Determination of iron sucrose (Venofer) or iron dextran (DexFerrum) removal by hemodialysis: an in-vitro study

BACKGROUND: Intravenous iron is typically administered during the hemodialysis (HD) procedure. HD patients may be prescribed high-flux (HF) or high-efficiency (HE) dialysis membranes. The extent of iron sucrose and iron dextran removal by HD using HF or HE membranes and by ultrafiltration rate (UFR) is unknown. METHODS: Two in vitro HD systems were designed and constructed to determine the dialyzabiltiy of iron from a simulated blood system (SBS) containing 100 mg iron sucrose or iron dextran (system A) or 1000 mg iron sucrose (system B). Both in vitro systems utilized a 6-L closed-loop SBS system that was subject to 4 different HD conditions conducted over 4 hours: HE membrane + 0 ml/hr UFR; HE membrane + 500 ml/hr UFR; HF membrane + 0 ml/hr UFR; HF membrane + 500 ml/hr UFR. Blood flow and dialysate flow rates were 500 ml/min and 800 ml/min, respectively. The dialysate compartment was a 192-L open system for system A and a 6-L closed-loop system for system B. Samples from the SBS and dialysate compartments were taken at various time points and iron elimination rate and HD clearance was determined. Iron removal from the SBS > 15% was considered clinically significant. RESULTS: The greatest percentage removal from the SBS was 13.5% and -0.03% utilizing system A and B, respectively. Iron sucrose and iron dextran dialysate concentration was below the lower limits of assay (< 2 ppm) for system A. Dialysate recovery of iron was negligible: 0 – 5.4 mg system A and 5.47 – 23.59 mg for system B. Dialyzer type or UFR did not affect iron removal. CONCLUSION: HF or HE dialysis membranes do not remove clinically significant amounts of iron sucrose or dextran formulations over a 4-hour HD session. This effect remained constant even controlling for UFR up to 500 ml/hour. Therefore, iron sucrose and iron dextran are not dialyzed by HE or HF dialysis membranes irrespective of UFR

Microstructural strain energy of α-uranium determined by calorimetry and neutron diffractometry

The microstructural contribution to the heat capacity of α-uranium was determined by measuring the heat-capacity difference between polycrystalline and single-crystal samples from 77 to 320 K. When cooled to 77 K and then heated to about 280 K, the uranium microstructure released (3±1) J/mol of strain energy. On further heating to 300 K, the microstructure absorbed energy as it began to redevelop microstrains. Anisotropic strain-broadening parameters were extracted from neutron-diffraction measurements on polycrystals. Combining the strain-broadening parameters with anisotropic elastic constants from the literature, the microstructural strain energy is predicted in the two limiting cases of statistically isotropic stress and statistically isotropic strain. The result calculated in the limit of statistically isotropic stress was (3.7±0.5) J/mol K at 77 K and (1±0.5) J/mol at room temperature. In the limit of statistically isotropic strain, the values were (7.8±0.5) J/mol K at 77 K and (4.5±0.5) J/mol at room temperature. In both cases the changes in the microstructural strain energy showed good agreement with the calorimetry

Large harmonic softening of the phonon density of states of uranium

Phonon density-of-states curves were obtained from inelastic neutron scattering spectra from the three crystalline phases of uranium at temperatures from 50 to 1213 K. The alpha -phase showed an unusually large thermal softening of phonon frequencies. Analysis of the vibrational power spectrum showed that this phonon softening originates with the softening of a harmonic solid, as opposed to vibrations in anharmonic potentials. It follows that thermal excitations of electronic states are more significant thermodynamically than are the classical volume effects. For the alpha-beta and beta-gamma phase transitions, vibrational and electronic entropies were comparable

The benefits of organic farming for biodiversity

Previous studies suggest widespread positive responses of biodiversity to organic farming. Many of these studies, however, have been small-scale. This project tested the generality of habitat and biodiversity differences between matched pairs of organic and non-organic farms containing cereal crops in lowland England on a large-scale across a range of taxa including plants, insects, birds and bats. The extent of both cropped and un-cropped habitats together with their composition and management on a range of scales were also compared. Organic farms was likely to favour higher levels of biodiversity and indeed organic farms tended to support higher numbers of species and overall abundance across most taxa. However, the magnitude of the response differed strikingly; plants showed stronger and more consistent responses than other taxa. Some, but not all, differences in biodiversity between systems appear to be a consequence of differences in habitat quantity

Intrinsic Localized Modes Observed in the High Temperature Vibrational Spectrum of NaI

Inelastic neutron measurements of the high-temperature lattice excitations in NaI show that in thermal equilibrium at 555 K an intrinsic mode, localized in three dimensions, occurs at a single frequency near the center of the spectral phonon gap, polarized along [111]. At higher temperatures the intrinsic localized mode gains intensity. Higher energy inelastic neutron and x-ray scattering measurements on a room-temperature NaI crystal indicate that the creation energy of the ground state of the intrinsic localized mode is 299 meV.Comment: 17 pages, 5 figures Revised version; final versio

Targeted in vivo extracellular matrix formation promotes neovascularization in a rodent model of myocardial infarction.

BackgroundThe extracellular matrix plays an important role in tissue regeneration. We investigated whether extracellular matrix protein fragments could be targeted with antibodies to ischemically injured myocardium to promote angiogenesis and myocardial repair.Methodology/principal findingsFour peptides, 2 derived from fibronectin and 2 derived from Type IV Collagen, were assessed for in vitro and in vivo tendencies for angiogenesis. Three of the four peptides--Hep I, Hep III, RGD--were identified and shown to increase endothelial cell attachment, proliferation, migration and cell activation in vitro. By chemically conjugating these peptides to an anti-myosin heavy chain antibody, the peptides could be administered intravenously and specifically targeted to the site of the myocardial infarction. When administered into Sprague-Dawley rats that underwent ischemia-reperfusion myocardial infarction, these peptides produced statistically significantly higher levels of angiogenesis and arteriogenesis 6 weeks post treatment.Conclusions/significanceWe demonstrated that antibody-targeted ECM-derived peptides alone can be used to sufficiently alter the extracellular matrix microenvironment to induce a dramatic angiogenic response in the myocardial infarct area. Our results indicate a potentially new non-invasive strategy for repairing damaged tissue, as well as a novel tool for investigating in vivo cell biology