Efficacy and safety of artemether in the treatment of chronic fascioliasis in Egypt: exploratory phase-2 trials

Background

Fascioliasis is an emerging zoonotic disease of considerable veterinary and public health importance. Triclabendazole is the only available drug for treatment. Laboratory studies have documented promising fasciocidal properties of the artemisinins (e.g., artemether).

Methodology

We carried out two exploratory phase-2 trials to assess the efficacy and safety of oral artemether administered at (i) 6×80 mg over 3 consecutive days, and (ii) 3×200 mg within 24 h in 36 Fasciola-infected individuals in Egypt. Efficacy was determined by cure rate (CR) and egg reduction rate (ERR) based on multiple Kato-Katz thick smears before and after drug administration. Patients who remained Fasciola-positive following artemether dosing were treated with single 10 mg/kg oral triclabendazole. In case of treatment failure, triclabendazole was re-administered at 20 mg/kg in two divided doses.

Principal Findings

CRs achieved with 6×80 mg and 3×200 mg artemether were 35% and 6%, respectively. The corresponding ERRs were 63% and nil, respectively. Artemether was well tolerated. A high efficacy was observed with triclabendazole administered at 10 mg/kg (16 patients; CR: 67%, ERR: 94%) and 20 mg/kg (4 patients; CR: 75%, ERR: 96%).

Conclusions/Significance

Artemether, administered at malaria treatment regimens, shows no or only little effect against fascioliasis, and hence does not represent an alternative to triclabendazole. The role of artemether and other artemisinin derivatives as partner drug in combination chemotherapy remains to be elucidated.     

Synthesis and in vitro behavior of β-TCP zirconia/polymeric biocomposites for bio-applications

Novel biocomposites were fabricated by impregnating β-tricalcium phosphate (β-TCP)/zirconia particles into the polymers matrix. The composite materials were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) analyzes and Scanning Electron Microscopy (SEM). The results confirmed the conversion of hydroxyapatite (HA) to β-TCP at a sintering temperature of 1150 °C with or without zirconia powder. The in vitro behavior was assessed via measurement of calcium and phosphorus ions in SBF (simulated body fluid). FT-IR and SEM of the composites were performed pre and post immersion in SBF. The results prove that the bone like apatite layer formation was enhanced on the β-TCP-Z20/polymeric composite surface more than that on the β-TCP-Z10/polymeric composite. Therefore, the data confirmed that zirconia plays an important role in the enhancement of the apatite formation. The conclusions proved that the β-TCP-Z20/polymeric biocomposites, containing 20% of zirconia, are promising for bone remodeling applications.     

HIV prevalence and impact on renutrition in children hospitalised for severe malnutrition in Niger: an argument for more systematic screening

Background

In developing countries, malnutrition is a contributing factor in over 50% of child deaths. Mortality rates are higher in underweight children, and HIV-infection is known to increase underweight. Our goals were to evaluate the prevalence of HIV among children hospitalised for severe malnutrition (SM) at the Niamey national hospital (Niger), and to compare renutrition and mortality by HIV-status.

Methods

Retrospective study based on all children <5 years hospitalised for SM between January 1^st 2008 and July 1^st 2009. HIV-prevalence was the ratio of HIV+ children on the number of children tested. Duration of renutrition and mortality were described using survival curves.

Results

During the study period, 477 children were hospitalised for SM. HIV testing was accepted in 470 (98.5%), of which 40 were HIV+ (HIV prevalence (95% confidence interval) of 8.6% (6.2–11.5)). Duration of renutrition was longer in HIV+ than HIV− children (mean: 22 vs. 15 days; p = 0.003). During renutrition, 8 (20%) and 61 (14%) HIV+ and HIV− children died, respectively (p = 0.81).

Conclusion

Around 9% of children hospitalised for severe malnutrition were HIV infected, while in Niger HIV prevalence in adults is estimated at 0.8%. This pleads for wider access to HIV testing in this population.     

DNA methylation profiles of primary colorectal carcinoma and matched liver metastasis

Background

The contribution of DNA methylation to the metastatic process in colorectal cancers (CRCs) is unclear.

