26 research outputs found
Therapeutic Potential of Adipose-Derived Therapeutic Factor Concentrate for Treating Critical Limb Ischemia
Transplantation of adipose-derived stem cells (ADSCs) is an emerging therapeutic option for addressing intractable diseases such as critical limb ischemia (CLI). Evidence suggests that therapeutic effects of ADSCs are primarily mediated through paracrine mechanisms rather than transdifferentiation. These secreted factors can be captured in conditioned medium (CM) and concentrated to prepare a therapeutic factor concentrate (TFC) composed of a cocktail of beneficial growth factors and cytokines that individually and in combination demonstrate disease-modifying effects. The ability of a TFC to promote reperfusion in a rabbit model of CLI was evaluated. A total of 27 adult female rabbits underwent surgery to induce ischemia in the left hindlimb. An additional five rabbits served as sham controls. One week after surgery, the ischemic limbs received intramuscular injections of either (1) placebo (control medium), (2) a low dose of TFC, or (3) a high dose of TFC. Limb perfusion was serially assessed with a Doppler probe. Blood samples were analyzed for growth factors and cytokines. Tissue was harvested postmortem on day 35 and assessed for capillary density by immunohistochemistry. At 1 month after treatment, tissue perfusion in ischemic limbs treated with a high dose of TFC was almost double (p < 0.05) that of the placebo group [58.8 ± 23 relative perfusion units (RPU) vs. 30.7 ± 13.6 RPU; mean ± SD]. This effect was correlated with greater capillary density in the affected tissues and with transiently higher serum levels of the angiogenic and prosurvival factors vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). The conclusions from this study are that a single bolus administration of TFC demonstrated robust effects for promoting tissue reperfusion in a rabbit model of CLI and that a possible mechanism of revascularization was promotion of angiogenesis by TFC. Results of this study demonstrate that TFC represents a potent therapeutic cocktail for patients with CLI, many of whom are at risk for amputation of the affected limb
Cation binding to 15-TBA quadruplex DNA is a multiple-pathway cation-dependent process
A combination of explicit solvent molecular dynamics simulation (30 simulations reaching 4 µs in total), hybrid quantum mechanics/molecular mechanics approach and isothermal titration calorimetry was used to investigate the atomistic picture of ion binding to 15-mer thrombin-binding quadruplex DNA (G-DNA) aptamer. Binding of ions to G-DNA is complex multiple pathway process, which is strongly affected by the type of the cation. The individual ion-binding events are substantially modulated by the connecting loops of the aptamer, which play several roles. They stabilize the molecule during time periods when the bound ions are not present, they modulate the route of the ion into the stem and they also stabilize the internal ions by closing the gates through which the ions enter the quadruplex. Using our extensive simulations, we for the first time observed full spontaneous exchange of internal cation between quadruplex molecule and bulk solvent at atomistic resolution. The simulation suggests that expulsion of the internally bound ion is correlated with initial binding of the incoming ion. The incoming ion then readily replaces the bound ion while minimizing any destabilization of the solute molecule during the exchange
Managing uncertainty in flood protection planning with climate projections
Technical flood protection is a necessary part of integrated strategies to
protect riverine settlements from extreme floods. Many technical flood
protection measures, such as dikes and protection walls, are costly to adapt
after their initial construction. This poses a challenge to decision makers
as there is large uncertainty in how the required protection level will
change during the measure lifetime, which is typically many decades long.
Flood protection requirements should account for multiple future uncertain
factors: socioeconomic, e.g., whether the population and with it the damage
potential grows or falls; technological, e.g., possible advancements in flood
protection; and climatic, e.g., whether extreme discharge will become more
frequent or not. This paper focuses on climatic uncertainty. Specifically, we
devise methodology to account for uncertainty associated with the use of
discharge projections, ultimately leading to planning implications. For
planning purposes, we categorize uncertainties as either visible, if they
can be quantified from available catchment data, or hidden, if they
cannot be quantified from catchment data and must be estimated, e.g., from
the literature. It is vital to consider the hidden uncertainty, since in
practical applications only a limited amount of information (e.g., a finite
projection ensemble) is available. We use a Bayesian approach to quantify the
visible uncertainties and combine them with an estimate of the hidden
uncertainties to learn a joint probability distribution of the parameters of
extreme discharge. The methodology is integrated into an optimization
framework and applied to a pre-alpine case study to give a quantitative,
cost-optimal recommendation on the required amount of flood protection. The
results show that hidden uncertainty ought to be considered in planning, but
the larger the uncertainty already present, the smaller the impact of adding
more. The recommended planning is robust to moderate changes in uncertainty
as well as in trend. In contrast, planning without consideration of bias and
dependencies in and between uncertainty components leads to strongly
suboptimal planning recommendations
Risk-based flood protection planning under climate change and modeling uncertainty: a pre-alpine case study
Planning authorities are faced with a range of questions when planning flood
protection measures: is the existing protection adequate for current and
future demands or should it be extended? How will flood patterns change in
the future? How should the uncertainty pertaining to this influence the
planning decision, e.g., for delaying planning or including a safety margin?
Is it sufficient to follow a protection criterion (e.g., to protect from the
100-year flood) or should the planning be conducted in a risk-based way? How
important is it for flood protection planning to accurately estimate flood
frequency (changes), costs and damage? These are questions that we address
for a medium-sized pre-alpine catchment in southern Germany, using a
sequential Bayesian decision making framework that quantitatively addresses
the full spectrum of uncertainty. We evaluate different flood protection
systems considered by local agencies in a test study catchment. Despite
large uncertainties in damage, cost and climate, the recommendation is
robust for the most conservative approach. This demonstrates the feasibility
of making robust decisions under large uncertainty. Furthermore, by
comparison to a previous study, it highlights the benefits of risk-based
planning over the planning of flood protection to a prescribed return period