Plasmodium falciparum malaria: rosettes are disrupted by quinine, artemisinin, mefloquine, primaquine, pyrimethamine, chloroquine and proguanil

An assay was developed measuring the disruption of rosettes between Plasmodium falciparuminfected (trophozoites) and uninfected erythrocytes by the antimalarial drugs quinine, artemisinin mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. At 4 hr incubation rosettes were disrupted by all the drugs in a dose dependent manner. Artemisinin and quinine were the most effective anti-malarials at disrupting rosettes at their therapeutic concentrations with South African RSA 14, 15, 17 and The Gambian FCR-3 P. falciparum strains. The least effective drugs were proguanil and chloroquine. A combination of artemisinin and mefloquine was more effective than each drug alone. The combinations of pyrimethamine or primaquine, with quinine disrupted more rosettes than quinine alone. Quinine may be an effective drug in the treatment of severe malaria because the drug efficiently reduces the number of rosettes.

Novel H3K4me3 marks are enriched at human- and chimpanzee-specific cytogenetic structures.

Human and chimpanzee genomes are 98.8% identical within comparable sequences. However, they differ structurally in nine pericentric inversions, one fusion that originated human chromosome 2, and content and localization of heterochromatin and lineage-specific segmental duplications. The possible functional consequences of these cytogenetic and structural differences are not fully understood and their possible involvement in speciation remains unclear. We show that subtelomeric regions-regions that have a species-specific organization, are more divergent in sequence, and are enriched in genes and recombination hotspots-are significantly enriched for species-specific histone modifications that decorate transcription start sites in different tissues in both human and chimpanzee. The human lineage-specific chromosome 2 fusion point and ancestral centromere locus as well as chromosome 1 and 18 pericentric inversion breakpoints showed enrichment of human-specific H3K4me3 peaks in the prefrontal cortex. Our results reveal an association between plastic regions and potential novel regulatory elements.

Food Security on the island of Ireland: are we sleep walking into a crisis?

IPH has developed a discussion paper on food security on the island. This makes the case that health is and needs to be central to food and agricultural policy. Population health, food systems and agricultural production are intimately linked.  A clear framework on food security is needed in both parts of the island of Ireland and this offers a key opportunity for cooperation. This article has been published in the latest edition of The Journal of Cross Border Studies in Ireland - No 6 launched on 8 March 2011.

Liver kidney microsomes type 1 antibodies are associated with 80% reduction of the CYP2D6 activity in patients with chronic hepatitis C

Introduction Liver kidney microsomal type 1 (LKM-1) antibodies have been shown to decrease CYP2D6 activity in vitro. We investigated whether LKM-1 antibodies might reduce CYP2D6 activity also in vivo.Materials and Methods All patients with chronic hepatitis C and LKM-1 antibodies enrolled in the Swiss Hepatitis C Cohort Study (SCCS) were assessed: ten were eligible and fi tted to patients without LKM-1 antibodies. Patients were genotyped for CYP2D6 variants to exclude individuals with a poor metabolizer genotype. CYP2D6 activity was measured by a specifi c substrate using the dextromethorphan/dextrorphan (DEM/DOR) metabolic ratio to classify patients into four activity phenotypes (i.e. ultrarapid, extensive, intermediate and poor metabolizers). The concordance between phenotype based on DEM/DOR ratio and phenotype expected from genotype was examined in LKM-1 positive and negative patients. Groups were compared with respect to the DEM/DOR metabolic ratio.Results All patients had a CYP2D6 extensive metabolizer genotype. The observed phenotype was concordant with CYP2D6 genotype in most LKM-negative patients, whereas only three (30%) LKM-1 positive patients had a concordant phenotype (six presented an intermediate and one a poor metabolizer phenotype). The median DEM/DOR ratio was six-fold higher in LKM-1 positive than in LKM-1 negative patients (0.096 vs. 0.016, p = 0.004), indicating that CYP2D6 metabolic function was significantly reduced in the presence of LKM-1 antibodies.Conclusion In chronic hepatitis C patients with LKM-1 antibodies, the CYP2D6 metabolic activity was on average reduced by 80%. The impact of LKM-1 antibodies on CYP2D6-mediated drug metabolism pathways warrants further translational studies in the setting of new protease inhibitor therapies

Bcl9/Bcl9l are critical for Wnt-mediated regulation of stem cell traits in colon epithelium and adenocarcinomas.

