9 Clinical Trials for Various Conditions
The purpose of this study is to evaluate the ability of a wearable Smart Underwear prototype device to quantify diet-induced changes in gut microbial hydrogen sulfide (H₂S) production. The core design is a single-site, 2-period, crossover feeding study with 6-day diet periods and an approximately 11-day washout period. Participants are fed each of two isocaloric diets designed to contrast gut microbial H₂S production (i.e., a high cysteine vs. low cysteine diet), in a random order.
A randomized, controlled trial to evaluate patient compliance and biologic mechanisms of a short-term pre-operative Protein-Calorie Restriction (PCR) diet in comparison to a normal ad libitum diet for 4 days before elective vascular surgery involving a major operation. After a pilot study exploring the safety and feasibility of the PCR diet conducted inpatient before carotid endarterectomy titled Short-Term Endogenous Hydrogen Sulfide Upregulation, and a follow-up study titled Dietary Restriction in Vascular Surgery, the investigators now aim to expand the study to at home diet among a variety of vascular surgery procedures. This study will further elucidate not only the practicality of pre-operative short term dietary restriction, but also provide early data to inform biologic mechanisms and to inform future efficacy trails.
Hydrogen sulfide is a signaling molecule that is important for vascular health. Because vascular factors such as hypertension and high cholesterol are risk factors for Alzheimer's disease and related dementias, we hypothesize that hydrogen sulfide plays an important role in brain health as well. We will compare blood levels of hydrogen sulfide across groups of people with and without dementia. We will also look at the relationship between hydrogen sulfide, cognitive dysfunction and measures of brain microvascular disease examine the contribution of hydrogen sulfide to cognitive decline. Our goal is to identify a biomarker of vascular dysfunction in dementia.
This research study will compare the impact of dietary restriction pre-operatively before carotid endarterectomy compared to the standard nutrition that a patient typically eats. The investigators want to find out how patients comply and generally how well patients do with this type of dietary restriction before their surgery since animal studies suggest that short - term dietary restriction may be beneficial before surgery.
Cardiovascular disease which includes coronary artery disease and peripheral artery disease remains the leading cause of death among women in the United States. The impact of cardiovascular in women was not recognized by clinicians for a long time. It is now evident that, women suffer the consequences of cardiovascular at rates at least as high as those observed in men but there are still major gaps in our understanding this disease in women. Hydrogen sulfide (H2S), a gaseous mediator plays an important role in the cardiovascular system. Research has demonstrated it's critical role in animal ischemia reperfusion models. Hydrogen sulfide exists in distinct biological pools in blood. Recently, the Kevil lab has pioneered the development of new analytical techniques for accurate measurement of all biological pools of H2S. By measuring these distinct pools of H2S in women with and without cardiovascular disease the investigators hope to further understanding of role of H2S in pathophysiology of cardiovascular disease. This research will help to assess the ability of H2S and its distinct biological pools to potentially be a diagnostic marker or a therapeutic target for cardiovascular disease.
This will be an observational study comparing the plasma levels of free hydrogen sulfide in patients with and without peripheral arterial disease using a novel recently published method of measuring hydrogen sulfide. The investigators will also see if there is any difference in these levels between symptomatic and asymptomatic patients. Will examine the relationship of these levels to known clinical risk factors as well as plasma nitrite and nitric oxide levels. In doing the above the investigators hope to explore the utility of free hydrogen sulfide as a biomarker for peripheral arterial disease. Atherosclerotic peripheral arterial disease (PAD) of the lower extremities represents a significant and growing cause of morbidity and mortality. The PARTNERS study of screening ABIs in a primary care population of nearly 7000 individuals demonstrated a remarkable 29% incidence of ABI \<0.9, which is the commonly accepted level of abnormal ABI diagnostic of PAD. Also of note in these patients with a new diagnosis of PAD the incidence of asymptomatic PAD was a striking 48%. The availability of a biomarker will greatly enhance the care of these patient and hopefully reduce morbidity and mortality. The investigators believe that hydrogen sulfide (H2S), an endogenously produced gasotransmitter, holds promise as a clinically useful biomarker for PAD and may also provide a possible explanation for the paradox of asymptomatic PAD in patients with ABIs less than 0.9. To date, research regarding H2S has demonstrated that it participates in a myriad of physiological functions including vasodilatation, anti-apoptotic effects, modulation of mitochondrial respiration, and changes in vascular remodeling.
This is a 5-week crossover pilot study of 15 highly motivated healthy volunteers who will consume two 7-day intervention diets: 1) a diet low in sulfur-containing amino acids (Low-S diet), emphasizing plant-based foods and fat sources; and 2) a diet high in sulfur-containing amino acids (High-S diet), emphasizing animal protein and fat sources. A 14-day washout period will follow each intervention, in which participants will eat their typical diets.
High blood pressure can cause physical changes to the blood vessels of the body (remodeling). If a person who has high blood pressure also has a lot of blood vessel remodeling with their condition, they are more likely to have poor results with medical treatment for hypertension. The researchers examine the impact of different classes of drugs that doctors use to treat high blood pressure (hypertension) on blood vessel remodeling. Some drugs that doctors prescribe for their patients contain a "sulfhydryl group" (a sulfur atom bonded to a hydrogen atom). Drugs that have the sulfhydryl group may reduce blood vessel remodeling more that drugs that do not. For this study, participants who have high blood pressure perform the experiments, take a drug for 16-weeks to lower blood pressure, and repeat the experiments. The researchers randomly assign one of three drugs to participants who have high blood pressure: a diuretic ("water pill"), a drug containing a sulfhydryl (SH) group, or a drug that does not contain a sulfhydryl group. Participants who do not have high blood pressure perform the experiments, but do not take any of the drugs. In some of our experiments, the researchers use a technique called "microdialysis" (MD). With MD, the researchers perfuse some research drugs into the skin on the forearm through tiny tubing that mimics capillaries. These MD drugs mimic or block substances the body naturally makes to control the small blood vessels in the skin. The drugs remain in nickel-sized areas around the tubing and do not go into the rest of the body. The researchers also analyze very small skin samples (skin biopsy) obtained from the forearm. Lastly, the researchers use a standard technique called "flow mediated dilation" (FMD) that uses blood pressure cuffs and ultrasound to look at the health of larger blood vessels in the body. FMD includes placing a small tablet of nitroglycerin under the tongue during part of the test.
GIC-1001 is a novel, orally-administered, colonic analgesic drug developed as an alternative to i.v. sedation during full colonoscopy. It will be evaluated for efficacy and safety in a multi-center, randomized, double-blind, placebo controlled, dose-ranging, proof of concept Phase 2a trial. Up to 240 patients will receive one of 3 doses of GIC-1001 or its matching placebo. A pharmacokinetic evaluation will be carried out on a subset of patients (N: 24).