Differential species-specific ectoparasitic mite intensities in two intimately coexisting sibling bat species: resource-mediated host attractiveness or parasite specialization?

1. The mechanisms underlying host choice strategies by parasites remain poorly understood. We address two main questions: (i) do parasites prefer vulnerable or well-fed hosts, and (ii) to what extent is a parasite species specialized towards a given host species? 2. To answer these questions, we investigated, both in the field and in the lab, a host-parasite system comprising one ectoparasitic mite (Spinturnix myoti) and its major hosts, two sibling species of bats (Myotis myotis and M blythii), which coexist intimately in colonial nursery roosts. We exploited the close physical associations between host species in colonial roosts as well as naturally occurring annual variation in food abundance to investigate the relationships between parasite intensities and (i) host species and (ii) individual nutritional status. 3. Although horizontal transmission of parasites was facilitated by the intimate aggregation of bats within their colonial clusters, we found significant interspecific differences in degree of infestation throughout the 6 years of the study, with M. myotis always more heavily parasitized than M. blythii. This pattern was replicated in a laboratory experiment in which any species-specific resistance induced by exploitation of different trophic niches in nature was removed. 4. Within both host species, S. myoti showed a clear preference for individuals with higher nutritional status. In years with high resource abundance, both bat hosts harboured more parasites than in low-resource years, although the relative difference in parasite burden across species was maintained. This pattern of host choice was also replicated in the laboratory. When offered a choice, parasites always colonized better-fed individuals. 5. These results show first that host specialization in our study system occurred. Second, immediate parasite choice clearly operated towards the selection of hosts in good nutritional state.

The effectiveness of brief alcohol interventions in primary care settings: a systematic review.

Issues. Numerous studies have reported that brief interventions delivered in primary care are effective in reducing excessive drinking. However, much of this work has been criticised for being clinically unrepresentative. This review aimed to assess the effectiveness of brief interventions in primary care and determine if outcomes differ between efficacy and effectiveness trials. Approach. A pre-specified search strategy was used to search all relevant electronic databases up to 2006. We also hand-searched the reference lists of key articles and reviews. We included randomised controlled trials (RCT) involving patients in primary care who were not seeking alcohol treatment and who received brief intervention. Two authors independently abstracted data and assessed trial quality. Random effects meta-analyses, subgroup and sensitivity analyses and meta-regression were conducted. Key Findings. The primary meta-analysis included 22 RCT and evaluated outcomes in over 5800 patients. At 1 year follow up, patients receiving brief intervention had a significant reduction in alcohol consumption compared with controls [mean difference: -38 g week(-1), 95%CI (confidence interval): -54 to -23], although there was substantial heterogeneity between trials (I(2) = 57%). Subgroup analysis confirmed the benefit of brief intervention in men but not in women. Extended intervention was associated with a non-significantly increased reduction in alcohol consumption compared with brief intervention. There was no significant difference in effect sizes for efficacy and effectiveness trials. Conclusions. Brief interventions can reduce alcohol consumption in men, with benefit at a year after intervention, but they are unproven in women for whom there is insufficient research data. Longer counselling has little additional effect over brief intervention. The lack of differences in outcomes between efficacy and effectiveness trials suggests that the current literature is relevant to routine primary care.

Neural activity of the anterior insula in emotional processing depends on the individuals' emotional susceptibility

Differences in personality factors between individuals may manifest themselves with different patterns of neural activity while individuals process stimuli with emotional content. We attempted to verify this hypothesis by investigating emotional susceptibility (ES), a specific emotional trait of the human personality defined as the tendency to "experience feelings of discomfort, helplessness, inadequacy and vulnerability" after exposure to stimuli with emotional valence. By administering a questionnaire evaluating the individuals' ES, we selected two groups of participants with high and low ES respectively. Then, we used functional magnetic resonance imaging to investigate differences between the groups in the neural activity involved while they were processing emotional stimuli in an explicit (focusing on the content of the stimuli) or an incidental (focusing on spatial features of the stimuli, irrespectively of their content) way. The results showed a selective difference in brain activity between groups only in the explicit processing of the emotional stimuli: bilateral activity of the anterior insula was present in subjects with high ES but not in subjects with low ES. This difference in neural activity within the anterior insula proved to be purely functional since no brain morphological differences were found between groups, as assessed by a voxel-based morphometry analysis. Although the role of the anterior insula in the processing of contexts perceived as emotionally salient is well established, the present study provides the first evidence of a modulation of the insular activity depending on the individuals' ES trait of personality.

