CNS: afferent mechanisms with emphasis on physiological and behavioral correlations.
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Auditory Cortex↗
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[A case of penetrating cerebellar injury (author's transl)].
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Adolescent↗
Effects of xerostomia on perception and performance of swallow function.
BACKGROUND: Head and neck cancer treatment with high-dose chemoradiation may cause xerostomia and affect the patient's perception of swallowing ability. METHOD: Whole saliva production was measured in 36 patients with advanced-stage cancer of the oropharynx before treatment and 3 months after treatment by weighing a 4 x 4 inch gauze before and after a 2-minute chewing period. Presence of multiple eating difficulties was measured by patient interview. Swallowing was examined videofluorographically (VFG). RESULTS: Saliva weight decreased from a mean (SEM) of 5.1 (0.5) g pretreatment to 1.4 (0.5) g after treatment (p<.0001). At 3 months, significantly more patients perceived difficulty swallowing, dry mouth, needing water while eating, food stuck in the mouth or throat, and change in taste. Saliva weight was not correlated with VFG measures of bolus transit or observations of residue. CONCLUSIONS: Chemoradiation treatment results in xerostomia and a significant increase in patient perception of swallowing difficulties. Saliva weight in patients who perceive swallowing problems was lower. Xerostomia did not affect the physiologic aspects of bolus transport. Xerostomia affected the sensory process and comfort of eating more than bolus transport.
Adult↗
Gustative sensitivity to glucose improvement in diabetics after sulphonylurea.
Sensitivity of the gustatory receptor to glucose has been studied in 20 diabetic patients given tolbutamid and glibenclamid as treatment or examined in the tolbutamid tolerance test (TTT). Tolbutamid and glibenclamid treatment significantly improves the diabetic taste for glucose, both for detection threshold (DT) (p less than 0.01) and recognition threshold (RT) (p less than 0.001). Also in TTT there is a significant improvement of taste reception: DT falls at 2 h (p less than 0.05), RT falls more slowly at 3 h (p less than 0.05). There is no direct correlation between perception for sweet and glycemia and insulinemia increase in TTT. Our results suggest that glucose receptivity is dependent on a receptor glucose-insulin complex, and tolbutamid (and glibenclamid) besides its capacity to stimulate insulin secretion has even a peripheral action, at this receptor level.
Adolescent↗
The relationship between phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) taster status and taste thresholds for sucrose and quinine.
OBJECTIVE: The aim of this study was to investigate the relationship of taster status with taste detection and recognition thresholds for sucrose and quinine. DESIGN: Sixty-nine subjects (35 men and 34 women; mean age, 23.9+/-1.2 years) were included. Stimulus fluids were prepared, one each for phenylthiocarbamide (PTC), 6-n-propylthiouracil (PROP), sucrose and quinine HCl. In each series, successive solutions, which comprised a total of 15 grades, differed by 0.25log units of the molar concentration. Two concentrations of NaCl (0.32 and 1.0 M) were prepared. The subjects were classified as nontasters and tasters using their PTC and PROP perceptions. Tasters were classified as medium-tasters and supertasters by the ratio of perceived bitterness of above-threshold PROP relative to the perceived saltiness of NaCl (PROP ratio). Taste detection and recognition thresholds for sucrose and quinine were determined by standard two-alternative forced choice trials. A Student's t-test, a Pearson's correlation analysis and linear contrasts in a one-way analysis of variance (ANOVA) were used. RESULTS: The percentages of nontaster, medium-taster and supertaster were 13, 70 and 17%, respectively. There were no significant gender differences in the taste detection and recognition thresholds for sucrose and quinine. The threshold for PTC and PROP showed significant correlations with taste threshold for quinine. Linear contrast in one-way ANOVA showed that the greater the value of PROP ratio, the more sensitive to sweet and bitter tastes (p<0.001). CONCLUSION: The PTC and PROP taster status is closely related with taste detection and recognition thresholds for sucrose and quinine.
Adult↗
Time-intensity evaluation of acid taste in subjects with saliva high flow and low flow rates for acids of various chemical properties.
The role of the chemical properties of sour stimuli and the role of the human saliva flow rate on acid perception were investigated in 11 high saliva flow rate (HF) and 11 low saliva flow rate (LF) subjects with a continuous stimulus delivery flow rate of 3.2 ml/min and using the time-intensity technique for perception recording. Continuously measuring the pH on the tongue surface on three HF and three LF subjects showed that HF subjects' saliva decreased the acidity of the acid solution more efficiently than the LF subjects' saliva did. However, HF subjects exhibited higher perceived intensity for acid solutions than LF subjects. At equal pH, the order of the efficiency of acids indicated that HCl was the least efficient acid stimulus and acetic acid the most efficient. At equal concentration, the order of efficiency was the opposite (citric acid > malic acid > lactic acid > acetic acid), indicating that titratable acidity rather than pH has to be considered when comparing weak acids. At high concentrations, the ratio of relative efficiency is more in favor of the hydrophobic than the hydrophilic acid in HF subjects compared with LF subjects, i.e. HF subjects are more sensitive to hydrophobic stimuli. Hydrophobic molecules may diffuse more easily into the epithelium of HF than LF subjects, and reach more efficiently trigeminal nerve endings in addition to taste receptor cells.
