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.     

SDS-PAGE heat-shock protein profiles of environmental Aeromonas strains

Aeromonas microorganisms normally grow at temperatures between 5 degrees C and 45 degrees C and therefore should have high thermotolerance. Thus it was of interest to find out whether A. hydrophila, A. caviae and A. veronii biovar sobria serovars respond to abrupt temperature changes with a heat shock-like response. To this end the present study was undertaken to determine whether Aeromonas species exhibits a heat shock response to different temperatures and time factors. The response of Aeromonas serovars to 24 h and 48 h of thermal stress at 25 degrees C, 42 degrees C and 50 degrees C involved the synthesis of 12-18 heat shock proteins (HSPs) bands with molecular weights ranging between 83.5-103.9 kDa in the high HSP molecular mass and 14.5-12.0 as low molecular mass HSP. Electrophoretic analysis of the HSPs showed that the serovars do not cluster very tightly and also that they are distinct from each other.     

Utilization of UF-permeate for production of beta-galactosidase by lactic acid bacteria

Four lactobacilli strains (Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacilus casei and Lactobacillus reuteri) were grown in MRS broth and three lactococci strains (Streptococcus thermophilus, Lactococcus lactis subsp. Lactis and Lactococcus lactis subsp. lactis biovar. diacetilactis) were grown in M17 broth. L. reuteri and S. thermophilus were chosen on the basis of the best mean beta-galactosidase activity of 10.44 and 10.01 U/ml respectively, for further studies on permeate-based medium. The maximum production of beta-galactosidase by L. reuteri was achieved at lactose concentration of 6%, initial pH 5.0-7.5, ammonium phosphate as nitrogen source at a concentration of 0.66 g N/L and incubation temperature at 30 degrees C/24 hrs to give 6.31 U/ml. While in case of S. thermophilus, maximum beta-galactosidase production was achieved at 10% lactose concentration of permeate medium, supplemented with phosphate buffer ratio of 0.5:0.5 (KH2PO4:K2HPO4, g/L), at initial pH 6.0-6.5, ammonium phosphate (0.66g N/L) as nitrogen source and incubation temperature 35 degrees C for 24 hrs to give 7.85 U/ml.     

Adsorption of sterigmatocystin by montmorillonite and inhibition of its genotoxicity in the Nile tilapia fish (Oreachromis nilaticus)

Sterigmatocystin (Stg) is closely related to the mycotoxin aflatoxin as a precursor in aflatoxin biosynthesis and classified as an IARC Group-2B carcinogen. The aim of this study was to investigate the efficacy of Egyptian montmorillonite (EM), a clay mineral, to adsorb Stg, to test the stability of the resulting complex under different conditions in vitro, and to utilize the Nile tilapia fish as an in vivo model to evaluate the protective effect of EM against Stg-induced toxicity and clastogenicity. In the in vitro study, four concentrations of EM (0.5, 1, 2 and 4 mg/L aqueous solution) and three concentrations of Stg (5, 10 and 50 microg/ml) were tested. The results show that EM had a high capacity of adsorbing Stg at different concentrations tested. The adsorption ranged from 93.1 to 97.8% of the available Stg in aqueous solutions. The complex was stable at different pHs at 37 degrees C in different organic solvents. An in vivo experiment was conducted to evaluate the ability of EM to prevent the toxicity and chromosomal aberrations induced by Stg in the Nile tilapia fish. Fish received an intragastric dose of EM in corn oil (0.5 mg/kg bw) with or without Stg (1.6 microg/kg bw) twice a week for 4 weeks. Body weight was recorded during dosing, and blood and tissue samples were collected at the end of treatment. Stg residues were determined in fish tissue. The results show that Stg was toxic and clastogenic to fish as indicated by the significant decrease of body weight and the increase in frequencies of micronucleated red blood cells (MN RBC) and chromosomal aberrations in the kidney. The intragastric administration of EM combined with Stg to fish resulted in a reduction of the number of MN RBC and the frequency of chromosomal aberrations in the kidney compared with the group treated with Stg alone. It could be concluded that EM itself was safe and successful in the prevention of Stg toxicity and clastogenicity.     

Licorice: A possible anti-inflammatory and anti-ulcer drug

The purpose of this investigation was to study the anti-inflammatory activities of both glycerrhitinic acid (GA) and the aqueous licorice extract (ALE) in comparison with diclofenac sodium (DS) (10 mg/kg), using the carrageenan-induced paw edema model in male albino rats. In addition, the anti-ulcer activities of ALE, famotidine (FT), and a combination of ALE and FT using indomethacin-induced ulceration technique in rat stomach were investigated. Conventional DS tablets containing GA, as well as DS chewable tablets containing either GA or ALE with different tastes were prepared. Also, rapidly disintegrating FT tablets were prepared using direct compression and camphor sublimation methods. ALE or GA produced significant anti-inflammatory activity similar to DS, and when taken concomitantly, there is no possible antagonism. The anti-ulcer activity of licorice was found to be similar to that of FT in indomethacin-induced ulceration technique in rat stomach. Combination therapy of both FT and licorice showed higher anti-ulcer activity than either of them alone. Generally, tablets containing the crosslinked sodium carboxymethyl cellulose (AcDisol) showed more rapidly disintegrating effect than those including Sodium starch glycolate (Primojel). The oral disintegration was very rapid for all the tested formulations. Also, the amount of FT absorbed from the oral cavity was nearly 9 from 10 mg theoretically present in each formula. It could be concluded that both GA and ALE have anti-inflammatory activity comparable with DS. It may be recommended to add ALE to either FT or diclofinac for more effective anti-inflammatory or anti-ulcer formulations, respectively.     

