In vitro activities of the biguanide PS-15 and its metabolite, WR99210, against cycloguanil-resistant Plasmodium falciparum isolates from Thailand

The in vitro activities of the new biguanide PS-15 and its putative active metabolite, WR99210, were determined against seven different isolates or clones of Plasmodium falciparum. The mean 50% inhibitory concentrations of PS-15 and WR99210 were 1,015 and 0.06 ng/ml, respectively. WR99210 was up to 363 times more potent than cycloguanil, the active metabolite of proguanil, against cycloguanil-resistant parasites. The pronounced activity of WR99210 against multidrug-resistant P. falciparum indicates that further studies are required to determine the value of the prodrug, PS-15, as an antimalarial agent

Provision of local bus services in Japan: focusing on the roles for local governments and nonprofit organisations

Japan’s bus deregulation program (coach and local) was carried out in February 2002. Its main point was to loosen or eliminate Demand-Supply Balancing (Jukyu-Chosei.) This regulation was a licensing system and functioned as entry/exit regulation. It defended incumbents (approximately 360 operators) and did not let potential entrants respond to increasing demand for some services. It also forced the incumbents to cross-subsidise noncommercial services. In other words, the incumbents were allowed to enjoy a situation of local monopoly but forced to maintain non-commercial services. Although five years have passed since the deregulation, we have not seen major changes in the structure of the local bus market, as there have been few entrants. On the other hand, the incumbents are apt to abandon non-commercial services, because they now have freedom of exit and cross-subsidisation is no longer sustainable. The supply of commercial services can be left to the market mechanism, but the problem is who is in charge of maintaining noncommercial but indispensable services, especially in rural areas. This is why the deregulation has had impact on the transport policy by local governments. In fact, local governments all over Japan have been more involved in policies for public transport. But many of them are now facing a budget deficit and need to cut expenditures, including subsidies for bus services. Thus, nonprofit organisations (NPOs) are also expected to play a crucial role in the local transport market, like community transport in England. Some NPOs have been founded by the inhabitants and have tried to form a partnership with bus operators, local governments, shops, hospitals and so on in their local communities. The aim of this paper is to analyse the roles for NPOs in the local bus market, in comparison with those for local government. First, we describe the Japanese local bus market before and after the deregulation. Secondly, we consider the roles for local governments and NPOs in the local bus market. Next, we analyse some pioneering cases. In conclusion, we give a future prospect of local bus service provision in Japan, from the viewpoint of partnerships among local governments, private operators and NPOs.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Cross-protection between attenuated Plasmodium berghei and P. yoelii sporozoites

An attenuatedPlasmodium falciparum sporozoite (PfSPZ) vaccine is under development, in part, based on studies in mice withP. berghei. We usedP. berghei andP. yoelii to study vaccine-induced protection against challenge with a species of parasite different from the immunizing parasite in BALB/c mice. One-hundred percent of mice were protected against homologous challenge. Seventy-nine percent immunized with attenuatedP. berghei sporozoite (PbSPZ)(six experiments) were protected against challenge withP. yoelii sporozoite (PySPZ), and 63% immunized with attenuatedPySPZ(three experiments) were protected against challenge withPbSPZ. Antibodies in sera of immunized mice only recognized homologous sporozoites and could not have mediated protection against heterologous challenge. Immunization with attenuatedPySPZ orPbSPZ induced CD8+ T cell-dependent protection against heterologous challenge. Immunization with attenuatedPySPZ induced CD8+ T cell-dependent protection against homologous challenge. However, homologous protection induced by attenuatedPbSPZ was not dependent on CD8+ or CD4+ T cells, and depletion of both populations only reduced protection by 36%. Immunization of C57BL/10 mice withPbSPZ induced CD8+ T cell-dependent protection againstP. berghei, but no protection againstP. yoelii. The cross-protection data in BALB/c mice support testing a human vaccine based on attenuatedPfSPZ for its efficacy againstP. vivax

A rapid and robust tri-color flow cytometry assay for monitoring malaria parasite development

Microscopic examination of Giemsa-stained thin blood smears remains the gold standard method used to quantify and stage malaria parasites. However, this technique is tedious, and requires trained microscopists. We have developed a fast and simple flow cytometry method to quantify and stage, various malaria parasites in red blood cells in whole blood or in vitro cultured Plasmodium falciparum. The parasites were stained with dihydroethidium and Hoechst 33342 or SYBR Green I and leukocytes were identified with an antibody against CD45. Depending on the DNA stains used, samples were analyzed using different models of flow cytometers. This protocol, which does not require any washing steps, allows infected red blood cells to be distinguished from leukocytes, as well as allowing non-infected reticulocytes and normocytes to be identified. It also allows assessing the proportion of parasites at different developmental stages. Lastly, we demonstrate how this technique can be applied to antimalarial drug testing

Exploring provider and community responses to the new malaria diagnostic and treatment regime in Solomon Islands

