848 resultados para Developmental toxicity


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This paper attempts to situate and deconstruct the meanings associated with the term development in the context of the developing world. The arguments made highlights the deeply contested and fragmented terrain of development. The paper provides a historical overview of the changing nature of discourses on development, how the imageries of development have shifted since the postwar period. It deploys diverse meanings associated with development as a concept and as a theory. Thus development without dignity means little for those living in the margins of the society. At the same time the language of development has undergone revolutions and convulsions and the role of buzzwords and catch phrases have only helped to prolong misery in a neoliberal world. Development has become a 'one size fits all' concept shorn of cultural and regional specificities. It has been decontextualised and dehumanised to relate to targets
resulting in greater dissonance than resolution of aim and outcomes. The way forward is a better appreciation of the cultural capacity of the social groups for whom development is critical for survival. The conclusion highlights the endemic contradictions inherent in the meaning and delivery of development as a goal, especially when we seek to achieve resilient and sustainable development.

Keywords: Development, Neoliberalism, growth, participation, empowerment,
efficiency, market, state, societies, entitlements and capabilities, stakeholder, rights, structural adjustments, globalisation, self-help, doing development, freedom and
unfreedom.

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OBJECTIVE: The antitumor effects of FK506-binding protein like (FKBPL) and its extracellular role in angiogenesis are well characterized; however, its role in physiological/developmental angiogenesis and the effect of FKBPL ablation has not been evaluated. This is important as effects of some angiogenic proteins are dosage dependent. Here we evaluate the regulation of FKBPL secretion under angiogenic stimuli, as well as the effect of FKBPL ablation in angiogenesis using mouse and zebrafish models.

APPROACH AND RESULTS: FKBPL is secreted maximally by human microvascular endothelial cells and fibroblasts, and this was specifically downregulated by proangiogenic hypoxic signals, but not by the angiogenic cytokines, VEGF or IL8. FKBPL's critical role in angiogenesis was supported by our inability to generate an Fkbpl knockout mouse, with embryonic lethality occurring before E8.5. However, whilst Fkbpl heterozygotic embryos showed some vasculature irregularities, the mice developed normally. In murine angiogenesis models, including the ex vivo aortic ring assay, in vivo sponge assay, and tumor growth assay, Fkbpl(+/-) mice exhibited increased sprouting, enhanced vessel recruitment, and faster tumor growth, respectively, supporting the antiangiogenic function of FKBPL. In zebrafish, knockdown of zFkbpl using morpholinos disrupted the vasculature, and the phenotype was rescued with hFKBPL. Interestingly, this vessel disruption was ineffective when zcd44 was knocked-down, supporting the dependency of zFkbpl on zCd44 in zebrafish.

CONCLUSIONS: FKBPL is an important regulator of angiogenesis, having an essential role in murine and zebrafish blood vessel development. Mouse models of angiogenesis demonstrated a proangiogenic phenotype in Fkbpl heterozygotes.

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Cyanobacterial toxins present in drinking water sources pose a considerable threat to human health. Conventional water treatment systems have proven unreliable for the removal of these toxins and hence new techniques have been investigated. Previous work has shown that TiO2 photocatalysis effectively destroys microcystin-LR in aqueous solutions, however, a variety of by-products were generated. In this paper, we report a mechanistic study of the photocatalytic destruction of microcystin-LR. In particular, the toxicity by-products of the process have been studied using both brine shrimp and protein phosphatase bioassays. 

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AIMS: To determine the incidence and predictive factors of rib fracture and chest wall pain after lung stereotactic ablative radiotherapy (SABR).

MATERIALS AND METHODS: Patients were treated with lung SABR of 48-60 Gy in four to five fractions. The treatment plan and follow-up computed tomography scans of 289 tumours in 239 patients were reviewed. Dose-volume histogram (DVH) metrics and clinical factors were evaluated as potential predictors of chest wall toxicity.

