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D Coyne

Publications and source records attributed to D Coyne.

15 recordsLinked to original sources
PubMed2006

Iron indices: what do they really mean?

Routine monitoring of body iron stores is an essential component of overall management for the patient on hemodialysis. Adequate iron levels are important for the prevention and treatment of iron-deficiency anemia, which is associated with reduced physical functioning, cardiovascular disease, and poor quality of life. Hemodialysis patients are at especially high risk for iron-deficiency anemia, owing to continuous blood losses and supraphysiologic levels of erythropoiesis driven by recombinant human erythropoietin therapy. Unfortunately, the accurate determination of iron status in these patients can be a challenging task, which is made more difficult by inflammation, infections, and the large number of comorbid conditions that can affect commonly used indices of body iron stores. Despite their limitations, transferrin saturation (TSAT) and serum ferritin remain the cornerstones of iron status assessment. Because these values can be altered by a number of non-iron-related factors, it is necessary to go beyond these measures and draw upon additional sources of information to determine the patient's iron status. Other important factors to consider when assessing the need for iron therapy include evidence of underlying inflammatory processes that may block iron mobilization and distort the standard iron indices, the results of alternative iron indices, and the patient's recent history of iron administration. Frequently, the response to a gram of intravenous (i.v.) iron is a safe and effective way to determine the role of iron deficiency in the anemia of the problematic patient. The chronic inflammatory state associated with malnutrition and clinical or subclinical infections substantially increases the risk of misdiagnosing the patient with iron overload and may place the patient at risk of iron deficiency owing to inappropriate withdrawal of i.v. iron therapy. To avoid the risks of withholding iron therapy, the nephrologist must keep this relationship in mind whenever serum ferritin testing suggests replete iron stores, whereas TSAT testing suggests insufficient iron availability.

Anemia, Iron-Deficiency↗
PubMed2005

Upper limits on a stochastic background of gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.

Journal Article↗
PubMed2005

Limits on gravitational-wave emission from selected pulsars using LIGO data.

We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10(-24). These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10(-5) for the four closest pulsars.

Journal Article↗
PubMed1989

Peptide hormones, cytosolic calcium and renal epithelial response.

We have reviewed the evidence that a number of hormones interact with renal tubular epithelial cells. The evidence suggests that in the mammalian renal tubule bradykinin and parathyroid hormone interact with cell surface receptors to initiate the hydrolysis of PIP2 leading to the formation of I 1,4,5P3 and diacylglycerol in the distal and proximal tubule, respectively. The activation of this second messenger system leads to the mobilization of Ca2+ from intracellular stores. Vasopressin does not activate this second messenger system in mammalian renal epithelial cells, and we cannot demonstrate I 1,4,5P3 formation and Ca2+ mobilization either in the rabbit papillary collecting tubules or in MDCK cells. There is evidence emerging, but not discussed here, that angiotensin II may also mediate some of its effects on the mammalian proximal tubule via the inositol polyphosphate second messenger system.

Animals↗