Genetic structure of Triatoma venosa (Hemiptera: Reduviidae): molecular and morphometric evidence

Triatoma venosa presents a restricted geographical distribution in America and is considered as a secondary vector of Chagas disease in Colombia and Ecuador. A total of 120 adult insects were collected in domestic and peridomestic habitats in an endemic area of the department of Boyacá, Colombia, in order to determine their genetic structure through morphometric and molecular techniques. The head and wings of each specimen were used for the analyses of size, shape, and sexual dimorphism. A significant sexual dimorphism was found, although no differences in size among the studied groups were detected. Differences were found in the analyzed structures except for male heads. DNA was extracted from the legs in order to carry out the internal transcriber space-2 (ITS-2) amplification and the randon amplified polymorphic DNA (RAPD) analyses. Length polymorphisms were not detected in the ITS-2. Fst and Nm values were estimated (0.047 and 3.4, respectively). The high genetic flow found among the insects captured in the domicile and peridomiciliary environment does not permit a genetic differentiation, thus establishing the peridomicile as an important place for epidemiological surveillance.

Production, characterization, and application of antibodies against heat-labile type-I toxin for detection of enterotoxigenic Escherichia coli

Strains of enterotoxigenic Escherichia coli (ETEC) are responsible for significant rates of morbidity and mortality among children, particularly in developing countries. The majority of clinical and public health laboratories are capable of isolating and identifying Salmonella, Shigella, Campylobacter, and Escherichia coli O157:H7 from stool samples, but ETEC cannot be identified by routine methods. The method most often used to identify ETEC is polymerase chain reaction for heat-stable and heat-labile enterotoxin genes, and subsequent serotyping, but most clinical and public health laboratories do not have the capacity or resources to perform these tests. In this study, polyclonal rabbit and monoclonal mouse IgG2b antibodies against ETEC heat-labile toxin-I (LT) were characterized and the potential applicability of a capture assay was analyzed. IgG-enriched fractions from rabbit polyclonal and the IgG2b monoclonal antibodies recognized LT in a conformational shape and they were excellent tools for detection of LT-producing strains. These findings indicate that the capture immunoassay could be used as a diagnostic assay of ETEC LT-producing strains in routine diagnosis and in epidemiological studies of diarrhea in developing countries as enzyme linked immunosorbent assay techniques remain as effective and economical choice for the detection of specific pathogen antigens in cultures.

Selection on age at first and at last reproduction in the long-lived Alpine Swift Apus melba

The way an organism spreads its reproduction over time is defined as a life-history trait, and selection is expected to favour life-history traits associated with the highest fitness return. We use a long-term dataset of 277 life histories to investigate the shape and strength of selection acting on the age at first reproduction and at last reproduction in the long-lived Alpine Swift. Both traits were under strong directional selection, but in opposite directions, with selection favouring birds starting their reproductive career early and being able to reproduce for longer. There was also evidence for stabilising selection acting on both traits, suggesting that individuals should nonetheless refrain from reproducing in their first 2 years of life (i.e. when inexperienced), and that reproducing after 7 years of age had little effect on lifetime fitness, probably due to senescence.

Urokinase receptor (uPAR, CD87) is a platelet receptor important for kinetics and TNF-induced endothelial adhesion in mice.

BACKGROUND: Urokinase plasminogen activator receptor (uPAR, CD87) is a widely distributed 55-kD, glycoprotein I-anchored surface receptor. On binding of its ligand uPA, it is known to increase leukocyte adhesion and traffic. Using genetically deficient mice, we explored the role of uPAR in platelet kinetics and TNF-induced platelet consumption. METHODS AND RESULTS: Anti-uPAR antibody stained platelets from normal (+/+) but not from uPAR-/- mice, as seen by fluorescence-activated cell sorter analysis. 51Cr-labeled platelets from uPAR-/- donors survived longer than those from +/+ donors when injected into a +/+ recipient. Intratracheal TNF injection induced thrombocytopenia and a platelet pulmonary localization, pronounced in +/+ but absent in uPAR-/- mice. Aprotinin, a plasmin inhibitor, decreased TNF-induced thrombocytopenia. TNF injection markedly reduced the survival and increased the pulmonary localization of 51Cr-labeled platelets from +/+ but not from uPAR-/- donors, indicating that it is the platelet uPAR that is critical for their response to TNF. As seen by electron microscopy, TNF injection increased the number of platelets and polymorphonuclear neutrophils (PMNs) in the alveolar capillaries of +/+ mice, whereas in uPAR-/- mice, platelet trapping was insignificant and PMN trapping was slightly reduced. Platelets within alveolar capillaries of TNF-injected mice were activated, as judged from their shape, and this was evident in +/+ but not in uPAR-/- mice. CONCLUSIONS: These results demonstrate for the first time the critical role of platelet uPAR for kinetics as well as for activation and endothelium adhesion associated with inflammation.

