Distinct Sensory Hedonic Functions for Sourness in Adults.

Over the last half-century, variable responses to sweetness have repeatedly been shown to fall into a small number of hedonic responses, implying that looking only at group means may can obfuscate meaningfully different response patterns. Comparative data for sourness is quite sparse, especially in adults. While increased liking with higher acid concentration has been reported for some children, in adults, sourness is classically assumed to be aversive, with a monotonic drop in liking with increasing sourness. Here, we test this assumption using a simple model system or experimental beverage in convenience samples of adults from the United States (increasing citric acid in water) and Italy (increasing citric acid in pear juice). Participants rated intensity and liking of sampled stimuli. For both cohorts, we find clear evidence of three distinct patterns of responses: a strong negative group where liking dropped with increased sourness, an intermediate group who showed a more muted drop in liking with more sourness, and a strong positive group where liking increased with more sourness. Strikingly, both cohorts showed similar proportions of response patterns, with ~63-70% in the strong negative group, and 11-12% in the strong positive group, suggesting these proportions may be stable across cultures. Notably, the three groups did not differ by age or gender. These data support the existence of different hedonic response profiles to sour stimuli in adults, once again highlighting the importance of looking at individual differences and potential consumer segments, rather than merely averaging hedonic responses across all individuals within a group.

High arousal as the source of food rejection in food neophobia.

Food neophobia (FN) at moderate to high levels is very common among adult populations in all cultures and is usually defined in terms of rejection of unfamiliar foods. However, food rejection in FN is only partly related to food familiarity. Experimental and survey studies have suggested that unpleasantly high arousal may be induced by food novelty, but also be produced by foods with intense or complex flavours, that are perceived as dangerous or foreign, or that have unusual ingredients. Liking for foods with these characteristics have recently been shown to be strongly negatively associated with FN. Thus, induced high arousal may underlie food rejection in FN. Here, we collected familiarity, liking and arousal ratings, and scores on the standard Food Neophobia Scale from more than 7000 consumers in four countries - Australia, United Kingdom, Singapore, Malaysia - for a series of food names that were manipulated to produce standard and 'high arousal' (variant) versions of the same foods. Consistent across all four countries, arousal ratings increased, and liking decreased, with decreases in food familiarity. Variant food names were always associated with ratings of higher arousal than the standard names. The variant foods were generally less familiar than the standard foods, although this was not a necessary condition for their higher arousal ratings, suggesting that the other arousal-inducing factors (e.g., flavour intensity) also played a role. Across all foods, arousal ratings increased, and liking ratings decreased, as FN increased, but these effects were accentuated for the variant foods. The consistency of these effects across multiple countries supports a view that arousal is universally a strong determinant of liking for foods and that this underlies the rejection of foods, familiar and novel, in FN.

Variations in the Strength of Association between Food Neophobia and Food and Beverage Acceptability: A Data-Driven Exploratory Study of an Arousal Hypothesis.

The negative impact of food neophobia (FN) on food and beverage (F&B) liking extends beyond foods and beverages that are novel. In addition, F&Bs that are high in flavour intensity, perceived as dangerous, or have connections to other cultures are likely to elicit rejection by those high in FN. Each of these factors have been established as producing increased arousal, potentially to an unpleasant degree. The aim of this study was to explore the hypothesis that increased arousal underlies all causes of rejection due to FN. To do this, we analysed and interpreted existing data based on online surveys that measured FN and liking for a broad range of F&B names from 8906 adult consumers in the USA, United Kingdom, Australia, Germany and Denmark. Negative associations between FN and liking of varying strengths were evident for 90% of the F&Bs. Consistent with the arousal hypothesis, F&Bs (a) with high flavour intensity, whether produced by chilli, other spices, or flavours, (b) from other cultures, (c) often perceived as dangerous, or (d) that were novel or had novel ingredients showed the strongest negative relationships between FN and liking. Conversely, F&Bs whose liking scores were only very weakly related to FN had low arousal characteristics: high familiarity, sweetness, mild flavours, strong connections to national food cultures, or some combination of these factors. Since this study was exploratory and conducted on existing data, there was no direct measure of arousal, but this is recommended for future, stronger tests of this arousal hypothesis.

Flavor Profiling by Consumers Segmented According to Product Involvement and Food Neophobia.

