Sleeping sickness (human African trypanosomiasis [HAT]) is caused by protozoan parasites and characterized by a chronic progressive course, which may last up to several years before death. We conducted two Phase 2 studies to determine the efficacy and safety of oral pafuramidine in African patients with first stage HAT.
Methods
The Phase 2a study was an open-label, non-controlled, proof-of-concept study where 32 patients were treated with 100 mg of pafuramidine orally twice a day (BID) for 5 days at two trypanosomiasis reference centers (Angola and the Democratic Republic of the Congo [DRC]) between August 2001 and November 2004. The Phase 2b study compared pafuramidine in 41 patients versus standard pentamidine therapy in 40 patients. The Phase 2b study was open-label, parallel-group, controlled, randomized, and conducted at two sites in the DRC between April 2003 and February 2007. The Phase 2b study was then amended to add an open-label sequence (Phase 2b-2), where 30 patients received pafuramidine for 10 days. The primary efficacy endpoint was parasitologic cure at 24 hours (Phase 2a) or 3 months (Phase 2b) after treatment completion. The primary safety outcome was the rate of occurrence of World Health Organization Toxicity Scale Grade 3 or higher adverse events. All subjects provided written informed consent.
Findings/Conclusion
Pafuramidine for the treatment of first stage HAT was comparable in efficacy to pentamidine after 10 days of dosing. The cure rates 3 months post-treatment were 79% in the 5-day pafuramidine, 100% in the 7-day pentamidine, and 93% in the 10-day pafuramidine groups. In Phase 2b, the percentage of patients with at least 1 treatment-emergent adverse event was notably higher after pentamidine treatment (93%) than pafuramidine treatment for 5 days (25%) and 10 days (57%). These results support continuation of the development program for pafuramidine into Phase 3. 相似文献
Sleeping sickness (human African trypanosomiasis [HAT]) is a neglected tropical disease with limited treatment options that currently require parenteral administration. In previous studies, orally administered pafuramidine was well tolerated in healthy patients (for up to 21 days) and stage 1 HAT patients (for up to 10 days), and demonstrated efficacy comparable to pentamidine.
Methods
This was a Phase 3, multi-center, randomized, open-label, parallel-group, active control study where 273 male and female patients with first stage Trypanosoma brucei gambiense HAT were treated at six sites: one trypanosomiasis reference center in Angola, one hospital in South Sudan, and four hospitals in the Democratic Republic of the Congo between August 2005 and September 2009 to support the registration of pafuramidine for treatment of first stage HAT in collaboration with the United States Food and Drug Administration. Patients were treated with either 100 mg of pafuramidine orally twice a day for 10 days or 4 mg/kg pentamidine intramuscularly once daily for 7 days to assess the efficacy and safety of pafuramidine versus pentamidine. Pregnant and lactating women as well as adolescents were included.The primary efficacy endpoint was the combined rate of clinical and parasitological cure at 12 months. The primary safety outcome was the frequency and severity of adverse events. The study was registered on the International Clinical Trials Registry Platform at www.clinicaltrials.gov with the number ISRCTN85534673.
Findings/Conclusions
The overall cure rate at 12 months was 89% in the pafuramidine group and 95% in the pentamidine group; pafuramidine was non-inferior to pentamidine as the upper bound of the 95% confidence interval did not exceed 15%. The safety profile of pafuramidine was superior to pentamidine; however, 3 patients in the pafuramidine group had glomerulonephritis or nephropathy approximately 8 weeks post-treatment. Two of these events were judged as possibly related to pafuramidine. Despite good tolerability observed in preceding studies, the development program for pafuramidine was discontinued due to delayed post-treatment toxicity. 相似文献
During the fallow period, non-legume cover crop species can capture mineral nitrogen (N) and thus decrease nitrate leaching, whereas legume cover crop species can provide a green manuring service that increases N availability for the subsequent crop. The aim of our study was to investigate the ability of bispecific mixtures to simultaneously produce these two services of N management in relation to their interspecific interactions.
