Overuse of non-prescription analgesics by dental clinic patients

<p>Abstract</p> <p>Background</p> <p>Many patients present to dental clinics for treatment of painful conditions. Prior to seeking treatment, many of these patients will self-medicate with non-prescription analgesics (NPA), and some will unintentionally overdose on these products. The objective of this study is to describe the use of NPA among dental patients.</p> <p>Methods</p> <p>All adult patients presenting to an urban dental clinic during a two-week period in January and February of 2001 were approached to participate in this research project. Trained research assistants using a standardized questionnaire interviewed patients. Patient demographics and the NPA usage over the 3 days preceding the office visit were recorded. We defined a supra-therapeutic dose as any dose greater than the total recommended daily dose stated on package labeling.</p> <p>Results</p> <p>We approached 194 patients and 127 participated. The mean age of participants was 35.5 years, 52% were male. Analgesic use preceding the visit was reported by 99 of 127 patients, and most (81/99) used a NPA exclusively. Fifty-four percent of NPA users were taking more than one NPA. NPA users reported using ibuprofen (37%), acetaminophen (27%), acetaminophen/aspirin combination product (8%), naproxen (8%), and aspirin (4%). Sixteen patients reported supra-therapeutic use of one or more NPA (some ingested multiple products): ibuprofen (14), acetaminophen (3), and naproxen (5).</p> <p>Conclusion</p> <p>NPA use was common in patients presenting to a dental clinic. A significant minority of patients reported excessive dosing of NPA. Ibuprofen was the most frequently misused product, followed by naproxen and acetaminophen. Though mostly aware of the potential toxicity of NPA, many patients used supra-therapeutic dosages.</p

Polarization and Strong Infra-Red Activity in Compressed Solid Hydrogen

Under a pressure of ~150 GPa solid molecular hydrogen undergoes a phase transition accompanied by a dramatic rise in infra-red absorption in the vibron frequency range. We use the Berry's phase approach to calculate the electric polarization in several candidate structures finding large, anisotropic dynamic charges and strongly IR-active vibron modes. The polarization is shown to be greatly affected by the overlap between the molecules in the crystal, so that the commonly used Clausius-Mossotti description in terms of polarizable, non-overlapping molecular charge densities is inadequate already at low pressures and even more so for the compressed solid.Comment: To appear in Phys. Rev. Let

Wannier-function description of the electronic polarization and infrared absorption of high-pressure hydrogen

We have constructed maximally-localized Wannier functions for prototype structures of solid molecular hydrogen under pressure, starting from LDA and tight-binding Bloch wave functions. Each occupied Wannier function can be associated with two paired protons, defining a ``Wannier molecule''. The sum of the dipole moments of these ``molecules'' always gives the correct macroscopic polarization, even under strong compression, when the overlap between nearby Wannier functions becomes significant. We find that at megabar pressures the contributions to the dipoles arising from the overlapping tails of the Wannier functions is very large. The strong vibron infrared absorption experimentally observed in phase III, above ~ 150 GPa, is analyzed in terms of the vibron-induced fluctuations of the Wannier dipoles. We decompose these fluctuations into ``static'' and ``dynamical'' contributions, and find that at such high densities the latter term, which increases much more steeply with pressure, is dominant.Comment: 17 pages, two-column style with 14 postscript figures embedded. Uses REVTEX and epsf macro

Genetic Control of Organ Shape and Tissue Polarity

A combination of experimental analysis and mathematical modelling shows how the genetic control of tissue polarity plays a fundamental role in the development and evolution of form

Generation of diverse biological forms through combinatorial interactions between tissue polarity and growth

A major problem in biology is to understand how complex tissue shapes may arise through growth. In many cases this process involves preferential growth along particular orientations raising the question of how these orientations are specified. One view is that orientations are specified through stresses in the tissue (axiality-based system). Another possibility is that orientations can be specified independently of stresses through molecular signalling (polarity-based system). The axiality-based system has recently been explored through computational modelling. Here we develop and apply a polarity-based system which we call the Growing Polarised Tissue (GPT) framework. Tissue is treated as a continuous material within which regionally expressed factors under genetic control may interact and propagate. Polarity is established by signals that propagate through the tissue and is anchored in regions termed tissue polarity organisers that are also under genetic control. Rates of growth parallel or perpendicular to the local polarity may then be specified through a regulatory network. The resulting growth depends on how specified growth patterns interact within the constraints of mechanically connected tissue. This constraint leads to the emergence of features such as curvature that were not directly specified by the regulatory networks. Resultant growth feeds back to influence spatial arrangements and local orientations of tissue, allowing complex shapes to emerge from simple rules. Moreover, asymmetries may emerge through interactions between polarity fields. We illustrate the value of the GPT-framework for understanding morphogenesis by applying it to a growing Snapdragon flower and indicate how the underlying hypotheses may be tested by computational simulation. We propose that combinatorial intractions between orientations and rates of growth, which are a key feature of polarity-based systems, have been exploited during evolution to generate a range of observed biological shapes