Activation of vascular endothelial growth factor receptor-2 in bone marrow leads to accumulation of myeloid cells: role of granulocyte-macrophage colony-stimulating factor

Vascular endothelial growth factor (VEGF) is a secreted cytokine that plays a major role in the formation and maintenance of the hemopoietic and vascular compartments. VEGF and its receptors, VEGFR-1 and VEGFR-2, have been found to be expressed on subsets of normal and malignant hemopoietic cells, but the role of the individual receptors in hemopoiesis requires further study. Using a VEGFR-2 fusion protein that can be dimerized with a synthetic drug, we were able to specifically examine the effects of VEGFR-2 signaling in hemopoietic cells in vivo. Mice transplanted with bone marrow transduced with this inducible VEGFR-2 fusion protein demonstrated expansion of myeloid cells (Gr-1+, CD11b+). Levels of myeloid progenitors were also increased following VEGFR-2 activation, through autocrine and paracrine mechanisms, as measured by clonogenic progenitor assays. VEGFR-2 activation induced expression of GM-CSF and increased serum levels in vivo. Abrogation of GM-CSF activity, either with neutralizing Abs or by using GM-CSF-null hemopoietic cells, inhibited VEGFR-2-mediated myeloid progenitor activity. Our findings indicate that VEGF signaling through VEGFR-2 promotes myelopoiesis through GM-CSF-dependent and -independent mechanisms.     

Minimal contribution of marrow-derived endothelial precursors to tumor vasculature

During embryogenesis, vascular and hemopoietic cells originate from a common precursor, the hemangioblast. Recent evidence suggests the existence of endothelial precursors in adult bone marrow cells, but it is unclear whether those precursors have a role in tumor neovascularization. In this report, we demonstrate that murine bone marrow contains endothelial progenitors, which arise from a cell with self-renewing capacity, and can integrate into tumor microvasculature, albeit at a very low frequency. A transgenic double-reporter strategy allowed us to demonstrate definitively that tumor bone marrow-derived endothelial cells arise by transdifferentiation of marrow progenitors rather than by cell fusion. Single cell transplants showed that a common precursor contributes to both the hemopoietic and endothelial lineages, thus demonstrating the presence of an adult hemangioblast. Furthermore, we demonstrate that increased vascular endothelial growth factor (VEGF)-A secretion by tumor cells, as well as activation of VEGF receptor-2 in bone marrow cells does not alter the mobilization and incorporation of marrow-derived endothelial progenitors into tumor vasculature. Finally, in human umbilical cord blood cells, we show that endothelial precursors make up only approximately 1 in 10(7) mononuclear cells but are highly enriched in the CD133+ cell population. By ruling out cell fusion, we clearly demonstrate the existence of an adult hemangioblast, but the differentiation of marrow stem cells toward the endothelial lineage is an extremely rare event. Furthermore, we show that VEGF-A stimulation of hemopoietic cells does not significantly alter this process.     

Heavy metals resistant plasmid-mediated utilization of solar by Pseudomonas aeruginosa AA301

Solar-degrading bacteria, Pseudomonas aeruginosa strains, were isolated from Egyptian soil by Mineral Salt Medium (MSM) supplemented with Solar (motor fuel) from different oil-contaminated sites in Sohag province. The strain AA301 of Pseudomonas aeruginosa showed appreciable growth in MSM medium containing high concentrations of Solar ranging from 0.5 to 3% (v/v), with optimum concentration at 1.5%. Solar was used as a sole carbon source and a source of energy by the bacterium. The ability to degrade Solar was found to be associated with a single 60-kb plasmid designated pSOL15. The plasmid-cured variant, which was obtained by culturing in LB broth with kanamycin, lost the plasmid indicative the ability to degrade Solar must depend on this plasmid. The wild type isolate, Pseudomonas aeruginosa AA301 and transformant strain, have maximum growth (OD600 = approximately 2) on Solar, however the plasmid-cured variant did not have any significant growth on Solar. Moreover, resistance to a wide range of heavy metals such as Mn2+, Hg2+, Mg2+, Cd2+, Zn2+, and Ni2+ was also 60-kb plasmid-mediated. Therefore, the strain AA301 could be good candidate for remediation of some heavy metals and oil hydrocarbons in heavily polluted sites.     

Synthesis of some quinolinyl chalcone analogues and investigation of their anticancer and synergistic anticancer effect with doxorubicin

Two derivatives of 2-(4-acetylanilino)quinolines (IIIa, b) were synthesized as scaffolds for synthesis of open chalcone analogues (Va-f) through Claisen-Schmidt condensation with a set of aromatic aldehydes (IVa-d). Derivatives (Va, b) were further manipulated into cyclic ??,??-unsaturated ketones by Michael-addition of acetylacetone and ethylacetoacetate affording derivatives (VI?CVII). Deethoxycarboxylation of derivatives (VIIa, b) afforded cyclohexenons (VIIIa, b) allowing formation of a mini library of ??,??-unsaturated ketones for screening their anticancer and synergistic anticancer effect with doxorubicin using colon cancer cell line (Caco-2). Two open enones, (Vb) and (Ve), showed significant anticancer activity with IC₅₀ of 5.0 and 2.5 ??M respectively. Only one cyclic enone, (VIa) showed synergistic anticancer activity with doxorubicin at 10 ??M.