The Working Capacity of Subjects from an Exhibition Crowd

A standard bicycle ergometer test was performed on 60 male volunteers at the Canadian National Exhibition. Most were drawn from Toronto and its environs, and “white-collar” workers predominated. Ages ranged from 19 to 61 years. The Astrand nomogram was used to predict the oxygen uptake of the 45 subjects with a normal resting pulse rate. The older subjects had a lower oxygen uptake than Scandinavian office workers, particularly relative to body weight. This conclusion is subject to the limitations of a non-random sample, but seems independent of the professional-class bias. Almost all subjects exceeded the “ideal” body weight. Working capacity was 20% greater in subjects taking regular exercise than in those who were inactive.     

An Evolutionary Cascade Model for Sauropod Dinosaur Gigantism - Overview,Update and Tests

Sauropod dinosaurs are a group of herbivorous dinosaurs which exceeded all other terrestrial vertebrates in mean and maximal body size. Sauropod dinosaurs were also the most successful and long-lived herbivorous tetrapod clade, but no abiological factors such as global environmental parameters conducive to their gigantism can be identified. These facts justify major efforts by evolutionary biologists and paleontologists to understand sauropods as living animals and to explain their evolutionary success and uniquely gigantic body size. Contributions to this research program have come from many fields and can be synthesized into a biological evolutionary cascade model of sauropod dinosaur gigantism (sauropod gigantism ECM). This review focuses on the sauropod gigantism ECM, providing an updated version based on the contributions to the PLoS ONE sauropod gigantism collection and on other very recent published evidence. The model consist of five separate evolutionary cascades (“Reproduction”, “Feeding”, “Head and neck”, “Avian-style lung”, and “Metabolism”). Each cascade starts with observed or inferred basal traits that either may be plesiomorphic or derived at the level of Sauropoda. Each trait confers hypothetical selective advantages which permit the evolution of the next trait. Feedback loops in the ECM consist of selective advantages originating from traits higher in the cascades but affecting lower traits. All cascades end in the trait “Very high body mass”. Each cascade is linked to at least one other cascade. Important plesiomorphic traits of sauropod dinosaurs that entered the model were ovipary as well as no mastication of food. Important evolutionary innovations (derived traits) were an avian-style respiratory system and an elevated basal metabolic rate. Comparison with other tetrapod lineages identifies factors limiting body size.     

Both Food Restriction and High-Fat Diet during Gestation Induce Low Birth Weight and Altered Physical Activity in Adult Rat Offspring: The “Similarities in the Inequalities” Model

We have previously described a theoretical model in humans, called “Similarities in the Inequalities”, in which extremely unequal social backgrounds coexist in a complex scenario promoting similar health outcomes in adulthood. Based on the potential applicability of and to further explore the “similarities in the inequalities” phenomenon, this study used a rat model to investigate the effect of different nutritional backgrounds during gestation on the willingness of offspring to engage in physical activity in adulthood. Sprague-Dawley rats were time mated and randomly allocated to one of three dietary groups: Control (Adlib), receiving standard laboratory chow ad libitum; 50% food restricted (FR), receiving 50% of the ad libitum-fed dam’s habitual intake; or high-fat diet (HF), receiving a diet containing 23% fat. The diets were provided from day 10 of pregnancy until weaning. Within 24 hours of birth, pups were cross-fostered to other dams, forming the following groups: Adlib_Adlib, FR_Adlib, and HF_Adlib. Maternal chow consumption and weight gain, and offspring birth weight, growth, physical activity (one week of free exercise in running wheels), abdominal adiposity and biochemical data were evaluated. Western blot was performed to assess D2 receptors in the dorsal striatum. The “similarities in the inequalities” effect was observed on birth weight (both FR and HF groups were smaller than the Adlib group at birth) and physical activity (both FR_Adlib and HF_Adlib groups were different from the Adlib_Adlib group, with less active males and more active females). Our findings contribute to the view that health inequalities in fetal life may program the health outcomes manifested in offspring adult life (such as altered physical activity and metabolic parameters), probably through different biological mechanisms.     