Physiological differences between cycling and running: lessons from triathletes

The purpose of this review was to provide a synopsis of the literature concerning the physiological differences between cycling and running. By comparing physiological variables such as maximal oxygen consumption (V O(2max)), anaerobic threshold (AT), heart rate, economy or delta efficiency measured in cycling and running in triathletes, runners or cyclists, this review aims to identify the effects of exercise modality on the underlying mechanisms (ventilatory responses, blood flow, muscle oxidative capacity, peripheral innervation and neuromuscular fatigue) of adaptation. The majority of studies indicate that runners achieve a higher V O(2max) on treadmill whereas cyclists can achieve a V O(2max) value in cycle ergometry similar to that in treadmill running. Hence, V O(2max) is specific to the exercise modality. In addition, the muscles adapt specifically to a given exercise task over a period of time, resulting in an improvement in submaximal physiological variables such as the ventilatory threshold, in some cases without a change in V O(2max). However, this effect is probably larger in cycling than in running. At the same time, skill influencing motor unit recruitment patterns is an important influence on the anaerobic threshold in cycling. Furthermore, it is likely that there is more physiological training transfer from running to cycling than vice versa. In triathletes, there is generally no difference in V O(2max) measured in cycle ergometry and treadmill running. The data concerning the anaerobic threshold in cycling and running in triathletes are conflicting. This is likely to be due to a combination of actual training load and prior training history in each discipline. The mechanisms surrounding the differences in the AT together with V O(2max) in cycling and running are not largely understood but are probably due to the relative adaptation of cardiac output influencing V O(2max) and also the recruitment of muscle mass in combination with the oxidative capacity of this mass influencing the AT. Several other physiological differences between cycling and running are addressed: heart rate is different between the two activities both for maximal and submaximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than in running. It has also been shown that pedalling cadence affects the metabolic responses during cycling but also during a subsequent running bout. However, the optimal cadence is still debated. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.

Genetic differentiation in two European tree frog (Hyla arborea) metapopulations in contrasted landscapes of Western Switzerland

The survival of threatened species as the European tree frog (Hyla arborea) is strongly dependent on the genetic variability within populations, as well as gene flow between them. In Switzerland, only two sectors in its western part still harbour metapopulations. The first is characterised by a very heterogeneous and urbanized landscape, while the second is characterised by a uninterrupted array of suitable habitats. In this study, six microsatellite loci were used to establish levels of genetic differentiation among the populations from the two different locations. The results show that the metapopulations have: (i) weak levels of genetic differentiation (FST within metapopulation ≈ 0.04), (ii) no difference in levels of genetic structuring between them, (iii) significant (p = 0.019) differences in terms of genetic diversity (Hs) and observed heterozygozity (Ho), the metapopulation located in a disturbed landscape showing lower values. Our results suggest that even if the dispersal of H. arborea among contiguous ponds seems to be efficient in areas of heterogeneous landscape, a loss of genetic diversity can occur.

The difference between the basal metabolic rate and the sleeping metabolic rate in Japanese.

