Endectocides for malaria control

Systemic endectocidal drugs, used to control nematodes in humans and other vertebrates, can be toxic to Anopheles spp. mosquitoes when they take a blood meal from a host that has recently received one of these drugs. Recent laboratory and field studies have highlighted the potential of ivermectin to control malaria parasite transmission if this drug is distributed strategically and more often. There are important theoretical benefits to this strategy, as well as caveats. A better understanding of drug effects against vectors and malaria ecologies are needed. In the near future, ivermectin and other endectocides could serve as potent and novel malaria transmission control tools that are directly linked to the control of neglected tropical diseases in the same communities.     

Proteomic profiling of human plasma by iTRAQ reveals down-regulation of ITI-HC3 and VDBP by cigarette smoking

Biomarkers in noninvasive fluids indicative of cigarette smoke's effects are urgently needed. In this pilot study, we utilized the proteomic approach, isobaric Tags for Relative and Absolute Quantitation (iTRAQ), to identify differentially expressed plasma proteins in healthy cigarette smokers compared to healthy nonsmokers; select proteins were further confirmed by immunoblot analysis. Significant, differentially expressed proteins identified in the plasma separated subjects based on their condition as smokers or nonsmokers. Several of the proteins identified in this study are associated with immunity and inflammatory responses and have been shown to be associated with tobacco-related diseases, including chronic obstructive pulmonary disease (COPD) and lung cancer. Proteins up-regulated in smokers included complement component 8 polypeptide chains α, β, and γ, and mannose-binding protein C, and proteins down-regulated included inter-α-trypsin inhibitor heavy chain H3 (ITI-HC3) and vitamin D-binding protein (VDBP). In addition, gelsolin and vitronectin, known tissue leakage proteins, were up- and down-regulated, respectively. Our results demonstrate for the first time that chronic cigarette smoking can influence the expression profile of the human plasma proteome. Proteins identified in this pilot study may serve as candidate biomarkers of diseases resulting from exposure to cigarette smoke in future molecular epidemiological studies.     

Assessment of molecular imaging of angiogenesis with three-dimensional ultrasonography

Molecular imaging (MI) with ultrasonography relies on microbubble contrast agents (MCAs) adhering to a ligand-specific target for applications such as characterizing tumor angiogenesis. It is projected that ultrasonic (US) MI can provide information about tumor therapeutic response before the detection of phenotypic changes. One of the limitations of preclinical US MI is that it lacks a comprehensive field of view. We attempted to improve targeted MCA visualization and quantification by performing three-dimensional (3D) MI of tumors expressing αvβ3 integrin. Volumetric acquisitions were obtained with a Siemens Sequoia system in cadence pulse sequencing mode by mechanically stepping the transducer elevationally across the tumor in 800-micron increments. MI was performed on rat fibrosarcoma tumors (n = 8) of similar sizes using MCAs conjugated with a cyclic RGD peptide targeted to αvβ3 integrin. US MI and immunohistochemical analyses show high microbubble targeting variability, suggesting that individual two-dimensional (2D) acquisitions risk misrepresenting more complex heterogeneous tissues. In 2D serial studies, where it may be challenging to image the same plane repeatedly, misalignments as small as 800 microns can introduce substantial error. 3D MI, including volumetric analysis of inter- and intra-animal targeting, provides a thorough way of characterizing angiogenesis and will be a more robust assessment technique for the future of MI.     

Synthesis and characterization of dendron cross-linked PEG hydrogels as corneal adhesives

In pursuit of a wound-specific corneal adhesive, hydrogels formed by the reaction of propionaldehyde, butyraldehyde, or 2-oxoethyl succinate-functionalized poly(ethylene glycol) (PEG) with a peptide-based dendritic cross-linker (Lys(3)Cys(4)) were characterized. These macromers react within minutes of mixing to form transparent and elastic hydrogels with in vitro degradation times that range from hours to months based on the type of bonds formed during the cross-linking reaction, either thiazolidine or pseudoproline. The mechanical properties of these materials, determined via parallel plate rheology, were dependent on the polymer concentration, as was the hydrogel adhesive strength, which was determined by lap shear adhesive testing. In addition, these hydrogels were efficacious in closing ex vivo 4.1 mm central corneal lacerations: wounds closed with these hydrogel adhesives were able to withstand intraocular pressure values equivalent to, or in excess of, those obtained by closing the wounds with suturing.     

