Active clinical trials for "Pure Autonomic Failure"

In its simplest terms, obesity is the results of a positive balance between food intake and energy expenditure (EE). I.e., we take in more energy, in the form of food, than we expend, e.g., by exercise. In our sedentary society, resting EE accounts for most of total energy expenditure. The sympathetic nervous system (SNS, the one that produces adrenaline) is thought to contribute to resting EE. This conclusion is based on experiments where resting EE is decreased by beta-blockers, high blood pressure medicines that block only one aspect of the sympathetic nervous system. The investigators propose to use a different approach, by using a medication called trimethaphan that produces transient withdrawal of the autonomic nervous system. The investigators will then compare the measured resting EE before and after SNS withdraw and quantify the degree of contribution to the resting EE by the SNS and delineate differences between healthy normal, healthy obese, and patients with autonomic dysfunctions.

When a patient with Type 1 diabetes exercises, he or she is more prone to low blood sugar, or hypoglycemia. It is known that antecedent exercise can blunt defense responses, called counterregulatory responses to subsequent hypoglycemia in Type 1 DM, causing him or her to be vulnerable to another bout of hypoglycemia. Epinephrine is one of the important hormones in the defense of blood glucose during both exercise and hypoglycemia. We will test the hypothesis that antecedent exercise will blunt the metabolic, neuroendocrine and cardiovascular effects of subsequent epinephrine infusion in Type 1 DM.

The purpose of this study is to test the hypothesis that endothelin plays a role in the pathogenesis of supine hypertension in pure autonomic failure by increasing vascular resistance. To gauge its contribution to blood pressure regulation, pure autonomic failure and multiple system atrophy patients with supine hypertension will undergo a medication testing with the endothelin blocker, BQ123. We will compare the hemodynamic effects between PAF and MSA patients. Our primary endpoint will be the decrease in blood pressure during the administration of this compound.

Epinephrine is one of the important hormones in the defense of hypoglycemia. We will test the hypothesis that antecedent hypoglycemia will blunt the metabolic, neuroendocrine and cardiovascular effects of subsequent epinephrine infusion in Type 1 DM.

People with POTS, autoimmune autonomic neuropathy (AAN), pure autonomic failure (PAF), SFN and Ehlers Danlos Syndrome (EDS) do not only suffer from orthostatic symptoms such as dizziness, headache, neck pain, blurred vision or (pre-) syncope. They also experience deficits in attention and concentration (more precisely deficits in selective perspective, operating speed, executive functions and memory performance) mainly in upright position. Only few studies concerning cognitive impairment in autonomic neuropathies, their frequency, aetiology and therapy exist. Many patients concerned, especially with POTS, report attention deficits and "brain fog" with problems in their everyday life and work, predominantly in upright posture. Specific symptomatic or medical therapies do not exist. Medical treatment with Modafinil is discussed and part of a current study at Vanderbilt Autonomic Dysfunction Centre (1-5). The investigators want to investigate if problems of concentration, attention and/or cognitive dysfunction exist in people with POTS, AAN, SFN and EDS compared to healthy controls (HC). Thus the investigators use detailed clinical, autonomic and neuropsychological tests in different body positions (lying, sitting and standing) as also acute therapy (leg crossing).

This study will explore whether an antibody is influencing the autonomic nervous system, and if its removal will eliminate signs and symptoms of failure in that system. The autonomic nervous system is responsible for many automatic changes involved in everyday activities, such as standing up, digesting food, and exercising in the heat. Antibodies fight germs but sometimes cause health problems. Removal of the antibody is done through a procedure called a plasma exchange. Patients with primary chronic autonomic failure and a circulating antibody to what is called the neuronal nicotinic receptor may be eligible for this study. To be eligible, patients will have participated in an earlier study, protocol number 03-N-0004. Patients will undergo tests and procedures that include an electrocardiogram, and blood collection for hepatitis, HIV, and pregnancy. Blood will be tested for a complete blood count, clotting factors, and chemistries. There will also be tests for liver function, kidney function, cortisol, and thyroid. Participants will be tested for signs and symptoms of autonomic failure, and will be asked to complete questionnaires about various symptoms before the plasma exchange, 1 or 2 weeks afterward, and then monthly or bimonthly for up to 1 year. Patients will undergo a series of other tests. In one test, a patient is upright and blows against a resistance (Valsalva maneuver). The quantitative sudomotor axon reflex test (QSART) uses iontophoresis, involving application of acetylcholine, a chemical messenger, and a small amount of electricity. QSART examines the regulation of sweating, a particular aspect of the autonomic nervous system. There will be a test using edrophonium, given intravenously (IV), to evaluate that drug's effects on the heart, skin, glands, gastrointestinal activity, bladder tone, and salivation. A glucagon test, also by IV, will show patients' ability to release the hormone adrenaline. The plasma exchange will be performed by use of an automated cell separator. Patients' blood will be removed continuously through a needle in the arm. Blood cells will be separated from the plasma by a spinning process and continuously returned to circulation through a needle in the patients' opposite arm. Blood cells that are returned will be mixed with albumin, a sterile replacement solution. A blood thinner, citrate, will be given, to prevent clotting of blood. This whole procedure will take about 2 hours. Patients will typically undergo five exchange procedures in about 10 days while they are inpatients at the NIH Clinical Center. The amount of plasma removed in a single session and the number of sessions will be set by the NIH Blood Bank. It is expected that patients' autonomic failure will improve after several days of starting the plasma exchange. Testing for symptoms of autonomic failure and autonomic function testing will occur about 1 month after the plasma exchange and monthly or bimonthly for up to 1 year. For each visit of testing, patients will be inpatients for about 2 days. If autonomic failure recurs, patients may have a second plasma exchange, with the same follow-up tests, for about 1 year.

The aim of the study is to evaluate the autonomic failure in Parkinson's disease by clinical, electrophysiological and neuropathological examination.

To determine whether retinal abnormalities, as measured by high definition optical coherence tomography (HD-OCT) and visual electrophysiology techniques can be used as a clinical biomarker to monitor disease progression overtime in patients with Parkinson disease. To establish whether these measures can be used to identify patients with PD in the premotor phase. To define the rate of progression of retinal abnormalities in PD (both in the motor and premotor stages) for potential use as a clinical outcome measure

The Synuclein-One Study will be evaluating α-synuclein in patients with Parkinson's disease, Multiple System Atrophy, Dementia with Lewy bodies and Pure Autonomic Failure. Using a simple diagnostic test will improve clinical accuracy in diagnosing, earlier diagnosis, and distinguish between neurodegenerative diseases.

The autonomic or automatic nervous system helps control blood pressure. Diseases of the autonomic nervous system may result in a drop in blood pressure on standing in many cases leading to fainting. Diseases that affect the autonomic nervous system include pure autonomic failure, multiple system atrophy and Parkinson's disease, and can present with very similar symptoms and it is sometimes difficult to determine an exact diagnosis. The purpose of the study is to find out if the blood pressure response from taking a single dose of the medication atomoxetine can help in the diagnosis of these diseases.