Water use practices limit the effectiveness of a temephos-based Aedes aegypti larval control program in Northern Argentina

Background

A five-year citywide control program based on regular application of temephos significantly reduced Aedes aegypti larval indices but failed to maintain them below target levels in Clorinda, northern Argentina. Incomplete surveillance coverage and reduced residuality of temephos were held as the main putative causes limiting effectiveness of control actions.

Methodology

The duration of temephos residual effects in household-owned water-holding tanks (the most productive container type and main target for control) was estimated prospectively in two trials. Temephos was applied using spoons or inside perforated small zip-lock bags. Water samples from the study tanks (including positive and negative controls) were collected weekly and subjected to larval mortality bioassays. Water turnover was estimated quantitatively by adding sodium chloride to the study tanks and measuring its dilution 48 hs later.

Principal Findings

The median duration of residual effects of temephos applied using spoons (2.4 weeks) was significantly lower than with zip-lock bags (3.4 weeks), and widely heterogeneous between tanks. Generalized estimating equations models showed that bioassay larval mortality was strongly affected by water type and type of temephos application depending on water type. Water type and water turnover were highly significantly associated. Tanks filled with piped water had high turnover rates and short-lasting residual effects, whereas tanks filled with rain water showed the opposite pattern. On average, larval infestations reappeared nine weeks post-treatment and seven weeks after estimated loss of residuality.

Conclusions

Temephos residuality in the field was much shorter and more variable than expected. The main factor limiting temephos residuality was fast water turnover, caused by householders'' practice of refilling tanks overnight to counteract the intermittence of the local water supply. Limited field residuality of temephos accounts in part for the inability of the larval control program to further reduce infestation levels with a treatment cycle period of 3 or 4 months.     

Proteomic signatures of human oral epithelial cells in HIV-infected subjects

The oral epithelium, the most abundant structural tissue lining the oral mucosa, is an important line of defense against infectious microorganisms. HIV infected subjects on highly active antiretroviral therapy (HAART) are susceptible to comorbid viral, bacterial and fungal infections in the oral cavity. To provide an assessment of the molecular alterations of oral epithelia potentially associated with susceptibility to comorbid infections in such subjects, we performed various proteomic studies on over twenty HIV infected and healthy subjects. In a discovery phase two Dimensional Difference Gel Electrophoresis (2-D DIGE) analyses of human oral gingival epithelial cell (HOEC) lysates were carried out; this identified 61 differentially expressed proteins between HIV-infected on HAART subjects and healthy controls. Down regulated proteins in HIV-infected subjects include proteins associated with maintenance of protein folding and pro- and anti-inflammatory responses (e.g., heat-shock proteins, Cryab, Calr, IL-1RA, and Galectin-3-binding protein) as well as proteins involved in redox homeostasis and detoxification (e.g., Gstp1, Prdx1, and Ero1). Up regulated proteins include: protein disulfide isomerases, proteins whose expression is negatively regulated by Hsp90 (e.g., Ndrg1), and proteins that maintain cellular integrity (e.g., Vimentin). In a verification phase, proteins identified in the protein profiling experiments and those inferred from Ingenuity Pathway Analysis were analyzed using Western blotting analysis on separate HOEC lysate samples, confirming many of the discovery findings. Additionally in HIV-infected patient samples Heat Shock Factor 1 is down regulated, which explains the reduced heat shock responses, while activation of the MAPK signal transduction cascade is observed. Overall, HAART therapy provides an incomplete immune recovery of the oral epithelial cells of the oral cavity for HIV-infected subjects, and the toxic side effects of HAART and/or HIV chronicity silence expression of multiple proteins that in healthy subjects function to provide robust innate immune responses and combat cellular stress.     

Random generation of RNA secondary structures according to native distributions

Background

Random biological sequences are a topic of great interest in genome analysis since, according to a powerful paradigm, they represent the background noise from which the actual biological information must differentiate. Accordingly, the generation of random sequences has been investigated for a long time. Similarly, random object of a more complicated structure like RNA molecules or proteins are of interest.

