Control of urinary schistosomiasis on Zanzibar (Unguja Island): a pilot evaluation of the educational impact of the Juma na Kichocho health booklet within primary schools

To improve health education within primary schools, the health education booklet Juma na kichocho was evaluated during a study within 5 schools using key-informant questionnaires that recorded children's knowledge and attitude (KA) towards schistosomiasis before and after daily structured-use of booklets. A total of 229 schoolchildren (114 boys : 115 girls) of between 11 and 15 years of age were interviewed and re-assessed after a working school week. Existing and putative booklet-induced changes in KA scores for schistosomiasis were compared directly against equivalent KA scores for malaria. In total 47.4% of children were already aware that schistosomiasis was a water-borne disease while only 10.5% knew of its exact aetiology; after booklet intervention these levels increased to 54.6 and 15.7%, respectively. The majority of children still failed, however, to realise that re-infection could take place soon after treatment. While a positive increase was observed for children's total KA questionnaire scores for both malaria and schistosomiasis after booklet intervention, these were not statistically significant. In the context of control, further educational efforts are needed to promote and guide behavioural change, especially in relation to reduction of environmental water contact.

Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR) protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA). The efficiency was 0.99 and the correlation coefficient (R²) was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83ºC). The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden) in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

Anchoring of an immunogenic Plasmodium falciparum circumsporozoite protein on the surface of Dictyostelium discoideum.

The circumsporozoite protein (CSP), a major antigen of Plasmodium falciparum, was expressed in the slime mold Dictyostelium discoideum. Fusion of the parasite protein to a leader peptide derived from Dictyostelium contact site A was essential for expression. The natural parasite surface antigen, however, was not detected at the slime mold cell surface as expected but retained intracellularly. Removal of the last 23 amino acids resulted in secretion of CSP, suggesting that the C-terminal segment of the CSP, rather than an ectoplasmic domain, was responsible for retention. Cell surface expression was obtained when the CSP C-terminal segment was replaced by the D. discoideum contact site A glycosyl phosphatidylinositol anchor signal sequence. Mice were immunized with Dictyostelium cells harboring CSP at their surface. The raised antibodies recognized two different regions of the CSP. Anti-sporozoite titers of these sera were equivalent to anti-peptide titers detected by enzyme-linked immunosorbent assay. Thus, cell surface targeting of antigens can be obtained in Dictyostelium, generating sporozoite-like cells having potentials for vaccination, diagnostic tests, or basic studies involving parasite cell surface proteins.

Schistosome vaccine testing: lessons from the baboon model

The high level of protection elicited in rodents and primates by the radiation-attenuated schistosome vaccine gives hope that a human vaccine relying on equivalent mechanisms is feasible. In humans, a vaccine would be undoubtedly administered to previously or currently infected individuals. We have therefore used the olive baboon to investigate whether vaccine-induced immunity is compromised by a schistosome infection. We showed that neither a preceding infection, terminated by chemotherapy, nor an ongoing chronic infection affected the level of protection. Whilst IgM responses to vaccination or infection were short-lived, IgG responses rose with each successive exposure to the vaccine. Such a rise was obscured by responses to egg deposition in already-infected animals. In human trials it would be necessary to use indirect estimates of infection intensity to determine vaccine efficacy. Using worm burden as the definitive criterion, we demonstrated that the surrogate measures, fecal eggs, and circulating antigens, consistently overestimated protection. Regression analysis of the surrogate parameters on worm burden revealed that the principal reason for overestimation was the threshold sensitivity of the assays. If we extrapolate our findings to human schistosomiasis mansoni, it is clear that more sensitive indirect measures of infection intensity are required for future vaccine trials.

L'hyperréactivité bronchique et son importance pour le clinician [Bronchial hyperresponsiveness and its importance for the clinician].

