High-density Peptide Arrays Help to Identify Linear Immunogenic B-cell Epitopes in Individuals Naturally Exposed to Malaria Infection.

High-density peptide arrays are an excellent means to profile anti-plasmodial antibody responses. Different protein intrinsic epitopes can be distinguished, and additional insights are gained, when compared with assays involving the full-length protein. Distinct reactivities to specific epitopes within one protein may explain differences in published results, regarding immunity or susceptibility to malaria. We pursued three approaches to find specific epitopes within important plasmodial proteins, (1) twelve leading vaccine candidates were mapped as overlapping 15-mer peptides, (2) a bioinformatical approach served to predict immunogenic malaria epitopes which were subsequently validated in the assay, and (3) randomly selected peptides from the malaria proteome were screened as a control. Several peptide array replicas were prepared, employing particle-based laser printing, and were used to screen 27 serum samples from a malaria-endemic area in Burkina Faso, West Africa. The immunological status of the individuals was classified as "protected" or "unprotected" based on clinical symptoms, parasite density, and age. The vaccine candidate screening approach resulted in significant hits in all twelve proteins and allowed us (1) to verify many known immunogenic structures, (2) to map B-cell epitopes across the entire sequence of each antigen and (3) to uncover novel immunogenic epitopes. Predicting immunogenic regions in the proteome of the human malaria parasite Plasmodium falciparum, via the bioinformatics approach and subsequent array screening, confirmed known immunogenic sequences, such as in the leading malaria vaccine candidate CSP and discovered immunogenic epitopes derived from hypothetical or unknown proteins.

Substantial increase in mutations in the genes pfdhfr and pfdhps puts sulphadoxine-pyrimethamine-based intermittent preventive treatment for malaria at risk in Burkina Faso.

OBJECTIVE: Sulphadoxine-pyrimethamine (SP) is widely used as intermittent preventive treatment (IPT) for malaria in pregnant women in Sub-Saharan Africa. There are reports of wide-spread SP resistance in countries where SP had once been used as a first-line treatment. It is unclear whether the development of SP resistance also affects countries where SP is mainly used in the context of IPT, as is the case in Burkina Faso. To assess the efficacy of SP-based IPT, we monitored the prevalence of SP conferring genetic mutations in the genes dhfr and dhps in Plasmodium falciparum populations in a rural area of Burkina Faso over a period of 13 years. METHODS: Molecular epidemiological study consisted of six consecutive cross-sectional surveys of rainy and dry seasons (2009-2012). Data from the rainy season in 2000 served as a baseline. Mutations in dhfr and dhps associated with SP resistance were analysed by pyrosequencing in 861 parasite-positive samples. RESULTS: The prevalence of the SP resistance conferring triple dhfr mutation 51I, 59R, 108N increased from 1.3% in the rainy season of 2000 to 35.3% in 2009, and 54.3% in 2011 (P ≤ 0.001). Comparing rainy and dry seasons, we observed an increasing step-like pattern with higher prevalence of the dhfr triple mutant in the respective dry season compared with the preceding rainy season. The proportion of the dhps 437Gly mutation in the rainy season of 2000 was 53.2% and subsequently increased to 77.6% in 2009 (P ≤ 0.001). CONCLUSION: The increase in molecular markers linked with SP resistance jeopardises the efficacy of IPTp and the planned IPTi interventions in Burkina Faso, calling for careful monitoring of genotypic resistance markers and in vivo validation of IPT efficacy.

Declining malaria parasite prevalence and trends of asymptomatic parasitaemia in a seasonal transmission setting in North-Western Burkina Faso between 2000 and 2009-2012.

BACKGROUND: Malaria transmission was reported to have declined in some East African countries. However, a comparable trend has not been confirmed for West Africa. This study aims to assess the dynamics of parasite prevalence and malaria species distribution over time in an area of highly seasonal transmission in Burkina Faso. The aim was also to compare frequency of asymptomatic parasitaemia between wet and dry season by parasite density status and age group. METHODS: During the years 2009-2012, six cross-sectional studies were performed in the rural village Bourasso in the Nouna Health District in north-west Burkina Faso. In subsequent rainy and dry seasons blood samples were collected to assess the parasite prevalence, species, density and clinical parameters. In total, 1,767 children and adults were examined and compared to a baseline collected in 2000. RESULTS: The microscopical parasite prevalence (mainly P. falciparum) measured over the rainy seasons decreased significantly from 78.9% (2000) to 58.4%, 55.9% and 49.3%, respectively (2009-2011; p <0.001). The frequency of Plasmodium malariae infections (mono- and co-infections) decreased parallel to the overall parasite prevalence from 13.4% in 2000 to 2.1%, 4.1% and 4.7% in 2009-2011 (p <0.001). Comparing parasite-positive subjects from the rainy season versus dry season, the risk of fever was significantly reduced in the dry season adjusting for parasite density (grouped) and age group. CONCLUSIONS: The results of this study suggest a decline of malaria transmission over the rainy seasons between 2000 and 2009-2011 in the region of Nouna, Burkina Faso. The decreased transmission intensity was associated with lower prevalence of P. malariae infections (both mono-infections and co-infections). Asymptomatic parasitaemia was more frequent in the dry season even adjusting for parasite density and age group in a multivariate regression. Possible reasons for this observation include the existence of less pathogenic Plasmodium falciparum genotypes prevailing in the dry season, or the effect of a reduced incidence density during the dry season.

