Evidence against Wolbachia symbiosis in Loa loa

BACKGROUND: The majority of filarial nematode species are host to Wolbachia bacterial endosymbionts, although a few including Acanthocheilonema viteae, Onchocerca flexuosa and Setaria equina have been shown to be free of infection. Comparisons of species with and without symbionts can provide important information on the role of Wolbachia symbiosis in the biology of the nematode hosts and the contribution of the bacteria to the development of disease. Previous studies by electron microscopy and PCR have failed to detect intracellular bacterial infection in Loa loa. Here we use molecular and immunohistological techniques to confirm this finding. METHODS: We have used a combination of PCR amplification of bacterial genes (16S ribosomal DNA [rDNA], ftsZ and Wolbachia surface protein [WSP]) on samples of L. loa adults, third-stage larvae (L3) and microfilariae (mf) and immunohistology on L. loa adults and mf derived from human volunteers to determine the presence or absence of Wolbachia endosymbionts. Samples used in the PCR analysis included 5 adult female worms, 4 adult male worms, 5 mf samples and 2 samples of L3. The quality and purity of nematode DNA was tested by PCR amplification of nematode 5S rDNA and with diagnostic primers from the target species and used to confirm the absence of contamination from Onchocerca sp., Mansonella perstans, M. streptocerca and Wuchereria bancrofti. Immunohistology was carried out by light and electron microscopy on L. loa adults and mf and sections were probed with rabbit antibodies raised to recombinant Brugia malayi Wolbachia WSP. Samples from nematodes known to be infected with Wolbachia (O. volvulus, O. ochengi, Litomosoides sigmodontis and B. malayi) were used as positive controls and A. viteae as a negative control. RESULTS: Single PCR analysis using primer sets for the bacterial genes 16S rDNA, ftsZ, and WSP were negative for all DNA samples from L. loa. Positive PCR reactions were obtained from DNA samples derived from species known to be infected with Wolbachia, which confirmed the suitability of the primers and PCR conditions. The quality and purity of nematode DNA samples was verified by PCR amplification of 5S rDNA and with nematode diagnostic primers. Additional analysis by 'long PCR' failed to produce any further evidence for Wolbachia symbiosis. Immunohistology of L. loa adults and mf confirmed the results of the PCR with no evidence for Wolbachia symbiosis. CONCLUSION: DNA analysis and immunohistology provided no evidence for Wolbachia symbiosis in L. loa

Pooled analysis of Phase III trials indicate contrasting influences of renal function on blood pressure, body weight, and HbA1c reductions with empagliflozin

Sodium glucose cotransporter 2 (SGLT2) inhibitors reduce HbA1c, blood pressure, and weight in patients with type 2 diabetes. To investigate the effect of renal function on reductions in these parameters with the SGLT2 inhibitor empagliflozin, we assessed subgroups by baseline estimated glomerular filtration rate (eGFR; Modification of Diet in Renal Disease) in pooled data from five 24-week trials of 2286 patients with type 2 diabetes randomized to empagliflozin or placebo. Reductions in HbA1c with empagliflozin versus placebo significantly diminished with decreasing baseline eGFR. Reductions in systolic blood pressure (SBP) with empagliflozin were maintained in patients with lower eGFR. The mean placebo-corrected changes from baseline in systolic blood pressure at week 24 with empagliflozin were -3.2 (95% confidence interval -4.9,-1.5) mmHg, -4.0 (-5.4, -2.6) mmHg, -5.5 (-7.6, -3.4) mmHg, and -6.6 (-11.4, -1.8) mmHg in patients with an eGFR of 90 or more, 60 to 89, 30 to 59, and under 30 ml/min/1.73m(2), respectively. Similar trends were observed for diastolic blood pressure. Weight loss with empagliflozin versus placebo tended to be attenuated in patients with a lower eGFR. Results were consistent in a 12-week ambulatory blood pressure monitoring trial in 823 patients with type 2 diabetes and hypertension. Thus, unlike HbA1c reductions, systolic blood pressure and weight reductions with empagliflozin are generally preserved in patients with chronic kidney disease.Peer reviewe

The effect of sodium glucose cotransporter 2 inhibition with empagliflozin on microalbuminuria and macroalbuminuria in patients with type 2 diabetes