Asthma is a chronic inflammatory airway disease, characterised by bronchial hyperresponsiveness causing bronchoconstriction, and thereby provoking typical symptoms (dyspnoea, cough, wheezing). Bronchial hyperres- ponsiveness indicates a temporary airflow limitation when exposed to a bronchoconstricting stimulus. Its measurement by challenge tests can be a valuable tool for confirming or excluding asthma, as well as for evaluating the efficacy of treatment. However, the origin of bronchial hyperresponsiveness is multifactorial and the different challenge tests are not equivalent. Direct challenge tests, like methacholine, mainly reflect chronic airway remo- delling, whereas indirect tests, like mannitol, better reflect bronchial inflammation.

Population structure of the malaria vector Anopheles darlingi in Rondônia, Brazilian Amazon, based on mitochondrial DNA

Anopheles darlingi is the most important Brazilian malaria vector, with a widespread distribution in the Amazon forest. Effective strategies for vector control could be better developed through knowledge of its genetic structure and gene flow among populations, to assess the vector diversity and competence in transmitting Plasmodium. The aim of this study was to assess the genetic diversity of An. darlingi collected at four locations in Porto Velho, by sequencing a fragment of the ND4 mitochondrial gene. From 218 individual mosquitoes, we obtained 20 different haplotypes with a diversity index of 0.756, equivalent to that found in other neotropical anophelines. The analysis did not demonstrate significant population structure. However, haplotype diversity within some populations seems to be over-represented, suggesting the presence of sub-populations, but the presence of highly represented haplotypes complicates this analysis. There was no clear correlation among genetic and geographical distance and there were differences in relation to seasonality, which is important for malarial epidemiology.

Early processing in the human lateral occipital complex is highly responsive to illusory contours but not to salient regions.

Human electrophysiological studies support a model whereby sensitivity to so-called illusory contour stimuli is first seen within the lateral occipital complex. A challenge to this model posits that the lateral occipital complex is a general site for crude region-based segmentation, based on findings of equivalent hemodynamic activations in the lateral occipital complex to illusory contour and so-called salient region stimuli, a stimulus class that lacks the classic bounding contours of illusory contours. Using high-density electrical mapping of visual evoked potentials, we show that early lateral occipital cortex activity is substantially stronger to illusory contour than to salient region stimuli, whereas later lateral occipital complex activity is stronger to salient region than to illusory contour stimuli. Our results suggest that equivalent hemodynamic activity to illusory contour and salient region stimuli probably reflects temporally integrated responses, a result of the poor temporal resolution of hemodynamic imaging. The temporal precision of visual evoked potentials is critical for establishing viable models of completion processes and visual scene analysis. We propose that crude spatial segmentation analyses, which are insensitive to illusory contours, occur first within dorsal visual regions, not the lateral occipital complex, and that initial illusory contour sensitivity is a function of the lateral occipital complex.

Aerobic and functional capacities in a selected active population of European octogenarians

Master athletes are often considered to represent the ideal rate of decline of aerobic function; however, most of the studies interested in active elderly people are often limited to people younger than 75. We aimed to determine the physiological adaptations and aerobic fitness in a selected European population of active octogenarians during maximal and submaximal exercise tests. Aerobic capacity was measured during maximal incremental tests on treadmill (TR) and cycle-ergometer (CE) and functional capacity during a 6-minute walk test (6-MWT) in 17 subjects aged 81.2 +/- 0.8 years. Pulmonary gas exchange and heart rate (HR) were continuously measured during the different exercise tests. Maximal oxygen consumption (V.O (2max)) on TR and CE was significantly higher than predicted values (TR: 28.7 +/- 1.2 vs. 17 +/- 0.5 ml . kg (-1) . min (-1); CE: 23 +/- 1.2 vs. 16 +/- 0.6 ml . kg (-1) . min (-1) for measured and predicted values respectively). V.O (2max) and HR (max), as well as V.O (2) and HR at the ventilatory threshold (V.O (2)T (V.E) and HR T (V.E)) were significantly higher on TR than on CE (HR (max): 144 +/- 4 vs. 138 +/- 4 bpm; V.O (2)T (V.E): 22.5 +/- 0.8 vs. 17.7 +/- 0.9 ml . kg (-1) . min (-1) for TR and CE respectively). V.O (2)T (V.E) and HR T (V.E) on TR were equivalent to V.O (2) and HR measured during the 6-MWT. HR T (V.E) on TR and mean HR during the 6-MWT were strongly correlated (R = 0.82, p < 0.01). Maintenance of regular physical activity provides high aerobic fitness, in octogenarians, as was shown by the higher values of our subjects in comparison to predicted values. Moreover, the close relation between the intensity developed at T (V.E) on TR and 6-MWT could support the idea that a walk test is a submaximal test performed at high intensity that could provide a basis for exercise prescription in an individualized manner in active elderly people.

