The enigmatic eosinophil: investigation of the biological role of eosinophils in parasitic helmint infection

In many helminth infected hosts the number of eosinophils increases dramatically, often without any concurrent increases in the number of other leukocytes, so that eosinophils become the dominant cell type. Many experimental investigations have shown that the eosinophilia is induced by interleukin-5 (IL-5) but its functional significance remains unclear. Mice genetically deficient in IL-5 (IL-5-/-) have been used to evaluate the functional consequences of the IL-5 dependent eosinophilia in helminth infected hosts. Host pathology and level of infection were determined in IL-5-/- and wild type mice infected with a range of species representative of each major group of helminths. The effects of IL-5 deficiency were very heterogeneous. Of the six species of helminth examined, IL-5 dependent immune responses had no detectable effect in infections with three species, namely the cestodes Mesocestoides corti and Hymenolepis diminuta and the trematode Fasciola hepatica. In contrast, IL-5 dependent immune responses were functionally important in mice infected with three species, notably all nematodes. Damage to the lungs caused by migrating larvae of Toxocara canis was reduced in IL-5-/- mice. Infections of the intestine by adult stages of either Strongyloides ratti or Heligmosomoides polygyrus were more severe in IL-5-/- mice. Adult intestinal nematodes were clearly deleteriously affected by IL-5 dependent processes since in its presence there were fewer worms which had reduced fecundity and longevity. The implications of these results for the viability of using inhibitors of IL-5 as a therapy for asthma are considered.

Detection of EPO doping and blood doping: the haematological module of the Athlete Biological Passport.

The increase of the body's capacity to transport oxygen is a prime target for doping athletes in all endurance sports. For this pupose, blood transfusions or erythropoiesis stimulating agents (ESA), such as erythropoietin, NESP, and CERA are used. As direct detection of such manipulations is difficult, biomarkers that are connected to the haematopoietic system (haemoglobin concentration, reticulocytes) are monitored over time (Athlete Biological Passport (ABP)) and analyzed using mathematical models to identify patterns suspicious of doping. With this information, athletes can either be sanctioned directly based on their profile or targeted with conventional doping tests. Key issues for the appropriate use of the ABP are correct targeting and use of all available information (e.g. whereabouts, cross sectional population data) in a forensic manner. Future developments of the passport include the correction of all concentration-based variables for shifts in plasma volume, which might considerably increase sensitivity. New passport markers from the genomic, proteomic, and metabolomic level might add further information, but need to be validated before integration into the passport procedure. A first assessment of blood data of federations that have implemented the passport show encouraging signs of a decreased blood-doping prevalence in their athletes, which adds scientific credibility to this innovative concept in the fight against ESA- and blood doping. Copyright © 2012 John Wiley & Sons, Ltd.

Trypanosoma cruzi: Correlations of Biological Aspects of the Life Cycle in Mice and Triatomines

The infection pattern in Swiss mice and Triatomine bugs (Rhodnius neglectus) of eleven clones and the original stock of a Trypanosoma cruzi isolate, derived from a naturally infected Didelphis marsupialis, were biochemically and biologically characterized. The clones and the original isolate were in the same zymodeme (Z1) except that two clones were found to be in zymodeme 2 when tested with G6PDH. Although infective, neither the original isolate nor the clones were highly virulent for the mice and lesions were only observed in mice infected with the original stock and one of the clones (F8). All clones and the original isolate infected bugs well while only the original isolate and clones E2 and F3 yielded high metacyclogenesis rates. An observed correlation between absence of lesions in the mammal host and high metacyclogenesis rates in the invertebrate host suggest a evolutionary trade off i.e. a fitness increase in one trait which is accompanied by a fitness reduction in a different one. Our results suggest that in a species as heterogeneous as T. cruzi, a cooperation effect among the subpopulations should be considered.

Effects of physiological self-crowding of DNA on shape and biological properties of DNA molecules with various levels of supercoiling.

DNA in bacterial chromosomes and bacterial plasmids is supercoiled. DNA supercoiling is essential for DNA replication and gene regulation. However, the density of supercoiling in vivo is circa twice smaller than in deproteinized DNA molecules isolated from bacteria. What are then the specific advantages of reduced supercoiling density that is maintained in vivo? Using Brownian dynamics simulations and atomic force microscopy we show here that thanks to physiological DNA-DNA crowding DNA molecules with reduced supercoiling density are still sufficiently supercoiled to stimulate interaction between cis-regulatory elements. On the other hand, weak supercoiling permits DNA molecules to modulate their overall shape in response to physiological changes in DNA crowding. This plasticity of DNA shapes may have regulatory role and be important for the postreplicative spontaneous segregation of bacterial chromosomes.

