Detection thresholds for quinine, PTC, and PROP measured using taste strips.

PURPOSE: In clinical practice, when ability to perceive bitter taste is studied, quinine is preferred to phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) as taste stimulus, because many subjects are genetically non-tasters for PTC/PROP. However, it is poorly known how sensitive anterior (front) and posterior (back) parts of the tongue are to different bitter tastants that are detected by different bitter taste receptors (TAS2Rs). In the present study, we aimed to characterize sensitivity to bitter taste at front and back parts of tongue. METHODS: We measured thresholds for quinine, PTC, and PROP using the "taste strips", employing seven concentrations of each stimulus both at front and back parts of tongue in 203 healthy participants (56% females, mean age 28 years). RESULTS: Our data confirmed the hypothesis that the inability to perceive quinine was less frequent than the inability to perceive PTC and PROP: People can still perceive the bitter taste of quinine even if they are "non-tasters" for PROP/PTC. As expected, strong correlations between PTC and PROP thresholds were observed. Interestingly, correlations between thresholds for quinine and PTC/PROP also emerged. Overall, the detection thresholds were lower when measured at front part of the tongue. CONCLUSIONS: Our data suggest that determining taster status for quinine using paper "taste strips", applied to front part of the tongue, represents a suitable method for the screening for ageusia for bitter taste.

Functional characterization of the TAS2R38 bitter taste receptor for phenylthiocarbamide in colobine monkeys.

Bitterness perception in mammals is mostly directed at natural toxins that induce innate avoidance behaviours. Bitter taste is mediated by the G protein-coupled receptor TAS2R, which is located in taste cell membranes. One of the best-studied bitter taste receptors is TAS2R38, which recognizes phenylthiocarbamide (PTC). Here we investigate the sensitivities of TAS2R38 receptors to PTC in four species of leaf-eating monkeys (subfamily Colobinae). Compared with macaque monkeys (subfamily Cercopithecinae), colobines have lower sensitivities to PTC in behavioural and in vitro functional analyses. We identified four non-synonymous mutations in colobine TAS2R38 that are responsible for the decreased sensitivity of the TAS2R38 receptor to PTC observed in colobines compared with macaques. These results suggest that tolerance to bitterness in colobines evolved from an ancestor that was sensitive to bitterness as an adaptation to eating leaves.

Taste Quality Confusions: Influences of Age, Smoking, PTC Taster Status, and other Subject Characteristics.

Many persons misidentify the quality of taste stimuli, a phenomenon termed "taste confusion." In this study of 1000 persons, we examined the influences of age, sex, causes of chemosensory disturbances, and genetically determined phenylthiocarbamide (PTC) taster status on taste quality confusions for four tastants (sucrose, citric acid, sodium chloride, caffeine). Overall, sour-bitter confusions were most common (19.3%), followed by bitter-sour (11.4%), salty-bitter (7.3%), salty-sour (7.0%), bitter-salty (3.5%), bitter-sweet (3.4), and sour-salty (2.4%) confusions. Confusions for sweet were <1%. Asymmetries were common (e.g., bitter-sour confusions were less frequent than sour-bitter confusions). Women had fewer salty-bitter confusions than did men (5.7% vs. 11.4%). Overall, PTC tasters had fewer confusions than non-tasters except for salty-bitter confusions. Confusions typically increased monotonically with age. Current smokers exhibited more sour-bitter confusions than never smokers (48.9% vs. 32.2%), whereas past smokers had more bitter-sour confusions than never smokers (23.8% vs. 14.2%). Previous head trauma was associated with higher bitter-salty and salty-bitter confusions relative to those of some other etiologies. This study demonstrates, for the first time, that multiple subject factors influence taste confusions and, along with literature accounts, supports the view that there are both biological and psychological determinants of taste quality confusions.

Relationship of Phenylthiocarbamide (PTC) Taster Status to Olfactory and Gustatory Function in Patients with Chemosensory Disturbances.