The role of bile acid retention and a common polymorphism in the ABCB11 gene as host factors affecting antiviral treatment response in chronic hepatitis C.

Summary.  The outcome of hepatitis C virus (HCV) infection and the likelihood of a sustained virological response (SVR) to antiviral therapy depends on both viral and host characteristics. In vitro studies demonstrated that bile acids (BA) interfere with antiviral interferon effects. We investigate the influence of plasma BA concentrations and an ABCB11 polymorphism associated with lower transporter expression on viral load and SVR. Four hundred and fifty-one Caucasian HCV-patients treated with PEG-interferon and ribavirin were included in the study. ABCB11 1331T>C was genotyped, and plasma BA levels were determined. The 1331C allele was slightly overrepresented in HCV-patients compared to controls. In HCV-patients, a significant difference between patients achieving SVR vs non-SVR was observed for HCV-2/3 (5 vs 9 μm; P = 0.0001), while median BA levels in HCV-1 were marginally elevated. Normal BA levels <8 μm were significantly associated with SVR (58.3%vs 36.3%; OR 2.48; P = 0.0001). This difference was significant for HCV-2/3 (90.7%vs 67.6%; P = 0.002) but marginal in HCV-1 (38.7%vs 27.8%; P = 0.058). SVR rates were equivalent between ABCB11 genotypes for HCV-1, but increased for HCV-2/3 (TT 100%vs CC 78%; OR 2.01; P = 0.043). IL28B genotype had no influence on these associations. No correlation between BA levels and HCV RNA was detected for any HCV genotype. The higher allelic frequency of ABCB11 1331C in HCV-patients compared to controls may indirectly link increased BA to HCV chronicity. Our data support a role for BA as host factor affecting therapy response in HCV-2/3 patients, whereas a weaker association was found for HCV-1.

The Formal Independence of Regulators: A Comparison of 17 Countries and 7 Sectors

This article seeks to explain the pattern of delegation to independent regulatory agencies in Western Europe. Two types of arguments are advanced to explain variations in the formal independence of regulators. Firstly, the need for governments to increase their credible commitment capacity may lead them to delegate regulation to an agency that is partly beyond their direct control. Secondly, delegation may be a response to the political uncertainty problem, which arises when governments are afraid of being replaced by another coalition with different preferences, which could decide to change existing policy choices. In addition, veto players may constitute a functional equivalent of delegation, since they influence policy stability and therefore tend to mitigate both the credibility and the political uncertainty problems. These arguments are consistent with the results of the empirical analysis of the formal independence of regulators in seventeen countries and seven sectors.