The relationship between food-related individual characteristics and performance in sensory evaluation was investigated. The study focused on differences in discriminative ability and perceptual sensitivity according to levels of product involvement or food neophobia during the intensity rating of sensory attributes in consumer profiling. Consumers (N = 247) rated the intensity of attributes for seven flavored black tea drinks and completed the Food Neophobia Scale and the Personal Involvement Inventory measuring product involvement with the flavored black tea drink. In the higher product involvement (IH) group and the lower food neophobia (NL) group, the number of sensory attributes representing the sample effect and of subsets discriminating the samples were greater, and more total variance of the samples was explained. The higher the product involvement or the lower the food neophobia, the greater the differentiation in characterizing samples with more attributes in the intensity ratings. Interestingly, the high food neophobia (NH) group showed less active performance compared to the NL group during the sensory evaluation overall, but the NH group was more concerned about unfamiliar attributes and samples. The results implied that the positive attitude resulting from high product involvement and low food neophobia may induce more active behavior and better performance during the sensory evaluation.

Phenol-Rich Food Acceptability: The Influence of Variations in Sweetness Optima and Sensory-Liking Patterns.

The consumption of phenol-rich foods is limited by their prominent bitterness and astringency. This issue has been addressed by adding sweet tastes, which suppress bitterness, but this is not a complete solution since individuals also differ in their preference for sweetness. In this study, we aimed at identifying groups of consumers differing in sweetness optima and sensory-liking patterns. To this end, increasing concentrations of sucrose were added to a chocolate pudding base. This allowed us to (1) investigate if individual differences in sensory responses are associated with different sweet liking optima in a product context, (2) define the psychological and oro-sensory profile of sweet liker phenotypes derived using a product context, and (3) assess if individuals differing in sweet liking optima differ also in consumption and liking of phenol-rich foods and beverages as a function of their sensory properties (e.g., sweeter vs. more bitter and astringent products). Individuals (1208; 58.4% women, 18-69 years) were characterised for demographics, responsiveness to 6-n-propylthiouracil (PROP), personality traits and attitudes toward foods. Three clusters were identified based on correlations between sensory responses (sweetness, bitterness and astringency) and liking of the samples: liking was positively related to sweetness and negatively to bitterness and astringency in High and Moderate Sweet Likers, and the opposite in Inverted U-Shaped. Differences between clusters were found in age, gender and personality. Furthermore, the Inverted-U Shaped cluster was found to have overall healthier food behaviours and preferences, with higher liking and consumption of phenol-rich vegetables and beverages without added sugar. These findings point out the importance of identifying the individual sensory-liking patterns in order to develop more effective strategies to promote the acceptability of healthy phenol-rich foods.

Leadership Development for Future Medical School Deans: Outcomes of the AAMC Council of Deans Fellowship Program.

PURPOSE: To determine the outcomes of the Association of American Medical Colleges (AAMC) Council of Deans (COD) Fellowship Program with respect to participants' achieving the goals of becoming a medical school dean and developing leadership skills, and to ascertain fellows' views about the program's value, beneficial aspects, and areas for improvement. METHOD: The 37 COD fellows from 2002 to 2016 were invited to participate in a 2017 survey addressing demographics, training, current leadership position, and value of the program. The survey also included 3 open-ended questions. A 2018 web-based search was conducted to determine fellows' senior leadership roles since their program participation. RESULTS: The survey response rate was 73% (27/37). The majority of respondents were male (82%, 22), aged 51-70 (89%, 25), and white (82%, 22). The top 5 medical specialties reported were internal medicine, pediatrics, anesthesiology, psychiatry, and surgery. Most respondents (63%, 17) reported having a graduate degree. All reported being in leadership positions in academia and/or health care. The web-based search found that 27% (10/37) of the fellows became medical school deans (average tenure 5.6 years); 2 fellows became deans of other types of schools. Overall, survey respondents perceived the program as valuable. Respondents identified shadowing a dean mentor, attending COD meetings, and attending the AAMC Executive Development Seminar for Deans as the most valuable program components. The majority (88%, 23/26) indicated their fellow experience persuaded them to pursue being a dean; 2 (8%) indicated it did not. Respondents identified 4 key opportunities for program improvement: more sponsorship by deans, development of a learning community, enhanced mentoring, and coaching. CONCLUSIONS: The COD Fellowship Program appears to be successful in preparing senior faculty to become deans and assume other senior leadership roles in academia and/or health care. Fellows' feedback will be used to inform future revisions to the program.