Single cell analysis reveals similar functional competence of dominant and nondominant CD8 T-cell clonotypes.

Immune protection from infectious diseases and cancer is mediated by individual T cells of different clonal origin. Their functions are tightly regulated but not yet fully characterized. Understanding the contribution of each T cell will improve the prediction of immune protection based on laboratory assessment of T-cell responses. Here we developed techniques for simultaneous molecular and functional assessment of single CD8 T cells directly ex vivo. We studied two groups of patients with melanoma after vaccination with two closely related tumor antigenic peptides. Vaccination induced T cells with strong memory and effector functions, as found in virtually all T cells of the first patient group, and fractions of T cells in the second group. Interestingly, high functionality was not restricted to dominant clonotypes. Rather, dominant and nondominant clonotypes acquired equal functional competence. In parallel, this was also found for EBV- and CMV-specific T cells. Thus, the nondominant clonotypes may contribute similarly to immunity as their dominant counterparts.

Accuracy of mucocutaneous leishmaniasis diagnosis using polymerase chain reaction: systematic literature review and meta-analysis

The diagnosis of mucocutaneous leishmaniasis (MCL) is hampered by the absence of a gold standard. An accurate diagnosis is essential because of the high toxicity of the medications for the disease. This study aimed to assess the ability of polymerase chain reaction (PCR) to identify MCL and to compare these results with clinical research recently published by the authors. A systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the PRISMA Statement was performed using comprehensive search criteria and communication with the authors. A meta-analysis considering the estimates of the univariate and bivariate models was performed. Specificity near 100% was common among the papers. The primary reason for accuracy differences was sensitivity. The meta-analysis, which was only possible for PCR samples of lesion fragments, revealed a sensitivity of 71% [95% confidence interval (CI) = 0.59; 0.81] and a specificity of 93% (95% CI = 0.83; 0.98) in the bivariate model. The search for measures that could increase the sensitivity of PCR should be encouraged. The quality of the collected material and the optimisation of the amplification of genetic material should be prioritised.

Tibial component positioning in total knee arthroplasty: bone coverage and extensor apparatus alignment.

Correct positioning of the tibial component in total knee arthroplasty (TKA) must take into account both an optimal bone coverage (defined by a maximal cortical bearing with posteromedial and anterolateral support) and satisfactory patellofemoral tracking. Consequently, a compromise position must be found by the surgeon during the operation to simultaneously meet these two requirements. Moreover, tibial tray positioning depends upon the tibial torsion, which has been shown to act mainly in the proximal quarter of the tibia. Therefore, the correct application of the tibial tray is also theoretically related to the level of bone resection. In this study, we first quantified the torsional profile given by an optimal bone coverage for a symmetrical tibial tray design and for an asymmetrical one. Then, for the two types of tibial trays, we measured the angle difference between optimal bone coverage and an alignment on the middle of the tibial tubercule. Results showed that the values of the torsional profile given by the symmetrical tray were more scattered than those from the asymmetrical one. However, determination of the mean differential angle between the position providing optimal bone coverage and the one providing the best patellofemoral tracking indicated that the symmetrical prosthetic tray offered the best compromise between these two requirements. Although the tibiofemoral joint is known to be asymmetric in both shape and dimension, the asymmetrical tray chosen in this study was found to fulfill this compromise with more difficulty.

Differences Between Posterior and Anterior Acute Ischaemic Circulation Strokes in 1449 Consecutive Patients

Background: The current data comparing posterior and anterior circulation strokes with regards to clinical, etiological, radiological and outcome factors are conflicting. We searched for distinguishing features between both territories in 1'449 consecutive acute ischemic stroke patients. Methods: All consecutive patients with acute ischemic stroke admitted to a single stroke unit from January 2003 to July 2008 were included in a prospective registry. Territory of acute stroke was determined by a combination of neuroimaging (MRI and / CT / CTP) and clinical symptoms and signs. Patients with uncertain localisation and patients with simultaneous strokes in the anterior and posterior circulation were excluded from this analysis. Results: Of a total of 1728 patients, 466 (17.0%) had had posterior, 983 (56.8%) anterior, 136 (7.9%) unknown territory, and 43 (2.5%) simultaneous posterior and anterior territory stroke. Of 39 variables that were compared, 29 differed significantly in univariate analysis, including less dependency (OR_0.50) and mortality (OR_0.56) at 3 months in posterior stroke. In multivariate analysis (see table), male gender, lacunar mechanism, arterial dissection and endovascular recanalisation were more frequent in posterior stroke, and admission NIHSS and IV-thrombolysis rate were lower. Significant acute arterial pathology (_50% stenosis) was less frequently found on acute imaging in posterior stroke (OR_0.33). Of 633 patients with significant arterial pathology, it was more frequently present intracranially in posterior (OR_1.62) and extracranially in anterior stroke (OR _ 0.87). In 610 patients where recanalisation was assessed at 24 hours, intracranial (OR_0.26), extracranial (OR_0.25) and overall recanalisation (OR_0.34) was less frequent in the posterior circulation. Conclusions: Acute posterior strokes are less severe and recover better, despite lower IV thrombolysis and recanalisation rates. They are more frequently due to lacunes and dissections and have less arterial pathology burden then anterior circulation strokes.