Methods

We evaluated the methylation status of 13 genes (MINT1, MINT2, MINT31, MLH1, p16, p14, TIMP3, CDH1, CDH13, THBS1, MGMT, HPP1 and ERα) by bisulfite-pyrosequencing in 79 CRCs comprising 36 CRCs without liver metastasis and 43 CRCs with liver metastasis, including 16 paired primary CRCs and liver metastasis. We also performed methylated CpG island amplification microarrays (MCAM) in three paired primary and metastatic cancers.

Results

Methylation of p14, TIMP3 and HPP1 in primary CRCs progressively decreased from absence to presence of liver metastasis (13.1% vs. 4.3%; 14.8% vs. 3.7%; 43.9% vs. 35.8%, respectively) (P<.05). When paired primary and metastatic tumors were compared, only MGMT methylation was significantly higher in metastatic cancers (27.4% vs. 13.4%, P = .013), and this difference was due to an increase in methylation density rather than frequency in the majority of cases. MCAM showed an average 7.4% increase in DNA methylated genes in the metastatic samples. The numbers of differentially hypermethylated genes in the liver metastases increased with increasing time between resection of the primary and resection of the liver metastasis. Bisulfite-pyrosequencing validation in 12 paired samples showed that most of these increases were not conserved, and could be explained by differences in methylation density rather than frequency.

Conclusions

Most DNA methylation differences between primary CRCs and matched liver metastasis are due to random variation and an increase in DNA methylation density rather than de-novo inactivation and silencing. Thus, DNA methylation changes occur for the most part before progression to liver metastasis.     

Adhesion of Vibrio cholerae to granular starches

Cholera is a severe diarrheal disease caused by specific serogroups of Vibrio cholerae that are pathogenic to humans. Cholera can become epidemic and deadly without adequate medical care. Appropriate rehydration therapy can reduce the mortality rate from as much as 50% of the affected individuals to <1%. Thus, oral rehydration therapy (ORT) is an important measure in the treatment of this disease. To further reduce the symptoms associated with cholera, improvements in oral rehydration solution (ORS) by starch incorporation were suggested. Here, we report that V. cholerae adheres to starch granules incorporated in ORS. Adhesion of 98% of the cells was observed within 2 min when cornstarch granules were used. Other starches showed varied adhesion rates, indicating that starch source and composition play an important role in the interaction of V. cholerae and starch granules. Sugars metabolized by V. cholerae showed a repressive effect on the adhesion process. The possible mechanisms involved are discussed. Comparing V. cholerae adhesion with the adhesion of other pathogens suggests the involvement of starch degradation capabilities. This adhesion to granular starch can be used to improve ORT.     

A miniaturized nebulization catheter for improved gene delivery to the mouse lung

BACKGROUND: The available methods for administration of gene delivery systems to the lungs of small animals via nebulization have several drawbacks. These include lack of control over the delivered dose and a negative impact on the stability of the formulation. This paper describes a new nebulization catheter device for the administration of plasmid-based gene delivery systems (polyplexes) as aerosols to the mouse lung in vivo. METHODS: The physical stability of naked pDNA and polyplexes formulated with chitosan oligomers and PEI was examined following nebulization with the catheter device. We also examined the in vitro transfection efficiency of the polyplexes recovered after nebulization. Lung distribution and gene expression after administration of the selected gene delivery systems to the mouse lung were also investigated. RESULTS: In contrast to previously described nebulization methods, the structural integrity of the unprotected naked pDNA was maintained following nebulization by the catheter device, which indicates relatively mild nebulization conditions. In addition, the nebulization procedure did not affect the physical stability of the formulated polyplexes. Small volumes of the pDNA aerosol (10-20 microl) were delivered in a highly controlled and reproducible manner. The aerosol droplet size varied with the molecular weight of the polycations. Aerosol delivery via this method resulted in improved lung distribution of pDNA polyplexes and a six-fold increase in the efficiency of gene delivery in vivo over that seen with the commonly used intratracheal instillation method. CONCLUSION: The use of the nebulization catheter device provides a promising alternative for aerosol gene delivery to the mouse lung.     

