Groundwater flow system analysis in the regolith of Dodowa on the Accra Plains, Ghana

Study Region: Accra Plains. Study Focus: We conducted a field geology mapping, a well inventory exercise, used ERT, drilled boreholes at 8 locations (15–60 m depth), took drill core samples which we subjected to dilute acid leaching experiments, installed piezometers and equipped them with pressure transducers, analyzed tidal signals in high frequency groundwater hydrographs, carried out pumping tests, and, finally, took 49 groundwater samples. New Insights: Our results indicated a diverse groundwater system. On the one hand, groundwater was found at shallow depths in the saprolite of the Togo Structural Unit (TSU), which, in unweathered state, is composed of phyllites, schists, and quartzites. This system was shallow and predominantly unconfined, as revealed by tidal analysis. In addition, transmissivities of TSU saprolite, all in the order of < 6e-5 m2/s, reduced with depth, which indicated either the lack of a stratiform fractured layer or the presence of such layer beyond drilled depths. On the other hand, groundwater was found in fractures of the gneisses of the Dahomeyan Structural Unit (DSU). This system was potentially deeper, but DSU transmissivities were significantly lower than those of TSU saprolite. Hydrochemically, groundwater was mainly characterized by infiltration of wastewater, evidenced by elevated ion concentrations, including nitrate. Due to the thinly weathered basement, groundwater system development in the area is local and restricted to the Dodowa area

TRIPS, the Doha Declaration and increasing access to medicines: policy options for Ghana

There are acute disparities in pharmaceutical access between developing and industrialized countries. Developing countries make up approximately 80% of the world's population but only represent approximately 20% of global pharmaceutical consumption. Among the many barriers to drug access are the potential consequences of the Trade Related Aspects of Intellectual Property Rights (TRIPS) Agreement. Many developing countries have recently modified their patent laws to conform to the TRIPS standards, given the 2005 deadline for developing countries. Safeguards to protect public health have been incorporated into the TRIPS Agreement; however, in practice governments may be reluctant to exercise such rights given concern about the international trade and political ramifications. The Doha Declaration and the recent Decision on the Implementation of Paragraph 6 of the Doha Declaration on the TRIPS Agreement and Public Health may provide more freedom for developing countries in using these safeguards. This paper focuses on Ghana, a developing country that recently changed its patent laws to conform to TRIPS standards. We examine Ghana's patent law changes in the context of the Doha Declaration and assess their meaning for access to drugs of its population. We discuss new and existing barriers, as well as possible solutions, to provide policy-makers with lessons learned from the Ghanaian experience

Nigella sativa (Black Cumin) Seed Extract Alleviates Symptoms of Allergic Diarrhea in Mice, Involving Opioid Receptors

The incidence of food hypersensitivity and food allergies is on the rise and new treatment approaches are needed. We investigated whether N. sativa, one of its components, thymoquinone, or synthetic opioid receptor (OR)-agonists can alleviate food allergy. Hence, ovalbumin (OVA) -sensitized BALB/c-mice were pre-treated either with a hexanic N. sativa seed extract, thymoquinone, kappa- (U50'4889) or mu-OR-agonists (DAMGO) and subsequently challenged intra-gastrically with OVA. All 4 treatments significantly decreased clinical scores of OVA-induced diarrhea. N. sativa seed extract, thymoquinone, and U50'488 also decreased intestinal mast cell numbers and plasma mouse mast cell protease-1 (MMCP-1). DAMGO, in contrast, had no effect on mast cell parameters but decreased IFNγ, IL-4, IL-5, and IL-10 concentration after ex vivo re-stimulation of mesenteric lymphocytes. The effects on allergy symptoms were reversible by OR-antagonist pre-treatment, whereas most of the effects on immunological parameter were not. We demonstrate that N. sativa seed extract significantly improves symptoms and immune parameters in murine OVA-induced allergic diarrhea; this effect is at least partially mediated by thymoquinone. ORs may also be involved and could be a new target for intestinal allergy symptom alleviation. N. sativa seed extract seems to be a promising candidate for nutritional interventions in humans with food allergy

Studies on the antidiarrhoeal activity of Aegle marmelos unripe fruit: Validating its traditional usage