Aims/hypothesis Sodium glucose cotransporter 2 (SGLT2) inhibition lowers HbA(1c), systolic BP (SBP) and weight in patients with type 2 diabetes and reduces renal hyperfiltration associated with type 1 diabetes, suggesting decreased intraglomerular hypertension. As lowering HbA(1c), SBP, weight and intraglomerular pressure is associated with antialbuminuric effects in diabetes, we hypothesised that SGLT2 inhibition would reduce the urine albumin-to-creatinine ratio (UACR) to a clinically meaningful extent. Methods We examined the effect of the SGLT2 inhibitor empagliflozin on UACR by pooling data from patients with type 2 diabetes and prevalent microalbuminuria (UACR=30-300 mg/g; n = 636) or macroalbuminuria (UACR>300 mg/g; n=215) who participated in one of five phase III randomised clinical trials. Primary assessment was defined as percentage change in geometric mean UACR from baseline to week 24. Results After controlling for clinical confounders including baseline log-transformed UACR, HbA(1c), SBP and estimated GFR (according to the Modification of Diet in Renal Disease [MDRD] formula), treatment with empagliflozin significantly reduced UACR in patients with microalbuminuria (-32% vs placebo; p Conclusions/interpretation In patients with type 2 diabetes and either micro-or macroalbuminuria, empagliflozin reduced UACR by a clinically meaningful amount. This effect was largely independent of the known metabolic or systemic haemodynamic effects of this drug class. Our results further support a direct renal effect of SGLT2 inhibitors. Prospective studies are needed to explore the potential of this intervention to alter the course of kidney disease in high-risk patients with diabetes. Trial registration: Clinicaltrials.gov NCT01177813 (study 1); NCT01159600 (study 2); NCT01159600 (study 3); NCT01210001 (study 4); and NCT01164501 (study 5).Peer reviewe

Spinning Strings, Black Holes and Stable Closed Timelike Geodesics

The existence and stability under linear perturbation of closed timelike curves in the spacetime associated to Schwarzschild black hole pierced by a spinning string are studied. Due to the superposition of the black hole, we find that the spinning string spacetime is deformed in such a way to allow the existence of closed timelike geodesics.Comment: 5 pages, RevTex4, some corrections and new material adde

Opening the black box of under-health people: the case of Spain

ABSTRACT: The most famous modern definition of health was created during a Preamble to the Constitution of the World Health Organization in 1946: "Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has not been amended and, since then, many indicators have been proposed to measure health such as Self-Assessed Health (SAH) status. It provides an overall measure of a population's health based on individuals' personal perceptions of their own health. In this paper, we focus our analysis on "under-health" as the fact of having a level that falls behind the health requirements necessary to perform what is considered an "expected life based on Self Assessed Health". For Spain using the European Union Statistics on Income and Living Conditions (EU-SILC), we can confirm there exist under-healthy people by occupation, age group and sex. Additionally, under-healthy workers are most likely to be found among skilled agricultural, fishery workers and elementary occupations

Goedel-type Universes and the Landau Problem

We point out a close relation between a family of Goedel-type solutions of 3+1 General Relativity and the Landau problem in S^2, R^2 and H_2; in particular, the classical geodesics correspond to Larmor orbits in the Landau problem. We discuss the extent of this relation, by analyzing the solutions of the Klein-Gordon equation in these backgrounds. For the R^2 case, this relation was independently noticed in hep-th/0306148. Guided by the analogy with the Landau problem, we speculate on the possible holographic description of a single chronologically safe region.Comment: Latex, 21 pages, 1 figure. v2 missing references to previous work on the subject adde

Unraveling cross-reactivity of anti-glycan IgG responses in filarial nematode infections

Parasitic nematodes responsible for filarial diseases cause chronic disablement in humans worldwide. Elimination programs have substantially reduced the rate of infection in certain areas, but limitations of current diagnostics for population surveillance have been pointed out and improved assays are needed to reach the elimination targets. While serological tests detecting antibodies to parasite antigens are convenient tools, those currently available are compromised by the occurrence of antibodies cross-reactive between nematodes, as well as by the presence of residual antibodies in sera years after treatment and clearance of the infection. We recently characterized the N-linked and glycosphingolipid derived glycans of the parasitic nematode Brugia malayi and revealed the presence of various antigenic structures that triggered immunoglobulin G (IgG) responses in infected individuals. To address the specificity of IgG binding to these glycan antigens, we screened microarrays containing Brugia malayi glycans with plasma from uninfected individuals and from individuals infected with Loa loa, Onchocerca volvulus, Mansonella perstans and Wuchereria bancrofti, four closely related filarial nematodes. IgG to a restricted subset of cross-reactive glycans was observed in infection plasmas from all four species. In plasma from Onchocerca volvulus and Mansonella perstans infected individuals, IgG binding to many more glycans was additionally detected, resulting in total IgG responses similar to the ones of Brugia malayi infected individuals. For these infection groups, Brugia malayi, Onchocerca volvulus and Mansonella perstans, we further studied the different IgG subclasses to Brugia malayi glycans. In all three infections, IgG1 and IgG2 appeared to be the major subclasses involved in response to glycan antigens. Interestingly, in Brugia malayi infected individuals, we observed a marked reduction in particular in IgG2 to parasite glycans post-treatment with anthelminthic, suggesting a promising potential for diagnostic applications. Thus, we compared the IgG response to a broad repertoire of Brugia malayi glycans in individuals infected with various filarial nematodes. We identified broadly cross-reactive and more specific glycan targets, extending the currently scarce knowledge of filarial nematode glycosylation and host anti-glycan antibody response. We believe that our initial findings could be further exploited to develop disease-specific diagnostics as part of an integrated approach for filarial disease control.Host-parasite interactio

