Implementation of an insecticide-treated net subsidy scheme under a public-private partnership for malaria control in Tanzania – challenges in implementation

Background

In the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs) and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM), the President's Malaria Initiative and the World Bank Booster programme.

Methods

The case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control – 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 – 2004) and implementation phases (2004 – 2005). Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs.

Results

The major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative.

Conclusion

The lessons gleaned from this synthesis include: (a) the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b) senior politicians often steered the policy agenda when the policy in question was a 'crisis event', the stakes and the visibility were high, (c) national stakeholders in policy making have an advantage in strengthening alliances with international organizations, where the latter can become extremely influential in solving bottlenecks as the need arises, and (d) conflict can be turned into an opportunity, for example the Presidential initiative has inadvertently provided Tanzania with important lessons in the organization of 'catch-up' campaigns.     

Immunolocalization of MMP-19 in the human intervertebral disc: implications for disc aging and degeneration

Matrix metalloproteinases (MMPs) degrade components of the extracellular matrix of the disc, but the presence of MMP-19 has not been explored. In other tissues, MMP-19 is known to act in proteolysis of the insulin-like growth factor (IGF) binding protein-3, thereby exposing this protein to make it available to influence cell behavior. MMP-19 also has been shown to inhibit capillary-like formation and thus play a role in the avascular nature of the disc. Using immunohistochemistry, normal discs from six subjects aged newborn through 10 years and 20 disc specimens from control donors or surgical patients aged 15-76 (mean age 40.2 years) were examined for immunolocalization of MMP-19; six Thompson grade I discs, five Thompson grade II, eight Thompson grade III, five Thompson grade IV, and one Thompson grade V discs were analyzed. The results indicate that in discs from young subjects, MMP-19 was uniformly localized in the outer annulus. In discs from adult donors and surgical patients, outer and inner annulus cells only occasionally showed MMP-19 localization. The greatest expression of MMP-19 was observed in young discs, and little expression was seen in older or degenerating discs. Because MMP-19 has been shown to regulate IGF-mediated proliferation in other tissues, its decline in the aging/degenerating disc may contribute to the age-related decrease in disc cell numbers.     

Haplotyping cryptic Adélie penguin taxa using low-cost,high-resolution melt curves

Distinguishing morphologically cryptic taxa, by definition, requires genetic data such as DNA sequences. However, DNA sequences may not be obtained easily for taxa from remote sites. Here we provide the details of a high-resolution melt-curve-based method using taxon-specific primers that can distinguish two taxa of Adélie penguins, and that will be usable in Antarctica when combined with some of the newly developed field-deployable thermal cyclers. We suggest that the wider adoption of field-deployable polymerase-chain-reaction-based techniques will enable faster assignation of haplotype to individuals in situ, and so allow the targeting of observations and sample collection to specimens relevant to the research question. Targeting individuals will also reduce the need to repeatedly handle animals and reduce the time and travel required to complete field work.     

Structure of dihydropyrimidinase from Sinorhizobium meliloti CECT4114: New features in an amidohydrolase family member

The recombinant dihydropyrimidinase from Sinorhizobium meliloti CECT4114 (SmelDhp) has been characterised and its crystal structure elucidated at 1.85 Å. The global architecture of the protein is reminiscent of that of the amidohydrolase superfamily, consisting of two domains; an (α/β)₈ TIM-like barrel domain, where the catalytic centre is located, and a smaller β-sheet sandwich domain of unknown function. The c-terminal tails of each subunit extend toward another monomer in a swapping-like manner, creating a hydrogen bond network which suggests its implication in protein oligomerisation. Mutational and structural evidence suggest the involvement of a conserved tyrosine in the reaction mechanism of the enzyme. SmelDhp presents both hydantoinase and dihydropyrimidinase activities, with higher affinity for the natural six-membered ring substrates. For the five-membered ring substrates, affinity was greater for those with aliphatic and apolar groups in the 5th carbon atom, with the highest rates of hydrolysis for d-5-methyl and d-5-ethyl hydantoin (k_cat/K_m = 2736 ± 380 and 944 ± 52 M^?1 s^?1, respectively). The optimal conditions for the enzyme activity were found to be 60 °C of temperature at pH 8.0. SmelDhp retains 95% of its activity after 6-hour preincubation at 60 °C. This is the first dihydropyrimidinase used for the hydrolytic opening of non-natural 6-monosubstituted dihydrouracils, which may be exploited for the production of β-amino acids.     