<p>Abstract</p> <p>Background</p> <p>Improvements in availability and accessibility of artemisinin-based combination therapy (ACT) for malaria treatment and the emergence of multi-drug-resistant parasites have prompted many countries to adopt ACT as the first-line drug. In 2009, Solomon Islands (SI) likewise implemented new national treatment guidelines for malaria. The ACT, Coartem^®(artemether-lumefantrine) is now the primary pharmacotherapy in SI for <it>Plasmodium falciparum </it>malaria, <it>Plasmodium vivax </it>malaria or mixed infections. Targeted treatment is also recommended in the new treatment regime through maintenance of quality microscopy services and the introduction of Rapid Diagnostic Tests (RDTs). Ascertaining the factors that influence community and provider acceptance of and adherence to the new treatment regime will be vital to improving the effectiveness of this intervention and reducing the risk of development of drug resistance.</p> <p>Methods</p> <p>In order to understand community and prescriber perceptions and acceptability of the new diagnostic and treatment interventions, 12 focus group discussions (FGDs) and 12 key informant interviews (KII) were carried out in rural and urban villages of Malaita Province, Solomon Islands four months subsequent to roll out of these interventions.</p> <p>Results</p> <p>Lack of access to microscopy or distrust in the accuracy of diagnostic tools were reported by some participants as reasons for the ongoing practice of presumptive treatment of malaria. Lack of confidence in RDT accuracy has negatively impacted its acceptability. Coartem^®had good acceptability among most participants, however, some rural participants questioned its effectiveness due to lack of side effects and the larger quantity of tablets required to be taken. Storing of left over medication for subsequent fever episodes was reported as common.</p> <p>Conclusion</p> <p>To address these issues, further training and supportive supervision of healthcare workers will be essential, as will the engagement of influential community members in health promotion activities to improve acceptability of RDTs and adherence to the new treatment regime. Exploring the extent of these issues beyond the study population must be a priority for malaria programme managers. Practices such as presumptive treatment and the taking of sub-curative doses are of considerable concern for both the health of individuals and the increased risk it poses to the development of parasite resistance to this important first-line treatment against malaria.</p

Combined chloroquine, sulfadoxine/pyrimethamine and primaquine against Plasmodium falciparum in Central Java, Indonesia

BACKGROUND: Chloroquine (CQ) or sulfadoxine-pyrimethamine (SP) monotherapy for Plasmodium falciparum often leads to therapeutic failure in Indonesia. Combining CQ with other drugs, like SP, may provide an affordable, available and effective option where artemisinin-combined therapies (ACT) are not licensed or are unavailable. METHODS: This study compared CQ (n = 29 subjects) versus CQ + SP (with or without primaquine; n = 88) for clinical and parasitological cure of uncomplicated falciparum malaria in the Menoreh Hills region of southern Central Java, Indonesia. Gametocyte clearance rates were measured with (n = 56 subjects) and without (n = 61) a single 45 mg dose of primaquine (PQ). RESULTS: After 28 days, 58% of subjects receiving CQ had cleared parasitaemia and remained aparasitaemic, compared to 94% receiving CQ combined with SP (p < 0.001). Msp-2 genotyping permitted reinfection-adjusted cure rates for CQ and CQ combined with SP, 70% and 99%, respectively (p = 0.0006). CONCLUSION: Primaquine exerted no apparent affect on cure of asexual stage parasitaemia, but clearly accelerated clearance of gametocytes. CQ combined with SP was safe and well-tolerated with superior efficacy over CQ for P. falciparum parasitaemia in this study

Assessment of therapeutic responses to gametocytocidal drugs in Plasmodium falciparum malaria

Indirect clinical measures assessing anti-malarial drug transmission-blocking activity in falciparum malaria include measurement of the duration of gametocytaemia, the rate of gametocyte clearance or the area under the gametocytaemia-time curve (AUC). These may provide useful comparative information, but they underestimate dose-response relationships for transmission-blocking activity. Following 8-aminoquinoline administration P. falciparum gametocytes are sterilized within hours, whereas clearance from blood takes days. Gametocytaemia AUC and clearance times are determined predominantly by the more numerous female gametocytes, which are generally less drug sensitive than the minority male gametocytes, whereas transmission-blocking activity and thus infectivity is determined by the more sensitive male forms. In choosing doses of transmission-blocking drugs there is no substitute yet for mosquito-feeding studies

Genes implicated in multiple sclerosis pathogenesis from consilience of genotyping and expression profiles in relapse and remission

<p>Abstract</p> <p>Background</p> <p>Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Although the pathogenesis of MS remains unknown, it is widely regarded as an autoimmune disease mediated by T-lymphocytes directed against myelin proteins and/or other oligodendrocyte epitopes.</p> <p>Methods</p> <p>In this study we investigated the gene expression profiles of peripheral blood cells from patients with RRMS during the relapse and the remission phases utilizing gene microarray technology. Dysregulated genes encoded in regions associated with MS susceptibility from genomic screens or previous trancriptomic studies were identified. The proximal promoter region polymorphisms of two genes were tested for association with disease and expression level.</p> <p>Results</p> <p>Distinct sets of dysregulated genes during the relapse and remission phases were identified including genes involved in apoptosis and inflammation. Three of these dysregulated genes have been previously implicated with MS susceptibility in genomic screens: TGFβ1, CD58 and DBC1. TGFβ1 has one common SNP in the proximal promoter: -508 T>C (rs1800469). Genotyping two Australian trio sets (total 620 families) found a trend for over-transmission of the T allele in MS in females (p < 0.13). Upregulation of CD58 and DBC1 in remission is consistent with their putative roles in promoting regulatory T cells and reducing cell proliferation, respectively. A fourth gene, ALOX5, is consistently found over-expressed in MS. Two common genetic variants were confirmed in the ALOX5 putatve promoter: -557 T>C (rs12762303) and a 6 bp tandem repeat polymorphism (GGGCGG) between position -147 and -176; but no evidence for transmission distortion found.</p> <p>Conclusion</p> <p>The dysregulation of these genes tags their metabolic pathways for further investigation for potential therapeutic intervention.</p