Medical suppression of hypercortisolemia in Cushing's syndrome with particular consideration of etomidate.

Cushing's syndrome is associated with excessive cortisol secretion by the adrenal gland or ectopic tumours and may result in diabetes, hypertension, and life-threatening infections with high mortality rates especially in the case of surgical resection. Although surgical resection is the treatment of choice, patients may benefit from preceding medical therapy. This may especially be useful as an adjunctive approach in emergency settings, if patients cannot undergo surgery, if surgery or radiotherapy fails, or if the tumour recurs. Medical therapy can be categorized in three different groups-inhibition of steroidogenesis, suppression of adrenocorticotropic hormone, and antagonism of the glucocorticoid receptor. However, the majority of common drugs are not available for parenteral administration, which may evoke a management problem in emergency settings or in patients unable to tolerate oral medication. The carboxylated imidazole etomidate is a well known parenteral induction agent for general anaesthesia. Besides its hypnotic properties, etomidate also has α-adrenergic characteristics and inhibits the enzyme 11-deoxycortisol ß-hydroxylase, which catalyzes the final step of the conversion of cholesterol to cortisol. Adverse outcomes have been reported when used for sedation in septic or trauma patients probably by its interference with steroid homeostasis. However, its capability of inhibition of the 11-deoxycortisol ß-hydroxylase leads to suppression of cortisol secretion which has been demonstrated to be a useful tool in severe and complicated hypercortisolemia. Within this article, we review the data concerning different pharmacological approaches with particular consideration of etomidate in order to suppress steroidogenesis in patients with Cushing's syndrome.

Nebivolol prevents vascular NOS III uncoupling in experimental hyperlipidemia and inhibits NADPH oxidase activity in inflammatory cells.

OBJECTIVE: Nebivolol, in contrast to other selective beta1-adrenergic receptor antagonists like atenolol, improves endothelial function in patients with oxidative stress within vascular tissue. With the present studies we sought to determine whether beta receptor blockade with nebivolol may improve endothelial function in hyperlipidemia and whether this is attributable to reductions in vascular oxidative stress. METHODS AND RESULTS: Watanabe heritable hyperlipidemic rabbits (WHHL) were treated with nebivolol (10 mg/kg per day for 8 weeks). New Zealand white rabbits (NZWR) served as controls. Nebivolol improved endothelial function, reduced vascular superoxide and vascular macrophage infiltration, and prevented NO synthase uncoupling in WHHL. Nebivolol treatment did not modify the expression of sGC or cGK-I but improved cGK-I activity (assessed by the phosphorylation state of the VAsodilator Stimulated Phosphoprotein at serine239, P-VASP). NAD(P)H oxidase activity in whole blood and isolated neutrophils was dose-dependently inhibited by nebivolol, whereas atenolol, metoprolol, and carvedilol were markedly less effective. CONCLUSIONS: Nebivolol therapy effectively prevents NO synthase III uncoupling and prevents activation of the neutrophil NAD(P)H oxidase and infiltration of inflammatory cells. These novel antioxidative stress actions of this compound may explain partly the beneficial effects on endothelial function in patients with enhanced vascular oxidative stress.

Plantar vein thrombosis due to busy night duty on intensive care unit.

A 32-year-old woman with severe foot pain came to our emergency department after a busy night duty in hospital followed by an extended sleep period. Physical examination revealed a discrete swelling of the medial aspect of the right foot and a painful plantar arch during digital examination. Magnetic resonance imaging (MRI) with intravenous gadolinium showed filling defects in the lateral plantar vein. Doppler sonography displayed noncompressible structures in the plantar veins without flow signals, suggesting a plantar vein thrombosis. Therapy was initiated with low-molecular-weight heparin in combination with customized elastic bandages for the lower leg. Follow-up sonography 6 weeks later showed complete patency of the plantar veins. To our knowledge, we present the first case of isolated plantar vein thrombosis independent of trauma, surgery, or malignant disease, most probably caused by a busy night duty on the intensive care unit (ICU) followed by a prolonged sleeping period.