Phenomorphology and ecomorphological characters of Maytenus senegalensis L. Shrublands in the Iberian Peninsula: A comparison with other Mediterranean plant communities

This work sets out to establish ecomorphological and phenomorphological patterns in the constituent flora of an Iberian Maytenus senegalensis plant community in order to relate it with or separate it from other types of Mediterranean vegetation. This plant community contains tall shrubs, scrubs, palms and vines of a variety of families. Typical ecomorphological adaptations to the Mediterranean climate were observed in the community studied: an abundance of thorny species or species with tomentose leaves and photosynthetic stems, small leaves and a high presence of species with organs capable of post-fire regeneration. However, the community also showed hybrid characteristics between scrubland (predominantly malacophyllous leaves lasting 9 months on average and low biomass) and tall shrubland communities (predominance of phanerophytes up to 3 m in height, predominantly smooth bark, periodical reposition of leaves, mean lifespan of plants 25 years and mainly fleshy fruit). The community also presents an outstanding quantity of amphiphytes (29%). From a phenological point of view, the formation of buds in winter, flowering in spring, summer–autumn seed dispersal and leaf shedding in summer are typical of other Mediterranean communities, while fructification and growth lasting three seasons, as in the case of Maytenus shrubland, is not. The RVA phenophasic index (balance between reproductive and vegetative phenophases) with values of 0.4–2 shows an intermediate value between typical shrubland (0.3–1) and forest community (1–2) values. The APC index (period of phenophasic activity of the community) differentiates it from others, since it remains at 100% for seven months, three of which are winter months. Phenophasic patterns (overlapping, or not, of flower bud formation, flowering and growth) show how similar M. senegalensis shrubland is to forests because of the absence of phenophase pattern type A (characteristic in open-scrublands); in addition, we have detected a new pattern (type G), still regarded as exclusive to M. senegalensis. As regards the existence of coenomorphs (group of species with similar morpho-functional strategies), the studied community showed much greater diversity than other communities studied to date, with an Strategies Richness index (SRi) of 0.79 (11 groups covering the 14 species existing), pointing to the co-existence of a great variety of eco-phenomorphological strategies, each with a successful response to the same ecological conditions. Finally, some of the species in the community, e.g. Asparagus horridus, Chamaerops humilis and M. senegalensis, stand out because of their unique ecomorphological and phenological characteristics.     

New techniques for membrane protein crystallization tested on photosystem II core complex of Pisum sativum

The crystallization of a given protein is a hard task being even more complicated when the protein shows a hydrophobic behavior. In the case of photosynthetic proteins, the difficulty of the experiments increased due to the high light sensitivity. Aqueous solutions of photosystem II core complex (OEC PSII) of Pisum sativum were screened for crystallization conditions using standard crystallization methods. Crystal improvement was achieved by counter-diffusion technique in single capillaries of 0.2 mm inner diameter with a three-layer configuration. The use of this advanced crystallization technique—for the first time applied to the crystallization of membrane proteins—improves the reproducibility of the experiments allowing the initial crystal characterization, and facilitates the manipulation under light protection.     

Monitoring and scoring counter-diffusion protein crystallization experiments in capillaries by in situ dynamic light scattering

In this paper, we demonstrate the feasibility of using in situ Dynamic Light Scattering (DLS) to monitor counter-diffusion crystallization experiments in capillaries. Firstly, we have validated the quality of the DLS signal in thin capillaries, which is comparable to that obtained in standard quartz cuvettes. Then, we have carried out DLS measurements of a counter-diffusion crystallization experiment of glucose isomerase in capillaries of different diameters (0.1, 0.2 and 0.3 mm) in order to follow the temporal evolution of protein supersaturation. Finally, we have compared DLS data with optical recordings of the progression of the crystallization front and with a simulation model of counter-diffusion in 1D.     

Force-clamp spectroscopy detects residue co-evolution in enzyme catalysis

Understanding how the catalytic mechanisms of enzymes are optimized through evolution remains a major challenge in molecular biology. The concept of co-evolution implicates that compensatory mutations occur to preserve the structure and function of proteins. We have combined statistical analysis of protein sequences with the sensitivity of single molecule force-clamp spectroscopy to probe how catalysis is affected by structurally distant correlated mutations in Escherichia coli thioredoxin. Our findings show that evolutionary anti-correlated mutations have an inhibitory effect on enzyme catalysis, whereas positively correlated mutations rescue the catalytic activity. We interpret these results in terms of an evolutionary tuning of both the enzyme-substrate binding process and the chemistry of the active site. Our results constitute a direct observation of distant residue co-evolution in enzyme catalysis.