Results

In this article, we present a new general framework for deriving algorithms for the non-uniform random generation of combinatorial objects according to the encoding and probability distribution implied by a stochastic context-free grammar. Briefly, the framework extends on the well-known recursive method for (uniform) random generation and uses the popular framework of admissible specifications of combinatorial classes, introducing weighted combinatorial classes to allow for the non-uniform generation by means of unranking. This framework is used to derive an algorithm for the generation of RNA secondary structures of a given fixed size. We address the random generation of these structures according to a realistic distribution obtained from real-life data by using a very detailed context-free grammar (that models the class of RNA secondary structures by distinguishing between all known motifs in RNA structure). Compared to well-known sampling approaches used in several structure prediction tools (such as SFold) ours has two major advantages: Firstly, after a preprocessing step in time for the computation of all weighted class sizes needed, with our approach a set of m random secondary structures of a given structure size n can be computed in worst-case time complexity while other algorithms typically have a runtime in . Secondly, our approach works with integer arithmetic only which is faster and saves us from all the discomforting details of using floating point arithmetic with logarithmized probabilities.

Conclusion

A number of experimental results shows that our random generation method produces realistic output, at least with respect to the appearance of the different structural motifs. The algorithm is available as a webservice at http://wwwagak.cs.uni-kl.de/NonUniRandGen and can be used for generating random secondary structures of any specified RNA type. A link to download an implementation of our method (in Wolfram Mathematica) can be found there, too.     

Reliability and short-term intra-individual variability of telomere length measurement using monochrome multiplexing quantitative PCR

Background

Studies examining the association between telomere length and cancer risk have often relied on measurement of telomere length from a single blood draw using a real-time PCR technique. We examined the reliability of telomere length measurement using sequential samples collected over a 9-month period.

Methods and Findings

Relative telomere length in peripheral blood was estimated using a single tube monochrome multiplex quantitative PCR assay in blood DNA samples from 27 non-pregnant adult women (aged 35 to 74 years) collected in 7 visits over a 9-month period. A linear mixed model was used to estimate the components of variance for telomere length measurements attributed to variation among women and variation between time points within women. Mean telomere length measurement at any single visit was not significantly different from the average of 7 visits. Plates had a significant systematic influence on telomere length measurements, although measurements between different plates were highly correlated. After controlling for plate effects, 64% of the remaining variance was estimated to be accounted for by variance due to subject. Variance explained by time of visit within a subject was minor, contributing 5% of the remaining variance.

Conclusion

Our data demonstrate good short-term reliability of telomere length measurement using blood from a single draw. However, the existence of technical variability, particularly plate effects, reinforces the need for technical replicates and balancing of case and control samples across plates.     

Mind perception: real but not artificial faces sustain neural activity beyond the N170/VPP

Faces are visual objects that hold special significance as the icons of other minds. Previous researchers using event-related potentials (ERPs) have found that faces are uniquely associated with an increased N170/vertex positive potential (VPP) and a more sustained frontal positivity. Here, we examined the processing of faces as objects vs. faces as cues to minds by contrasting images of faces possessing minds (human faces), faces lacking minds (doll faces), and non-face objects (i.e., clocks). Although both doll and human faces were associated with an increased N170/VPP from 175-200 ms following stimulus onset, only human faces were associated with a sustained positivity beyond 400 ms. Our data suggest that the N170/VPP reflects the object-based processing of faces, whether of dolls or humans; on the other hand, the later positivity appears to uniquely index the processing of human faces--which are more salient and convey information about identity and the presence of other minds.     