Methods
Three field experiments were conducted at contrasting sites from summer to autumn to evaluate 25 mixtures and 10 sole crops. We measured biomass, N acquisition, C:N ratio and soil mineral N. Ecosystem services were assessed using both experimental data and simulation model predictions.
Results
Overall, prediction of N mineralized from cover crop residues was significantly higher for mixtures than for non-legume sole crops. Predictions of nitrate leached after mixtures did not differ significantly from those after non-legume sole crops and remained significantly lower than those under bare soil, especially for mixtures with turnip rape which benefitted greatly from being in mixtures.
Conclusions
Some of the mixtures provided a choice of compromises between the two ecosystem services, which helps define solutions for adapting mixture choice according to the site’s soil and climate characteristics and to fallow period management.
Uroplakins (UPs) are major differentiation products of urothelial umbrella cells and play important roles in forming the permeability barrier and in the expansion/stabilization of the apical membrane. Further, UPIa serves as a uropathogenic Escherichia coli receptor. Although it is understood that UPs are delivered to the apical membrane via fusiform vesicles (FVs), the mechanisms that regulate this exocytic pathway remain poorly understood. Immunomicroscopy of normal and mutant mouse urothelia show that the UP-delivering FVs contained Rab8/11 and Rab27b/Slac2-a, which mediate apical transport along actin filaments. Subsequently a Rab27b/Slp2-a complex mediated FV–membrane anchorage before SNARE-mediated and MAL-facilitated apical fusion. We also show that keratin 20 (K20), which forms a chicken-wire network ∼200 nm below the apical membrane and has hole sizes allowing FV passage, defines a subapical compartment containing FVs primed and strategically located for fusion. Finally, we show that Rab8/11 and Rab27b function in the same pathway, Rab27b knockout leads to uroplakin and Slp2-a destabilization, and Rab27b works upstream from MAL. These data support a unifying model in which UP cargoes are targeted for apical insertion via sequential interactions with Rabs and their effectors, SNAREs and MAL, and in which K20 plays a key role in regulating vesicular trafficking. 相似文献
Effect of exogenous H(2)O(2) and catalase was tested in liquid cultures of the deoxynivalenol and 15-acetyldeoxynivalenol-producing fungus Fusarium graminearum. Accordingly to previous results, H(2)O(2) supplementation of the culture medium leads to increased toxin production. This study indicates that this event seems to be linked to a general up regulation of genes involved in the deoxynivalenol and 15-acetyldeoxynivalenol biosynthesis pathway, commonly named Tri genes. In catalase-treated cultures, toxin accumulation is reduced, and Tri genes expression is significantly down regulated. Furthermore, kinetics of expression of several Tri genes is proposed in relation to toxin accumulation. Biological meanings of these findings are discussed. 相似文献
In this work, we investigated the reaction of ferric Mycobacterium tuberculosis truncated hemoglobin O (trHbO) with hydrogen peroxide. Stopped-flow spectrophotometric experiments under single turnover conditions showed that trHbO reacts with H(2)O(2) to give transient intermediate(s), among which is an oxyferryl heme, different from a typical peroxidase Compound I (oxyferryl heme pi-cation radical). EPR spectroscopy indicated evidence for both tryptophanyl and tyrosyl radicals, whereas redox titrations demonstrated that the peroxide-treated protein product retains 2 oxidizing eq. We propose that Compound I formed transiently is reduced with concomitant oxidation of Trp(G8) to give the detected oxoferryl heme and a radical on Trp(G8) (detected by EPR of the trHbO Tyr(CD1)Phe mutant). In the wild-type protein, the Trp(G8) radical is in turn reduced rapidly by Tyr(CD1). In a second cycle, Trp(G8) may be reoxidized by the ferryl heme to yield ferric heme and two protein radicals. In turn, these migrate to form tyrosyl radicals on Tyr(55) and Tyr(115), which lead, in the absence of a reducing substrate, to oligomerization of the protein. Steady-state kinetics in the presence of H(2)O(2) and the one-electron donor 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) indicated that trHbO has peroxidase activity, in accord with the presence of typical peroxidase intermediates. These findings suggest an oxidation/reduction function for trHbO and, by analogy, for other Group II trHbs. 相似文献