Acetic Acid↗
Aesthetic experience, medical practice, and moral judgement. Critical remarks on possibilities to understand a complex relationship.
The aim of the paper is to examine the possible relationships between the different dimensions of aesthetics on the one hand, and medical practice and medical ethics on the other hand. Firstly, I consider whether the aesthetic perception of the human body is relevant for medical practice. Secondly, a possible analogy between the artistic process and medical action is examined. The third section concerns the comparison between medical ethical judgements and aesthetic judgement of taste. It is concluded that the mutual relevance between the aesthetic sphere, moral judgement and medical practice can be understood only if we recognize these spheres as distinct.
Esthetics↗
Taste as a factor in the management of nutrition.
The sense of taste lies at the interface between the external and internal milieux, at the point at which the animal must decide which chemicals from the environment to incorporate into itself. Accordingly, taste is organized along a neural dimension of nutrients versus toxins, which corresponds to a behavioral dimension of acceptance versus rejection, and to a hedonic dimension of appetitive versus aversive qualities. Reflexive responses, cognitive analyses, and hedonic reactions appear to be managed at different levels of the nervous system. At the first central relay, the nucleus of the solitary tract, somatic reflexes for acceptance or rejection, and autonomic reflexes anticipating digestion are orchestrated. At the second, the parabrachial nucleus of the rodent, associative mechanisms important to the development of conditioned aversions and sodium appetite are manifested. In the thalamic taste relay, gustatory memories associated with non-visceral events may be formed. Primary taste cortex appears to be the site for a cognitive evaluation of gustatory quality and intensity. Finally, a hedonic assessment of the chemical may be made in secondary taste cortex and in the ventral forebrain sites to which it projects. With this assessment comes integration of the gustatory signal with those from other senses, perhaps to create a perception of flavor. Therefore, a sequence that begins with an analysis of the molecular structure of a chemical in the mouth serves to incorporate that gustatory component into an appreciation of flavor, and to participate in the control of motivational processes that guide dietary selection.
Animals↗
An experimental study of the relationship between thoughts and eating behaviour in bulimia nervosa.
This study tested the hypothesis that cognitive disturbance has a causal role in the maintenance of disturbed eating in bulimia nervosa. Thoughts about eating, weight and shape were activated in one group of patients with bulimia nervosa (the experimental group) but not in another (the control group). There was an increase in negative self-statements in the experimental group following the experimental manipulation. Food consumption was then measured in a taste test. As predicted, the experimental group ate less in the short term than the control group. Contrary to expectations, they did not subsequently report more objective bulimic episodes as a consequence of this decreased food intake. They did, however, report significantly fewer subjective bulimic episodes.
Adult↗
Plants and animals: a different taste for microbes?
Plants and animals can recognize potential pathogens by detecting pathogen-associated molecular patterns (PAMPs). Significant advances over the past few years have begun to unveil the molecular basis of PAMP perception by pattern recognition receptors (PRRs). Although these discoveries highlight common recognition strategies among higher eukaryotes, they also show differences with respect to the nature of the receptors involved and the exact molecular patterns recognized. This suggests a convergent evolution of microbe sensing by the innate immune systems of these various organisms.
Animals↗
Human development and umami taste.
Previously we demonstrated that in very brief, one-bottle intake tests, human infants, both well nourished and protein calorie malnourished, ingested greater amounts of soup with added MSG compared with soup alone. The potentiating effect of MSG in plain aqueous solution was tested in the current experiments. In contrast to data with sucrose and salt solution, where infants preferentially ingest these compounds compared with a water diluent, aqueous MSG solutions were rejected relative to water. The implications of this observation for understanding the mechanisms of MSG perception and pleasantness were discussed.
Child Development↗
The effect of color on perceived flavor intensity and acceptance of foods by young adults and elderly adults.
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Adult↗
Volatile flavor release from foods during eating.