Adult non-biting midges: possible windborne carriers of Vibrio cholerae non-O1 non-O139

Vibrio cholerae is a waterborne bacterium native to the aquatic environment. There are over 200 known serogroups yet only two cause cholera pandemics in humans. Direct contact of human sewage with drinking water, sea-born currents and marine transportation, represent modes of dissemination of the bacteria and thus the disease. The simultaneous cholera outbreaks that occur sometimes in distant localities within continental landmasses are puzzling. Here we present evidence that flying, non-biting midges (Diptera; Chironomidae), collected in the air, carry viable non-O1 non-O139 serogroups of V. cholerae. The association of V. cholerae with chironomid egg masses, which serve as a V. cholerae reservoir, was further confirmed. In simulated field experiments, we recorded the transfer of environmental V. cholerae by adult midges from the aquatic environment into bacteria-free water-pools. In laboratory experiments, flying adult midges that emerged from V. cholerae (O1 or O139) contaminated water transferred the green fluorescent protein (GFP)-tagged pathogenic bacteria from one laboratory flasks to another. Our findings show that aerial transfer by flying chironomids may play a role in the dissemination of V. cholerae in nature.     

Role of active site residues and solvent in proton transfer and the modulation of flavin reduction potential in bacterial morphinone reductase

The reactions of several active site mutant forms of bacterial morphinone reductase (MR) with NADH and 2-cyclohexen-1-one as substrates have been studied by stopped-flow and steady-state kinetic methods and redox potentiometry. The enzymes were designed to (i) probe a role for potential proton donors (Tyr-72 and Tyr-356) in the oxidative half-reaction of MR; (ii) assess the function of a highly conserved tryptophan residue (Trp-106) in catalysis; (iii) investigate the role of Thr-32 in modulating the FMN reduction potential and catalysis. The Y72F and Y356F enzymes retained activity in both steady-state and stopped-flow kinetic studies, indicating they do not serve as key proton donors in the oxidative reaction of MR. Taken together with our recently published data (Messiha, H. L., Munro, A. W., Bruce, N. C., Barsukov, I., and Scrutton, N. S. (2005) J. Biol. Chem. 280, 4627-4631) that rule out roles for Cys-191 (corresponding with the proton donor, Tyr-196, in the structurally related OYE1 enzyme) and His-186 as proton donors, we infer solvent is the source of the proton in the oxidative half-reaction of MR. We demonstrate a key role for Thr-32 in modulating the reduction potential of the FMN, which is decreased approximately 50 mV in the T32A mutant MR. This effects a change in rate-limiting step in the catalytic cycle of the T32A enzyme with the oxidizing substrate 2-cyclohexenone. Despite the conservation of Trp-106 throughout the OYE family, we show this residue does not play a major role in catalysis, although affects on substrate and coenzyme binding are observed in a W106F enzyme. Our studies show some similarities, but also major differences, in the catalytic mechanism of MR and OYE1, and emphasize the need for caution in inferring mechanism by structural comparison of highly related enzymes in the absence of solution studies.     

Effects of ocean acidification on the growth and biochemical composition of a green alga (Ulva fasciata) and its associated microbiota

In marine ecosystems, fluctuations in surface-seawater carbon dioxide (CO₂), significantly influence the whole metabolism of marine algae, especially during the early stages of macroalgal development. In this study, the response of the green alga Ulva fasciata for elevating ocean acidification was investigated using four levels of pCO₂ ~ 280, 550, 750 and 1050 µatm. Maximum growth rate (6.6% day⁻¹), protein (32.43 %DW) and pigment (2.9 mg/g) accumulation were observed at pCO₂-550 with an increase of ~2-fold compared to control. On the other hand, lipid and carbohydrate contents recorded their maximum production (4.23 and 46.96 %DW, respectively) at pCO₂-750 while control showed 3.70 and 42.37 %DW, respectively. SDS-PAGE showed the presence of unique bands in response to pCO_2, especially at 550 µatm. Dominant associated bacteria was shifted from Halomonas hydrothermalis of control to Vibrio toranzoniae at pCO₂-1050. These findings suggest that ocean acidification at 550 µatm might impose noticeable effects on growth, protein, pigments, and protein profile of U. fasciata, which could be a good source for fish farming. While, pCO₂-750 was recommended for energetic purpose, due to its high lipid and carbohydrate contents.