Some observations on the effect of Daflon (micronized purified flavonoid fraction of Rutaceae aurantiae) in bancroftian filarial lymphoedema

BACKGROUND: Morbidity management is a core component of the global programme for the elimination of lymphatic filariasis. In a double-blind clinical trial, the tolerability and efficacy of Daflon (500 mg) + DEC (25 mg) or DEC (25 mg) alone, twice daily for 90 days, was studied in 26 patients with bancroftian filarial lymphoedema. RESULTS: None of the patients in either drug group reported any adverse reaction throughout the treatment period (90 days). Haematological and biochemical parameters were within normal limits and there was no significant difference between the pre-treatment (day 0) and post-treatment (day 90) values. The group receiving Daflon showed significant reduction in oedema volume from day 90 (140.6 PlusMinus; 18.8 ml) to day 360 (71.8 PlusMinus; 20.7 ml) compared to the pre-treatment (day 0, 198.4 PlusMinus; 16.5 ml) value. This accounted for a 63.8% reduction in oedema volume by day 360 (considering the pre-treatment (day 0) as 100%). In the DEC group, the changes in oedema volume (between day 1 and day 360) were not significant when compared to the pre-treatment (day 0) value. The percentage reduction at day 360 was only 9%, which was not significant (P > 0.05). CONCLUSION: This study has shown that Daflon (500 mg, twice a day for 90 days) is both safe and efficacious in reducing oedema volume in bancroftian filarial lymphoedema. Further clinical trials are essential for strengthening the evidence base on the role of this drug in the morbidity management of lymphatic filariasis.     

The type and yield of lipopolysaccharide from symbiotically deficient rhizobium lipopolysaccharide mutants vary depending on the extraction method

At least 18 lipopolysaccharide (LPS) extraction methods are available, and no single method is universally applicable. Here, the LPSs from four R.etli, one R.leguminosarum bv. trifolii mutant, 24AR, and the R.etli parent strain, CE3, were isolated by hot phenol/water (phi;/W), and phenol/EDTA/triethylamine (phi/EDTA/TEA) extraction. The LPS in various preparations was quantified, analyzed by deoxycholate polyacrylamide gel electrophoresis (DOC-PAGE), and by immunoblotting. These rhizobia normally have two prominent LPS forms: LPS I, which has O-polysaccharide, and LPS II, which has none. The LPS forms obtained depend on the method of extraction and vary depending on the mutant that is extracted. Both methods extract LPS I and LPS II from CE3. The phi/EDTA/TEA, but not the phi/W, method extracts LPS I from mutants CE358 and CE359. Conversely, the phi;/W but not the phi;/EDTA/TEA method extracts CE359 LPS V, an LPS form with a truncated O-polysaccharide. phi/EDTA/TEA extraction of mutant CE406 gives good yields of LPS I and II, while phi/W extraction gives very small amounts of LPS I. The LPS yield from all the strains using phi/EDTA/TEA extraction is fairly consistent (3-fold range), while the yields from phi/W extraction are highly variable (850-fold range). The phi/EDTA/TEA method extracts LPS I and LPS II from mutant 24AR, but the phi/W method partitions LPS II exclusively into the phenol phase, making its recovery difficult. Overall, phi/EDTA/TEA extraction yields more forms of LPS from the mutants and provides a simpler, faster, and less hazardous alternative to phi/W extraction. Nevertheless, it is concluded that careful analysis of any LPS mutant requires the use of more than one extraction method.     

Design and construction of a uniaxial cell stretcher

In vitro mechanical cell stimulators are used for the study of the effect of mechanical stimulation on anchorage-dependent cells. We developed a new mechanical cell stimulator, which uses stepper motor technology and computer control to achieve a high degree of accuracy and repeatability. This device also uses high-performance plastic components that have been shown to be noncytotoxic, dimensionally stable, and resistant to chemical degradation from common culture laboratory chemicals. We show that treatment with glow discharge for 25 s at 20 mA is sufficient to modify the surface of the rubber to allow proper adhesion for polymerization of aligned collagen. We show through finite element analysis that the middle area of the membrane, away from the clamped ends, is predictable, homogeneous, and has negligible shear strain. To test the efficacy of the mechanical stretch, we examined the effect of mechanical stimulation on the production of beta(1)-integrin by neonatal rat cardiac fibroblasts. Mechanical stimulation was tested in the range of 0-12% stretch and 0-10-cycles/min stretch frequency. The fibroblasts respond with an increase in beta(1)-integrin at 3% stretch and a decrease at 6 and 12% stretch. Stretch frequency was found to not significantly effect the concentration of beta(1)-integrin. These studies yield a new and improved mechanical cell stimulator and demonstrate that mechanical stimulation has an effect on the expression of beta(1)-integrin.     