Poor sensitivity to the bitter taste of phenylthiocarbamide (PTC) and related substances has been associated with a number of diseases. We determined, in patients with chemosensory dysfunction from multiple etiologies, whether PTC "tasters" (n = 511) exhibit less smell and taste dysfunction than their non-PTC-tasting counterparts (n = 432) on a comprehensive battery of olfactory and gustatory tests. The proportion of tasters (54%) in our study population was much lower than that calculated from 11 North American population studies (76.5%; P < 0.0001). This taster/nontaster ratio was maintained across a range of etiologic categories. More women (60.7%) than men (45.5%) were PTC tasters (P < 0.0001). Although PTC tasting status was unrelated to scores on the olfactory tests (which included tests of odor identification, detection threshold, and odor memory/discrimination), tasters significantly outperformed nontasters on suprathreshold identification and intensity taste tests employing both bitter (caffeine) and nonbitter (sucrose, citric acid, sodium chloride) tasting stimuli. Regardless of PTC taster status, women outperformed men on the taste tests. Our findings suggest the possibility that the T2R38 gene may protect against significant olfactory dysfunction, but once such dysfunction becomes manifest at a level where professional help is sought, such protection is not evident. However, other hypotheses for this phenomenon are possible. This study demonstrates that patients with chemosensory disturbances who are PTC tasters outperform their non-PTC taster counterparts in both identifying and perceiving the intensity of a range of suprathreshold tastants, including ones that do not taste bitter.

Differential Activation of TAS2R4 May Recover Ability to Taste Propylthiouracil for Some TAS2R38 AVI Homozygotes.

Bitterness from phenylthiocarbamide and 6-n-propylthiouracil (PROP) varies with polymorphisms in the TAS2R38 gene. Three SNPs form two common (AVI, PAV) and four rare haplotypes (AAI, AAV, PVI, and PAI). AVI homozygotes exhibit higher detection thresholds and lower suprathreshold bitterness for PROP compared to PAV homozygotes and heterozygotes, and these differences may influence alcohol and vegetable intake. Within a diplotype, substantial variation in suprathreshold bitterness persists, and some AVI homozygotes report moderate bitterness at high concentrations. A second receptor encoded by a gene containing a functional polymorphism may explain this. Early work has suggested that PROP might activate TAS2R4 in vitro, but later work did not replicate this. Here, we identify three TAS2R4 SNPs that result in three diplotypes-SLN/SLN, FVS/SLN, and FVS/FVS-which make up 25.1%, 44.9%, and 23.9% of our sample. These TAS2R4 haplotypes show minimal linkage disequilibrium with TAS2R38, so we examined the suprathreshold bitterness as a function of both. The participants (n = 243) rated five PROP concentrations in duplicate, interleaved with other stimuli. As expected, the TAS2R38 haplotypes explained ~29% (p < 0.0001) of the variation in the bitterness ratings, with substantial variation within the haplotypes (AVI/AVI, PAV/AVI, and PAV/PAV). Notably, the TAS2R4 diplotypes (independent of the TAS2R38 haplotypes) explained ~7-8% of the variation in the bitterness ratings (p = 0.0001). Given this, we revisited if PROP could activate heterologously expressed TAS2R4 in HEK293T cells, and calcium imaging indicated 3 mM PROP is a weak TAS2R4 agonist. In sum, our data are consistent with the second receptor hypothesis and may explain the recovery of the PROP tasting phenotype in some AVI homozygotes; further, this finding may potentially help explain the conflicting results on the TAS2R38 diplotype and food intake.

Genetic, functional, and phenotypic diversity in TAS2R38-mediated bitter taste perception.