TREATMENT PROGRAM FOR MENTAL HOSPITALS

Many thousands of patients in the “chronic” wards of mental hospitals have been considered unsuitable subjects for active treatment, on the assumption that little could be accomplished. However, a well integrated therapeutic program under skilled psychiatric direction and involving all personnel who will come in contact with the patient gives promise of returning a substantial number of patients to their homes. The program suggested in this paper also retards personality disorganization and refutes the current nihilistic attitude concerning the patient whose mental condition has been deemed to be chronic.     

Blood pressure reduction in “borderline” hypertensives following physical training

One hundred and sixty-five middle-aged, apparently normal men were submitted to a six-month conditioning program. On the basis of a casual blood pressure measurement during the pre-training evaluation, 37 individuals (23%) were classified as “borderline” hypertensive. The remaining subjects (n = 128) were normotensive. At the conclusion of the program both groups exhibited significant reductions in systolic and diastolic blood pressures at rest and after submaximal work. Moreover, the reductions of the resting systolic and diastolic and of the exercise (300 kg.m./min.) systolic blood pressures were significantly greater for the hypertensives.     

The Sicker Sex: Understanding Male Biases in Parasitic Infection,Resource Allocation and Fitness

The “sicker sex” idea summarizes our knowledge of sex biases in parasite burden and immune ability whereby males fare worse than females. The theoretical basis of this is that because males invest more on mating effort than females, the former pay the costs by having a weaker immune system and thus being more susceptible to parasites. Females, conversely, have a greater parental investment. Here we tested the following: a) whether both sexes differ in their ability to defend against parasites using a natural host-parasite system; b) the differences in resource allocation conflict between mating effort and parental investment traits between sexes; and, c) effect of parasitism on survival for both sexes. We used a number of insect damselfly species as study subjects. For (a), we quantified gregarine and mite parasites, and experimentally manipulated gregarine levels in both sexes during adult ontogeny. For (b), first, we manipulated food during adult ontogeny and recorded thoracic fat gain (a proxy of mating effort) and abdominal weight (a proxy of parental investment) in both sexes. Secondly for (b), we manipulated food and gregarine levels in both sexes when adults were about to become sexually mature, and recorded gregarine number. For (c), we infected male and female adults of different ages and measured their survival. Males consistently showed more parasites than females apparently due to an increased resource allocation to fat production in males. Conversely, females invested more on abdominal weight. These differences were independent of how much food/infecting parasites were provided. The cost of this was that males had more parasites and reduced survival than females. Our results provide a resource allocation mechanism for understanding sexual differences in parasite defense as well as survival consequences for each sex.     

From Chihuahua to Saint-Bernard: how did digestion and microbiota evolve with dog sizes

Health and well-being of dogs are of paramount importance to their owners. Digestion plays a key role in dog health, involving physicochemical, mechanical and microbial actors. However, decades of breeding selection led to various dog sizes associated with different digestive physiology and disease sensitivity. Developing new products requires the consideration of all the multi-faceted aspects of canine digestion, the evaluation of food digestibility, drug release and absorption in the gut. This review paper provides an exhaustive literature survey on canine digestive physiology, focusing on size effect on anatomy and digestive parameters, with graphical representation of data classified as “small”, “medium” and “large” dogs. Despite the huge variability between protocols and animals, interesting size effects on gastrointestinal physiology were highlighted, mainly related to the colonic compartment. Colonic measurements, transit time permeability, fibre degradation, faecal short-chain fatty acid concentration and faecal water content increase while faecal bile acid concentration decreases with body size. A negative correlation between body weight and Proteobacteria relative abundance was observed suggesting an effect of dog body size on faecal microbiota. This paper gathers helpful in vivo data for academics and industrials and supports the development of new food and pharma products to move towards canine personalized nutrition and health.     