Previous studies have demonstrated the difference between the basal metabolic rate (BMR) and the sleeping metabolic rate (SMR): however, the difference in the Japanese population has not yet been explored. This study examined the relationship between the BMR and SMR in ninety-four healthy Japanese subjects (37 males and 57 females, 39 +/- 12 y of age and 22.0 +/- 7.4% body fat) in a respiratory chamber. The SMR was significantly lower than the BMR (1416 +/- 245 vs. 1492 +/- 256 kcal/d): however, there was a highly significant correlation between the two (r = 0.867; p < 0.001). The ratio of SMR/BMR largely varied among individuals (0.95 +/-0.08, 8.4% of the coefficient of variation). The ratio was significantly lower in males than in females (0.93 +/- 0.10 vs. 0.97 +/- 0.06, p < 0.05). None of the anthropometric measures (age, weight, body mass index, body surface area or percent body fat) correlated with the ratio. These results showed that SMR was 95%, of BMR on average in a healthy Japanese group. However, when applied over a longer time period (24 h or more), the difference tends to become negligible for most analyses in a group. Although the difference between SMR and BMR will induce a 5% gap of physical activity level defined as the total energy expenditure divided by the BMR or SMR, this factor seems to have little practical importance in epidemiological research.

Strategy selection during exploratory behavior: sex differences

This study was designed to assess sex-related differences in the selection of an appropriate strategy when facing novelty. A simple visuo-spatial task was used to investigate exploratory behavior as a specific response to novelty. The exploration task was followed by a visual discrimination task, and the responses were analyzed using signal detection theory. During exploration women selected a local searching strategy in which the metric distance between what is already known and what is unknown was reduced, whereas men adopted a global strategy based on an approximately uniform distribution of choices. Women's exploratory behavior gives rise to a notion of a secure base warranting a sense of safety while men's behavior does not appear to be influenced by risk. This sex-related difference was interpreted as a difference in beliefs concerning the likelihood of uncertain events influencing risk evaluation. Keywords: exploration, spontaneous strategies, sex differences, decision-making.

Vom Finanz- zum Wissenschaftsbetrug : Methode, den Irrungen in der medizinischen Literatur beizukommen [From financial to scientific fraud : Methods to detect discrepancies in the medical literature].

Fraud is as old as Mankind. There are an enormous number of historical documents which show the interaction between truth and untruth; therefore it is not really surprising that the prevalence of publication discrepancies is increasing. More surprising is that new cases especially in the medical field generate such a huge astonishment. In financial mathematics a statistical tool for detection of fraud is known which uses the knowledge of Newcomb and Benford regarding the distribution of natural numbers. This distribution is not equal and lower numbers are more likely to be detected compared to higher ones. In this investigation all numbers contained in the blinded abstracts of the 2009 annual meeting of the Swiss Society of Anesthesia and Resuscitation (SGAR) were recorded and analyzed regarding the distribution. A manipulated abstract was also included in the investigation. The χ(2)-test was used to determine statistical differences between expected and observed counts of numbers. There was also a faked abstract integrated in the investigation. A p<0.05 was considered significant. The distribution of the 1,800 numbers in the 77 submitted abstracts followed Benford's law. The manipulated abstract was detected by statistical means (difference in expected versus observed p<0.05). Statistics cannot prove whether the content is true or not but can give some serious hints to look into the details in such conspicuous material. These are the first results of a test for the distribution of numbers presented in medical research.

Protease activity in Giardia duodenalis trophozoites of axenic strains isolated from symptomatic and asymptomatic patients

We have examined by gelatin-SDS-PAGE the protease activity in cell lysates of Giardia duodenalis trophozoites of two axenic strains isolated in Brazil from a symptomatic patient (BTU-11) and an asymptomatic carrier (BTU-10), and the reference strain Portland 1 (P1). The proteolysis band patterns showed differences among strains isolated from asymptomatic and symptomatic individuals. The lysate of the strain BTU-10, showed only five hydrolysis bands, while a greater number of bands (10-11 bands) was seen in strains BTU-11 and P1. The protease activity in all lysates was inhibited by cysteine (E-64 and iodoacetamide) and serine proteases (TPCK and TLCK) inhibitors, but not by PMSF and EDTA. In general, the results revealed protease activities in G. duodenalis trophozoites of Brazilian axenic strains and the predominance of cysteine proteinases. It should be stressed the inter-strain difference in hydrolysis band patterns observed between strains isolated from symptomatic patients and the strain obtained from an asymptomatic carrier.