The genome of Populus trichocarpa contains five methionine sulfoxide reductase A genes. Here, both cytosolic (cMsrA) and plastidial (pMsrA) poplar MsrAs were analyzed. The two recombinant enzymes are active in the reduction of methionine sulfoxide with either dithiothreitol or poplar thioredoxin as a reductant. In both enzymes, five cysteines, at positions 46, 81, 100, 196, and 202, are conserved. Biochemical and enzymatic analyses of the cysteine-mutated MsrAs support a catalytic mechanism involving three cysteines at positions 46, 196, and 202. Cys(46) is the catalytic cysteine, and the two C-terminal cysteines, Cys(196) and Cys(202), are implicated in the thioredoxin-dependent recycling mechanism. Inspection of the pMsrA x-ray three-dimensional structure, which has been determined in this study, strongly suggests that contrary to bacterial and Bos taurus MsrAs, which also contain three essential Cys, the last C-terminal Cys(202), but not Cys(196), is the first recycling cysteine that forms a disulfide bond with the catalytic Cys(46). Then Cys(202) forms a disulfide bond with the second recycling cysteine Cys(196) that is preferentially reduced by thioredoxin. In agreement with this assumption, Cys(202) is located closer to Cys(46) compared with Cys(196) and is included in a (202)CYG(204) signature specific for most plant MsrAs. The tyrosine residue corresponds to the one described to be involved in substrate binding in bacterial and B. taurus MsrAs. In these MsrAs, the tyrosine residue belongs to a similar signature as found in plant MsrAs but with the first C-terminal cysteine instead of the last C-terminal cysteine. 相似文献
NOD2 plays an important role in the innate immunity of the intestinal tract. By sensing the muramyl dipeptide (MDP), a bacterial wall component, NOD2 triggers the NF-kappaB signaling pathway and promotes the release of proinflammatory cytokines such as interleukin-8. Mutations in Nod2 (1007FS, R702W, G908R) impinge on NOD2 functions and are associated with the pathogenesis of Crohn disease, a chronic inflammatory bowel disease. Although NOD2 is usually described as a cytosolic receptor for MDP, the protein is also localized at the plasma membrane, and the 1007FS mutation delocalizes NOD2 to the cytoplasm (Barnich, N., Aguirre, J. E., Reinecker, H. C., Xavier, R., and Podolsky, D. K. (2005) J. Cell Biol. 170, 21-26; McDonald, C., Chen, F. F., Ollendorff, V., Ogura, Y., Marchetto, S., Lecine, P., Borg, J. P., and Nunez, G. (2005) J. Biol. Chem. 280, 40301-40309). In this study, we demonstrate that membrane-bound versions of NOD2 and Crohn disease-associated mutants R702W and G908R are capable of responding to MDP and activating the NF-kappaB pathway from this location. In contrast, the 1007FS mutant remains unable to respond to MDP from the plasma membrane. We also show that NOD2 promotes the membrane recruitment of RICK, a serine-threonine kinase involved in NF-kappaB activation downstream of NOD2. Furthermore, the artificial attachment of RICK at the plasma membrane provokes a constitutive and strong activation of the NF-kappaB pathway and secretion of interleukin-8 showing that optimal RICK activity depends upon its subcellular localization. Finally, we show that endogenous RICK localizes at the plasma membrane in the THP1 cell line. Thus, our data suggest that NOD2 is responsible for the membrane recruitment of RICK to induce a regulated NF-kappaB signaling and production of proinflammatory cytokines. 相似文献