Mutational polymorphism in the TAS2R38 bitter taste receptor is a key determinant of threshold taste detection of isolated compounds, such as phenylthiocarbamide (PTC) and propylthiouracil (PROP), as well as complex orosensation-mediated traits such as diet choice and smoking habits. These relationships are accounted for, in part, by 2 common alleles differing in functionality, TAS2R38-PAV and TAS2R38-AVI. However, TAS2R38 harbors extensive additional polymorphism whose functional significance remains unknown. To examine this variation, we ascertained genetic diversity in 56 Caucasian subjects via whole-gene sequencing, analyzed allele-specific responses to 5 TAS2R38 agonists (PTC, PROP, goitrin, methimazole, and sinigrin) using in vitro assays, and assessed genotypic associations with threshold detection phenotypes. Sequencing identified 3 single-nucleotide substitutions encoding 3 amino acid changes (C145G/P49A, C785T/A262V, and A886G/I296V), which combined to form 6 haplotypes in our sample. In vitro assays revealed a continuous range of response across alleles, and associations with threshold were significant for all single nucleotide polymorphisms (P < 0.002) and PAV/AVI haplotypes (P < 0.001). Haplotypes other than PAV and AVI did not exhibit phenotypic associations in our sample, possibly as a result of their low frequencies. However, prior studies have indicated that these alleles are common in some global regions, suggesting that alleles rare in our sample may be phenotypically relevant in other populations.

Avoidance of phenylthiocarbamide in mature Targhee and Rambouillet rams.

Shrub encroachment on grasslands is a worldwide issue and sheep are a potential tool for mitigating shrub encroachment. Many shrubs, however, contain bitter-tasting compounds that may deter grazers. Cattle and sheep commonly graze rangelands, but of the two, sheep have a greater tolerance for bitter compounds and would be expected to consume more bitter-tasting vegetation. We hypothesized that sheep could detect (i.e., taste) bitter-tasting compounds and the sensitivity to these compounds would vary from animal to animal. The objective of this study was to determine whether sheep could detect the bitter-tasting compound phenylthiocarbamide (PTC), and if so, what PTC concentration would elicit an avoidance response. Using a crossover study design, mature Rambouillet and Targhee rams (n = 30) were subjected in randomized order to various PTC concentrations mixed in the drinking water (PTC solution). In trials 1 and 2 (n = 15/trial), 0.20, 0.56, 1.57, 4.39, and 12.29 mM and 0.20, 0.43, 0.94, 2.03, and 4.39 mM of PTC were tested, respectively. On test days, PTC solution (trial 1: 1.5 kg; trial 2: 3.0 kg) and water (same amounts) were offered for ad libitum intake in a side-by-side presentation for 1 h in trial 1 and 2 h in trial 2. Each test day was followed by a rest day where PTC solution was replaced with water to limit potential carry over effects into the next test day. Consumption of PTC solution for each PTC concentration was expressed as the percentage of PTC solution intake of total morning fluid intake. There was no effect (P > 0.74) of sequence that rams received PTC solutions on PTC consumption during either trial. As PTC concentration increased, percentage of PTC solution intake decreased (P ≤ 0.01) for both trials. The greatest decrease in percentage of PTC solution intake occurred between 1.57 and 4.39 mM (58%) for trial 1 and 2.03 and 4.39 mM (72%) for trial 2. In trial 2, the least percentage of PTC solution intake was the 4.39 mM PTC concentration, which was different (P ≤ 0.05) from lesser PTC concentrations. All other PTC concentrations did not differ (P > 0.05) from each other in percentage intake. This research suggests rams could taste the PTC, and the concentration at which PTC solution was avoided varied across rams. It may be possible to select sheep, based on demonstrated avoidance of PTC, for targeted grazing applications to manipulate vegetation toward range management goals.

Emotional stability is associated with the MAOA promoter uVNTR polymorphism in women.

