Active clinical trials for "Hypersensitivity"

Introduction and aim Stress is well known to affect visceral sensitivity in Human. The investigators speculate that visceral hypersensitivity plays an important role in symptom perception in gastro-esophageal reflux disease (GERD). The role of acute stress mimicked by corticotrophin releasing hormone (CRH) administration on esophageal sensitivity has not been studied. The investigators hypothesize that stress mediated through CRH-release increases esophageal sensitivity. A first step in the investigation of this hypothesis is to study whether administration of CRH has an influence on esophageal sensitivity in healthy volunteers (HV). Therefore, the aim of this study is to investigate the effect of CRH-administration on esophageal sensitivity in a group of HV. Methods The study will be performed in cross-over on 15 HV with no prior history of digestive disease. Esophageal sensitivity will be tested by multimodal stimulation on two sessions (placebo and CRH-administration), with an interval at least of one week. The two sessions will be scheduled by randomization for every subject. After blinded administration of CRH 100µg or placebo IV, esophageal sensitivity will be assessed using a multimodal esophageal stimulation probe which allows thermal, mechanical, electrical and chemical stimulations of the esophagus. Esophageal sensitivity will be assessed using Visual Analogue Scale (VAS), the mood with specific questionnaires (Manikin Self assessment SAM, Profile of Mood Schedule (POMS, State Trait Anxiety Inventory (STAI)) and the cortisol with salivary samples. Statistical analysis Esophageal sensitivity for the different stimuli (heat, mechanical, electrical and chemical) will be compared between CRH and placebo conditions. To determine the stress-inducing capability of CRH-administration, the POMS questionnaire, STAI, Manikin self assessment and cortisol levels after the stress-protocol will be compared with the basal measurements. Perspectives If CRH-administration increases esophageal sensitivity, a stress model could be applied to investigate the influence of a real life stressor on esophageal sensitivity in healthy subjects. In a third part, a mast-cell stabilizing drug could be tested after administration of a stressor in order to investigate its role on esophageal sensitivity. In the future, this might be proposed to refractory GERD in a controlled randomized trial.

Background: Some people have allergic reactions to COVID-19 mRNA vaccines. Researchers want to learn more about these reactions to provide guidance on who can safely receive the vaccines, including a second dose in people who had a reaction to the first. Objective: To study the safety of giving a second mRNA COVID-19 vaccine dose to people who had a systemic allergic reaction to their first dose. Eligibility: People aged 16-69 who had a systemic allergic reaction to their first dose of COVID-19 vaccine. Design: Individuals who have underlying health issues may need to come to the NIH for screening tests to make sure they are safe to receive the vaccine. People who are eligible to participate in the study will be admitted to the NIH hospital and stay for at least 4 days. They will give urine samples. They will have a nasal swab SARS-CoV-2 test. They will have an intravenous line placed in each arm. They will get the study vaccine (Pfizer-BioNTech COVID-19 vaccine) and one dose of placebo on different days. They will have breathing tests. They may have clinical photography if they develop a rash. Participants will have 4 follow-up visits - 2 by phone and 2 in-person visits at the NIH campus . They will have allergy skin testing at one visit. Drops of different allergens or controls will be placed on their back or arm. The skin under each drop will be scratched with a tool. If the results are negative, a small amount of allergen will be injected just below the surface of their skin. Participants who have no or only a mild allergic reaction to the second dose of the vaccine may be eligible to receive a Booster dose at the NIH. Participation will last for approximately 5 months.

Understanding sources of variability in human drug dosing is important to the beneficial and safe use of any drug. Understanding and applying the science of individualizing a drug dose to a patient is called precision medicine. Aspirin is one of the oldest most utilized medications for its ability to lower fever, relieve pain, and to reduce the stickiness of platelets (tiny blood cells that help your body form clots to stop bleeding. Aspirin dosing is currently the same for all patients and is not individualized. In the last century, aspirin has shown benefit in reducing cancer, stroke, and preventing cardiovascular events after one has already had a heart attack or stroke. Previous human studies have not found consistent positive effects of aspirin when dosed by body weight. Therefore, how should aspirin be dosed in 2019? Aspirin resistance is the failure of aspirin to reduce platelet stickiness and thin the blood and most importantly, is associated with higher risk of heart attacks and strokes. Aspirin resistance may occur due to not taking aspirin on a regular basis, differences in how platelets behave in some persons, use of over the counter pain medicines like Motrin®, reduced amount of drug in the body, and/or a lack of being able to predict a dose for a certain individual. To find out the best way to dose aspirin, the investigators propose to study healthy volunteers (persons without any known disease) with different ages and body sizes to see if aspirin blood levels are tied to platelet stickiness. This information will be used to mathematically build a computer-based picture of aspirin dosing that will help physicians pick the best dose of aspirin for each patient. The investigators will then extend studies for the aspirin dose estimator to be used in other countries in people with heart problems and stroke, recording future events in a randomized (i.e., coin toss) manner, to determine if the ability of the aspirin dose estimator to prevent future heart attacks and stroke compared to people receiving aspirin doses that were chosen without the estimator.