<p>Abstract</p> <p>Background</p> <p><it>Aegle marmelos </it>(L.) Correa has been widely used in indigenous systems of Indian medicine due to its various medicinal properties. However, despite its traditional usage as an anti-diarrhoeal there is limited information regarding its mode of action in infectious forms of diarrhoea. Hence, we evaluated the hot aqueous extract (decoction) of dried unripe fruit pulp of <it>A. marmelos </it>for its antimicrobial activity and effect on various aspects of pathogenicity of infectious diarrhoea.</p> <p>Methods</p> <p>The decoction was assessed for its antibacterial, antigiardial and antirotaviral activities. The effect of the decoction on adherence of enteropathogenic <it>Escherichia coli </it>and invasion of enteroinvasive <it>E. coli </it>and <it>Shigella flexneri </it>to HEp-2 cells were assessed as a measure of its effect on colonization. The effect of the decoction on production of <it>E. coli </it>heat labile toxin (LT) and cholera toxin (CT) and their binding to ganglioside monosialic acid receptor (GM1) were assessed by GM1-enzyme linked immuno sorbent assay whereas its effect on production and action of <it>E. coli </it>heat stable toxin (ST) was assessed by suckling mouse assay.</p> <p>Results</p> <p>The decoction showed cidal activity against <it>Giardia </it>and rotavirus whereas viability of none of the six bacterial strains tested was affected. It significantly reduced bacterial adherence to and invasion of HEp-2 cells. The extract also affected production of CT and binding of both LT and CT to GM1. However, it had no effect on ST.</p> <p>Conclusion</p> <p>The decoction of the unripe fruit pulp of <it>A. marmelos</it>, despite having limited antimicrobial activity, affected the bacterial colonization to gut epithelium and production and action of certain enterotoxins. These observations suggest the varied possible modes of action of <it>A. marmelos </it>in infectious forms of diarrhoea thereby validating its mention in the ancient Indian texts and continued use by local communities for the treatment of diarrhoeal diseases.</p

Botany, chemistry, and pharmaceutical significance of Sida cordifolia: a traditional medicinal plant

Sida cordifolia Linn. belonging to the family, Malvaceae has been widely employed in traditional medications in many parts of the world including India, Brazil, and other Asian and African countries. The plant is extensively used in the Ayurvedic medicine preparation. There are more than 200 plant species within the genus Sida, which are distributed predominantly in the tropical regions. The correct taxonomic identification is a major concern due to the fact that S. cordifolia looks morphologically similar with its related species. It possesses activity against various human ailments, including cancer, asthma, cough, diarrhea, malaria, gonorrhea, tuberculosis, obesity, ulcer, Parkinson’s disease, urinary infections, and many others. The medical importance of this plant is mainly correlated to the occurrence of diverse biologically active phytochemical compounds such as alkaloids, flavonoids, and steroids. The major compounds include β-phenylamines, 2-carboxylated tryptamines, quinazoline, quinoline, indole, ephedrine, vasicinone, 5-3-isoprenyl flavone, 5,7-dihydroxy-3-isoprenyl flavone, and 6-(isoprenyl)- 3-methoxy- 8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl[1–4]-α-D-glucoside. The literature survey reveals that most of the pharmacological investigations on S. cordifolia are limited to crude plant extracts and few isolated pure compounds. Therefore, there is a need to evaluate many other unexplored bioactive phytoconstituents with evidences so as to justify the traditional usages of S. cordifolia. Furthermore, detailed studies on the action of mechanisms of these isolated compounds supported by clinical research are necessary for validating their application in contemporary medicines. The aim of the present chapter is to provide a detailed information on the ethnobotanical, phytochemical, and pharmacological aspects of S. cordifolia