BACKGROUND: Neuroticism is associated with low emotional stability, and it is characterized by a tendency to perceive ordinary situations as threatening and difficult to manage. This personality trait has been associated with psychological distress and predicts some mental disorders. Previous studies have shown that women tend to be more neurotic than men and, in general, females have also a higher incidence of anxious and depressive disorders. METHODS: We analyzed in a sample of 99 female university students (from 18 to 26 years old) if emotional stability, measured using the Big Five Questionnaire, was linked to polymorphic variants in candidate genes related to dopaminergic and serotonergic systems, and other personality variables. RESULTS: We found that emotional stability and its subdimensions are genetically associated with MAOA-uVNTR polymorphism. Thus, women carriers of the 3-repeat allele (lower MAO-A expression) showed higher levels of emotional stability. No associations were found with other polymorphisms analyzed, including COMT Val158 Met, 5-HTTLPR, and DAT 3'UTR VNTR. Furthermore, our results showed a negative correlation between emotional stability and depression, state anxiety, and trait anxiety. In fact, MAOA-uVNTR and trait anxiety also explained emotional stability and its subdimensions. We also found that other genetic characteristic, phenylthiocarbamide tasting, explained impulsivity, specifically tasters controlled impulses better than nontasters. CONCLUSION: Our results indicate that neuroticism might be regulated by MAOA and could be a common factor between different phenotypes, such as aggressive behaviors or personality disorders, observed in women with higher activity genotype who had been exposed to negative environments during childhood. This study could lead to a better understanding of the basis of emotional stability and could lead to future projects for this purpose.

Taste disorders are partly genetically determined: Role of the TAS2R38 gene, a pilot study.

OBJECTIVES/HYPOTHESIS: Taste sensitivity varies greatly among individuals influencing eating behavior and health, consequently the disorders of this sense can affect the quality of life. The ability to perceive the bitter of thiourea compounds, such as phenylthiocarbamide (PTC), has been largely reported as a marker of the general taste sensitivity, food preferences, and health. PTC sensitivity is mediated by the TAS2R38 receptor and its genetic common variants. We study the role of the TAS2R38 receptor in taste disorders with the aim of understanding if these can be genetically determined. STUDY DESIGN: Prospective cohort study. METHODS: Differences in the PTC responsiveness between the patients cohort and healthy controls were assessed. All subjects received standardized tests for smell and taste function and were genotyped for the TAS2R38 gene. RESULTS: PAV/PAV homozygous patients gave high PTC ratings, whereas PAV/AVI genotypes reported lower values, which are similar to those determined in AVI/AVI or rare genotypes. In addition, the patients cohort did not meet the Hardy-Weinberg equilibrium at the TAS2R38 locus, showing a very low frequency of subjects carrying the PAV/AVI diplotype. Independently, in healthy controls who were in equilibrium at the locus, PAV/PAV homozygous and heterozygous rated PTC bitterness higher compared to AVI/AVI or rare genotypes. CONCLUSIONS: Our findings, by showing that an only taster haplotype (PAV) is not sufficient to evoke high responses of TAS2R38 receptor in patients with taste disorders, suggest that the genetic constitution may represent a risk factor for the development of taste disorders. LEVEL OF EVIDENCE: 2c Laryngoscope, 129:E307-E312, 2019.

The roles of genes in the bitter taste.

The aims of this review were to understand the roles of bitter taste genes in humans. Some of the peoples have the capacity to taste some chemical substance such as phenylthiocarbamide (PTC) while others cant not based on the dietary hazards and food preferences. There are two alleles responsible to express these phenotypes which are homozygous recessive. In human TAS2R38 genes located on the chromosome number 7 and consist of different nucleotide polymorphism that related to detection of the phenotype of different chemical compounds such as 6-n-propylthiouracil (PROP) and phenylthiocarbamide bitterness and this Gene is the member of the TAS2R genes which are eleven pseudogenes and twenty that has roles in many biological processes. There are many factors that affect the bitter taste such as food, age, sex, and different diseases. The mechanism of food bitter taste and genotype of TAS2R38 until know not well understood due to that the proof of relation between bitter taste sensitivity and food is harmful. there are many different diseases can impact the influence of taste such as neoplasm and lifestyle such as consumption of alcohol along with the use of medication, head trauma, upper tract infections. On the other hand, A relation between TAS2R38 genotype and meal preferences has been observed among children, however, no associations have been mentioned among older adults. Some previous research proved some vital points that show an association between type 1 of diabetes and phenylthiocarbamide (PTC) but other studies cannot demonstrate that. However, of other disease such as obesity is controversial but other studies reported to the relationship between them.