NetF-producing Clostridium perfringens and its associated diseases in dogs and foals.

The role of type A Clostridium perfringens in canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis is poorly characterized. However, a highly significant association between the presence of novel toxigenic C. perfringens and these specific enteric diseases has been described. These novel toxigenic strains produce 3 novel putative toxins, which have been designated NetE, NetF, and NetG. Although not conclusively demonstrated, current evidence suggests that NetF is likely the major virulence factor in strains responsible for canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis. NetF is a beta-pore-forming toxin that belongs to the same toxin superfamily as CPB and NetB toxins produced by C. perfringens. The netF gene is encoded on a conjugative plasmid that, in the case of netF, also carries another putative toxin gene, netE. In addition, these strains consistently also carry a cpe tcp-conjugative plasmid, and a proportion also carry a separate netG tcp-conjugative plasmid. The netF and netG genes form part of a locus with all the features of the pathogenicity loci of tcp-conjugative plasmids. The netF-positive isolates are clonal in origin and fall into 2 clades. Disease in dogs or foals can be associated with either clade. Thus, these are strains with unique virulence-associated characteristics associated with serious and sometimes fatal cases of important enteric diseases in 2 animal species.

Developing a Culture of Mentorship to Strengthen Academic Medical Centers.

Mentorship is central to academic medicine and its missions, and it has long played a critical role in the training and career development of physicians and scientists. A growing body of literature has documented the positive impact of mentorship on various outcomes, including research productivity, academic promotion, faculty retention, and career satisfaction. These benefits span academic medical centers' missions and have the potential to enhance biomedical research, patient care, education, and faculty diversity and leadership.In this Invited Commentary, the authors argue that a dynamic culture of mentorship is essential to the success of academic medical centers and should be elevated to the level of a major strategic priority. This culture of mentorship would capitalize on an institution's intellectual resources and seek to develop leaders in biomedical discovery, patient care, and education. The bidirectional transmission of knowledge between mentors and mentees, through both formal programs and informal relationships, can foster the growth of faculty members needed to meet the complex challenges currently confronting medical schools and teaching hospitals.Developing a culture of mentorship requires a strong commitment by leaders at all levels to nurture the next generation of physicians and scientists as well as grassroots efforts by trainees and faculty to seek out and create mentorship opportunities. The authors conclude by outlining possible mechanisms and incentives for elevating mentorship to the level of a strategic priority to strengthen academic medical centers across their missions.

Prevalence of Clostridium perfringens netE and netF toxin genes in the feces of dogs with acute hemorrhagic diarrhea syndrome.

BACKGROUND: Recently, novel pore-forming toxin genes designated netE and netF were identified in a Clostridium perfringens type A strain isolated from a dog with acute hemorrhagic diarrhea. OBJECTIVES: Pore-forming toxins could play an important role in the disease pattern of acute hemorrhagic diarrhea syndrome (AHDS) in dogs. Thus, we aimed to determine the prevalence of C. perfringens genes encoding for netE and netF in the feces of dogs with AHDS and to evaluate any association between selected clinical variables and the presence of these toxin genes. ANIMALS: In total, 174 dogs were included in the study. METHODS: Fecal samples of all dogs were tested by real-time polymerase chain reaction for netE and netF genes. Time to recovery, hospitalization time, and selected laboratory variables were compared between dogs with AHDS that were positive or negative for the toxin genes. RESULTS: A significant difference was found among the 3 groups in the prevalence of the pore-forming toxin genes netE and netF: dogs with AHDS: 26 of 54 (48.1%); dogs with canine parvovirus (CPV) infection: 0 of 54 (0%); and healthy dogs: 8 of 66 (12.1%; P < .001). In dogs with AHDS, no significant difference was detected in any variables evaluated between netE-positive and netF-positive and netE-negative and netF-negative dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: The prevalence of C. perfringens encoding for netE and netF is significantly higher in dogs with AHDS compared to control dogs. Further studies are warranted to evaluate whether these toxins are an inciting cause for AHDS in dogs.

Antimicrobial Susceptibility and Clonal Relationship of Tetracycline Resistance Genes in netF-Positive Clostridium perfringens.

