2,195 research outputs found
Economic Evaluation of Newborn Screening for Severe Combined Immunodeficiency
Evidence on the cost-effectiveness of newborn screening (NBS) for severe combined immunodeficiency (SCID) in the Australian policy context is lacking. In this study, a pilot population-based screening program in Australia was used to model the cost-effectiveness of NBS for SCID from the government perspective. Markov cohort simulations were nested within a decision analytic model to compare the costs and quality-adjusted life-years (QALYs) over a time horizon of 5 and 60 years for two strategies: (1) NBS for SCID and treat with early hematopoietic stem cell transplantation (HSCT); (2) no NBS for SCID and treat with late HSCT. Incremental costs were compared to incremental QALYs to calculate the incremental cost-effectiveness ratios (ICER). Sensitivity analyses were performed to assess the model uncertainty and identify key parameters impacting on the ICER. In the long-term over 60 years, universal NBS for SCID would gain 10 QALYs at a cost of US 33,600/QALY. Probabilistic sensitivity analysis showed that more than half of the simulated ICERs were considered cost-effective against the common willingness-to-pay threshold of A35,000/QALY). In the Australian context, screening for SCID should be introduced into the current NBS program from both clinical and economic perspectives
Effective repair of articular cartilage using human pluripotent stem cell-derived tissue
In an effort to develop an effective source of clinically relevant cells and tissues for cartilage repair a directed
differentiation method was used to generate articular chondrocytes and cartilage tissues from human
embryonic stem cells (hESCs). It has previously been demonstrated that chondrocytes derived from hESCs
retain a stable cartilage-forming phenotype following subcutaneous implantation in mice. In this report, the
potential of hESC-derived articular-like cartilage to repair osteochondral defects created in the rat trochlea
was evaluated. Articular cartilage-like tissues were generated from hESCs and implanted into the defects.
After 6 and 12 weeks, the defects were evaluated histologically and immunohistochemically, and the quality
of repair was assessed using a modified ICRS II scoring system. Following 6 and 12 weeks after implantation,
hESC-derived cartilage tissues maintained their proteoglycan and type II collagen-rich matrix and scored
significantly higher than control defects, which had been filled with fibrin glue alone. Implants were found
to be well integrated with native host tissue at the basal and lateral surfaces, although implanted human
cells and host cells remained regionally separated. A subset of implants underwent a process of remodeling
similar to endochondral ossification, suggesting the potential for a single cartilaginous implant to promote
the generation of new subchondral bone in addition to repair of the articular cartilage. The ability to create
cartilage tissues with integrative and reparative properties from an unlimited and robust cell source represents
a significant advance for cartilage repair that can be further developed in large animal models before clinicalsetting application
External sources of clean technology: evidence from the clean development mechanism
New technology is fundamental to sustainable development. However, inventors from industrialized countries often refuse technology transfer because they worry about reverse-engineering. When can clean technology transfer succeed? We develop a formal model of the political economy of North–South technology transfer. According to the model, technology transfer is possible if (1) the technology in focus has limited global commercial potential or (2) the host developing country does not have the capacity to absorb new technologies for commercial use. If both conditions fail, inventors from industrialized countries worry about the adverse competitiveness effects of reverse-engineering, so technology transfer fails. Data analysis of technology transfer in 4,894 projects implemented under the Kyoto Protocol’s Clean Development Mechanism during the 2004–2010 period provides evidence in support of the model
Sensory Measurements: Coordination and Standardization
Do sensory measurements deserve the label of “measurement”? We argue that they do. They fit with an epistemological view of measurement held in current philosophy of science, and they face the same kinds of epistemological challenges as physical measurements do: the problem of coordination and the problem of standardization. These problems are addressed through the process of “epistemic iteration,” for all measurements. We also argue for distinguishing the problem of standardization from the problem of coordination. To exemplify our claims, we draw on olfactory performance tests, especially studies linking olfactory decline to neurodegenerative disorders
Change and Aging Senescence as an adaptation
Understanding why we age is a long-lived open problem in evolutionary
biology. Aging is prejudicial to the individual and evolutionary forces should
prevent it, but many species show signs of senescence as individuals age. Here,
I will propose a model for aging based on assumptions that are compatible with
evolutionary theory: i) competition is between individuals; ii) there is some
degree of locality, so quite often competition will between parents and their
progeny; iii) optimal conditions are not stationary, mutation helps each
species to keep competitive. When conditions change, a senescent species can
drive immortal competitors to extinction. This counter-intuitive result arises
from the pruning caused by the death of elder individuals. When there is change
and mutation, each generation is slightly better adapted to the new conditions,
but some older individuals survive by random chance. Senescence can eliminate
those from the genetic pool. Even though individual selection forces always win
over group selection ones, it is not exactly the individual that is selected,
but its lineage. While senescence damages the individuals and has an
evolutionary cost, it has a benefit of its own. It allows each lineage to adapt
faster to changing conditions. We age because the world changes.Comment: 19 pages, 4 figure
Dimensionality and dynamics in the behavior of C. elegans
A major challenge in analyzing animal behavior is to discover some underlying
simplicity in complex motor actions. Here we show that the space of shapes
adopted by the nematode C. elegans is surprisingly low dimensional, with just
four dimensions accounting for 95% of the shape variance, and we partially
reconstruct "equations of motion" for the dynamics in this space. These
dynamics have multiple attractors, and we find that the worm visits these in a
rapid and almost completely deterministic response to weak thermal stimuli.
Stimulus-dependent correlations among the different modes suggest that one can
generate more reliable behaviors by synchronizing stimuli to the state of the
worm in shape space. We confirm this prediction, effectively "steering" the
worm in real time.Comment: 9 pages, 6 figures, minor correction
Escherichia coli induces apoptosis and proliferation of mammary cells
Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation
Life-threatening hypersensitivity pneumonitis induced by docetaxel (taxotere)
4 patients with advanced non-small-cell lung cancer (NSCLC) treated with docetaxel developed life-threatening pneumonitis requiring mechanical ventilation. Docetaxel (30–60 mg m−2, according to a different protocol) was infused within one hour with standard premedications. One patient's pneumonitis occurred 5 days after the first dose of docetaxel, and that of the other 3 between the 2nd and 6th cycles. Based on the clinical course, radiological findings of an interstitial pneumonitis, and exclusion of other possible resultant causes, including metastatic cancer, radiation pulmonary injury, infection, or connective tissue disease, hypersensitivity pneumonitis was diagnosed. The patients were treated with hydrocortisone at 1200 mg per day or methylprednisolone at 240 mg per day. Although 3 of the 4 had a partial improvement in lung oxygenation, all patients’ conditions of hypersensitivity pneumonitis persisted and were complicated by other events, such as hospital-acquired infection and tension pneumothorax. The presence of this unusual hypersensitivity pneumonitis, which was so severe as to be life-threatening and refractory to high-dose corticosteroid therapy, should be taken into account during docetaxel treatment. © 2001 Cancer Research Campaig
Degeneracy: a link between evolvability, robustness and complexity in biological systems
A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability) and evidence of an intimate relationship between robustness and complexity in biology.
This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability
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