Dengue Virus Neutralizing Antibody Levels Associated with Protection from Infection in Thai Cluster Studies

Background

Long-term homologous and temporary heterologous protection from dengue virus (DENV) infection may be mediated by neutralizing antibodies. However, neutralizing antibody titers (NTs) have not been clearly associated with protection from infection.

Methodology/Principal Findings

Data from two geographic cluster studies conducted in Kamphaeng Phet, Thailand were used for this analysis. In the first study (2004–2007), cluster investigations of 100-meter radius were triggered by DENV-infected index cases from a concurrent prospective cohort. Subjects between 6 months and 15 years old were evaluated for DENV infection at days 0 and 15 by DENV PCR and IgM ELISA. In the second study (2009–2012), clusters of 200-meter radius were triggered by DENV-infected index cases admitted to the provincial hospital. Subjects of any age ≥6 months were evaluated for DENV infection at days 0 and 14. In both studies, subjects who were DENV PCR positive at day 14/15 were considered to have been “susceptible” on day 0. Comparison subjects from houses in which someone had documented DENV infection, but the subject remained DENV negative at days 0 and 14/15, were considered “non-susceptible.” Day 0 samples were presumed to be from just before virus exposure, and underwent plaque reduction neutralization testing (PRNT). Seventeen “susceptible” (six DENV-1, five DENV-2, and six DENV-4), and 32 “non-susceptible” (13 exposed to DENV-1, 10 DENV-2, and 9 DENV-4) subjects were evaluated. Comparing subjects exposed to the same serotype, receiver operating characteristic (ROC) curves identified homotypic PRNT titers of 11, 323 and 16 for DENV-1, -2 and -4, respectively, to differentiate “susceptible” from “non-susceptible” subjects.

Conclusions/Significance

PRNT titers were associated with protection from infection by DENV-1, -2 and -4. Protective NTs appeared to be serotype-dependent and may be higher for DENV-2 than other serotypes. These findings are relevant for both dengue epidemiology studies and vaccine development efforts.     

New Year’s Res-Illusions: Food Shopping in the New Year Competes with Healthy Intentions

Objective

How do the holidays – and the possible New Year’s resolutions that follow – influence a household’s purchase patterns of healthier foods versus less healthy foods? This has important implications for both holiday food shopping and post-holiday shopping.

Methods

207 households were recruited to participate in a randomized-controlled trial conducted at two regional-grocery chain locations in upstate New York. Item-level transaction records were tracked over a seven-month period (July 2010 to March 2011). The cooperating grocer’s proprietary nutrient-rating system was used to designate “healthy,” and “less healthy” items. Calorie data were extracted from online nutritional databases. Expenditures and calories purchased for the holiday period (Thanksgiving-New Year’s), and the post-holiday period (New Year’s-March), were compared to baseline (July-Thanksgiving) amounts.

Results

During the holiday season, household food expenditures increased 15% compared to baseline ($105.74 to $121.83; p<0.001), with 75% of additional expenditures accounted for by less-healthy items. Consistent with what one would expect from New Year’s resolutions, sales of healthy foods increased 29.4% ($13.24/week) after the holiday season compared to baseline, and 18.9% ($9.26/week) compared to the holiday period. Unfortunately, sales of less-healthy foods remained at holiday levels ($72.85/week holiday period vs. $72.52/week post-holiday). Calories purchased each week increased 9.3% (450 calories per serving/week) after the New Year compared to the holiday period, and increased 20.2% (890 calories per serving/week) compared to baseline.

Conclusions

Despite resolutions to eat more healthfully after New Year’s, consumers may adjust to a new “status quo” of increased less-healthy food purchasing during the holidays, and dubiously fulfill their New Year’s resolutions by spending more on healthy foods. Encouraging consumers to substitute healthy items for less-healthy items may be one way for practitioners and public health officials to help consumers fulfill New Year’s resolutions, and reverse holiday weight gain.     

