In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper methysticum)

Kava (Piper methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity. To investigate the key components responsible for the liver toxicity, bioassay-guided fractionation was carried out in this study. Kava roots, leaves, and stem peelings were extracted with methanol, and the resulting residues were subjected to partition with a different polarity of solvents (hexane, ethyl acetate, n-butanol, and water) for evaluation of their cytotoxicity on HepG2 cells based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase and aspartate aminotransferase enzyme leakage assays. Organic solvent fractions displayed a much stronger cytotoxicity than water fractions for all parts of kava. The hexane fraction of the root exhibited stronger cytotoxic effects than fractions of root extracted with other solvents or extracts from the other parts of kava. Further investigations using bioassay-directed isolation and analysis of the hexane fraction indicated that the compound responsible for the cytotoxicity was flavokavain B. The identity of the compound was confirmed by (1)H and (13) C NMR and MS techniques.     

The N-acetyl-D-glucosamine specific adhesin from Mannheimia haemolytica activates bovine neutrophils oxidative burst

In this work we identified specific bovine leukocytes that were bound by the Mannheimia haemolytica adhesin molecule (MhA) and the biological effect on the leukocytes. Histochemical staining and flow cytometry showed that MhA bind neutrophils (90%) and monocytes (5%). MhA induced an oxidative response in purified neutrophils; this effect was 1.5-fold higher than the effect observed with control cells activated with Zymosan. Cellular binding by MhA was inhibited with GlcNAc and its oligomers, as well as by glycoproteins containing tri- and tetra-antennary N-glycosydically linked glycans. MhA-induced oxidative burst was significantly inhibited by GlcNAc, iodoacetamide, superoxide dismutase, and piroxicam (p<0.05). Our findings suggest that among bovine leukocytes, neutrophils are the main target for MhA, inducing production of oxidative radicals by non-opsonic mechanism that seem to play an important role in tissue damage during mannheimiosis.     

The clinical usefulness of the ventrodorsal versus dorsoventral thoracic radiograph in dogs

Differences exist in the ventrodorsal (VD) and dorsoventral (DV) radiographic views of the canine thorax. One view may be preferred over another because of how it portrays different areas of interest or different disease conditions. The VD view is indicated for evaluation of the cranial and caudal mediastinum, the caudal vena cava, and the accessory lung lobe, and in cases of pleural effusion. Indications for the DV view include assessment of a consistent cardiac silhouette, evaluation of the pulmonary lobar vessels, and evaluation of the structures of the dorsal thorax, such as hilar lymph nodes, the caudal dorsal lungs, trachea, mainstem bronchi, and left atrium.     

Illusions promote mating success in great bowerbirds

Sexual selection studies normally compare signal strengths, but signal components and sensory processing may interact to create misleading or attention-capturing illusions. Visual illusions can be produced by altering object and scene geometry in ways that trick the viewer when seen from a particular direction. Male great bowerbirds actively maintain size-distance gradients of objects on their bower courts that create forced-perspective illusions for females viewing their displays from within the bower avenue. We show a significant relationship between mating success and the female's view of the gradient; this view explains substantially more variance in mating success than the strength of the gradients. Illusions may be widespread in other animals because males of most species display to females with characteristic orientation and distance, providing excellent conditions for illusions.     

Technology characteristics, choice architecture, and farmer knowledge: the case of phytase

Phytase is an enzyme that frees the phosphorus bound in feed grains and thus reduces the amount of dicalcium phosphate supplementation required for non-ruminants, reducing phosphorous excretion and thus reducing water pollution. This innovation has been widely adopted by feed companies in the US due to decreased phytase production costs and increased dicalcium phosphate costs. The roles played by phytase characteristics and choice architecture in the widespread use of this win–win technology are examined. A recent survey has also revealed that Midwestern farmers are largely unaware of this technology even though they are using it. One implication is that further research on win–win technologies that will be adopted by industries, rather than being dependent on adoption by individuals, may be beneficial.     

How geographically concentrated is poverty in Fiji?

In this paper, we present highly disaggregated estimates of expenditure‐based poverty in Fiji using data from the 2007 national census and 2008–2009 Household Income and Expenditure Survey. Predicted poverty is estimated at provincial and tikina levels. Poverty in Fiji is marked by considerable spatial heterogeneity that cannot be gauged by the division level household survey estimates revealing pockets of poverty even within relatively well‐off regions. Predicted poverty is highest in Cakaudrove province in Northern Division. Most strikingly, we find that 50% of all the poor in Fiji are concentrated in just 6 out of 85 tikinas, namely Suva, Labasa, Ba, Naitasiri, Vuda and Nadi. This finding has important implications for efficiency of targeted poverty alleviation programmes. We also focus on squatter settlements for which poverty headcount estimates using the Household Income and Expenditure Survey are not feasible. We find these settlements have rates of poverty headcount ratio that range from 38–55% depending on the Division the squatter settlement is located in; this range is significantly higher compared with the average urban poverty estimated at 26% and raises important social policy issues for addressing urban poverty.