Anatomic and functional outcome after 23-gauge sutureless transconjunctival vitrectomy, peeling and intravitreal triamcinolone for idiopathic macular epiretinal membranes

Purpose:To report the functional, anatomic outcome and safety profile of 23-gauge pars plana vitrectomy (PPV) combined with peeling and intravitreal injection of triamcinolone acetonide (TA) in eyes with idiopathic epiretinal membranes (ERM). Methods:Retrospective, nonrandomized study of consecutive patients who underwent 23-gauge transconjunctival sutureless PPV with subsequent membrane peeling and intravitreal TA injection for an idiopathic ERM. All patients were operated between February 2007 and February 2008 at the Jules Gonin University Eye Hospital. The minimum follow-up was 6-months. Results:Thirty-nine eyes of 39 patients were included. The mean follow-up was 7 months (SD: 2.2, range: 6-15 months). Twenty-two (56%) eyes were pseudophakic and 17 (44%) were phakic at the time of surgery. Mean preoperative intraocular pressure (IOP) was 14 mmHg (SD: 3.5). At the final follow-up mean IOP was 14.5 (SD: 2.7) that did not differ significantly from the IOP at baseline (P: 0.14- 2-tailed t test). Five patients (13%) needed temporary topical anti-glaucoma treatment.Mean preoperative BCVA was 0.28 decimal equivalent (logMAR 0.54, SD: 0.2, range: 1.0 - 0.2). and improved significantly (P <0.0001, 2-tailed t test) to a mean of 0.6 decimal equivalent (logMAR 0.22, SD: 0.16, range: 0.6 - 0) at the final follow-up. The visual acuity improved by a mean of 3.2 lines (SD 2.1, range 0- 8). Twenty-nine patients (74%) demonstrated a gain of 3 or more lines.Mean central macular thickness (CMT) was 456 µm (SD: 77) at the baseline that reduced significantly (P <0.0001, 2-tailed t test) at the final follow-up to 327µm (SD: 79). Average CMT reduction was 131µm (SD: 77, range: 36- 380 µm). A subgroup analysis of 15 selected cases that had CMT measurement 1 week after surgery demonstrated that 84% of the total final reduction in CMT occurred during the first week. Conclusions:23-gauge sutureless transconjunctival vitrectomy with the concomitant administration of intravitreal TA is a safe and effective technique for the treatment of idiopathic ERM and may speed up anatomical recovery.

Standardisation of 18F by a coincidence method using full solid angle detectors.

A solution of (18)F was standardised with a 4pibeta-4pigamma coincidence counting system in which the beta detector is a one-inch diameter cylindrical UPS89 plastic scintillator, positioned at the bottom of a well-type 5''x5'' NaI(Tl) gamma-ray detector. Almost full detection efficiency-which was varied downwards electronically-was achieved in the beta-channel. Aliquots of this (18)F solution were also measured using 4pigamma NaI(Tl) integral counting and Monte Carlo calculated efficiencies as well as the CIEMAT-NIST method. Secondary measurements of the same solution were also performed with an IG11 ionisation chamber whose equivalent activity is traceable to the Système International de Référence through the contribution IRA-METAS made to it in 2001; IRA's degree of equivalence was found to be close to the key comparison reference value (KCRV). The (18)F activity predicted by this coincidence system agrees closely with the ionisation chamber measurement and is compatible within one standard deviation of the other primary measurements. This work demonstrates that our new coincidence system can standardise short-lived radionuclides used in nuclear medicine.

Conditioning of stochastic 3-D fracture networks to hydrological and geophysical data