The goal of this study is to see how the type and size of particles found in air pollution affects inflammation in the nose in people who are skin test positive to at least one allergen. It has been observed that pollution makes allergies worse. It has also been suggested that very small particles may affect allergies more than larger particles.

Healthy subjects with low Vitamin D levels will be randomly assigned to either Vitamin D replacement or placebo for a period of 8 weeks. Insulin sensitivity will be measured before and after the intervention, and the changes will be compared between the two groups. This will help us understand if Vitamin D replacement improves insulin sensitivity. Serum Retinol Binding Protein 4 levels will also be measured to see if changes in insulin sensitivity are mediated by RBP4.

This study is for people with sensitive teeth and involves going to the dentist for 6 visits over 8 weeks. During the first 2 weeks, everyone will just brush their teeth two times a day with the fluoride toothpaste provided. Then you will be assigned to a mouthwash group if you qualify to continue in the study. Two groups will get mouthwash with a certain amount of an experimental ingredient and one group will get a mouthwash with no experimental ingredients. You will have an equal chance of being assigned to any one of the three groups. For the next 6 weeks, you will rinse with your assigned mouthwash after brushing. A dentist will look at your mouth, teeth, tongue and gums and check for sensitive teeth. The investigators will see if the mouthwash helps to reduce tooth sensitivity during the study.

Alterations in fatty acid mobilization and oxidation may be primary adaptations responsible for the improvements in metabolic health after a single session of endurance exercise. The investigators will determine the effect of a single session of endurance exercise on whole-body fatty acid mobilization and oxidation, IMTG concentration and the expression of factors that regulate these processes in skeletal muscle of 11 women with abdominal obesity (age: 18-45y). In addition, the investigators will evaluate how these factors, and exercise, effect insulin signalling and insulin sensitivity. Every effort will be made to recruit subjects from ethnic and minority groups. Before participating in the study, subjects will be informed of all the procedures and potential risks, and they will sign an informed consent form approved by The University of Michigan Institutional Review Board. Eligible volunteers will participate in three separate trials, in a randomized order. In two trials subjects will eat exactly the same amount of calories, except in one trial they will exercise (eucaloric + exercise) and in the other trial they will remain sedentary (hypercaloric). In a third trial subjects will again remain sedentary but instead they will ingest appropriate calories to maintain caloric balance (eucaloric + sedentary). By doing this the investigators are also able to investigate the effect of acute caloric perturbations on insulin sensitivity, because it is possible that the enhanced insulin sensitivity evident after exercise, as compared to the sedentary state, is due to caloric deficit and not the exercise bout, per se.

Many of the beneficial metabolic effects of endurance exercise training are not due to adaptations to weeks, months, or even years of training, but rather much is due to the response to the most recent exercise session(s). Therefore, the investigators contend that lifestyle interventions for obese individuals should be tailored to optimize the metabolic effects of the most recent exercise session(s). But the "dose" of exercise necessary to evoke these beneficial responses is not known, and the mechanisms responsible for these improvements are poorly understood. The findings from these studies will: 1) establish the minimum "dose" of a single exercise session necessary to improve insulin sensitivity the next day in obese adults, 2) characterize the underlying metabolic factors responsible for the improvement in insulin sensitivity, and 3) assess the cumulative metabolic adaptations that occur over days, weeks, and months of a low-intensity/low-volume lifestyle exercise program. Findings from these studies will provide valuable information for the development of lifestyle programs aimed at maximizing the key metabolic health benefits of each exercise session in obese patients.

This research is being done to study the effects of the drug omalizumab (Xolair) in people with cat allergies. The investigators will use omalizumab to study changes in the cells in the nose, cells in the blood and cells in the skin that cause allergies. The investigators will compare the changes in the nose to changes in the skin and blood cells. Objective: To test the hypothesis that treatment with omalizumab will decrease the nasal allergen challenge late-phase eosinophil count in nasal brushings at the time when blood basophils have become hypo-responsive to in vitro allergen exposure.

The restoration of indirect partial and full coverage restorations in dentistry necessitates the use of a luting agent to act as a means of mechanical and potentially, chemical retention of the restoration. Upon the introduction of the first generation of glass Ionomer cements for use as a luting agent, an elevated short-term post operative hypersentivity was reported. In part, this adverse event was considered to be due to a desiccating effect of the cement as water is utilized in the setting reaction and thus a desiccation of the dentinal tubules was proposed as a potential mechanism leading to disruption of the neurosensory odontoblasts. Further materials development in the field of dental cement luting agents has lead to the introduction to the current market of resin formulations that have an alternative mechanism of setting. Consequently, there are anecdotal reports of a decrease in the incidence of post-operative sensitivity but no comparison with the effect of conventionally used dentin desensitizing agents as a part of the bonding process of the restoration. The purpose of this trial is a single blinded parallel design randomized clinical trial to evaluate the perceived incidence of post-operative sensitivity when full coverage all ceramic crowns or short-span three unit fixed partial dentures (dental bridge) is fabricated in the posterior part of the mouth. The dental crowns or bridges will be bonded with conventional glass ionomer cement or a Urethane dimethacrylate / Bis-GMA composite resin dental cement. Outcome measures will be both objective clinical criteria and the use of a calibrated pain survey instrument.