Contribution of Psychosocial Factors to the Association between Socioeconomic Position and Takeaway Food Consumption

Objective

To examine whether psychosocial factors mediate (explain) the association between socioeconomic position and takeaway food consumption.

Design

A cross-sectional postal survey conducted in 2009.

Setting

Participants reported their usual consumption of 22 takeaway food items, and these were grouped into a “healthy” and “less healthy” index based on each items'' nutritional properties. Principal Components Analysis was used to derive three psychosocial scales that measured beliefs about the relationship between diet and health (α = 0.73), and perceptions about the value (α = 0.79) and pleasure (α = 0.61) of takeaway food. A nutrition knowledge index was also used. Socioeconomic position was measured by highest attained education level.

Subjects

Randomly selected adults (n = 1,500) aged between 25–64 years in Brisbane, Australia (response rate  =  63.7%, N = 903).

Results

Compared with those with a bachelor degree or higher, participants with a diploma level of education were more likely to consume “healthy” takeaway food (p = 0.023) whereas the least educated (high school only) were more likely to consume “less healthy” choices (p = 0.002). The least educated were less likely to believe in a relationship between diet and health (p<0.001), and more likely to have lower nutritional knowledge compared with their highly educated counterparts (p<0.001). Education differences in beliefs about the relationship between diet and health partly and significantly mediated the association between education and “healthy” takeaway food consumption. Diet- and health-related beliefs and nutritional knowledge partly and significantly mediated the education differences in “less healthy” takeaway food consumption.

Conclusions

Interventions that target beliefs about the relationship between diet and health, and nutritional knowledge may reduce socioeconomic differences in takeaway food consumption, particularly for “less healthy” options.     

Short-Term Effects of Traditional and Alternative Community Interventions to Address Food Insecurity

Background

Despite the effects of food insecurity on health are well documented, clear governmental policies to face food insecurity do not exist in western countries. In Canada, interventions to face food insecurity are developed at the community level and can be categorized into two basic strategies: those providing an immediate response to the need for food, defined “traditional” and those targeting the improvement of participants’ social cohesion, capabilities and management of their own nutrition, defined “alternative”.

Objective

The objective of this study was to evaluate the effects of food insecurity interventions on food security status and perceived health of participants.

Design

This was a longitudinal multilevel study implemented in Montreal, Quebec, Canada. Participants were recruited in a two-stage cluster sampling frame. Clustering units were community organizations working on food insecurity; units of analysis were participants in community food security interventions. A total of 450 participants were interviewed at the beginning and after 9 months of participation in traditional or alternative food security interventions. Food security and perceived health were investigated as dependent variables. Differences overtime were assessed through multilevel regression models.

Results

Participants in traditional interventions lowered their food insecurity at follow-up. Decreases among participants in alternative interventions were not statistically significant. Participants in traditional interventions also improved physical (B coefficient 3.00, CI 95% 0.42–5.59) and mental health (B coefficient 6.25, CI 95% 4.15–8.35).

Conclusions

Our results challenge the widely held view suggesting the ineffectiveness of traditional interventions in the short term. Although effects may be intervention-dependent, food banks decreased food insecurity and, in so doing, positively affected perceived health. Although study findings demonstrate that food banks offer short term reprise from the effects of food insecurity, the question as to whether food banks are the most appropriate solution to food insecurity still needs to be addressed.     

Generous Leaders and Selfish Underdogs: Pro-Sociality in Despotic Macaques

Actively granting food to a companion is called pro-social behavior and is considered to be part of altruism. Recent findings show that some non-human primates behave pro-socially. However, pro-social behavior is not expected in despotic species, since the steep dominance hierarchy will hamper pro-sociality. We show that some despotic long-tailed macaques do grant others access to food. Moreover, their dominance hierarchy determines pro-social behavior in an unexpected way: high-ranking individuals grant, while low-ranking individuals withhold their partner access to food. Surprisingly, pro-social behavior is not used by subordinates to obtain benefits from dominants, but by dominants to emphasize their dominance position. Hence, Machiavellian macaques rule not through “fear above love”, but through “be feared when needed and loved when possible”.     