Transport of multiple Escherichia coli strains in saturated porous media

The deviation of bacteria transport and deposition patterns on grains in porous media from theory has resulted in the inability to accurately predict transport distances in aquifers, with consequences of polluting drinking water sources (springs, boreholes and wells). Due to the importance of Escherichia coli (E. coli) as an indicator of faecal contamination of drinking water supplies, this thesis research focused on their transport in saturated porous media. The objectives were to (i) study inter-strain and intra-strain attachment variability among multiple E. coli strains, (ii) characterize the distribution of sticking efficiencies within cell populations (iii) develop a methodology to measure minimum values of sticking efficiencies, and (iv) to assess the contribution of various cell properties on bacterial attachment to quartz grains. Most of this research was carried out under laboratory conditions (e.g. column and batch experiments), but a part of this work focused on the transport characteristics of E. coli strains isolated at the termination point of groundwater flow lines (springs) in Kampala, Uganda. The underlying hypothesis was that transport by a group of E. coli strains could possibly be characterized by a similar set of transport parameters. Transport of E. coli strains isolated from different sources of the environment was studied using saturated quartz columns. Short (7 cm) and long (1.5 - 25 m) columns were used to investigate inter-strain attachment variations among E. coli strains, distributions in attachment efficiency within E. coli strains and to develop a methodology to measure the minimum sticking efficiency. Furthermore, long column experiments were applied in order to be able to measure low sticking efficiency values. Prior to the experiments E. coli strains were cultured and their phenotypic characteristics and selected genes encoding structures at the outer membrane were measured to investigate their effects on transport/attachment. The results indicated that none of the studied cell characteristics significantly influenced E. coli attachment on sedimentary quartz grains; however, cell motility and antigen-43 expression promoted attachment to quartz grains over relatively short transport distances. For spring E. coli isolates from Kampala, a substantial percentage belonged to the same serotype (E. coli O21:H7). Therefore, we concluded that strains possessing this particular serotype may possess certain characteristics that promote their selective transport through the aquifers in the Kampala area in Uganda and might have determined an overall transport homogeneity observed for this particular group of E. coli isolates. With the exception of spring E. coli isolates which showed overall inter-strain transport homogeneity, results indicated that intra-strain and inter-strain attachment heterogeneities existed within and among the various E. coli strains, respectively. Environmentally relevant low values of sticking efficiencies were measured over long transport distances and thus demonstrated the importance of the use of long columns for this type of research. The measured low values of sticking efficiency indicated that, for bacterial populations leaked into groundwater environments, sub-populations may possess non-attaching characteristics and therefore increase their chances of being transported over considerable distances, that might be underestimated using common drinking water protection guidelines. Intra-strain attachment variability resulted in a power-law distribution between fraction of cells and their sticking efficiencies. Minimum sticking efficiency was extrapolated from the power-law distribution. The minimum sticking efficiency is defined as the sticking efficiency belonging to a bacteria fraction of 0.001% of initial bacteria mass flowing into a column, after removal of 99.999% (5 log reduction) of the original bacteria mass has taken place. Values extrapolated were lower than those measured from experiments; the low values make the minimum sticking efficiency a valuable tool in delineating well-head protection areas in real-world cases. Future research should focus on cell surface structures known to be involved in initial attachment to host tissues and/or abiotic surfaces. In addition, we advocate to carry out field bacteria transport experiments instead of laboratory experiments, since interpreting the results of the latter is limited by transport dependent scale issues.Water ManagementCivil Engineering and Geoscience

Transport of multiple Escherichia coli strains in saturated porous media; Dissertation, UNESCO-IHE Institute for Water Education, Delft.

Delineation of well-head protection areas, deep well injection of wastewater and pre-treatment of surface water by passage through sand to remove pathogenic microorganisms are based on the knowledge of microbial transport distances. Prediction of microbial transport distances are usually based on the sticking efficiency, a parameter in the classical colloid filtration theory, this parameter represents the interaction between colloid and collector surfaces resulting in deposition. According to the theory, the sticking efficiency is invariable when physico-chemical characteristics of aquifer media are homogeneous. However, many research results have indicated variations within and among bacterial strains. In this research, the transport of Escherichia Coli in saturated quartz columns were conducted in the laboratory. The objectives were to characterise the distribution of sticking efficiency, measure low sticking efficiency values of cells, and to develop a methodology to measure minimum values of sticking efficiencies within bacterial sub-populations. Also, the work assesses the effect of various phenotypic and genotypic characteristics of Escherichia coli on their attachment to quartz grains. Field work was conducted to assess the chemo-physical and bacteriological status of the springs in the Kampala area of Uganda. Furthermore, transport and cell characteristics of E. coli strains isolated from springs were studied