Classical analyses for volatile flavors (headspace or distillation/extract methods) give information on either the volatiles present in the air above a food before eating or the total volatile composition of the food. When foods are eaten, however, many changes take place (such as hydration/dilution with saliva, increase in surface area, etc.) that affect the release of volatiles from the food and therefore the profile of volatiles that are sensed in the nose. If we wish to study the relationship between flavor volatiles and the sensory properties of a food, it seems logical to measure the volatile profile that exists during eating. Although volatile flavor release during eating has been measured using a variety of sensory and psychophysiological analyses, only recently have instrumental methods been developed to measure the release of volatile compounds in humans as they eat. Whereas the sensory data give an overall measure of flavor perception, instrumental analyses can potentially follow the release of each and every flavor volatile and thus give a full picture of the aroma profiles generated during eating. From these instrumental measurements, a number of key factors have been identified. First, it has been shown that the volatile profile measured during eating is indeed different from the headspace profile of whole foods. Second, it is clear that the volatile profile in-mouth changes with time as the state of the food changes with chewing. Third, the volatile release from low-water foods is affected by the rate and extent of hydration in-mouth. The ability to measure aroma before, during, and after eating may lead to an understanding of the links between aroma release, interaction of volatiles with aroma sensors in the nose, and the overall perception of food flavor.
Eating↗
Turbidity as a measure of salivary protein reactions with astringent substances.
Binding of tannins to proline-rich proteins has been proposed as an initial step in the development of astringent sensations. In beer and fruit juices, formation of tannin-protein complexes leads to the well-known effect of haze development or turbidity. Two experiments examined the development of turbidity in human saliva when mixed with tannins as a potential in vitro correlate of astringent sensations. In the first study, haze was measured in filtered human saliva mixed with a range of tannic acid concentrations known to produce supra-threshold psychophysical responses. The second study examined relationships among individual differences in haze development and the magnitude of astringency ratings. Mostly negative correlations were found, consistent with the notion that high levels of salivary proteins protect oral tissues from the drying effects of tannic acid.
Adolescent↗
The psychological and physiological effects of an intensive-care unit environment on healthy individuals.
OBJECTIVE: The ideal inpatient environment would be one in which patient stress and anxiety are alleviated, but current inpatient hospital settings often do not seem to take this fact into consideration. To date, the effects of the actual hospital environment itself on patients is poorly understood. The purpose of the present study was to investigate the types of psychological and physiological changes that people undergo in response to being placed in an inpatient setting. DESIGN AND SETTING: Ten healthy volunteers were admitted to an intensive-care unit (ICU) for 4 days and 3 nights. The psychological and physiological changes before and after admission were examined. A qualitative assessment was also performed. RESULTS: Most healthy individuals at times develop feelings of depression, which can be measured by the Profile of Mood States and the Zung Self-Rating Depression Scale (P < .05). In this study, participants' fatigue and confusion increased (P < .05) and vigor decreased (P < .01) as measured by the Profile of Mood States. There was also an increase in the General Health Questionnaire scores (P < .01). However, no significant physiological effects were apparent, as measured by peripheral lymphocyte counts, natural killer cells activity, and urinary 17-kerosteroid and 17-hydroxycorticosteroid levels. Subjects often engaged in introspection during hospitalization and often had a negative attitude towards the hospital environment. CONCLUSIONS: The findings of increased feelings of depression attributable solely to being in an ICU setting are inconsistent with the type of environment generally considered necessary to alleviate patient anxiety and tension in a critical-care-ward environment. The negative perception of this environment strongly suggests room for improvement. Efforts in this regard should focus on improving the five senses, particularly sight, sound, and taste within the ICU.
Critical Care↗
Public thresholds for chlorinous flavors in U.S. tap water.
Considering this rapid growth in the purchasing of bottled water and home filtration devices, utilities are increasingly concerned about consumer dissatisfaction with tap water quality. This project aimed to characterize public perceptions of chlorinous flavors in drinking water, and how these impact customers' choices with respect to consumption of tap water alternatives. On-site taste tests at seven water utilities with 30 to 40 panelists at each site, were conducted using a forced-choice triangle test method (ASTM method E679-91) to measure public sensitivity to chlorine and chloramine in drinking water. The chlor(am)ine concentration increased from set to set. The best-estimate sensitivity limit for each panelist was the geometric mean of that concentration at which the last miss occurred and the next (adjacent) higher concentration. The measured sensitivity limit of average American populations to free chlorine (159 persons tested) and chloramine (93 persons tested) in tap water were 0.8 and 3.7 mg/L Cl2, respectively. These thresholds are much higher than those previously reported in the literature using trained FPA panels. No significant differences were observed between tap water users and users of tap water alternatives or between the various markets tested with respect to average sensitivity, though individual sensitivity varied widely.
Community Participation↗
The study of sensory and learning processes of the newborn.
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Color Perception↗
Basic anatomy and physiology of olfaction and taste.
The chemical senses of taste and smell are important to survival and quality of life. Both senses rely on the binding of odorant molecules to receptors located on the receptor cells. Olfaction and gustation have complex systems of coding, but they display differing methods for coding the receptor stimulus. Both have numerous central projections that allow for the perception and interpretation of these important sensory inputs.
Chemoreceptor Cells↗