The geometry and connectivity of fractures exert a strong influence on the flow and transport properties of fracture networks. We present a novel approach to stochastically generate three-dimensional discrete networks of connected fractures that are conditioned to hydrological and geophysical data. A hierarchical rejection sampling algorithm is used to draw realizations from the posterior probability density function at different conditioning levels. The method is applied to a well-studied granitic formation using data acquired within two boreholes located 6 m apart. The prior models include 27 fractures with their geometry (position and orientation) bounded by information derived from single-hole ground-penetrating radar (GPR) data acquired during saline tracer tests and optical televiewer logs. Eleven cross-hole hydraulic connections between fractures in neighboring boreholes and the order in which the tracer arrives at different fractures are used for conditioning. Furthermore, the networks are conditioned to the observed relative hydraulic importance of the different hydraulic connections by numerically simulating the flow response. Among the conditioning data considered, constraints on the relative flow contributions were the most effective in determining the variability among the network realizations. Nevertheless, we find that the posterior model space is strongly determined by the imposed prior bounds. Strong prior bounds were derived from GPR measurements and helped to make the approach computationally feasible. We analyze a set of 230 posterior realizations that reproduce all data given their uncertainties assuming the same uniform transmissivity in all fractures. The posterior models provide valuable statistics on length scales and density of connected fractures, as well as their connectivity. In an additional analysis, effective transmissivity estimates of the posterior realizations indicate a strong influence of the DFN structure, in that it induces large variations of equivalent transmissivities between realizations. The transmissivity estimates agree well with previous estimates at the site based on pumping, flowmeter and temperature data.

Mutation screening of multiple genes in Spanish patients with autosomal recessive retinitis pigmentosa by targeted resequencing.

Retinitis Pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. RP is the leading cause of visual loss in individuals younger than 60 years, with a prevalence of about 1 in 4000. The molecular genetic diagnosis of autosomal recessive RP (arRP) is challenging due to the large genetic and clinical heterogeneity. Traditional methods for sequencing arRP genes are often laborious and not easily available and a screening technique that enables the rapid detection of the genetic cause would be very helpful in the clinical practice. The goal of this study was to develop and apply microarray-based resequencing technology capable of detecting both known and novel mutations on a single high-throughput platform. Hence, the coding regions and exon/intron boundaries of 16 arRP genes were resequenced using microarrays in 102 Spanish patients with clinical diagnosis of arRP. All the detected variations were confirmed by direct sequencing and potential pathogenicity was assessed by functional predictions and frequency in controls. For validation purposes 4 positive controls for variants consisting of previously identified changes were hybridized on the array. As a result of the screening, we detected 44 variants, of which 15 are very likely pathogenic detected in 14 arRP families (14%). Finally, the design of this array can easily be transformed in an equivalent diagnostic system based on targeted enrichment followed by next generation sequencing.

Malaria entomological inoculation rates in gold mining areas of Southern Venezuela

A longitudinal study of malaria vectors aiming to describe the intensity of transmission was carried out in five villages of Southern Venezuela between January 1999-April 2000. The man-biting, sporozoite and entomological inoculation rates (EIR) were calculated based on 121 all-night collections of anophelines landing on humans, CDC light traps and ultra violet up-draft traps. A total of 6,027 female mosquitoes representing seven species were collected. The most abundant species were Anopheles marajoara Galvão & Damasceno (56.7%) and Anopheles darlingi Root (33%), which together accounted for 89.7% of the total anophelines collected. The mean biting rate for An. marajoara was 1.27 (SD + 0.81); it was 0.74 (SD + 0.91) for An. darlingand 0.11 (SD + 0.10) for Anopheles neomaculipalpus Curry and the overall biting rate was 2.29 (SD + 1.06). A total of 5,886 mosquitoes collected by all three methods were assayed by ELISA and 28 pools, equivalent to 28 mosquitoes, yielded positive results for Plasmodium spp. CS protein. An. neomaculipalpus had the highest sporozoite rate 0.84% (3/356), followed by An. darlingi 0.82% (16/1,948) and An. marajoara 0.27% (9/3,332). The overall sporozoite rate was 0.48% (28/5,886). The rates of infection by Plasmodium species in mosquitoes were 0.37% (22/5,886) for Plasmodium vivax(Grassi & Feletti) and 0.10% (6/5,886) for Plasmodium falciparum (Welch). The estimated overall EIR for An. darling was 2.21 infective bites/person/year, 1.25 for An. marajoara and 0.34 for An. neomaculipalpus. The overall EIR was four infective bites/person/year. The biting rate, the sporozoite rate and the EIR are too low to be indicators of the efficacy of control campaigns in this area.