Twenty-four-hour energy expenditure in pregnant and nonpregnant Gambian women, measured in a whole-body indirect calorimeter.

Twenty-four-hour energy expenditure (EE), daily and sleeping EE, and the energy cost of a standardized treadmill exercise were assessed in a respiration chamber in 41 young pregnant Gambian women at 12 (n = 11), 24 (n = 15), and 36 (n = 15) wk of gestation and compared with 13 nonpregnant nonlactating (NPNL) control women. The rate of 24-h EE was significantly higher (P less than 0.001) at 36 wk gestation (8443 +/- 243 kJ/d) than in the NPNL group (6971 +/- 172 kJ/d) or at 12 and 24 wk (7088 +/- 222 and 7188 +/- 192 kJ/d, respectively). Per unit body weight, no more differences in 24-h EE, daily and sleeping EE, or energy cost of walking were observed between pregnant and NPNL women. There was no statistical difference in the 24-h respiratory quotient among the groups. We conclude that the state of pregnancy in Gambian women induces a progressive rise in 24-h EE, which becomes significant in the third trimester and is proportional to body weight.

Genome size rather than content might affect call properties in toads of three ploidy levels (Anura: Bufonidae: Bufo viridis subgroup).

In vertebrates, genome size has been shown to correlate with nuclear and cell sizes, and influences phenotypic features, such as brain complexity. In three different anuran families, advertisement calls of polyploids exhibit longer notes and intervals than diploids, and difference in cellular dimensions have been hypothesized to cause these modifications. We investigated this phenomenon in green toads (Bufo viridis subgroup) of three ploidy levels, in a different call type (release calls) that may evolve independently from advertisement calls, examining 1205 calls, from ten species, subspecies, and hybrid forms. Significant differences between pulse rates of six diploid and four polyploid (3n, 4n) green toad forms across a range of temperatures from 7 to 27 °C were found. Laboratory data supported differences in pulse rates of triploids vs. tetraploids, but failed to reach significance when including field recordings. This study supports the idea that genome size, irrespective of call type, phylogenetic context, and geographical background, might affect call properties in anurans and suggests a common principle governing this relationship. The nuclear-cell size ratio, affected by genome size, seems the most plausible explanation. However, we cannot rule out hypotheses under which call-influencing genes from an unexamined diploid ancestral species might also affect call properties in the hybrid-origin polyploids.

Effects of timber harvest on phlebotomine sand flies (Diptera: Psychodidae) in a production forest: abundance of species on tree trunks and prevalence of trypanosomatids

The Amazon forest is being exploited for timber production. The harvest removes trees, used by sand flies as resting sites, and decreases the canopy, used as refuges by some hosts. The present study evaluated the impact of the timber harvest, the abundance of sand flies, and their trypanosomatid infection rates before and after selective logging. The study was accomplished in terra-firme production forest in an area of timber harvest, state of Amazonas, Brazil. Sand fly catches were carried out in three areas: one before and after the timber harvest, and two control areas, a nature preservation area and a previously exploited area. The flies were caught by aspiration on tree trunks. Samples of sand flies were dissected for parasitological examination. In the site that suffered a harvest, a larger number of individuals was caught before the selective extraction of timber, showing significant difference in relation to the number of individuals and their flagellate infection rates after the logging. The other two areas did not show differences among their sand fly populations. This fact is suggestive of a fauna sensitive to the environmental alterations associated with selective logging.

Changes in the transcriptional profile of transporters in the intestine along the anterior-posterior and crypt-villus axes.