Effect of Energy Under-Reporting on Secular Trends of Dietary Patterns in a Mediterranean Population

BackgroundDiet is an important factor in the prevention of chronic diseases. Analysis of secular trends of dietary patterns can be biased by energy under-reporting. Therefore, the objective of the present study was to analyse the impact of energy under-reporting on dietary patterns and secular trends in dietary patterns defined by cluster analysis.ResultsThree clusters, “healthy”, “mixed” and “western”, were identified for both surveys. The “mixed” cluster was the predominant cluster in both surveys. Excluding EUR reduced the proportion of the “mixed” cluster up to 6.40% in the 2000 survey; this caused secular trend increase in the prevalence of the “mixed” pattern. Cross-classification analysis of all participants and PER’ data showed substantial agreement in cluster assignments: 68.7% in 2000 and 84.4% in 2005. Excluding EUR did not cause meaningful (≥15%) changes in the “healthy” pattern. It provoked changes in consumption of some food groups in the “mixed” and “western” patterns: mainly decreases of unhealthy foods within the 2000 and increases of unhealthy foods within the 2005 surveys. Secular trend effects of EUR were similar to those within the 2005 survey. Excluding EUR reversed the direction of secular trends in consumption of several food groups in PER in the “mixed” and “western” patterns.ConclusionsEUR affected distribution of participants between dietary patterns within and between surveys, secular trends in food group consumption and amount of food consumed in all, but not in the “healthy” pattern. Our findings emphasize threats from energy under-reporting in dietary data analysis.     

Electrocardiographic Study of 20 Champion Swimmers Before and After 110-Yard Sprint Swimming Competition

In order to record the strain of actual competition, 20 healthy young athletes were studied by serial electrocardiograms recorded after swimming races of 110 yards. Blood pressures and electrocardiograms were taken at 3, 6, 9, 12, 15, 20, 25 and 30 minutes after each race. Of the 20 cases studied, 18 showed at least one of the following abnormal findings: (1) The PR interval was prolonged by at least 0.04 second and up to 0.10 second (12 subjects). (2) “True” ST depression (two subjects) or “false” ST depression (six subjects) was seen. (3) A marked loss of T potential (all subjects) or T inversion (eight subjects), which in some had developed as late as the 12-minute reading, was recorded. The causes for these alterations are considered physiological under the conditions of this experiment.     

Social Effects of Genetic Counselling

In a follow-up study of 104 subjects referred for genetic counselling between 1965 and 1969 all were at risk of having children with a variety of serious genetic disorders. Most subjects were in social classes III and IV, were married, in their late 20s, and already had an affected child. Sixty-three per cent. were referred by hospital consultants, 27% by their general practitioners, and 10% were self-referrals. All of those counselled appeared to have appreciated the genetic implications, although four overestimated the risks and 11 underestimated the risks.Of those at high risk (greater than 1 in 10) of having an affected child 10 out of 55 couples “planned” further pregnancies despite the risks. In two this was because they had been unable to adopt a child, in four because they had no living children and the disorders in question usually resulted in stillbirth or death in infancy so that the “burden” of an affected child would be of relatively short duration, and one mother had had antenatal diagnosis and selective abortion. Most of the couples in the low-risk group (less than 1 in 20) were reassured and planned further pregnancies.     

Excitability of the Primary Motor Cortex Increases More Strongly with Slow- than with Normal-Speed Presentation of Actions

Introduction

The aim of the present study was to investigate how the speed of observed action affects the excitability of the primary motor cortex (M1), as assessed by the size of motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS).