Canonical Wnt signaling plays a critical role in stem cell maintenance in epithelial homeostasis and carcinogenesis. Here, we show that in the mouse this role is critically mediated by Bcl9/Bcl9l, the mammalian homologues of Legless, which in Drosophila is required for Armadillo/beta-catenin signaling. Conditional ablation of Bcl9/Bcl9l in the intestinal epithelium, where the essential role of Wnt signaling in epithelial homeostasis and stem cell maintenance is well documented, resulted in decreased expression of intestinal stem cell markers and impaired regeneration of ulcerated colon epithelium. Adenocarcinomas with aberrant Wnt signaling arose with similar incidence in wild-type and mutant mice. However, transcriptional profiles were vastly different: Whereas wild-type tumors displayed characteristics of epithelial-mesenchymal transition (EMT) and stem cell-like properties, these properties were largely abrogated in mutant tumors. These findings reveal an essential role for Bcl9/Bcl9l in regulating a subset of Wnt target genes involved in controlling EMT and stem cell-related features and suggest that targeting the Bcl9/Bcl9l arm of Wnt signaling in Wnt-activated cancers might attenuate these traits, which are associated with tumor invasion, metastasis, and resistance to therapy.

Estimation of glomerular filtration rate in hospitalised patients: are we overestimating renal function?

QUESTIONS UNDER STUDY AND PRINCIPLES: Estimating glomerular filtration rate (GFR) in hospitalised patients with chronic kidney disease (CKD) is important for drug prescription but it remains a difficult task. The purpose of this study was to investigate the reliability of selected algorithms based on serum creatinine, cystatin C and beta-trace protein to estimate GFR and the potential added advantage of measuring muscle mass by bioimpedance. In a prospective unselected group of patients hospitalised in a general internal medicine ward with CKD, GFR was evaluated using inulin clearance as the gold standard and the algorithms of Cockcroft, MDRD, Larsson (cystatin C), White (beta-trace) and MacDonald (creatinine and muscle mass by bioimpedance). 69 patients were included in the study. Median age (interquartile range) was 80 years (73-83); weight 74.7 kg (67.0-85.6), appendicular lean mass 19.1 kg (14.9-22.3), serum creatinine 126 μmol/l (100-149), cystatin C 1.45 mg/l (1.19-1.90), beta-trace protein 1.17 mg/l (0.99-1.53) and GFR measured by inulin 30.9 ml/min (22.0-43.3). The errors in the estimation of GFR and the area under the ROC curves (95% confidence interval) relative to inulin were respectively: Cockcroft 14.3 ml/min (5.55-23.2) and 0.68 (0.55-0.81), MDRD 16.3 ml/min (6.4-27.5) and 0.76 (0.64-0.87), Larsson 12.8 ml/min (4.50-25.3) and 0.82 (0.72-0.92), White 17.6 ml/min (11.5-31.5) and 0.75 (0.63-0.87), MacDonald 32.2 ml/min (13.9-45.4) and 0.65 (0.52-0.78). Currently used algorithms overestimate GFR in hospitalised patients with CKD. As a consequence eGFR targeted prescriptions of renal-cleared drugs, might expose patients to overdosing. The best results were obtained with the Larsson algorithm. The determination of muscle mass by bioimpedance did not provide significant contributions.

Proliferation capacity and cytotoxic activity are mediated by functionally and phenotypically distinct virus-specific CD8 T cells defined by interleukin-7R{alpha} (CD127) and perforin expression.

Cytotoxicity and proliferation capacity are key functions of antiviral CD8 T cells. In the present study, we investigated a series of markers to define these functions in virus-specific CD8 T cells. We provide evidence that there is a lack of coexpression of perforin and CD127 in human CD8 T cells. CD127 expression on virus-specific CD8 T cells correlated positively with proliferation capacity and negatively with perforin expression and cytotoxicity. Influenza virus-, cytomegalovirus-, and Epstein-Barr virus/human immunodeficiency virus type 1-specific CD8 T cells were predominantly composed of CD127(+) perforin(-)/CD127(-) perforin(+), and CD127(-)/perforin(-) CD8 T cells, respectively. CD127(-)/perforin(-) and CD127(-)/perforin(+) cells expressed significantly more PD-1 and CD57, respectively. Consistently, intracellular cytokine (gamma interferon, tumor necrosis factor alpha, and interleukin-2 [IL-2]) responses combined to perforin detection confirmed that virus-specific CD8 T cells were mostly composed of either perforin(+)/IL-2(-) or perforin(-)/IL-2(+) cells. In addition, perforin expression and IL-2 secretion were negatively correlated in virus-specific CD8 T cells (P < 0.01). As previously shown for perforin, changes in antigen exposure modulated also CD127 expression. Based on the above results, proliferating (CD127(+)/IL-2-secreting) and cytotoxic (perforin(+)) CD8 T cells were contained within phenotypically distinct T-cell populations at different stages of activation or differentiation and showed different levels of exhaustion and senescence. Furthermore, the composition of proliferating and cytotoxic CD8 T cells for a given antiviral CD8 T-cell population appeared to be influenced by antigen exposure. These results advance our understanding of the relationship between cytotoxicity, proliferation capacity, the levels of senescence and exhaustion, and antigen exposure of antiviral memory CD8 T cells.

Gross Hemoglobinuria and Oliguria are Common Transient Complications of Sclerotherapy for Venous Malformations: Review of 475 Procedures.