RESULTS: The median follow-up was 21.0 months (range 6.2-52.1). Seventeen per cent (50/289) developed a rib fracture, 44% (22/50) were symptomatic; the median time to fracture was 16.4 months. On univariate analysis, female gender, osteoporosis, tumours adjacent (within 5 mm) to the chest wall and all of the chest wall DVH metrics predicted for rib fracture, but only tumour location adjacent to the chest wall remained significant on the multivariate model (P < 0.01). The 2 year fracture-free probability for those adjacent to the chest wall was 65.6%. Among those tumours adjacent to the chest wall, only osteoporosis (P = 0.02) predicted for fracture, whereas none of the chest wall DVH metrics were predictive. Eight per cent (24/289) experienced chest wall pain without fracture.

CONCLUSIONS: None of the chest wall DVH metrics independently predicted for SABR-induced rib fracture when tumour location is taken into account. Patients with tumours adjacent (within 5 mm) to the chest wall are at greater risk of rib fracture after lung SABR, and among these, an additional risk was observed in osteoporotic patients.

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Kenyan tannery and associated environmental samples were selected for ecotoxicological assessment. A tool-kit of techniques was developed, including whole-cell biosensor and chemical assays. A luminescence based bacterial biosensor (Escherichia coli HB101 pUCD607) (via a multi-copy plasmid) was used for toxicity assessment. Samples were manipulated prior to biosensor interrogation to identify the nature of the toxic contaminants. Untreated samples (before any manipulations) showed a strong toxic effect at the discharge point in comparison to other sampling points. Sparging was used to identify toxicity associated with volatile organics. The toxicity of contaminants, removed by treatment with activated charcoal was identified for all the sampling points except for those upstream of effluent discharges. Filtration identified toxicity associated with suspended solids. Changes in availability of toxic contaminants due to pH adjustment of most samples from the tannery effluent treatment pits were also associated with the extreme pH values (4.0 and 8.0). The approach used has highlighted the complexicity of toxic pollutants in effluent from the tanning industry and the dissection of toxicity points to possible remediation strategies for effluents from the tanning industry.

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Elevated soil arsenic levels resulting from long-term use of arsenic contaminated ground for irrigation in Bangladesh may inhibit seed germination and seedling establishment of rice, the country's main food crop. A germination study on rice seeds and a short-term toxicity experiment with different concentrations of arsenite and arsenate on rice seedlings were conducted. Percent germination over control decreased significantly with increasing concentrations of arsenite and arsenate. Arsenite was found to be more toxic than arsenate for rice seed germination. There were varietal differences among the test varieties in response to arsenite and arsenate exposure. The performance of the dry season variety Purbachi was the best among the varieties. Germination of Purbachi was not inhibited at all up to 4 mg l-1 arsenite and 8 mg l-1 arsenate treatment. Root tolerance index (RTI) and relative shoot height (RSH) for rice seedlings decreased with increasing concentrations of arsenite and arsenate. Reduction of RTI caused by arsenate was higher than that of arsenite. In general, dry season varieties have more tolerance to arsenite or arsenate than the wet season varieties.

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Bioluminescence-based, solid-contact toxicity assays allow test bacterium and toxicant to interact at the solid-solution interface. A lux- marked bacterium, Burkholderia sp. RASC, and 2,4-dichlorophenol (2,4-DCP) were used to characterize these interactions. In the basic bioassay, cells were added to soil slurries containing 2,4-DCP (0-120 μg ml-1). After 15 min, soil was removed by centrifugation, and bioluminescence in the supernatant was determined. Investigation of 2,4-DCP adsorption to soil revealed that sorption was linear and not significantly (p > 0.1) affected by the presence of Burkholderia cells. The numbers of culturable Burkholderia cells in the assay supernatant were 48.2 to 64.8% of the inoculum and independent of the soil weight. The effect of soil on 2,4-DCP toxicity was investigated by comparing soil aqueous extract and contact assays. The percentage bioluminescence for the contact assay was consistently higher than the extract assay at all test concentrations, and counts of viable Burkholderia cells were enhanced by the presence of 2,4-DCP in the contact assay. Expressing results as specific bioluminescence decreased the variability in response and the discrepancy in results between the two protocols. We suggest that solid-contact assays need improvement to ensure defined contact between cells and solid phase, and that the reporting of specific activity should be emphasized.