An unexpected influence of widely used significance thresholds on the distribution of reported P-values

We consider the problematic relationship between publication success and statistical significance in the light of analyses in which we examine the distribution of published probability (P) values across the statistical 'significance' range, below the 5% probability threshold. P-values are often judged according to whether they lie beneath traditionally accepted thresholds (< 0.05, < 0.01, < 0.001, < 0.0001); we examine how these thresholds influence the distribution of reported absolute P-values in published scientific papers, the majority in biological sciences. We collected published P-values from three leading journals, and summarized their distribution using the frequencies falling across and within these four threshold values between 0.05 and 0. These published frequencies were then fitted to three complementary null models which allowed us to predict the expected proportions of P-values in the top and bottom half of each inter-threshold interval (i.e. those lying below, as opposed to above, each P-value threshold). Statistical comparison of these predicted proportions, against those actually observed, provides the first empirical evidence for a remarkable excess of probability values being cited on, or just below, each threshold relative to the smoothed theoretical distributions. The pattern is consistent across thresholds and journals, and for whichever theoretical approach used to generate our expected proportions. We discuss this novel finding and its implications for solving the problems of publication bias and selective reporting in evolutionary biology.     

Blebs on the move

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Potential sources of Campylobacter infection on chicken farms: contamination and control of broiler-harvesting equipment, vehicles and personnel

Aims: To test the efficacy of enhanced biosecurity measures on poultry farms for reducing environmental contamination with Campylobacter during partial depopulation of broiler flocks prior to normal slaughter age. The study has also evaluated the risk of infection from live‐bird transport crates that are routinely cleaned at the slaughterhouse, but may remain contaminated. Methods and Results: On‐farm sampling and Campylobacter isolation was undertaken to compare the prevalence of contamination on vehicles, equipment and catching personnel during farm visits that took place under normal or enhanced biosecurity. Campylobacters were found in almost all types of sample examined and enhanced biosecurity reduced the prevalence. However, the additional measures failed to prevent colonisation of the flocks. For transport crates, challenge trials involved exposure of broilers to commercially cleaned crates and genotyping of any campylobacters isolated. The birds were rapidly colonised with the same genotypes as those isolated from the cleaned crates. Conclusions: The enhanced biosecurity measures were insufficient to prevent flock colonisation, and the problem was exacerbated by inadequate cleaning of transport crates at the slaughterhouse. Significance and Impact of the Study: Current commercial practices in the United Kingdom facilitate the spread of campylobacters among broiler chicken flocks. Prevention of flock infection appears to require more stringent biosecurity than that studied here.     

Integrated dataset of screening hits against multiple neglected disease pathogens

New chemical entities are desperately needed that overcome the limitations of existing drugs for neglected diseases. Screening a diverse library of 10,000 drug-like compounds against 7 neglected disease pathogens resulted in an integrated dataset of 744 hits. We discuss the prioritization of these hits for each pathogen and the strong correlation observed between compounds active against more than two pathogens and mammalian cell toxicity. Our work suggests that the efficiency of early drug discovery for neglected diseases can be enhanced through a collaborative, multi-pathogen approach.     

Involvement of phosphoinositide 3-kinase gamma, Rac, and PAK signaling in chemokine-induced macrophage migration

In macrophages, chemotactic stimuli cause the activation of Rac and PAK, but little is known about the signaling pathways involved and their role in chemotactic gradient sensing. Herein, we report that in macrophages, the chemokine RANTES (regulated on activation normal T cell expressed and secreted)/CCL5 activates the small GTPase Rac and its downstream target PAK2 within seconds. This response depends on Gi activation and largely on the subsequent triggering of phosphoinositide 3-kinase gamma (PI3Kgamma) and Rac. Retroviral transduction of tagged Rac1 and -2 indicates that RANTES/CCL5-mediated activation of PI3Kgamma triggers Rac1 but not Rac2. In agreement, silencing of Rac1 by shRNA blocks PAK2 activity and inhibits RANTES/CCL5-induced macrophage polarization and directional migration. On the other hand, the tyrosine kinase receptor agonist CSF-1 activates PAK2 independently of PI3Kgamma and Rac. Our results thus demonstrate a chemokine-specific signaling pathway in which Gi and PI3Kgamma coordinate to drive Rac1 and PAK2 activation that eventually controls the chemotactic response.