Methods

Eighteen healthy subjects watched a video clip of a person catching a ball, played at three different speeds (normal-, half-, and quarter-speed). MEPs were induced by TMS when the model''s hand had opened to the widest extent just before catching the ball (“open”) and when the model had just caught the ball (“catch”). These two events were locked to specific frames of the video clip (“phases”), rather than occurring at specific absolute times, so that they could easily be compared across different speeds. MEPs were recorded from the thenar (TH) and abductor digiti minimi (ADM) muscles of the right hand.

Results

The MEP amplitudes were higher when the subjects watched the video clip at low speed than when they watched the clip at normal speed. A repeated-measures ANOVA, with the factor VIDEO-SPEED, showed significant main effects. Bonferroni''s post hoc test showed that the following MEP amplitude differences were significant: TH, normal vs. quarter; ADM, normal vs. half; and ADM, normal vs. quarter. Paired t-tests showed that the significant MEP amplitude differences between TMS phases under each speed condition were TH, “catch” higher than “open” at quarter speed; ADM, “catch” higher than “open” at half speed.

Conclusions

These results indicate that the excitability of M1 was higher when the observed action was played at low speed. Our findings suggest that the action observation system became more active when the subjects observed the video clip at low speed, because the subjects could then recognize the elements of action and intention in others.     

The “Genetic Program”: Behind the Genesis of an Influential Metaphor

The metaphor of the “genetic program,” indicating the genome as a set of instructions required to build a phenotype, has been very influential in biology despite various criticisms over the years. This metaphor, first published in 1961, is thought to have been invented independently in two different articles, one by Ernst Mayr and the other by François Jacob and Jacques Monod. Here, after a detailed analysis of what both parties meant by “genetic program,” I show, using unpublished archives, the strong resemblance between the ideas of Mayr and Monod and suggest that their idea of genetic program probably shares a common origin. I explore the possibility that the two men met before 1961 and also exchanged their ideas through common friends and colleagues in the field of molecular biology. Based on unpublished correspondence of Jacob and Monod, I highlight the important events that influenced the preparation of their influential paper, which introduced the concept of the genetic program. Finally, I suggest that the genetic program metaphor may have preceded both papers and that it was probably used informally before 1961.     

Blood Pressure in a Scottish Town

As part of a general health screening survey in the Burgh of Renfrew blood pressure was measured in 3,001 subjects (78·8% of those eligible) aged 45 to 64. In 468 (15·6%) diastolic blood pressure was 100 mm Hg or more. A year later the mean blood pressure for those of the population re-examined showed no change, there being an equal number of subjects with increased and decreased pressures. The prognostic significance of those showing the larger fluctuations remains to be determined through medical-record linkage.Examination of the general practitioners'' medical records of 422 of the 468 subjects with diastolic blood pressure of 100 mm Hg or more showed that 255 had no previous documented hypertension. Of the remainder 73 were receiving antihypertensive therapy. Examination of the records of subjects whose blood pressure was under 100 mm Hg showed that 55 were receiving antihypertensive treatment and that another 113 had previously been recorded as having a diastolic blood pressure of 100 mm Hg or more by their general practitioner. Altogether at least 636 (21·2%) of those who were examined had been considered at some time to have evidence of hypertension.The prevalence of undetected hypertension in the general population has important implications for the resources of the National Health Service if current trials show benefit to the health of the community from treating “mild” as well as “moderate” hypertension.     

The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings

Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects (“avoiders”) reliably avoided trials where there was a risk of punishment, but other subjects (“non-avoiders”) never made any avoidance responses at all. One possible interpretation is that the “non-avoiders” valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects’ tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as “avoiders.” To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better-than-expected outcomes, compared to subjects in the no-feedback condition. Additionally, in both task conditions, “avoiders” adjusted their behavior faster following worse-than-expected outcomes, and treated the ambiguous no-feedback outcome as less rewarding, compared to non-avoiders. Together, results shed light on the important role of ambiguous and informative feedback in avoidance behavior.