schizophrenia/schizoaffective disorder. Design: * Participants will be asked to avoid consuming alcohol and restrict consuming caffeinated beverages for 24 hours before the study days. Participants will provide urine and breath samples at the start of the study to be tested for chemicals that may interfere with the study. * The study will require two to four visits, with two fMRI sessions and other visits for a clinical interview or training. Participants will have a training session with a possible mock MRI scan to learn how to do tasks that track eye movement and measure ability to pay attention. * During the fMRI scanning sessions, participants will receive either a nicotine patch or a placebo patch without nicotine. After the patch is in place, participants will perform tasks while receiving MRI scans. The scans will take up to 2 hours. * Participants will provide blood samples after finishing the MRI sessions.
NCT00089622
This study will evaluate the effectiveness of a skin patch formulation of the dopamine agonist Lisuride in controlling parkinsonian symptoms and dyskinesias (involuntary movements) caused by levodopa. Lisuride is currently available in tablet form; this study will test whether a patch formulation that provides continuous stimulation of the dopamine receptors will better control disease symptoms. Patients between 40 and 80 years old with Parkinson's disease and dyskinesias may be eligible for this 4-month study. Participants undergo the following procedures: Screening and baseline evaluation: Participants are evaluated with a medical history, physical examination, neurologic evaluation, blood tests, urinalysis, and electrocardiogram. A chest X-ray and MRI or CT scan of the brain are done, if needed. If possible, patients stop taking all antiparkinsonian medications except levodopa (Sinemet) for 1 month (2 months for Selegiline) before the study begins and throughout its duration. Dose-finding phase: Patients are admitted to the NIH Clinical Center for 2 to 3 days for a levodopa "dose-finding" procedure. For this test, patients stop taking Sinemet and instead have levodopa infused through a vein. During the infusions, the drug dose is increased slowly until parkinsonian symptoms improve or unacceptable side effects occur or the maximum study dose is reached. Symptoms are monitored frequently. (Patients who have had dosing infusions in the last 3 months do not have to undergo this phase of the study.) Active study phase: Patients are randomly assigned to one of two treatment groups. One group receives a placebo (a patch with no active drug) and a patch that contains Lisuride; the other group receives placebo throughout the entire study. Patients are instructed on how to apply the patches. During the first 2 weeks of this study phase, the number of patches containing active drug is gradually increased until the individual's optimum dose is reached. Patches are changed about every 2 days. During this time, intake of other antiparkinsonian medications is tapered down and patients are evaluated frequently. For the next 3 months, patients wear the patches continuously at the optimum dose. The patches are changed every 2 days or once a week, depending on the individual patient's need. Two levodopa infusion studies are done in the active study phase as they were in the dose-finding phase - at the beginning of the dose escalation phase and again at the end of the dose maintenance phase. In addition, patients are tested for their ability to perform different motor tasks. Sleep studies: Because oral Lisuride can cause excessive sleepiness, some patients are asked to participate in a sleep study to evaluate sleep patterns during the night and daytime sleepiness. The subject's brain, muscles, and breathing are continuously monitored during sleep. Also, an electroencephalogram (EEG) is done to record brain waves while the subject lies quietly, breathes deeply, watches flashes of light, sleeps, or performs a task. Safety checks: Patients are monitored closely for safety with a history of side effects, blood tests, and ECG each time a new supply of study drug is dispensed. Follow-up: 2 weeks after completing the active phase of the study, patients are contacted by phone for a follow-up evaluation.