Recognition of phenylthiocarbamide (PTC) in taste test is related to blood group B phenotype, females, and risk of developing food allergy: a cross-sectional Brazilian-based study.

Anti-nutritional factors, including hemagglutinins, are natural substances that reduce nutritional bioavailability and/or generate adverse physiological effects. Most are bitter toxic compounds, but present chemo-protective properties at low concentrations. Responses to phenylthiocarbamide (PTC) allow for an evaluation of humans' perception of bitter taste, a perception that has evolutionary advantages. Therefore, we hypothesized that relationships between food preference, dietary exposures and disease risk could reflect possible associations not only with the recognition threshold for the bitter taste of PTC, but also with ABO/Rh blood group phenotypes. To test this hypothesis, 375 volunteers of both genders, aged 16-49 years, were recruited. Data were obtained from laboratory tests and questionnaires. PTC test followed literature; blood typing used commercially available sera. Allele frequencies calculated from phenotypes were: T=0.51, t=0.49 (PTC); IA=0.22, IB=0.08, i=0.70 (ABO); D=0.57, d=0.43 (Rh). Associations with the recognition threshold for bitter taste were found for blood group B, females, and risk of developing food allergy for bitter taste at PTC dilution 1 (the highest concentration) (OR=3.862; 95%CI=1.387-10.756; p=0.016); for each more diluted PTC solution, the chance of food allergy fell 25.2% (95%CI = 0.764-0.836), while for each more concentrated solution the chance of food allergy increased 20.1% (p=0.000). There were also nominally significant differences among PTC tasting, ABO/Rh, genders and age-groups in relation to food preferences. Results demonstrated that the ability to recognize PTC in taste test is related to blood group B, females, and risk of developing food allergy, thus confirming the research hypothesis, and presenting original and important associations.

Evolution of phenylthiocarbamide taster trait in Mysore, South India.

BACKGROUND: The ability to taste phenylthiocarbamide (PTC), a bitter chemical has long been known to be a heritable trait, which is being widely used for both genetic and anthropological studies. The frequency of taster and non-taster allele is found to vary in different populations. AIMS AND OBJECTIVE: To investigate the frequency of taster trait in Mysore, South India. MATERIALS AND METHODS: The present investigation was conducted in Mysore, South India during 2002 - 2003. About 3282 subjects irrespective of age, sex, religion, food habits, socio-economic status were randomly selected from various parts of the city and a total of 180 families, which included Christian (50), Hindu (61) and Muslim (69) were screened from different localities of the city. Harris and Kalmus method was used to assess the PTC taster and nontaster phenotype. RESULTS: It was found that tasters were significantly more frequent than nontasters in all the four categories. The incidence of tasters was more in unbiased category (85%) and less in Muslim category (58%). Investigations on PTC tasting in the families of three different religious groups revealed that the tasters were significantly more frequent than nontasters. It was also found that heterozygous father or mother for the taster genes with nontaster partner had taster and nontaster progenies in the ratio 1.0: 1.54 indicating the deviation in the segregation pattern of test cross. CONCLUSION: In Mysore, tasters are more frequent than nontasters. Variation in the frequency of nontaster allele in the religious groups could be due to inbreeding.

Correlation of T2R38 taste phenotype and in vitro biofilm formation from nonpolypoid chronic rhinosinusitis patients.