Design and initial characterization of the SC-200 proteomics standard mixture

High-throughput (HTP) proteomics studies generate large amounts of data. Interpretation of these data requires effective approaches to distinguish noise from biological signal, particularly as instrument and computational capacity increase and studies become more complex. Resolving this issue requires validated and reproducible methods and models, which in turn requires complex experimental and computational standards. The absence of appropriate standards and data sets for validating experimental and computational workflows hinders the development of HTP proteomics methods. Most protein standards are simple mixtures of proteins or peptides, or undercharacterized reference standards in which the identity and concentration of the constituent proteins is unknown. The Seattle Children's 200 (SC-200) proposed proteomics standard mixture is the next step toward developing realistic, fully characterized HTP proteomics standards. The SC-200 exhibits a unique modular design to extend its functionality, and consists of 200 proteins of known identities and molar concentrations from 6 microbial genomes, distributed into 10 molar concentration tiers spanning a 1,000-fold range. We describe the SC-200's design, potential uses, and initial characterization. We identified 84% of SC-200 proteins with an LTQ-Orbitrap and 65% with an LTQ-Velos (false discovery rate?=?1% for both). There were obvious trends in success rate, sequence coverage, and spectral counts with protein concentration; however, protein identification, sequence coverage, and spectral counts vary greatly within concentration levels.     

The key to enabling biosurveillance is cooperative technology development

The world population will continue to face biological threats, whether they are naturally occurring or intentional events. The speed with which diseases can emerge and spread presents serious challenges, because the impact on public health, the economy, and development can be huge. The U.S. government recognizes that global public health can also have an impact on national security. This global perspective manifests itself in U.S. policy documents that clearly articulate the importance of biosurveillance in providing early warning, detection, and situational awareness of infectious disease threats in order to mount a rapid response and save lives. In this commentary, we suggest that early recognition of infectious disease threats, whether naturally occurring or man-made, requires a globally distributed array of interoperable hardware and software fielded in sufficient numbers to create a network of linked collection nodes. We argue that achievement of this end state will require a degree of cooperation that does not exist at this time-either across the U.S. federal government or among our global partners. Successful fielding of a family of interoperable technologies will require interagency research, development, and purchase ("acquisition") of biosurveillance systems through cooperative ventures that likely will involve our strategic allies and public-private partnerships. To this end, we propose leveraging an existing federal interagency group to integrate the acquisition of technologies to enable global biosurveillance.     

The Strain-Encoded Relationship between PrPSc Replication,Stability and Processing in Neurons is Predictive of the Incubation Period of Disease

Prion strains are characterized by differences in the outcome of disease, most notably incubation period and neuropathological features. While it is established that the disease specific isoform of the prion protein, PrP^Sc, is an essential component of the infectious agent, the strain-specific relationship between PrP^Sc properties and the biological features of the resulting disease is not clear. To investigate this relationship, we examined the amplification efficiency and conformational stability of PrP^Sc from eight hamster-adapted prion strains and compared it to the resulting incubation period of disease and processing of PrP^Sc in neurons and glia. We found that short incubation period strains were characterized by more efficient PrP^Sc amplification and higher PrP^Sc conformational stabilities compared to long incubation period strains. In the CNS, the short incubation period strains were characterized by the accumulation of N-terminally truncated PrP^Sc in the soma of neurons, astrocytes and microglia in contrast to long incubation period strains where PrP^Sc did not accumulate to detectable levels in the soma of neurons but was detected in glia similar to short incubation period strains. These results are inconsistent with the hypothesis that a decrease in conformational stability results in a corresponding increase in replication efficiency and suggest that glia mediated neurodegeneration results in longer survival times compared to direct replication of PrP^Sc in neurons.