328 research outputs found
Ethical principles and recommendations for the medical management of differences of sex development (DSD)/intersex in children and adolescents
Cardiovascular Disease in Blacks with HIV/AIDS in the United States: A Systematic Review of the Literature
Employing the Metabolic “Branch Point Effect” to Generate an All-or-None, Digital-like Response in Enzymatic Outputs and Enzyme-Based Sensors
Here, we demonstrate a strategy to convert the
graded Michaelis−Menten response typical of unregulated
enzymes into a sharp, effectively all-or-none response. We do
so using an approach analogous to the “branch point effect”, a
mechanism observed in naturally occurring metabolic networks
in which two or more enzymes compete for the same
substrate. As a model system, we used the enzymatic reaction
of glucose oxidase (GOx) and coupled it to a second,
nonsignaling reaction catalyzed by the higher affinity enzyme
hexokinase (HK) such that, at low substrate concentrations,
the second enzyme outcompetes the first, turning off the
latter’s response. Above an arbitrarily selected “threshold” substrate concentration, the nonsignaling HK enzyme saturates leading
to a “sudden” activation of the first signaling GOx enzyme and a far steeper dose−response curve than that observed for simple
Michaelis−Menten kinetics. Using the well-known GOx-based amperometric glucose sensor to validate our strategy, we have
steepen the normally graded response of this enzymatic sensor into a discrete yes/no output similar to that of a multimeric
cooperative enzyme with a Hill coefficient above 13. We have also shown that, by controlling the HK reaction we can precisely
tune the threshold target concentration at which we observe the enzyme output. Finally, we demonstrate the utility of this
strategy for achieving effective noise attenuation in enzyme logic gates. In addition to supporting the development of biosensors
with digital-like output, we envisage that the use of all-or-none enzymatic responses will also improve our ability to engineer
efficient enzyme-based catalysis reactions in synthetic biology applications
Branchial cleft anomalies: a pictorial review of embryological development and spectrum of imaging findings
ER sliding dynamics and ER–mitochondrial contacts occur on acetylated microtubules
Movement of the ER and mitochondria is coupled by limited interactions of the ER with a subset of posttranslationally modified microtubules
Side effects associated with the use of dexamethasone for prophylaxis of delayed emesis after moderately emetogenic chemotherapy
The role of dexamethasone to reduce delayed emesis following highly emetogenic chemotherapy is proven, but there is less evidence of benefit after mild–moderately emetogenic regimens. Here, we develop and evaluate a Dexamethasone Symptom Questionnaire (DSQ) to assess the side effects of dexamethasone in the week after patients receive moderately emetogenic chemotherapy. The DSQ was first optimised with the aid of a focus group. Sixty patients receiving oral dexamethasone for prophylaxis of delayed emesis after moderately emetogenic chemotherapy for cancer completed and then evaluated the DSQ. Patients reported that the DSQ was clearly worded and addressed items important to them. Patients receiving dexamethasone reported moderate–severe problems with insomnia (45%), indigestion/epigastric discomfort (27%), agitation (27%), increased appetite (19%), weight gain (16%) and acne (15%) in the week following chemotherapy. The side effects of dexamethasone may outweigh its benefits when used with moderately emetogenic chemotherapy. A randomised, double-blind crossover trial is underway to determine the effect of dexamethasone on nausea and vomiting, and the impact of side effects of dexamethasone and of nausea and vomiting on quality of life
The Mediterranean Sea Regime Shift at the End of the 1980s, and Intriguing Parallelisms with Other European Basins
Background: Regime shifts are abrupt changes encompassing a multitude of physical properties and ecosystem variables,
which lead to new regime conditions. Recent investigations focus on the changes in ecosystem diversity and functioning
associated to such shifts. Of particular interest, because of the implication on climate drivers, are shifts that occur
synchronously in separated basins.
Principal Findings: In this work we analyze and review long-term records of Mediterranean ecological and hydro-climate variables and find that all point to a synchronous change in the late 1980s. A quantitative synthesis of the literature (including observed oceanic data, models and satellite analyses) shows that these years mark a major change in Mediterranean hydrographic properties, surface circulation, and deep water convection (the Eastern Mediterranean Transient). We provide novel analyses that link local, regional and basin scale hydrological properties with two major indicators of large scale climate, the North Atlantic Oscillation index and the Northern Hemisphere Temperature index, suggesting that the Mediterranean shift is part of a large scale change in the Northern Hemisphere. We provide a simplified scheme of the different effects of climate vs. temperature on pelagic ecosystems.
Conclusions: Our results show that the Mediterranean Sea underwent a major change at the end of the 1980s that
encompassed atmospheric, hydrological, and ecological systems, for which it can be considered a regime shift. We further provide evidence that the local hydrography is linked to the larger scale, northern hemisphere climate. These results suggest that the shifts that affected the North, Baltic, Black and Mediterranean (this work) Seas at the end of the 1980s, that have been so far only partly associated, are likely linked as part a northern hemisphere change. These findings bear wide implications for the development of climate change scenarios, as synchronous shifts may provide the key for distinguishing local (i.e., basin) anthropogenic drivers, such as eutrophication or fishing, from larger scale (hemispheric) climate drivers
LmABCB3, an atypical mitochondrial ABC transporter essential for Leishmania major virulence, acts in heme and cytosolic iron/sulfur clusters biogenesis
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