BACKGROUND: Sinonasal biofilms have been demonstrated in specimens collected from chronic rhinosinusitis (CRS) patients. Mounting evidence suggests that biofilms contribute to therapeutically recalcitrant CRS. Recently, the bitter taste receptor T2R38 has been implicated in the regulation of the sinonasal mucosal innate immune response. TAS2R38 gene polymorphisms affect receptor functionality and contribute to variations seen in sinonasal innate defense as well as taste perception reflected in gustatory sensitivity to the bitter compound phenylthiocarbamide (PTC). In a population of CRS patients with active infection or inflammation, we sought to determine if a correlation between T2R38 phenotype and in vitro biofilm formation existed. METHODS: Endoscopically guided sinonasal swabs were obtained prospectively from CRS (±polyp) patients with evidence of persistent inflammation or mucopurulence. In vitro biofilm formation was assessed with a modified Calgary Biofilm Detection Assay. Patients' phenotypic (functional) expression of the bitter taste receptor T2R38 was evaluated with a taste test including the compound PTC. Linear regression was used to determine the level of significance between mean in vitro biofilm formation levels and mean PTC taste test intensity ratings across CRS patients. RESULTS: Sinonasal swabs were obtained from 59 patients, with 42 of the 59 samples demonstrating in vitro biofilm formation. Analysis revealed an inverse linear association between in vitro biofilm formation and PTC taste intensity ratings (p = 0.019) for all patients. This association was exclusively driven by nonpolypoid CRS patients (p = 0.0026). CONCLUSION: In vitro biofilm formation from sinonasal clinical isolates is inversely correlated with PTC taste sensitivity in nonpolypoid CRS patients.

Taste perception and sensory sensitivity: Relationship to feeding problems in boys with Barth Syndrome.

BACKGROUND: Feeding problems are common in boys with Barth syndrome and may contribute to the population's propensity for growth delay and muscle weakness. The purpose of this study was to quantify and describe these feeding issues and examine altered taste perception and sensory sensitivity as contributing factors. METHODOLOGY: A cross-sectional, two-group comparison design was used to examine feeding preferences and behaviors, chemical taste perception, and sensory sensitivities in fifty boys with (n=24) and without (n=26) Barth ages 4-17 years. Taste perception was measured using chemical test strips saturated with phenylthiocarbamide (PTC) and sodium benzoate (NaB). Feeding problems were documented by parents using a Food Inventory, while sensory sensitivities were recorded using a Short Sensory Profile. RESULTS: Boys with Barth differed significantly from typical peers with regards to problem feeding behaviors. For boys with Barth, food refusal and food selectivity were identified as being present in 50% the sample, while 70% of had identified problems related to gagging or swallowing foods. About half of all Barth families noted that their child's eating habits did not match the family's and that separate meals were often prepared. As demonstrated in previous research, about 50% of boys with Barth demonstrated probable or definite differences in taste/smell sensitivity, which was significantly higher than controls. On tests of chemical taste perception, boys with Barth were significantly more likely to be supertasters to PTC and non-tasters to NaB. Taster-status did not directly relate to the presence of feeding problems, however, taste/smell sensitivity did significantly relate to food selectivity by type and texture. CONCLUSIONS: Results indicate feeding problems in at least 50-70% of boys with Barth syndrome, and suggest that behaviors are often present before 6 months of age. Differences in taste perception may influence dietary choices in boys with Barth, particularly their craving of salty foods. Taste/smell sensitivity also appears to influence food selectivity, and therefore may be important to consider in this population, particularly in light of dietary influences on cardiac function, energy consumption, and overall growth.

A avaliação da sensibilidade à feniltiocarbamida em docentes de uma faculdade privada / The assessment of sensitivity to phenylthiocarbamide in teachers of a private college / La evaluación de la sensibilidad a la feniltiocarbamida en profesores de un colegio privado

Avaliar a sensibilidade gustativa a proteína PTC nos docentes de uma faculdade privada de Goiás, associando esta sensibilidade gustativa à ingestão de alimentos que contém essa substância, hábitos socioculturais e alimentares. Método: A avaliação da sensibilidade ao composto PTC (Feniltiocarbamida) ocorreu junto a 40 docentes de uma faculdade privada do estado de Goiás após administração oral de uma gota da solução de concentração 0,01% do composto, seguida pela aplicação do questionário para avaliar à substância testada. Os dados foram analisados no programa EpiInfo versão 7.2.3.0. Para se verificar a associação entre a sensibilidade gustativa ao PTC e as variáveis dependentes. utilizou-se os testes do qui-quadrado ou o teste exato de Fisher. Resultados: Observou-se que 65% dos docentes recrutados apresentam sensibilidade ao PTC. De 40 participantes, 47,5% eram do sexo feminino e 52,5% do sexo masculino. A população era da faixa etária entre 24 e 62 anos. Após a administração da solução do composto PTC (0,01%), a sensibilidade ao sabor amargo foi a mais relatada. Não houve associação entre a sensibilidade gustativa ao PTC e as variáveis estudadas. Conclusão: A inclusão na dieta de alimentos considerados saudáveis, associados ao sabor amargo, pode também ser influenciada pelo grau de sensibilidade e tolerância à esses alimentos.