Rosuvastatin reduces experimental left ventricular infarct size after ischemia-reperfusion injury but not total coronary occlusion

This study compared the effects of rosuvastatin on left ventricular infarct size in mice after permanent coronary occlusion vs. 60 min of ischemia followed by 24 h of reperfusion. Statins can inhibit neutrophil adhesion, increase nitric oxide synthase (NOS) expression, and mobilize progenitor stem cells after ischemic injury. Mice received blinded and randomized administration of rosuvastatin (20 mg.kg(-1).day(-1)) or saline from 2 days before surgery until death. After 60 min of ischemia with reperfusion, infarct size was reduced by 18% (P = 0.03) in mice randomized to receive rosuvastatin (n = 18) vs. saline (n = 22) but was similar after permanent occlusion in rosuvastatin (n = 17) and saline (n = 20) groups (P = not significant). Myocardial infarct size after permanent left anterior descending coronary artery occlusion (n = 6) tended to be greater in NOS3-deficient mice than in the wild-type saline group (33 +/- 4 vs. 23 +/- 2%, P = 0.08). Infarct size in NOS3-deficient mice was not modified by treatment with rosuvastatin (34 +/- 5%, n = 6, P = not significant vs. NOS3-deficient saline group). After 60 min of ischemia-reperfusion, neutrophil infiltration was similar in rosuvastatin and saline groups as was the percentage of CD34(+), Sca-1(+), and c-Kit(+) cells. Left ventricular NOS3 mRNA and protein levels were unchanged by rosuvastatin. Rosuvastatin reduces infarct size after 60 min of ischemia-reperfusion but not after permanent coronary occlusion, suggesting a potential anti-inflammatory effect. Although we were unable to demonstrate that the myocardial protection was due to an effect on neutrophil infiltration, stem cell mobilization, or induction of NOS3, these data suggest that rosuvastatin may be particularly beneficial in myocardial protection after ischemia-reperfusion injury.     

Estrogen and growth factor receptor interactions in human breast and non-small cell lung cancer cells

Extranuclear estrogen receptors may mediate rapid effects of estradiol that communicate with nuclear receptors and contribute to proliferation of human cancers bearing these signaling proteins. To assess these growth-promoting pathways, we undertook controlled homogenization and fractionation of NIH-H23 non-small cell lung cancer cells. As many breast tumors, NIH-H23 cells express estrogen receptors (ER), with the bulk of specific estradiol binding in nuclear fractions. However, as in breast cells, a significant portion of specific, high-affinity estradiol-17beta binding-sites are also enriched in plasma membranes of lung tumor cells. These estrogen binding-sites co-purify with plasma membrane-marker enzymes and are not significantly contaminated by cytosol or nuclei. On further purification of membrane caveolae from lung tumor cells, proteins recognized by monoclonal antibodies to nuclear ER-alpha and to ER-beta were identified in close association with EGF receptor in caveolae. In parallel studies, ER-alpha and ER-beta are also detected in nuclear and extranuclear sites in archival human breast and lung tumor samples and are noted to occur in clusters at the cell membrane by using confocal microscopy to visualize fluorescent-labeled monoclonal antibodies to ER-alpha. Data on site-directed mutagenesis of cysteine-447 in ER-alpha suggest that association of ER forms with membrane sites may depend on acylation of cysteine by palmitate. Estrogen-induced growth of MCF-7 breast cancer and NIH-H23 lung cancer cells in vitro correlated closely with acute hormonal activation of mitogen-activated protein kinase signaling and was significantly reduced by treatment with Faslodex, a pure anti-estrogen. Further, combination of Faslodex with selected growth factor receptor inhibitors elicited a more pronounced inhibiton of tumor cell growth. Thus, extranuclear forms of ER play a role in promoting downstream signaling for hormone-mediated proliferation and survival of breast, as well as lung, cancers and offer a new target for anti-tumor therapy.     

Stromal fibroblasts present in invasive human breast carcinomas promote tumor growth and angiogenesis through elevated SDF-1/CXCL12 secretion

Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.     

2-Piperazinecarboxamides as potent and selective melanocortin subtype-4 receptor agonists

We report the discovery and optimization of substituted 2-piperazinecarboxamides as potent and selective agonists of the melanocortin subtype-4 receptor. The 5- and 6-alkylated piperazine compounds exhibit low bioactivation potential as measured by covalent binding in microsome preparations.