Optimisation des doses en tomographie computérisée pédiatrique [Patient dose optimization in pediatric computerized tomography]

The development of CT applications might become a public health problem if no effort is made on the justification and the optimisation of the examinations. This paper presents some hints to assure that the risk-benefit compromise remains in favour of the patient, especially when one deals with the examinations of young patients. In this context a particular attention has to be made on the justification of the examination. When performing the acquisition one needs to optimise the extension of the volume investigated together with the number of acquisition sequences used. Finally, the use of automatic exposure systems, now available on all the units, and the use of the Diagnostic Reference Levels (DRL) should allow help radiologists to control the exposure of their patients.

Determination of Transmembrane Water Fluxes in Neurons Elicited by Glutamate Ionotropic Receptors and by the Cotransporters KCC2 and NKCC1: A Digital Holographic Microscopy Study.

Digital holographic microscopy (DHM) is a noninvasive optical imaging technique that provides quantitative phase images of living cells. In a recent study, we showed that the quantitative monitoring of the phase signal by DHM was a simple label-free method to study the effects of glutamate on neuronal optical responses (Pavillon et al., 2010). Here, we refine these observations and show that glutamate produces the following three distinct optical responses in mouse primary cortical neurons in culture, predominantly mediated by NMDA receptors: biphasic, reversible decrease (RD) and irreversible decrease (ID) responses. The shape and amplitude of the optical signal were not associated with a particular cellular phenotype but reflected the physiopathological status of neurons linked to the degree of NMDA activity. Thus, the biphasic, RD, and ID responses indicated, respectively, a low-level, a high-level, and an "excitotoxic" level of NMDA activation. Moreover, furosemide and bumetanide, two inhibitors of sodium-coupled and/or potassium-coupled chloride movement strongly modified the phase shift, suggesting an involvement of two neuronal cotransporters, NKCC1 (Na-K-Cl) and KCC2 (K-Cl) in the genesis of the optical signal. This observation is of particular interest since it shows that DHM is the first imaging technique able to monitor dynamically and in situ the activity of these cotransporters during physiological and/or pathological neuronal conditions.

The effects of arterial flow on platelet activation, thrombus growth, and stabilization.

Injury of an arterial vessel wall acutely triggers a multifaceted process of thrombus formation, which is dictated by the high-shear flow conditions in the artery. In this overview, we describe how the classical concept of arterial thrombus formation and vascular occlusion, driven by platelet activation and fibrin formation, can be extended and fine-tuned. This has become possible because of recent insight into the mechanisms of: (i) platelet-vessel wall and platelet-platelet communication, (ii) autocrine platelet activation, and (iii) platelet-coagulation interactions, in relation to blood flow dynamics. We list over 40 studies with genetically modified mice showing a role of platelet and plasma proteins in the control of thrombus stability after vascular injury. These include multiple platelet adhesive receptors and other junctional molecules, components of the ADP receptor signalling cascade to integrin activation, proteins controlling platelet shape, and autocrine activation processes, as well as multiple plasma proteins binding to platelets and proteins of the intrinsic coagulation cascade. Regulatory roles herein of the endothelium and other blood cells are recapitulated as well. Patient studies support the contribution of platelet- and coagulation activation in the regulation of thrombus stability. Analysis of the factors determining flow-dependent thrombus stabilization and embolus formation in mice will help to understand the regulation of this process in human arterial disease.

