Why Can't Rodents Vomit? A Comparative Behavioral, Anatomical, and Physiological Study

The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats and mice appear to lack this response. It is unclear whether these rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or lack of key neural circuits. Moreover, it is unknown whether laboratory rodents are representative of Rodentia with regards to this reflex. Here we conducted behavioral testing of members of all three major groups of Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), and squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine (sc), and copper sulfate (ig), failed to produce either retching or vomiting in these species (although other behavioral effects, e.g., locomotion, were noted). These rodents also had anatomical constraints, which could limit the efficiency of vomiting should it be attempted, including reduced muscularity of the diaphragm and stomach geometry that is not well structured for moving contents towards the esophagus compared to species that can vomit (cat, ferret, and musk shrew). Lastly, an in situ brainstem preparation was used to make sensitive measures of mouth, esophagus, and shoulder muscular movements, and phrenic nerve activity-key features of emetic episodes. Laboratory mice and rats failed to display any of the common coordinated actions of these indices after typical emetic stimulation (resiniferatoxin and vagal afferent stimulation) compared to musk shrews. Overall the results suggest that the inability to vomit is a general property of Rodentia and that an absent brainstem neurological component is the most likely cause. The implications of these findings for the utility of rodents as models in the area of emesis research are discussed. © 2013 Horn et al

Should we adjust health education methodology to low-educated employees needs? Findings from Latvia, Poland, Slovenia and Spain

Objectives: The presented study explored health beliefs and experiences as well as health education needs of low-educated employees (LEEs) (incomplete primary, primary, lower secondary and basic vocational education) in comparison to those with higher education (secondary and tertiary education) in four European countries: Latvia, Poland, Slovenia and Spain. The main aim was to identify a specificity of low-educated employees (LEEs) by capturing their opinions, experiences, attitudes and needs concerning health education. Material and Methods: The sample consisted of 1691 individuals with the status of an employee (approximately 400 respondents in each of 4 countries participating in the project). The respondents were aged 25-54 (both the control group and the target group consisted in 1/3 of the following age groups: 25-34, 35-44 and 45-54). The respondents were interviewed during the years 2009 and 2010 with a structured questionnaire concerning their health, health behaviours as well as educational needs concerning health education. Results: The study revealed substantial differences in the attitudes of people from this group concerning methodology of health education. LEEs prefer more competitions and campaigns and less written educational materials in comparison to those with higher education. Additionally, they more often perceive a fee, longer time, necessity to take part in a knowledge test and a concern that their health will be checked as factors that can discourage them from taking part in a health training. On the other hand, LEEs can by encouraged to take part in such a training by a media broadcast concerning the event, snacks or lottery during the training, or financial incentives. Conclusions: The results of the study proved the need for specific health education guidelines to conduct health education for low-educated employees. These guidelines should take in account the sources of health education preferred by LEEs as well as the factors that can encourage/discourage their participation in trainings concerning health

Aphid Wing Induction and Ecological Costs of Alarm Pheromone Emission under Field Conditions

The pea aphid, Acyrthosiphon pisum Harris, (Homoptera: Aphididae) releases the volatile sesquiterpene (E)-β-farnesene (EBF) when attacked by a predator, triggering escape responses in the aphid colony. Recently, it was shown that this alarm pheromone also mediates the production of the winged dispersal morph under laboratory conditions. The present work tested the wing-inducing effect of EBF under field conditions. Aphid colonies were exposed to two treatments (control and EBF) and tested in two different environmental conditions (field and laboratory). As in previous experiments aphids produced higher proportion of winged morphs among their offspring when exposed to EBF in the laboratory but even under field conditions the proportion of winged offspring was higher after EBF application (6.84±0.98%) compared to the hexane control (1.54±0.25%). In the field, the proportion of adult aphids found on the plant at the end of the experiment was lower in the EBF treatment (58.1±5.5%) than in the control (66.9±4.6%), in contrast to the climate chamber test where the numbers of adult aphids found on the plant at the end of the experiment were, in both treatments, similar to the numbers put on the plant initially. Our results show that the role of EBF in aphid wing induction is also apparent under field conditions and they may indicate a potential cost of EBF emission. They also emphasize the importance of investigating the ecological role of induced defences under field conditions

Heterogeneity of mammary lesions represent molecular differences

BACKGROUND: Human breast cancer is a heterogeneous disease, histopathologically, molecularly and phenotypically. The molecular basis of this heterogeneity is not well understood. We have used a mouse model of DCIS that consists of unique lines of mammary intraepithelial neoplasia (MIN) outgrowths, the premalignant lesion in the mouse that progress to invasive carcinoma, to understand the molecular changes that are characteristic to certain phenotypes. Each MIN-O line has distinguishable morphologies, metastatic potentials and estrogen dependencies. METHODS: We utilized oligonucleotide expression arrays and high resolution array comparative genomic hybridization (aCGH) to investigate whole genome expression patterns and whole genome aberrations in both the MIN-O and tumor from four different MIN-O lines that each have different phenotypes. From the whole genome analysis at 35 kb resolution, we found that chromosome 1, 2, 10, and 11 were frequently associated with whole chromosome gains in the MIN-Os. In particular, two MIN-O lines had the majority of the chromosome gains. Although we did not find any whole chromosome loss, we identified 3 recurring chromosome losses (2F1-2, 3E4, 17E2) and two chromosome copy number gains on chromosome 11. These interstitial deletions and duplications were verified with a custom made array designed to interrogate the specific regions at approximately 550 bp resolution. RESULTS: We demonstrated that expression and genomic changes are present in the early premalignant lesions and that these molecular profiles can be correlated to phenotype (metastasis and estrogen responsiveness). We also identified expression changes associated with genomic instability. Progression to invasive carcinoma was associated with few additional changes in gene expression and genomic organization. Therefore, in the MIN-O mice, early premalignant lesions have the major molecular and genetic changes required and these changes have important phenotypic significance. In contrast, the changes that occur in the transition to invasive carcinoma are subtle, with few consistent changes and no association with phenotype. CONCLUSION: We propose that the early lesions carry the important genetic changes that reflect the major phenotypic information, while additional genetic changes that accumulate in the invasive carcinoma are less associated with the overall phenotype

Making direct democracy work: A rational-actor perspective on the graphe paranomon in ancient Athens

The specific way the Athenians set up their democracy presents both theoretical and empirical challenges. Decisions were taken by majority vote in the Assembly. To keep politicians in line, the Athenians first used ostracism, which however was replaced by the graphe paranomon around 415 BCE. The latter provided that anybody who had made a proposal in the Assembly could be accused of having made an unconstitutional suggestion, bringing a potentially severe penalty if found guilty. We know of 35 such cases between 403 and 322. During the fourth century the notion of illegality was extended to a mere question of political undesirability. Henceforth any decision by the Assembly could be overturned by the courts, but if the accuser failed to get at least 20% of the jury votes, he was punished instead. While these rules can be seen as a safeguard against bad decisions, they also provided the Athenian politicians with important information about the relative strength of their political support. This effect has not been analysed before, and it may help explain the relative stability of political life in classical Athens. Furthermore this analysis also contributes to our understanding of a curious but often overlooked fact, namely that the decrees of the Athenian Assembly to a great extent concerned honorary rewards, and the use of the graphe paranomon in turn was largely focussed on the honorary decrees