A novel in vitro microbial-based model for studying caries formation--development and initial testing

We report on the development and the initial testing of a new microbial-based caries model. Specimens were fixed on a rotating mount within a reaction chamber hermetically surrounded by a sterilised glove box. A cariogenic environment was obtained by inoculation with Streptococcus mutans (ATCC 25175) combined with a continuously repeating supply of sucrose solution, trypticase soy broth and artificial saliva applied by dripping. Twenty-five caries-free upper premolars were used. The mesial parts of the occlusal fissures had been sealed with a resin-based fissure sealant (test group 1). To produce marginal gaps, the distal parts had been moistened with saliva before resin application (test group 2). Five teeth served as control and were exposed to all fluids under sterile conditions before being removed from the system after 7 days. Test specimens were infected with S. mutans and were incubated for another 14 days. No unintentional contamination occurred during the 3-week period of operation. Demineralizations were evaluated by using confocal laser scanning microscopy. Only the test specimens showed clearly visible signs of biofilm formation and caries-like lesions. The mean primary lesion depth did not differ significantly between test groups. Wall lesion depths and surface areas of demineralizations underneath the fissure sealants were significantly higher in test group 2. Thus, our model allows the simultaneous production of primary and secondary caries-like enamel lesions in a considerable number of specimens and facilitates the possibility to manipulate and transfer them without necessarily terminating the experiment, opening new possibilities for in vitro caries research.     

Genetic Risk For Nicotine Dependence in the Cholinergic System and Activation of the Brain Reward System in Healthy Adolescents

Genetic variation in a genomic region on chromosome 15q25.1, which encodes the alpha5, alpha3, and beta4 subunits of the cholinergic nicotinic receptor genes, confers risk to smoking and nicotine dependence (ND). Neural reward-related responses have previously been identified as important factors in the development of drug dependence involving ND. Applying an imaging genetics approach in two cohorts (N=487; N=478) of healthy non-smoking adolescents, we aimed to elucidate the impact of genome-wide significant smoking-associated variants in the CHRNA5–CHRNA3–CHRNB4 gene cluster on reward-related neural responses in central regions such as the striatum, orbitofrontal and anterior cingulate cortex (ACC), and personality traits related to addiction. In both samples, carriers of the rs578776 GG compared with AG/AA genotype showed a significantly lower neural response to reward outcomes in the right ventral and dorsal ACC but not the striatum or the orbitofrontal cortex. Rs578776 was unrelated to neural reward anticipation or reward magnitude. Significantly higher scores of anxiety sensitivity in GG compared with AG/AA carriers were found only in sample 1. Associations with other personality traits were not observed. Our findings suggest that the rs578776 risk variant influences susceptibility to ND by dampening the response of the ACC to reward feedback, without recruiting the striatum or orbitofrontal cortex during feedback or anticipation. Thus, it seems to have a major role in the processing of and behavioral adaptation to changing reward outcomes.     

The hemodynamics of vein grafts: Measurement and meaning

Summary The long-term patency of infrainguinal vein grafts appears to depend primarily on the size and quality of the venous conduit. Therefore, those quantities which directly relate to the conduit’s ability to act as a transporter of blood, namely internal diameter and longitudinal impedance (Z _L ), have predictive value for patency. Autologous grafts of good quality frequently remain patent even with compromised outflow. Therefore, those quantities that are outflow dependent, including ‡P, flow, velocity, shear stress, and resistance, carry less predictive value for long-term performance.     

Iliac bone defects revealing systemic sarcoidosis

Bone lesions are fairly uncommon in sarcoidosis (5 to 10% of cases). We report the case of a 40-year-old man in whom sarcoidosis of the lungs and bones was revealed by excruciating buttock and sacral pain. Computed tomography showed multiple punched-out defects in the left iliac bone. No similar cases have been reported in the literature.     

A target sample of adolescents and reward processing: same neural and behavioral correlates engaged in common paradigms?

Adolescence is a transition period that is assumed to be characterized by increased sensitivity to reward. While there is growing research on reward processing in adolescents, investigations into the engagement of brain regions under different reward-related conditions in one sample of healthy adolescents, especially in a target age group, are missing. We aimed to identify brain regions preferentially activated in a reaction time task (monetary incentive delay (MID) task) and a simple guessing task (SGT) in a sample of 14-year-old adolescents (N?=?54) using two commonly used reward paradigms. Functional magnetic resonance imaging was employed during the MID with big versus small versus no win conditions and the SGT with big versus small win and big versus small loss conditions. Analyses focused on changes in blood oxygen level?Cdependent contrasts during reward and punishment processing in anticipation and feedback phases. We found clear magnitude-sensitive response in reward-related brain regions such as the ventral striatum during anticipation in the MID task, but not in the SGT. This was also true for reaction times. The feedback phase showed clear reward-related, but magnitude-independent, response patterns, for example in the anterior cingulate cortex, in both tasks. Our findings highlight neural and behavioral response patterns engaged in two different reward paradigms in one sample of 14-year-old healthy adolescents and might be important for reference in future studies investigating reward and punishment processing in a target age group.     

Stability and change in patterns of eating disorder symptoms from adolescence to young adulthood

Using a community adolescent sample, we aimed to (a) empirically derive eating disorder (ED) symptom groups, (b) examine the longitudinal stability of those groups over 10 years, and (c) identify risk factors associated with ED group stability and transition through young adulthood. Young people (N = 2,287) from the Project EAT cohort participated at baseline (1998–1999) and at 10‐year follow‐up (2008–2009). Participants completed anthropometric measures at baseline and self‐report surveys on disordered eating symptoms and risk factors at both time points. Latent transition modeling was used to test the first two aims and multinomial logistic regression was used for the third aim. Three groups emerged and were labeled as: (a) asymptomatic, (b) dieting, (c) disordered eating (e.g., binge eating, compensatory behaviors). Stability of group membership over 10 years was highest for those in the asymptomatic group, while those in the dieting group showed equal likelihood of transitioning to any group. There was a 75% chance that those in the disordered eating group would continue to belong to a symptomatic group 10 years later. We found that these transitions could be predicted by baseline risk factors. For example, adolescents with one standard deviation higher depressive symptoms than their peers had 53% higher odds (OR = 1.53, 95% CI 1.09–2.16) of transitioning from the asymptomatic group to the disordered eating group. Transition among ED groups is relatively common during adolescence and early adulthood. By targeting risk factors such as self‐esteem and familial factors in early adolescence, prevention efforts may be improved.