Viability and Management of an Endangered Capercaillie (Tetrao urogallus) Metapopulation in the Jura Mountains, Western Switzerland

The populations of Capercaillie (Tetrao urogallus), the largest European grouse, have seriously declined during the last century over most of their distribution in western and central Europe. In the Jura mountains, the relict population is now isolated and critically endangered (about 500 breeding adults). We developed a simulation software (TetrasPool) that accounts for age and spatial structure as well as stochastic processes, to perform a viability analysis and explore management scenarios for this population, capitalizing on a 24 years-long series of field data. Simulations predict a marked decline and a significant extinction risk over the next century, largely due to environmental and demographic stochasticity (average values of life-history parameters would otherwise allow stability). Variances among scenarios mainly stem from uncertainties about the shape and intensity of density dependence. Uncertainty analyses suggest to focus conservation efforts on enhancing, not only adult survival (as often advocated for long-lived species), but also recruitment. The juvenile stage matters when local populations undergo extinctions, because it ensures connectivity and recolonization. Besides limiting human perturbations, a silvicultural strategy aimed at opening forest structure should improve the quality and surface of available patches, independent of their size and localization. Such measures are to be taken urgently, if the population is to be saved.

Neurophysiological origin of human brain asymmetry for speech and language.

The physiological basis of human cerebral asymmetry for language remains mysterious. We have used simultaneous physiological and anatomical measurements to investigate the issue. Concentrating on neural oscillatory activity in speech-specific frequency bands and exploring interactions between gestural (motor) and auditory-evoked activity, we find, in the absence of language-related processing, that left auditory, somatosensory, articulatory motor, and inferior parietal cortices show specific, lateralized, speech-related physiological properties. With the addition of ecologically valid audiovisual stimulation, activity in auditory cortex synchronizes with left-dominant input from the motor cortex at frequencies corresponding to syllabic, but not phonemic, speech rhythms. Our results support theories of language lateralization that posit a major role for intrinsic, hardwired perceptuomotor processing in syllabic parsing and are compatible both with the evolutionary view that speech arose from a combination of syllable-sized vocalizations and meaningful hand gestures and with developmental observations suggesting phonemic analysis is a developmentally acquired process.

Combined Electrostatic and Covalent Polymer Networks for Cell Microencapsulation

Two types of hydrogel microspheres have been developed. Fast ionotropic gelation of sodium alginate (Na-alg) in the presence of calcium ions was combined with slow covalent cross-linking of poly(ethylene glycol) (PEG) derivatives. For the first type, the fast obtainable Ca-alg hydrogel served as spherical matrix for the simultaneously occurring covalent cross-linking of multi-arm PEG derivative. A two-component interpenetrating network was formed in one step upon extruding the mixture of the two polymers into the gelation bath. For the second type, heterobifunctional PEG was grafted onto Na-alg prior to gelation. Upon extrusion of the polymer solution into the gelation bath, fast Ca-alg formation ensured the spherical shape and was accompanied by cross-linker-free covalent cross-linking of the PEG side chains. Thus, one-component hydrogel microspheres resulted. We present the physical properties of the hydrogel microspheres and demonstrate the feasibility of cell microencapsulation for both types of polymer networks.

Anemia and brain oxygen after severe traumatic brain injury.

PURPOSE: To investigate the relationship between hemoglobin (Hgb) and brain tissue oxygen tension (PbtO(2)) after severe traumatic brain injury (TBI) and to examine its impact on outcome. METHODS: This was a retrospective analysis of a prospective cohort of severe TBI patients whose PbtO(2) was monitored. The relationship between Hgb-categorized into four quartiles (≤9; 9-10; 10.1-11; >11 g/dl)-and PbtO(2) was analyzed using mixed-effects models. Anemia with compromised PbtO(2) was defined as episodes of Hgb ≤ 9 g/dl with simultaneous PbtO(2) < 20 mmHg. Outcome was assessed at 30 days using the Glasgow outcome score (GOS), dichotomized as favorable (GOS 4-5) vs. unfavorable (GOS 1-3). RESULTS: We analyzed 474 simultaneous Hgb and PbtO(2) samples from 80 patients (mean age 44 ± 20 years, median GCS 4 (3-7)). Using Hgb > 11 g/dl as the reference level, and controlling for important physiologic covariates (CPP, PaO(2), PaCO(2)), Hgb ≤ 9 g/dl was the only Hgb level that was associated with lower PbtO(2) (coefficient -6.53 (95 % CI -9.13; -3.94), p < 0.001). Anemia with simultaneous PbtO(2) < 20 mmHg, but not anemia alone, increased the risk of unfavorable outcome (odds ratio 6.24 (95 % CI 1.61; 24.22), p = 0.008), controlling for age, GCS, Marshall CT grade, and APACHE II score. CONCLUSIONS: In this cohort of severe TBI patients whose PbtO(2) was monitored, a Hgb level no greater than 9 g/dl was associated with compromised PbtO(2). Anemia with simultaneous compromised PbtO(2), but not anemia alone, was a risk factor for unfavorable outcome, irrespective of injury severity.