To evaluate the taste sensitivity to PTC protein in the teachers of a private college in Goiás, associating this taste sensitivity to the ingestion of foods that contain this substance, sociocultural and eating habits. Method: The sensitivity assessment to the compound PTC (Phenylthiocarbamide) occurred with 40 teachers from a private college in the state of Goiás after oral administration of a drop of the 0.01% concentration solution of the compound, followed by the application of the questionnaire to evaluate the tested substance. The data were fulfilled using the EpiInfo program version 7.2.3.0. To verify an association between taste sensitivity to PTC and as dependent dependents. chi-square tests or Fisher's exact test are used. Results: It was observed that 65% of the recruited professors are sensitive to PTC. Of the 40 participants, 47.5% were female and 52.5% male. The population was between 24 and 62 years old. After administration of the PTC compound solution (0.01%), sensitivity to bitter taste was the most reported. There was no association between taste sensitivity to PTC and the variables studied. Conclusion: The inclusion in the diet of foods considered considered, associated with the bitter taste, can also be influenced by the degree of sensitivity and tolerance to these foods.

Evaluar la sensibilidad gustativa a la proteína PTC en los profesores de un colegio privado de Goiás, asociando esta sensibilidad gustativa a la ingestión de alimentos que contienen esta sustancia, hábitos socioculturales y alimentarios. Método: La evaluación de sensibilidad al compuesto PTC (Feniltiocarbamida) se realizó con 40 profesores de un colegio privado en el estado de Goiás luego de la administración oral de una gota de la solución de concentración al 0.01% del compuesto, seguida de la aplicación del cuestionario para evaluar la sustancia probada. Los datos se cumplieron utilizando el programa EpiInfo versión 7.2.3.0. Verificar una asociación entre la sensibilidad gustativa a PTC y como dependientes dependientes. Se utilizan pruebas de chicuadrado o la prueba exacta de Fisher. Resultados: Se observó que el 65% de los profesores reclutados son sensibles al PTC. De los 40 participantes, el 47,5% eran mujeres y el 52,5% hombres. La población tenía entre 24 y 62 años. Después de la administración de la solución del compuesto PTC (0,01%), la sensibilidad al sabor amargo fue la más notificada. No hubo asociación entre la sensibilidad gustativa al PTC y las variables estudiadas. Conclusión: La inclusión en la dieta de los alimentos considerados considerados, asociados al sabor amargo, también puede estar influenciada por el grado de sensibilidad y tolerancia a estos alimentos.

Prevalence and Genetic Analysis of Bitter Taste Perception for Phenylthiocarbamide (PTC) Among Some Muslim Populations of Uttar Pradesh, India.

BACKGROUND: The ability to taste Phenylthiocarbamide (PTC), a bitter organic compound, described as a bimodal autosomal trait is widely used to know the heritable trait in both genetic and anthropological studies. The present study was carried out to analyze the prevalence of PTC taste sensitivity and to determine the gene frequencies among some Muslim populations of Uttar Pradesh, India. This study has some physiological relevance to highlight the adaptability of endogamous groups to behavioral traits in the same place. METHODS: Unrelated, healthy individuals of both sexes (Male-403, Female-418) belonging to different populations of Uttar Pradesh, India were randomly selected with the age range of 16-45 years observed for phenylthiocarbamide to taste sensitivity. PTC tasting ability was measured by using a serial dilution method of Harris and Kalmus. RESULTS: The phenotypic frequency of tasters was higher as compared to non-tasters, and the same is statistically significant (χ(2)= 11.92, df = 5, P = 0.036). There were more females among tasters (67.94%) than males (64.76%). This observation was statistically significant (χ(2) = 14.79, df = 5, P = 0.011). CONCLUSION: The frequency of PTC tasters is greater than non-tasters and the females have lower non-taster pheno-types as compared to males. This type of study will provide background information about genetic structure of population and serves as useful interaction of genetics, food preferences and dietary patterns.

