Comber SD et al. (2006) Environ Pollut "Chronic toxicity of sediment-associated linear alkylbenzene sulphonates (LAS) to freshwater benthic organisms."

Hoss S, Webb S, Comber SD, Conrad AU, Marshall S

[Environ Pollut, 2006]

The toxicity of linear alkylbenzene sulphonates (LAS), to freshwater benthic organisms was assessed during exposure to spiked sediment. Lethal and sub-lethal end-points were monitored for two organisms (oligochaete Lumbriculus variegatus and nematode Caenorhabditis elegans). Results demonstrated relatively low toxicity (LOECs >100mg/kg dry weight). No observed effect concentrations (NOECs) of 81mg/kg dw (Lumbriculus) and 100mg/kg dw (Caenorhabditis) were determined. For the oligochaete, no specific endpoint was particularly sensitive to LAS. For the nematode, egg production was the most sensitive endpoint. Significant degradation was measured over the 28-day duration of the Lumbriculus study, equating to a half-life of 20days in sediment.

Darge K et al. (1994) Am J Trop Med Hyg "Evaluation of ultrasonography for the detection of drug-induced changes in onchocercal nodules."

Darge K, Buettner DW, Nelle M, Awadzi K, Troeger J, Leichsenring M, Engelke C

[Am J Trop Med Hyg, 1994]

Clinical trials of macrofilaricidal drugs against Onchocerca volvulus are impeded due to the lack of means for assessing in vivo drug-induced changes in the onchocercomas. The application of ultrasonography in the sequential monitoring of morphologic alterations of onchocercal nodules after six weeks of suramin therapy was evaluated in 20 male patients from Ghana with a total of 64 nodule sites. After each follow-up session, a number of onchocercal nodules were extirpated so that by the end of one year, all nodules had been removed for histologic examination. The sonomorphologic changes observed and their time of appearance correlated well with the histologic findings of the onchocercomas. Eighty-three percent of the onchocercal nodules became hyperechogenic and 22% developed echo-free areas at the end of the follow-up period. Absence of the lateral acoustic shadow increased by more than 30% and the lack of differentiation of the worm center from the capsule and the nodule from its surrounding tissue increased by the end of one-year posttreatment to 100% and 91%, respectively. A mean reduction of nodule size of 27% was also documented. The histologic studies revealed that the proportion of the dead female worms increased from 17% at the end of the suramin therapy to 48% six months later and reached 61% at one year. It is concluded that ultrasonographic monitoring of onchocercomas can provide essential information on drug effects and facilitate clinical trials of macrofilaricidal drugs, limiting histologic evaluation to a few objectively selected onchocercomas.

Mitsui Y et al. (2017) J Helminthol "Chemoattractant activity of tris-(hydroxymethyl)aminomethane for Brugia pahangi infective third-stage larvae."

Urena-Tatis KE, Aoki Y, Mitsui Y

[J Helminthol, 2017]

Urocanic acid (UCA) is known as a major chemoattractant for Strongyloides stercoralis infective third-stage larvae (L3). Since Brugia pahangi is a skin-penetrating parasitic nematode similar to S. stercoralis, UCA was expected to be a chemoattractant for B. pahangi L3. Thus, the chemoattractant activity of UCA for B. pahangi L3 was assessed. The chemotactic responses of B. pahangi L3 to UCA or acetic acid (CH3COOH) dissolved in amine solutions were assessed using an agar-plate assay. A test solution of 200 mm UCA dissolved in aqueous 270 mm tris(hydroxymethyl)aminomethane (Tris) significantly attracted B. pahangi L3 compared with deionized water (DW), while neither a solution of 200 mm UCA dissolved in aqueous 230 mm ammonia (NH3) nor 290 mm triethylamine (TEA) significantly attracted L3. Similarly, a test solution of 200 mm CH3COOH dissolved with 200 mm Tris significantly attracted L3, but neither a test solution of 200 mm CH3COOH plus 200 mm NH3 nor 200 mm TEA attracted L3. Furthermore, L3 were significantly attracted to 200 mm Tris alone, compared with DW, but avoided 200 mm NH3 and 200 mm TEA. Moreover, the chemoattractant activity of Tris for L3 was observed even at a low concentration of 25 mm, and it was observed in a mild alkaline condition but not in an acidic condition. The present study reveals that Tris is a potential chemoattractant for B. pahangi L3 while UCA is not. This finding will contribute to an understanding of the mechanisms of skin-penetrating infection of filarial L3.

Freire SL et al. (2014) J Vis Exp "Taking advantage of reduced droplet-surface interaction to optimize transport of bioanalytes in digital microfluidics."

Freire SL, Dao S, Wutkowski M, Thorne N

[J Vis Exp, 2014]

Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of "lab-on-a-chip" platforms. Often, droplet motion relies on the wetting of a surface, directly associated with the application of an electric field; surface interactions, however, make motion dependent on droplet contents, limiting the breadth of applications of the technique. Some alternatives have been presented to minimize this dependence. However, they rely on the addition of extra chemical species to the droplet or its surroundings, which could potentially interact with droplet moieties. Addressing this challenge, our group recently developed Field-DW devices to allow the transport of cells and proteins in DMF, without extra additives. Here, the protocol for device fabrication and operation is provided, including the electronic interface for motion control. We also continue the studies with the devices, showing that multicellular, relatively large, model organisms can also be transported, arguably unaffected by the electric fields required for device operation.