BACKGROUND: The purpose of this work was to characterize the expression of drug and nutrient carriers along the anterior-posterior and crypt-villus axes of the intestinal epithelium and to study the validity of utilizing whole gut tissue rather than purified epithelial cells to examine regional variations in gene expression. RESULTS: We have characterized the mRNA expression profiles of 76 % of all currently known transporters along the anterior-posterior axis of the gut. This is the first study to describe the expression profiles of the majority of all known transporters in the intestine. The expression profiles of transporters, as defined according to the Gene Ontology consortium, were measured in whole tissue of the murine duodenum, jejunum, ileum and colon using high-density microarrays. For nine transporters (Abca1, Abcc1, Abcc3, Abcg8, Slc10a2, Slc28a2, Slc2a1, Slc34a2 and Slc5a8), the mRNA profiles were further measured by RT-PCR in laser micro-dissected crypt and villus epithelial cells corresponding to the aforementioned intestinal regions. With respect to differentially regulated transporters, the colon had a distinct expression profile from small intestinal segments. The majority (59 % for p cutoff < or = 0.05) of transporter mRNA levels were constant across the intestinal sections studied. For the transporter subclass "carrier activity", which contains the majority of known carriers for biologically active compounds, a significant change (p < or = 0.05) along the anterior-posterior axis was observed. CONCLUSION: All nine transporters examined in laser-dissected material demonstrated good replication of the region-specific profiles revealed by microarray. Furthermore, we suggest that the distribution characteristics of Slc5a8 along the intestinal tract render it a suitable candidate carrier for monocarboxylate drugs in the posterior portion of the intestine. Our findings also predict that there is a significant difference in the absorption of carrier-mediated compounds in the different intestinal segments. The most pronounced differences can be expected between the adjoining segments ileum and colon, but the differences between the other adjoining segments are not negligible. Finally, for the examined genes, profiles measured in whole intestinal tissue extracts are representative of epithelial cell-only gene expression.

Preliminary results in the immunodiagnosis of tuberculosis in children based on T cell responses to ESAT-6 and PPD antigens

The aim of this work was to study the difference in interferon gamma (IFN-gamma) production by T lymphocytes after early secretory antigen target 6 (ESAT-6) or purified protein derivate (PPD) stimulation in whole blood culture supernatants from children with suspected tuberculosis (TB) disease (n = 21), latent TB infection (n = 16) and negative controls (NC) (n = 22) from an endemic area in Brazil. The concentration of IFN-gamma (pg/ml) was measured by enzyme linked immunosorbent assay and the differences in the IFN-gamma levels for each group were compared and evaluated using an unpaired Student's t-test; p values < 0.05 were considered significant. Measurement of IFN-gamma levels after ESAT-6 stimulation raised the possibility of early diagnosis in the latent TB group (p = 0.0030). Nevertheless, the same group showed similar responses to the NC group (p > 0.05) after PPD stimulation. The IFN-gamma assay using ESAT-6 as an antigenic stimulus has the potential to be used as a tool for the immunodiagnosis of early TB in children.

Evolutionary implications of a high selfing rate in the freshwater snail Lymnaea truncatula.

Self-compatible hermaphroditic organisms that mix self-fertilization and outcrossing are of great interest for investigating the evolution of mating systems. We investigate the evolution of selfing in Lymnaea truncatula, a self-compatible hermaphroditic freshwater snail. We first analyze the consequences of selfing in terms of genetic variability within and among populations and then investigate how these consequences along with the species ecology (harshness of the habitat and parasitism) might govern the evolution of selfing. Snails from 13 localities (classified as temporary or permanent depending on their water availability) were sampled in western Switzerland and genotyped for seven microsatellite loci. F(IS) (estimated on adults) and progeny array analyses (on hatchlings) provided similar selfing rate estimates of 80%. Populations presented a low polymorphism and were highly differentiated (F(ST) = 0.58). Although the reproductive assurance hypothesis would predict higher selfing rate in temporary populations, no difference in selfing level was observed between temporary and permanent populations. However, allelic richness and gene diversity declined in temporary habitats, presumably reflecting drift. Infection levels varied but were not simply related to either estimated population selfing rate or to differences in heterozygosity. These findings and the similar selfing rates estimated for hatchlings and adults suggest that within-population inbreeding depression is low in L. truncatula.