An examination of associations between the inability to taste phenylthiocarbamide (PTC) and clinical characteristics and trait markers in first-episode, nonaffective psychotic disorders.

Research findings are mixed as to whether or not the inability to taste phenylthiocarbamide (PTC) might represent an endophenotypic trait marker for schizophrenia. We hypothesized associations between PTC-tasting status and select clinical characteristics and trait markers in patients with psychotic disorders that, if present, would provide support for the inability to taste PTC as a trait marker. In a first-episode psychosis sample (n=93), we measured PTC tasting, family history of psychosis, age at onset of prodrome and psychosis, severity of positive and negative symptoms, global impairment in functioning, neurological soft signs, and four neurocognitive domains (verbal learning/memory, visual learning/memory, verbal working memory, and spatial working memory). Associations between PTC-non-tasting and clinical/neurocognitive variables were examined with χ(2) tests and independent samples t tests. Among participants, 67.7% tasted PTC in comparison to a strip of control paper, and 25.8% were non-tasters. Tasters and non-tasters did not show statistically significant differences with respect to family history, age at onset, severity of symptoms, neurological soft signs, or the four neurocognitive domains. In conjunction with other findings, it is unlikely that PTC-non-tasting is a trait marker of schizophrenia, though a conclusive study is warranted.

Role of phenylthiocarbamide as a genetic marker in predicting the predisposition of disease traits in humans.

The main objective of this study is to find out the genetic variation and predisposition of overweight/obese, smoking/alcoholism and thyroid disease traits among tasters and non-tasters in Mysore population, South India. Bitter-taste perception for phenylthiocarbamide (PTC) is a classically variable trait both within and between human populations. Many studies have reported that in world population, approximately 30% of them are PTC non-tasters and 70% are tasters. This investigation was conducted during the year 2009-2010 involving a total 1352 study subjects and divided into three different groups, considering the age ranging from 13 to 50 years. Phenylthiocarbamide taste sensitivity was measured by administering a freshly prepared 0.025% of phenylthiocarbamide solution using the Harris and Kalmus method with a slight modification and the results were recorded. In the first group of 100 obese/overweight children, 28% are taster and 72% are non-taster and among 100 control group 67% are tasters and 43% are non-tasters. In second group, out of 1152 individuals 710 (61.63%) are tasters and 442 (38.37%) are non-tasters including both males and females. In the third group, out of each 100 thyroid patients and the control group, tasters are significantly more frequent (61.41%) than the non-tasters (38.58%) in the control group, but a higher proportion of non-tasters are recorded among individuals with thyroid problems (68%) compared to tasters (32%). There is a significant higher incidence of PTC tasters than non-tasters among general population in this study. As phenotypic variation in PTC sensitivity is genetic in origin, this may represent a surrogate risk factor for the development of multifactorial disease and disorders.

[Study of gustatory sensitivity to phenylthiocarbamide in thyroid diseases].

The aim of the study was to reveal a relationship between gustatory sensitivity to phenylthiocarbamide (PTC) and thyroid disease. The distribution of PTC sensitivity was studied in 198 healthy individuals, 100 patients with autoimmune thyroiditis (AIT), 139 patients with nodular euthyroid goiter, and 100 patients operated on for thyroid cancer. There was a statistically significant decrease in the number of PTC-resistant male and females patients in the thyroid cancer group and an increase in the proportion of PTC-resistant male patients in the AIT and nodular euthyroid goiter groups.