Anti-relapse neurons in the infralimbic cortex of rats drive relapse-suppression by drug omission cues

Drug addiction is a chronic relapsing disorder of compulsive drug use. Studies of the neurobehavioral factors that promote drug relapse have yet to produce an effective treatment. Here we take a different approach and examine the factors that suppress – rather than promote – relapse. Adapting Pavlovian procedures to suppress operant drug response, we determined the anti-relapse action of environmental cues that signal drug omission (unavailability) in rats. Under laboratory conditions linked to compulsive drug use and heightened relapse risk, drug omission cues suppressed three major modes of relapse-promotion (drug-predictive cues, stress, and drug exposure) for cocaine and alcohol. This relapse-suppression is partially driven by omission cue-reactive neurons, which constitute small subsets of glutamatergic and GABAergic cells, in the infralimbic cortex. Future studies of such neural activity-based cellular units (neuronal ensembles/memory engram cells) for relapse-suppression can be used to identify alternate targets for addiction medicine through functional characterization of anti-relapse mechanisms

Efficient in vitro RNA interference and immunofluorescence-based phenotype analysis in a human parasitic nematode, Brugia malayi

<p>Abstract</p> <p>Background</p> <p>RNA interference (RNAi) is an efficient reverse genetics technique for investigating gene function in eukaryotes. The method has been widely used in model organisms, such as the free-living nematode <it>Caenorhabditis elegans</it>, where it has been deployed in genome-wide high throughput screens to identify genes involved in many cellular and developmental processes. However, RNAi techniques have not translated efficiently to animal parasitic nematodes that afflict humans, livestock and companion animals across the globe, creating a dependency on data tentatively inferred from <it>C. elegans</it>.</p> <p>Results</p> <p>We report improved and effective <it>in vitro </it>RNAi procedures we have developed using heterogeneous short interfering RNA (hsiRNA) mixtures that when coupled with optimized immunostaining techniques yield detailed analysis of cytological defects in the human parasitic nematode, <it>Brugia malayi</it>. The cellular disorganization observed in <it>B. malayi </it>embryos following RNAi targeting the genes encoding γ-tubulin, and the polarity determinant protein, PAR-1, faithfully phenocopy the known defects associated with gene silencing of their <it>C. elegans </it>orthologs. Targeting the <it>B. malayi </it>cell junction protein, AJM-1 gave a similar but more severe phenotype than that observed in <it>C. elegans</it>. Cellular phenotypes induced by our <it>in vitro </it>RNAi procedure can be observed by immunofluorescence in as little as one week.</p> <p>Conclusions</p> <p>We observed cytological defects following RNAi targeting all seven <it>B. malayi </it>transcripts tested and the phenotypes mirror those documented for orthologous genes in the model organism <it>C. elegans</it>. This highlights the reliability, effectiveness and specificity of our RNAi and immunostaining procedures. We anticipate that these techniques will be widely applicable to other important animal parasitic nematodes, which have hitherto been mostly refractory to such genetic analysis.</p

The Wolbachia endosymbiont as an anti-filarial nematode target

Human disease caused by parasitic filarial nematodes is a major cause of global morbidity. The parasites are transmitted by arthropod intermediate hosts and are responsible for lymphatic filariasis (elephantiasis) or onchocerciasis (river blindness). Within these filarial parasites are intracellular alpha-proteobacteria, Wolbachia, that were first observed almost 30 years ago. The obligate endosymbiont has been recognized as a target for anti-filarial nematode chemotherapy as evidenced by the loss of worm fertility and viability upon antibiotic treatment in an extensive series of human trials. While current treatments with doxycycline and rifampicin are not practical for widespread use due to the length of required treatments and contraindications, anti-Wolbachia targeting nevertheless appears a promising alternative for filariasis control in situations where current programmatic strategies fail or are unable to be delivered and it provides a superior efficacy for individual therapy. The mechanisms that underlie the symbiotic relationship between Wolbachia and its nematode hosts remain elusive. Comparative genomics, bioinfomatic and experimental analyses have identified a number of potential interactions, which may be drug targets. One candidate is de novo heme biosynthesis, due to its absence in the genome sequence of the host nematode, Brugia malayi, but presence in Wolbachia and its potential roles in worm biology. We describe this and several additional candidate targets, as well as our approaches for understanding the nature of the host-symbiont relationship