Reducing adverse impacts of Amazon hydropower expansion.

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth's largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multiobjective optimization to identify portfolios of sites that simultaneously minimize impacts on river flow, river connectivity, sediment transport, fish diversity, and greenhouse gas emissions while achieving energy production goals. We find that uncoordinated, dam-by-dam hydropower expansion has resulted in forgone ecosystem service benefits. Minimizing further damage from hydropower development requires considering diverse environmental impacts across the entire basin, as well as cooperation among Amazonian nations. Our findings offer a transferable model for the evaluation of hydropower expansion in transboundary basins.

Reducing greenhouse gas emissions of Amazon hydropower with strategic dam planning.

Hundreds of dams have been proposed throughout the Amazon basin, one of the world's largest untapped hydropower frontiers. While hydropower is a potentially clean source of renewable energy, some projects produce high greenhouse gas (GHG) emissions per unit electricity generated (carbon intensity). Here we show how carbon intensities of proposed Amazon upland dams (median = 39 kg CO2eq MWh-1, 100-year horizon) are often comparable with solar and wind energy, whereas some lowland dams (median = 133 kg CO2eq MWh-1) may exceed carbon intensities of fossil-fuel power plants. Based on 158 existing and 351 proposed dams, we present a multi-objective optimization framework showing that low-carbon expansion of Amazon hydropower relies on strategic planning, which is generally linked to placing dams in higher elevations and smaller streams. Ultimately, basin-scale dam planning that considers GHG emissions along with social and ecological externalities will be decisive for sustainable energy development where new hydropower is contemplated.

Protein and micronutrient deficiencies in patients with radiation cystitis and outcome after hyperbaric oxygen therapy.

BACKGROUND & AIMS: Haemorrhagic radiation cystitis (HRC) is a late complication of pelvic radiotherapy. Severe cases are difficult to treat due to persistent or recurrent bleeding, despite urological and hyperbaric oxygen therapy (HBOT). However, wound healing requires a good nutritional status. In this respect, we aimed at analysing the nutritional status of patients with HRC prior to the onset of HBOT and at highlighting predictive nutritional factors of outcome. METHODS: Data were retrospectively collected from a cohort of 179 patients with HRC (between 2011 and 2015). Haematuria was graded according to the Subjective, Objective, Management, Analytic scale (SOMA): grade-4 (n = 46) was compared with grade-3 (n = 56), and with grades 1 and 2 (n = 77). S-albumin, prealbumin, vitamins C, D and B6, zinc, selenium, and essential fatty acids were evaluated before HBOT. HBOT response was measured at 3 months according to the haematuria SOMA grade. The Mann-Whitney test, Fisher's exact test and principal-component analysis were used to compare groups. RESULTS: Patients with higher haematuria grades (3 and 4) harboured significant deficiencies in S-albumin, prealbumin, vitamins C, D and B6, zinc, selenium and essential fatty acids. Moreover, grade-4 patients without improvement after 3 months of HBOT had significant lower initial levels of S-albumin, vitamin C, selenium and linoleic acid. Vitamin C levels <2.5 mg/L were strongly associated with HBOT non-response (OR 23.14, 95% CI 3.73-143.69, p = 0.002). CONCLUSIONS: Our analyses show serious nutritional deficiencies associated with higher grades of HRC and worse prognoses. Patients with haemorrhagic cystitis might benefit from an adequate dietary supplementation to support healing of their bladder mucosa.

Api5 contributes to E2F1 control of the G1/S cell cycle phase transition.

BACKGROUND: The E2f transcription factor family has a pivotal role in controlling the cell fate in general, and in particular cancer development, by regulating the expression of several genes required for S phase entry and progression through the cell cycle. It has become clear that the transcriptional activation of at least one member of the family, E2F1, can also induce apoptosis. An appropriate balance of positive and negative regulators appears to be necessary to modulate E2F1 transcriptional activity, and thus cell fate. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we show that Api5, already known as a regulator of E2F1 induced-apoptosis, is required for the E2F1 transcriptional activation of G1/S transition genes, and consequently, for cell cycle progression and cell proliferation. Api5 appears to be a cell cycle regulated protein. Removal of Api5 reduces cyclin E, cyclin A, cyclin D1 and Cdk2 levels, causing G1 cell cycle arrest and cell cycle delay. Luciferase assays established that Api5 directly regulates the expression of several G1/S genes under E2F1 control. Using protein/protein and protein/DNA immunoprecipitation studies, we demonstrate that Api5, even if not physically interacting with E2F1, contributes positively to E2F1 transcriptional activity by increasing E2F1 binding to its target promoters, through an indirect mechanism. CONCLUSION/SIGNIFICANCE: The results described here support the pivotal role of cell cycle related proteins, that like E2F1, may act as tumor suppressors or as proto-oncogenes during cancer development, depending on the behavior of their positive and negative regulators. According to our findings, Api5 contributes to E2F1 transcriptional activation of cell cycle-associated genes by facilitating E2F1 recruitment onto its target promoters and thus E2F1 target gene transcription.

Aging-related decrease of human ASC angiogenic potential is reversed by hypoxia preconditioning through ROS production.

Adipose stroma/stem cells (ASC) represent an ideal source of autologous cells for cell-based therapy. Their transplantation enhances neovascularization after experimental ischemic injury. Aging is associated with a progressive decrease in the regenerative potential of mesenchymal stem cells (MSCs) from bone marrow. This work aims to determine the aging effect on human ASC capacities. First, we show that aging impairs angiogenic capacities of human ASC (hASC) in a mouse ischemic hindlimb model. Although no change in hASC number, phenotype, and proliferation was observed with aging, several mechanisms involved in the adverse effects of aging have been identified in vitro combining a concomitant decrease in (i) ASC ability to differentiate towards endothelial cells, (ii) secretion of proangiogenic and pro-survival factors, and (iii) oxidative stress. These effects were counteracted by a hypoxic preconditioning that improved in vivo angiogenic capacities of hASC from older donors, while hASC from young donors that have a strong ability to manage hypoxic stress were not. Finally, we identified reactive oxygen species (ROS) generation as a key signal of hypoxia on hASC angiogenic capacities. This study demonstrates for the first time that age of donor impaired angiogenic capacities of hASC in ischemic muscle and change in ROS generation by hypoxic preconditioning reverse the adverse effect of aging.