Social Interaction Effects on Fertility: Intentions and Behaviors

The existing literature shows that social interactions in individuals' networks affect their reproductive attitudes and behaviors through three mechanisms: social influence, social learning, and social support. In this paper, we discuss to what extent the Theory of Planned Behavior (TPB), an individual based theorization of intentions and behavior used to model fertility, takes these social mechanisms into account. We argue that the TPB already integrates social influence and that it could easily accommodate the two other social network mechanisms. By doing so, the theory would be enriched in two respects. First, it will explain more completely how macro level changes eventually ends in micro level changes in behavioral intentions. Indeed, mechanisms of social influence may explain why changes in representations of parenthood and ideal family size can be slower than changes in socio-economic conditions and institutions. Social learning mechanisms should also be considered, since they are crucial to distinguish who adopts new behavioral beliefs and practices, when change at the macro level finally sinks in. Secondly, relationships are a capital of services that can complement institutional offering (informal child care) as well as a capital of knowledge which help individuals navigate in a complex institutional reality, providing a crucial element to explain heterogeneity in the successful realization of fertility intentions across individuals. We develop specific hypotheses concerning the effect of social interactions on fertility intentions and their realization to conclude with a critical review of the existing surveys suitable to test them and their limits.

Biological monitoring of exposure to solvents using the chemical itself in urine: application to toluene

Objective Biomonitoring of solvents using the unchanged substance in urine as exposure indicator is still relatively scarce due to some discrepancies between the results reported in the literature. Based on the assessment of toluene exposure, the aim of this work was to evaluate the effects of some steps likely to bias the results and to measure urinary toluene both in volunteers experimentally exposed and in workers of rotogravure factories. Methods Static headspace was used for toluene analysis. o-Cresol was also measured for comparison. Urine collection, storage and conservation conditions were studied to evaluate possible loss or contamination of toluene in controlled situations applied to six volunteers in an exposure chamber according to four scenarios with exposure at stable levels from 10 to 50 ppm. Kinetics of elimination of toluene were determined over 24 h. A field study was then carried out in a total of 29 workers from two rotogravure printing facilities. Results Potential contamination during urine collection in the field is confirmed to be a real problem but technical precautions for sampling, storage and analysis can be easily followed to control the situation. In the volunteers at rest, urinary toluene showed a rapid increase after 2 h with a steady level after about 3 h. At 47.1 ppm the mean cumulated excretion was about 0.005% of the amount of the toluene ventilated. Correlation between the toluene levels in air and in end of exposure urinary sample was excellent (r = 0.965). In the field study, the median personal exposure to toluene was 32 ppm (range 3.6-148). According to the correlations between environmental and biological monitoring data, the post-shift urinary toluene (r = 0.921) and o-cresol (r = 0.873) concentrations were, respectively, 75.6 mu g/l and 0.76 mg/g creatinine for 50 ppm toluene personal exposure. The corresponding urinary toluene concentration before the next shift was 11 mu g/l (r = 0.883). Conclusion Urinary toluene was shown once more time a very interesting surrogate to o-cresol and could be recommended as a biomarker of choice for solvent exposure. [Authors]

Haematophagy and cleptohaematophagy of Clerada apicicornis (Hemiptera: Lygaeidae), a potential biological control agent of Rhodnius prolixus (Hemiptera: Reduviidae)

Because of its ability to prey on Triatominae in rural houses, Clerada apicicornis has been suggested as a potential biological control agent of Rhodnius prolixus. It has also been suggested as a potential vector of mammalian trypanosomes such as Trypanosoma cruzi, because of its ability to take blood directly from mammals. To help resolve these conflicting ideas, we assessed the haematophagic behaviour of C. apicicornis by carrying out feeding trials on laboratory animals. Cleptohaematophagic behaviour was also assessed by allowing C. apicicornis to feed on R. prolixus previously engorged with avian blood. The low proportion of blood meals taken directly from laboratory animals indicates a facultative haematophagy in this species, whereas a greater proportion of nymphs and adults were able to obtain vertebrate blood by predation on engorged R. prolixus. The results suggest that C. apicicornis is unlikely to be effective as a biological control agent, but is also unlikely to have a significant role in the transmission of vertebrate pathogens.