NetF-producing type A Clostridium perfringens, a pathotype of C. perfringens, causes necrotizing enteritis in neonatal foals and necrotizing and hemorrhagic enteritis in dogs. Recent core genome multilocus sequence typing study revealed that netF+ C. perfringens strains belong to two distinct clonal populations (clonal complexes I and II). There are no reports on susceptibility to antimicrobial drugs of isolates from this pathotype. The susceptibility to 13 different antimicrobial drugs of 49 netF+ strains recovered from foals or dogs with necrotizing enteritis in Canada, the United States, and Switzerland was assessed using a commercial microdilution panel designed for anaerobic human pathogens. All isolates were highly susceptible to 12 antimicrobial agents, including all beta-lactams tested, such as penicillin G and ampicillin, as well as clindamycin, chloramphenicol, and metronidazole. The isolates consistently presented a reduced susceptibility or resistance to tetracycline, which was associated with previously described tetracycline resistance genes. Clonal complex I isolates (n = 41) possessed the tetA408(P) gene, whereas clonal complex II isolates (n = 8) possessed the tetA(P)-tetB(P) genes and were more likely to be fully resistant.

Sialic acid facilitates binding and cytotoxic activity of the pore-forming Clostridium perfringens NetF toxin to host cells.

NetF-producing type A Clostridium perfringens is an important cause of canine and foal necrotizing enteritis. NetF, related to the ß-sheet pore-forming Leukocidin/Hemolysin superfamily, is considered a major virulence factor for this disease. The main purpose of this work is to demonstrate the pore-forming activity of NetF and characterize the chemical nature of its binding site. Electron microscopy using recombinant NetF (rNetF) confirmed that NetF is able to oligomerize and form large pores in equine ovarian (EO) cell membranes and sheep red blood cells. These oligomeric pores appear to be about 4-6 nm in diameter, and the number of oligomer subunits to vary from 6 to 9. Sodium periodate treatment rendered EO cells non-susceptible to NetF, suggesting that NetF binding requires cell surface carbohydrates. NetF cytotoxicity was also inhibited by a lectin that binds sialic acid, by sialidase, and by free sialic acid in excess, all of which clearly implicate sialic acid-containing membrane carbohydrates in NetF binding and/or toxicity for EO cells. Binding of NetF to sheep red blood cells was not inhibited by the gangliosides GM1, GM2 and GM3, nor did the latter promote membrane permeabilization in liposomes, suggesting that they do not constitute the cellular receptors. In contrast, treatment of EO cells with different proteases reduced their susceptibility to NetF, suggesting that the NetF receptor is a sialic acid-containing glycoprotein.

Individual Variation in PROP Status, Fungiform Papillae Density, and Responsiveness to Taste Stimuli in a Large Population Sample.

Despite considerable research investigating the role of 6-n-propylthiouracil bitterness perception and variation of fungiform papillae density in food perception, this relationship remains controversial as well as the association between the 2 phenotypes. Data from 1119 subjects (38.6% male; 18-60 years) enrolled in the Italian Taste project were analyzed. Responsiveness to the bitterness of 6-n-propylthiouracil was assessed on the general Labeled Magnitude Scale. Fungiform papillae density was determined from manual counting on digital images of the tongue. Solutions of tastes, astringent, and pungent sensations were prepared to be moderate/strong on a general Labeled Magnitude Scale. Four foods had tastants added to produce 4 variations in target sensations from weak to strong (pear juice: citric acid, sourness; chocolate pudding: sucrose, sweetness; bean purée: sodium chloride, saltiness; and tomato juice: capsaicin, pungency). Women gave ratings to 6-n-propylthiouracil and showed fungiform papillae density that was significantly higher than men. Both phenotype markers significantly decreased with age. No significant correlations were found between 6-n-propylthiouracil ratings and fungiform papillae density. Fungiform papillae density variation does not affect perceived intensity of solutions. Responsiveness to 6-n-propylthiouracil positively correlated to perceived intensity of most stimuli in solution. A significant effect of fungiform papillae density on perceived intensity of target sensation in foods was found in a few cases. Responsiveness to 6-n-propylthiouracil positively affected all taste intensities in subjects with low fungiform papillae density whereas there were no significant effects of 6-n-propylthiouracil in those with high fungiform papillae density. These data highlight a complex interplay between 6-n-propylthiouracil status and fungiform papillae density and the need of a critical reconsideration of their role in food perception and acceptability.