10,930 research outputs found
Influx of Ca2+ into isolated secretory vesicles from adrenal medulla Influence of external K+ and Na+
Secretory vesic1es from adrenal medulla contain
catecholamines, nuc1eotides and proteins, all of which
are released into the extracellular fluid during exocytosis.
Adrenal medullary secretory vesic1es also contain
high concentrations of Ca'+ [1]. The mechanism
of the aecumulation of Ca 2+ into the vesicles is largely
unknown and the experimental data eoncerning the
uptake of Ca'+ into isolated secretory vesicles are
contradictory. It has been reported that secretory
vesicle membranes are impermeable to Ca'+ [2], that
secretory vesicles take up Ca 2+ independently of ATP
[3] and that they possess an ATP-stimulated uptake
system [4,5].
In earlier work relatively impure and unstable
seeretory vesicle fractions were used for the determination
of Ca 2+ -uptake. We have developed a method
to isolate highly purified and stable secretory vesicles
from bovine medulla [6]. With these vesic1es we
repeated earlier Ca'+ -uptake experiments and found
that:
(i) The vesic1es take up <sCa2+ in K+-containingmedia;
(ü) 4SCa2+ uptake is abolished in the presence ofNa+;
(üi) nie Ca 2+ content of isolated secretory vesic1es is
increased when incubated with Ca 2+ in media
containing K+, but not in media containing Na +
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"What's Wrong With Plastic Trees?" or Rationales for the Preservation of Natural Environments
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PLANNING FOR AN AFFECT BASED SOCIETY: PREDICTION, INDICATORS, AND STRUCTURE
Theory, Locality, and Methodology in Archaeology: Just Add Water?
Continuing the work of the ‘Vienna Circle’, philosopher Carl Hempel created explanatory models to ground scientific inquiry in logic and empirical truth. Beginning with the physical sciences, he explored the application of these models to the social sciences as well. Terrestrial archaeologists incorporated Hempelian concepts by calling for global changes in archaeological methodology. These changes, explicitly designed to maximize data collection (a necessary first step to develop archaeological general laws crucial to Hempelian explanation and confirmation), were developed using particular idiosyncratic geographical cues that would undermine archaeology if implemented in other contexts. In this article, I argue that similarly unconscious artifacts of particular archaeologists’ goals and locations have also governed underwater archaeology’s growth as a discipline, much to its detriment. It is my hope that understanding the philosophical and archaeological issues that have led archaeology to this point will help to move archaeology (both land and sea) forward
Medical Apps: Public and Academic Perspectives
Medical apps have featured in popular websites and mainstream news media in recent months. However, there has been almost no mention of these tools in journals focusing on relevant ethical or social issues, including conflict of interest, the role of politics in science, and technological oversight.This essay examines the role that these philosophical issues might play in answering both public and academic questions about these pieces of emergent technology
When Are Medical Apps Medical? Off-Label Use and the Food and Drug Administration
People have a love/hate relationship with rapidly changing healthcare technology. While consumer demand for medical apps continues to grow as rapidly as does supply (there are over 100,000 health, wellness and medical applications, or ‘apps’ on the market), healthcare professionals and safety experts worry about the impact of these apps on the health consumer. In response to the rapidly growing mobile healthcare sector, the Food and Drug Administration has put forth guidelines to regulate ‘mobile medical apps’ (MMAs), those health-related apps that are (self) designated as medical devices. In this article, I argue that this decision, to only regulate apps that bill themselves as medical devices, will create a market for ‘off-label’ app use. Further, I will talk about the oft used analogy between off-label apps and off-label pharmaceuticals, showing that off-labeling apps will provide patients none of the benefits that come with a physician prescribing a drug off-label, while exposing the mobile healthcare consumer to significant risks that go significantly beyond those that we know of (and must accept) from prescription drugs. Recognizing that the Food and Drug Administration is not going to be able to significantly change its policies on oversight, I will suggest specific actions to at least mitigate some of the risks associated with off-label app use
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