This study was designed to assess the safety, acceptability, pharmacokinetic (PK), and pharmacodynamic (PD) responses to rectal administration of tenofovir (TFV) 1% vaginally formulated gel and oral tenofovir disoproxil fumarate (TDF). This study was designed as a phase 1, randomized, two-site (United States), double-blind, placebo-controlled study of sexually abstinent men and women. Eighteen participants received a single 300-mg exposure of oral TDF and were then randomized 2:1 to receive a single and then seven daily exposures of rectal TFV or hydroxyethyl cellulose (HEC) placebo gel. Safety endpoints included clinical adverse events (AEs) and mucosal safety parameters. Blood and colonic biopsies were collected for PK analyses and ex vivo HIV-1 challenge. No serious AEs were reported. However, AEs were significantly increased with 7-day TFV gel use, most prominently with gastrointestinal AEs ( p = 0.002). Only 25% of participants liked the TFV gel. Likelihood of use ''if somewhat protective'' was *75% in both groups. Indices of mucosal damage showed minimal changes. Tissue TFV diphosphate (TFV-DP) C max 30 min after single rectal exposure was 6-10 times greater than single oral exposure; tissue TFV-DP was 5.7 times greater following 7-day versus single rectal exposure. In vivo exposure correlated with significant ex vivo tissue infectibility suppression [single-rectal: p = 0.12, analysis of covariance (ANCOVA) p = 0.006; 7-day rectal: p = 0.02, ANCOVA p = 0.005]. Tissue PK-PD was significantly correlated ( p = 0.002). We conclude that rectal dosing with TFV 1% gel resulted in greater TFV-DP tissue detection than oral dosing with reduced ex vivo biopsy infectibility, enabling PK-PD correlations. On the basis of increased gastrointestinal AEs, rectally applied, vaginally formulated TFV was not entirely safe or acceptable, suggesting the need for alternative rectal-specific formulations.

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin–ethyl acetate sedimentation-digestion (FEA–SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.

When a treatment has a positive average causal effect (ACE) on an intermediate variable or surrogate end point which in turn has a positive ACE on a true end point, the treatment may have a negative ACE on the true end point due to the presence of unobserved confounders, which is called the surrogate paradox. A criterion for surrogate end points based on ACEs has recently been proposed to avoid the surrogate paradox. For a continuous or ordinal discrete end point, the distributional causal effect (DCE) may be a more appropriate measure for a causal effect than the ACE. We discuss criteria for surrogate end points based on DCEs. We show that commonly used models, such as generalized linear models and Cox's proportional hazard models, can make the sign of the DCE of the treatment on the true end point determinable by the sign of the DCE of the treatment on the surrogate even if the models include unobserved confounders. Furthermore, for a general distribution without any assumption of parametric models, we give a sufficient condition for a distributionally consistent surrogate and prove that it is almost necessary. Copyright (c) 2010 Royal Statistical Society.

Schistosomiasis is a parasitic zoonosis posing great threat to human health. The infection is acquired by larval cercariae penetrating host skin and transforming into juveniles, schistosomula. Proteolytic enzymes secreted from the cercarial acetabular glands are known to aid to the skin penetration, but molecular mechanisms remain largely unclear. To profile the protein composition and identify potential invasive proteases, we developed a new method for simulating cercarial transformation and collecting schistosomula, and for the first time, we compared the proteomes of Schistosoma japonicum cercariae and schistosomula by using in-gel shotgun proteomic analysis. Totally, 1972 proteins were identified in association with ten main biological processes based on Gene Ontology analysis; 46 proteases were detected in cercariae, and among them, 25 proteases disappeared after penetrated. Notably, leishmanolysins and serine and cysteine proteases were found abundant but differentially expressed. Recombinant serine protease SjCE2b and cysteine protease SjCB2 were produced and used for validation of native proteins. Immunofluorescence and Western blotting assays detected SjCE2b and SjCB2 in cercariae but not in schistosomula, suggesting the two enzymes might be consumed upon skin migration. Our data comprehensively chart the proteomic changes during cercarial invasion, revealing the potential proteases involved, providing a platform for the development of molecular anti-infection strategy.

The schistosome tegument plays a crucial role in host-parasite interactions and there are several tegument proteins that proved to be potential vaccine candidates. However, vaccines are not yet available, thus it is important to identify new target antigens from schistosome tegument proteome. Herein, we demonstrate that the S. japonicum tegument proteins were analyzed by an integrated immunoproteomics and bioinformatics approach. We found that thirty highly immunoreactive tegument proteins and 10 antigens with an AUC value greater than 0.90 were identified for the first time. In particularly, we found 17 of tegument immunoproteomes having putative interaction networks with other proteins of S. japonicum. The results will provide clues of potential target molecules for vaccine development and biomarkers for diagnostics of schistosomiasis.

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High throughput immunomics is a powerful platform to discover potential targets of host immunity and develop diagnostic tests for infectious diseases. We screened the sera of Plasmodium vivax-exposed individuals to profile the antibody response to blood-stage antigens of P. vivax using a P. vivax protein microarray. A total of 1936 genes encoding the P. vivax proteins were expressed, printed and screened with sera from P. vivax-exposed individuals and normal subjects. Total of 151 (7.8% of the 1936 targets) highly immunoreactive antigens were identified, including five well-characterized antigens of P. vivax (ETRAMP11.2, Pv34, SUB1, RAP2 and MSP4). Among the highly immunoreactive antigens, 5 antigens were predicted as adhesins by MAAP, and 11 antigens were predicted as merozoite invasion-related proteins based on homology with P. falciparum proteins. There are 40 proteins that have serodiagnostic potential for antibody surveillance. These novel Plasmodium antigens identified provide the clues for understanding host immune response to P. vivax infection and the development of antibody surveillance tools.

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