View clinical trials related to Healthy Volunteers.
Filter by:This study is being done to learn if yohimbine, a naturally occurring drug, affects the speed at which food travels through the stomach, intestines and colon, and if yohimbine affects the amount of liquid you can drink in a short period of time. Understanding how yohimbine works on the gut may help develop new treatments for patients with constipation. Yohimbine has been approved by the Food and Drug Administration (FDA) for routine clinical use, however, its use as proposed in this study is considered investigational.
Gut barrier plays a major role in defence of the organism. During catabolic states, like major surgery or inflammation, gut barrier could be altered. It has been reported that preoperative nutritional support may have beneficial effects on clinical outcome in patients with surgery on gastrointestinal tract. Glutamine, which is a conditionally essential amino, have been reported to modulate inflammatory, antioxidant responses and protein metabolism in intestine. In addition, glutamine supply improves clinical outcome in critically ill patients. Antioxidant micronutrients may also have some beneficial effects in intestine by improving antioxidant response and might also regulate protein expression. Nevertheless, effects of glutamine combined to antioxidant micronutrients have not been evaluated. Thus, the aim of this study will be to assess the influence of glutamine and glutamine-antioxidant micronutrients-containing solutions on intestinal response in humans.
We wanted to compare the relation of two different psychophysiological paradigms (PrePulse Inhibition of the startle response = PPI and P50 suppression) to each other. Additionally, we wanted to test the effect of the combined serotonin- and noradrenaline re-uptake inhibitor, imipramine, on these measures. The primary hypothesis was that PPI and P50 gating would not correlate with each other at baseline. The secondary hypothesis was that increased noradrenergic and serotonergic activity would disrupt PPI as well as P50 gating.
It is of great clinical relevance to know if selective serotonin re-uptake inhibitors affect information processing. Our hypothesis was that aspects of information processing would be disturbed whereas others would improve.
DHEA or dehydroepiandrosterone is a naturally occurring hormone secreted by tghe adrenal galnds. The secretion of HDEA declines with aging. DHEA is considered a food supplement and it is not regulated by the FDA. The purpose of this research is to evaluate ceratin of the biological effects of a reaplcement dose of DHEA. As you get older, DHEA levels are lower than you were younger. The replamcent dose is the dose of DHEA that will raise DHEA levesl to the levels found in young people. Anotehr purpose is to determine whether DHEA enhances the adaptations to an exercise training program.
In this study we are looking at the blood flow to the heart using two different chemical tags or tracers that give off a low level of radiation. The tracers used in this study are called O15-water and F17-fluoromethane. These tracers mix with the blood and will move through the body. The researchers will use positron emission tomography (PET scans)to track the tracers as they moe through the heart and chest.
The purpose of this study is to explore the possible cognitive effects of darifenacin modified release and long-acting oxybutynin.
Microvascular dysfunctions are critical events in several diseases including diabetes. This study will develop a methodology for microvascular investigation in human skin. The purpose of the study is to investigate the physiological response of the cutaneous microcirculation to physical, thermal, mechanical or chemical stimulations.
The purpose of this study is to determine the levels of testosterone and/or estradiol at which changes in bone turnover, body composition, strength, sexual function etc. begin to occur in older men. This information may help determine when to intervene with hormone replacement therapy in aging men.
This study will examine abnormalities in mitochondria (energy-producing machinery of cells) and in genes related to mitochondria in the blood cells, muscle, and fat of HIV-positive patients who are taking nucleoside reverse transcriptase inhibitors (NRTIs) and in patients not currently taking HIV medications, and compare the results to healthy volunteers. Many patients with HIV infection take NRTIs to help control the infection. These medications may damage cell mitochondria, possibly causing side effects such as fatigue. This study will explore the relationship between changes in mitochondria and related genes and patient reports of energy level, mood and quality of life. Healthy volunteers and HIV-infected patients between 18 and 55 years of age may be eligible for this study. Healthy volunteers must test negative for the HIV antibody. HIV-positive patients must have been diagnosed positive for at least 1 year. Patients who are taking antiretroviral therapy must have been taking the same drug regimen (with at least two NTRIs and no protease inhibitors) for at least 3 months. HIV positive patients not taking antiretroviral medication must not have had antiretroviral therapy for at least 1 year. Candidates are screened with a medical history, brief physical examination, blood and urine tests, and questionnaires related to mood and energy. Qualified volunteers will undergo the following procedures during three or four study visits: Visit 1 Complete history and physical examination, blood tests, and questionnaires about energy level, mood, and quality of life. Visit 2 Muscle and fat biopsy: Before the biopsy, blood is drawn to check blood counts and to test for pregnancy in women who can become pregnant. The biopsy is done on an outpatient basis in the operating room. The site of the biopsy (an area on the upper arm or upper leg) is numbed with an injection under the skin. A 1-inch incision is made over the muscle to be biopsied and a small sample of muscle tissue and small sample of fat are removed. The incision is then closed and bandaged. Following the biopsy, you will be monitored for about 4 hours in the clinic. Strenuous physical activity should be restricted in the week following biopsy to allow healing. Visit 3 Examination of biopsy site and possible apheresis: The biopsy site is examined for healing. Apheresis may be scheduled for this visit or for an extra visit between the biopsy and the final visit. This procedure for obtaining white blood cells for study is optional. For apheresis, blood is withdrawn from a needle placed in a vein in the arm and the white cells are separated from the rest of the blood. The white cells are extracted and the red cells and plasma are then returned to the body through a second needle.