Biological screening of Brazilian medicinal plants

In this study, we screened sixty medicinal plant species from the Brazilian savanna ("cerrado") that could contain useful compounds for the control of tropical diseases. The plant selection was based on existing ethnobotanic information and interviews with local healers. Plant extracts were screened for: (a) molluscicidal activity against Biomphalaria glabrata, (b) toxicity to brine shrimp (Artemia salina L.), (c) antifungal activity in the bioautographic assay with Cladosporium sphaerospermum and (d) antibacterial activity in the agar diffusion assay against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Pseudomonas aeruginosa. Forty-two species afforded extracts that showed some degree of activity in one or more of these bioassays.

Biological characterization of Trypanosoma cruzi strains

Biological parameters of five Trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. Differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. Regarding to pharmacological assays, Y strain was the most sensitive to the three assayed compounds. These data demonstrate the heterogeneity of natural populations of T. cruzi, the only responsible of infection in humans.

Free-living amoebae: Biological by-passes in water treatment.

Free-living amoebae constitute reservoirs for many bacteria including not only well-known pathogens but also emerging pathogens responsible for respiratory diseases, and contribute to the protection, survival and dissemination of these bacteria in water systems, despite the application of disinfection or thermal treatments. In this article we review the available information on the presence of free-living amoebae and amoebae-resisting bacteria in drinking water systems, on the factors that contribute to their presence in the water and/or the biofilms, on the possible control measures and their effectiveness, and we identify some gaps in current knowledge needing further research.

Relationship between biological behaviour and randomly amplified polymorphic DNA profiles of Trypanosoma cruzi strains

Once known some biological characteristics of six Trypanosoma cruzi strains, randomly amplified polymorphic DNA (RAPD) analysis was made. Cluster analysis by UPGMA (unweighted pair group method analysis) was then applied both to biological parameters and RAPD profiles. Inspection of the UPGMA phenograms indicates identical clusters, so supporting that usefulness of biological parameters to characterization of T. cruzi strains still remains.

Health-risk behaviors and quality of life among young men.

PURPOSE: To examine the associations between substance use and other health-risk behaviors and quality of life (QOL) among young men. METHODS: The analytical sample consisted of 5,306 young Swiss men who participated in the Cohort Study on Substance Use Risk Factors. Associations between seven distinct self-reported health-risk behaviors (risky single-occasion drinking; volume drinking; cigarette smoking; cannabis use; use of any other illicit drugs; sexual intercourse without a condom; low physical activity) were assessed via chi-square analysis. Logistic regression analyses were conducted to study the associations between each particular health-risk behavior and either physical or mental QOL (assessed with the SF-12v2) while adjusting for socio-demographic variables and the presence of all other health-risk behaviors. RESULTS: Most health-risk behaviors co-occurred. However, low physical activity was not or negatively related to other health-risk behaviors. Almost all health-risk behaviors were associated with a greater likelihood of compromised QOL. However, sexual intercourse without a condom (not associated with both physical and mental QOL) and frequent risky single-occasion drinking (not related to mental QOL after adjusting for the presence of other health-risk behaviors; positively associated with physical QOL) differed from this pattern. CONCLUSIONS: Health-risk behaviors are mostly associated with compromised QOL. However, sexual intercourse without a condom and frequent risky single-occasion drinking differ from this pattern and are therefore possibly particularly difficult to change relative to other health-risk behaviors.

Biological activities of Curcuma longa L.

There are several data in the literature indicating a great variety of pharmacological activities of Curcuma longa L. (Zingiberaceae), which exhibit anti-inflammatory, anti-human immunodeficiency virus, anti-bacteria, antioxidant effects and nematocidal activities. Curcumin is a major component in Curcuma longa L., being responsible for its biological actions. Other extracts of this plant has been showing potency too. In vitro, curcumin exhibits anti-parasitic, antispasmodic, anti-inflammatory and gastrointestinal effects; and also inhibits carcinogenesis and cancer growth. In vivo, there are experiments showing the anti-parasitic, anti-inflammatory potency of curcumin and extracts of C. longa L. by parenteral and oral application in animal models. In this present work we make an overview of the pharmacological activities of C. longa L., showing its importance.