7 Clinical Trials for Various Conditions
Differences in human oral sensitivity for caproic, lauric, oleic, linoleic, and linolenic acids will be explored. Prior work indicates that there may be a learning effect in measuring detection thresholds for free fatty acids. This study is designed to determine the number of visits necessary to attenuate this learning effect and also to test whether this effect continues across different types of fatty acids or is specific to each fatty acid. This will aid in understanding how many visits are required to obtain reliable data and if less expensive fatty acids can be used to attenuate learning before testing thresholds for more expensive fatty acids.
This single-site, within-subject, experimental study is designed to test the hypothesis children who live in a household in which one or both of their parent smoke will exhibit a higher cough threshold and will prefer more intense sweet tastes than children who live in a household where neither parent smokes. Subjects will include at least 50 racially and ethnically diverse, healthy children aged 10 to 17 years (a critical time for experimenting with tobacco) and a parent. The sample will comprise two groups: Non-Environmental Tobacco Smoke (ETS) Exposed (neither the child nor parents has ever smoked or been exposed to environmental tobacco smoke (ETS) in the home), and ETS-Exposed (the parent has smoked at least 3 cigarettes per day for at least five years in the home, with the child living in the home continuously). Cough sensitivity will be measured using a standard single-inhalation challenge, a test of the minimum concentration of capsaicin (the spicy chemical in hot peppers) needed to elicit cough. Sweet taste preferences will be measured using a forced-choice paired comparison method of liquids which differ in sucrose content. Measures of breath carbon monoxide will validate the smoking status of parents and their adolescent children. The key comparison will be between Non-ETS Exposed and ETS-Exposed children, with the difference between smoking and non-smoking parents as a positive control. Because smoking and non-smoking families may differ in ways besides tobacco exposure, the investigators will obtain health histories (with a focus on respiratory illness), smoking histories, measures of body weight, diet, and responses to personality tests (including susceptibility to addiction). The investigators will also obtain genomic DNA from saliva samples. Genes for chemosensory receptors that are part of the cough reflex pathway and genotype may account for aspects of cough sensitivity.
In this study we are determining whether the hormones associated with the phases of the menstrual cycle (menstruation \& ovulation) influence taste sensitivity to glucose. We hypothesized that women would be more sensitive to oral glucose as assessed by absolute detection threshold during ovulation than when assessed during menstruation. These phases of the cycle are associated with peak plasma estradiol levels and nadir estradiol levels. There is evidence that estrogen can increase the sensitivity of the metabolic signaling pathway of the pancreatic beta-islet cells to stimulate insulin release more readily when glucose is present by increasing sensitivity of the K-ATP channel to ATP. Since the same metabolic signaling pathway is reported to be present in taste tissue, we tested whether peak estrogen levels would enhance taste detection of glucose but not sweeteners that cannot generate ATP, such as sucralose or methyl-D-glucopyranoside (MDG).
Flavor is the primary dimension by which young children determine food acceptance. However, children are not merely miniature adults since sensory systems mature postnatally and their responses to certain tastes differ markedly from adults. Moreover, emerging research has revealed that there are sensitive periods during infancy such that early flavor experiences serve to modify later responses to flavors and foods. The proposed study aims to investigate this important issue by using as a model system a class of infant formulas which are hydrolyzed protein based and thus have very pronounced and distinctive flavors which are unpalatable to older-aged infants and adults. This research was initiated because of anecdotal reports by pediatricians that although it is easy to introduce this type of formula to infants during the first months of life, it becomes extremely difficult to do so later in infancy. Indeed, recent studies in the investigators' laboratory provided the first experimental demonstration that infants younger than 4 months of age willingly accept substantial amounts of, and satiate while feeding, a novel, protein hydrolysate formula. In marked contrast, infants older than 4 months reject the protein hydrolysate formula and this rejection occurs within the first minute of a feed, a finding that strongly suggests the sensory qualities of the formula are responsible, at least in part, for this rejection. Moreover, this rejection is not evident when the investigators test older-aged infants with other unfamiliar, but non-hydrolysate, formulas. In other words, the rejection appears to be in response to a particular component or components of protein hydrolysate formulas. This shift in acceptability can be ameliorated by prior exposure. That is, if these formulas are introduced to infants within the first few months of life and are fed continuously, they remain highly acceptable throughout infancy and early childhood. These observations implicate a sensitive period during development, occurring somewhere before 4 months of age, during which exposure to a formula, which is unpalatable to adults and infants over 4 months of age without exposure, renders it acceptable and presumably palatable. To the investigators' knowledge, this is the clearest example of a sensitive period in the development of responses to foods and flavors in humans thus far identified. There is a paucity of information on whether and how the composition of formulas fed to infants influences their short-term feeding behaviors during the first few months of life. The primary objective of this longitudinal study is to determine the period during early infancy when exposure to the casein-hydrolysate formula, Nutramigen, renders it acceptable during later infancy. The study also aims to determine how early sensory experiences with formula impact upon food acceptance during infancy (8-9 months of age) and childhood. The investigators will also explore how variation in the genes that encode for taste receptors influence preferences for foods and other behaviors.
The purpose of this study is to find out whether the hormones in the taste buds are affected by tasting and eating food, and also whether these hormone levels are affected by an increase in body weight or type 2 diabetes.
This study seeks to determine if non-esterified fatty acid (NEFA) taste detection thresholds change with repeated testing. Threshold testing for NEFA taste has been reported by a number of laboratories, including our own; however, these studies have reported data for only one testing occasion. The investigators seek to conduct repeated testing to measure the test-retest reliability of these methods. The investigators believe that with repeated exposure to NEFA, a person's sensitivity increases. The investigators are also testing the efficiency of testing by two methods (forced-choice ascending trial versus staircase). Additionally, the association between taste responses, diet and BMI will be explored.
This single-site, within-subject, experimental study is designed to test the hypothesis that individuals express taste receptors differently and have different sensitivities to bitter taste samples, which results from uneven expression. Subjects will include 100 racially and ethnically diverse, healthy adults. All subjects will provide saliva samples for genetic analysis and undergo taste testing with common psychophysical stimuli. From the pool of 100 subjects, 36 subjects from the common heterozygous group (PAV/AVI) and two from each homozygous group (AVI/AVI, nontaster and PAV/PAV, taster) will be invited to return for two additional sessions. During both sessions the investigators will 1) measure bitterness thresholds for PROP, a common psychophysical stimulus; 2) measure bitterness perception of several vegetables; 3) obtain a saliva sample and 4) collect taste papillae. The investigators will then isolate DNA and RNA from the taste papillae and isolate DNA from saliva to evaluate molecular differences over time and between individuals and how it relates to taste psychophysics. All psychophysical and cellular measurements will be done during both sessions so that the investigators can determine how much variation is observed over a one-week time period in both cellular phenotype and psychophysical phenotype.