Estudi retrospectiu per analitzar la incidència, factors de risc i tractament de la hemoglobinuria macroscòpica i oliguria després del tractament de malformacions venoses amb escleroteràpia. Un total de 475 procediments es van realitzar en 131 malalts usant etanol, sulfat tetradecil sòdic o ambdos. Hemoglobinuria temporal es va donar després del 34% de procediments i el 57% d’aquests es van asociar amb oliguria temporal. Aquest risc augmenta amb el increment de dosis. La resolució de la hemoglobinuria i oliguria va ser satisfactòria en tots els malalts. El risc d’hemoglobinuria augmenta a les malformacions que afecten les extremitats inferiors i a les de localitzacions mútiples.

Drug monographs on drugs which are frequently analysed in the context of Therapeutic Drug Monitoring = Arzneimittel-Monographien für Medikamente, die regelmässig im Rahmen des Therapeutic Drug Monitorings analysiert werden

In addition to the monographs which were published last year by the working group "Drug Monitoring" of the Swiss Society of Clinical Chemistry (SSCC) [1], new monographs have been written. The aim of these monographs is to give an overview of the most important information necessary for ordering a drug analysis or interpreting the results. Therefore, the targeted readers comprise laboratory health professionals and all receivers of laboratory reports. There is information provided on the indication for therapeutic drug monitoring, protein binding, metabolic pathways and enzymes involved, elimination half-life and elimination routes, and on therapeutic or toxic concentrations. Preanalytical considerations are of particular importance for therapeutic drug monitoring. Therefore, information is provided regarding a reasonable timing for the determination of drug concentrations as well as steady-state concentrations after changing the dose. Furthermore, the stability of the drug and its metabolite(s) after blood sampling is described. For readers with a specific interest in drug analysis, references to important publications are given. The number of monographs will be continuously enlarged. The updated files are presented on the homepage of the SSCC (www.sscc.ch).

Host specialist clownfishes are environmental niche generalists.

Why generalist and specialist species coexist in nature is a question that has interested evolutionary biologists for a long time. While the coexistence of specialists and generalists exploiting resources on a single ecological dimension has been theoretically and empirically explored, biological systems with multiple resource dimensions (e.g. trophic, ecological) are less well understood. Yet, such systems may provide an alternative to the classical theory of stable evolutionary coexistence of generalist and specialist species on a single resource dimension. We explore such systems and the potential trade-offs between different resource dimensions in clownfishes. All species of this iconic clade are obligate mutualists with sea anemones yet show interspecific variation in anemone host specificity. Moreover, clownfishes developed variable environmental specialization across their distribution. In this study, we test for the existence of a relationship between host-specificity (number of anemones associated with a clownfish species) and environmental-specificity (expressed as the size of the ecological niche breadth across climatic gradients). We find a negative correlation between host range and environmental specificities in temperature, salinity and pH, probably indicating a trade-off between both types of specialization forcing species to specialize only in a single direction. Trade-offs in a multi-dimensional resource space could be a novel way of explaining the coexistence of generalist and specialists.

PAP1 [poly(A) polymerase 1] homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole-resistant clinical isolates of Candida albicans.

Using genetically matched azole-susceptible (AS) and azole-resistant (AR) clinical isolates of Candida albicans, we recently demonstrated that CDR1 overexpression in AR isolates is due to its enhanced transcriptional activation and mRNA stability. This study examines the molecular mechanisms underlying enhanced CDR1 mRNA stability in AR isolates. Mapping of the 3' untranslated region (3' UTR) of CDR1 revealed that it was rich in adenylate/uridylate (AU) elements, possessed heterogeneous polyadenylation sites, and had putative consensus sequences for RNA-binding proteins. Swapping of heterologous and chimeric lacZ-CDR1 3' UTR transcriptional reporter fusion constructs did not alter the reporter activity in AS and AR isolates, indicating that cis-acting sequences within the CDR1 3' UTR itself are not sufficient to confer the observed differential mRNA decay. Interestingly, the poly(A) tail of the CDR1 mRNA of AR isolates was approximately 35-50 % hyperadenylated as compared with AS isolates. C. albicans poly(A) polymerase (PAP1), responsible for mRNA adenylation, resides on chromosome 5 in close proximity to the mating type-like (MTL) locus. Two different PAP1 alleles, PAP1-a/PAP1-alpha, were recovered from AS (MTL-a/MTL-alpha), while a single type of PAP1 allele (PAP1-alpha) was recovered from AR isolates (MTL-alpha/MTL-alpha). Among the heterozygous deletions of PAP1-a (Deltapap1-a/PAP1-alpha) and PAP1-alpha (PAP1-a/Deltapap1-alpha), only the former led to relatively enhanced drug resistance, to polyadenylation and to transcript stability of CDR1 in the AS isolate. This suggests a dominant negative role of PAP1-a in CDR1 transcript polyadenylation and stability. Taken together, our study provides the first evidence, to our knowledge, that loss of heterozygosity at the PAP1 locus is linked to hyperadenylation and subsequent increased stability of CDR1 transcripts, thus contributing to enhanced drug resistance.