Effectiveness and cost of replacing a calcineurin inhibitor with sirolimus to slow the course of chronic kidney disease in renal allografts

Renal grafts suffer a progressive decrease in glomerular filtration rate (GFR) because of several factors including calcineurin inhibitor (CNI) nephrotoxicity. Switching CNIs to sirolimus may improve this adverse prognosis. We performed a prospective, open-label clinical trial among 18 kidney transplant patients with more than 12 months of evolution (range, 385-1826 days), showing progressive GFR decreases and biopsies with interstitial fibrosis and tubular atrophy (IFTA). Immunosuppressive treatment included cyclosporine, ketoconazole, and steroids associated with azathioprine or mycophenolate mofetil. After signing an Institutional Review Board-approved written consent, cyclosporine was switched to sirolimus seeking to achieve a trough blood sirolimus concentration of 6-15 ng/mL. Wilcoxon and Student's t-tests were used to compare the values in the annual periods before and after the switch. GFR was estimated by the Modification of Diet in Renal Disease formula. There were no acute rejection episodes. Estimated GFR on the day of the switch was 38.0 +/- 12.1 mL/min. After CNI switch, the slope of the estimated GFR significantly improved from -6.5 +/- 9.2 to 8.1 +/- 14.0 mL/min/year (P < .01). The estimated GFR 1 year after the switch was 47.2 +/- 16.9 mL/min (P = .003 vs baseline). Total expenditures increased. The ratio of post-switch versus baseline total expenditures was 1.93 (95% confidence interval, 1.54-2.31) and the ratio of sirolimus to CNI cost was 2.16 (95% confidence interval, 1.53-2.78). Switching from CNI to sirolimus for kidney transplants with decreasing GFR and a biopsy with IFTA changes, suggesting progressive graft nephropathy, almost doubled total expenses. It is necessary to conduct trials using clinical end points to definitively validate this therapeutic intervention.

Gold(III) biosorption and bioreduction with the brown alga Fucus vesiculosus

In this paper, the bioreduction of Au(III) to Au(0) using biomass of the brown alga Fucus vesiculosus was investigated. The recovery and reduction process took place in two stages with an optimum pH range of 4-9 with a maximum uptake obtained at pH 7. In the first stage, an induction period previous to gold reduction, the variation of pH, redox potential and gold concentration in solution was practically negligible and no color change was observed. In the second stage, the gold reduction was followed by a sharp decrease of gold concentration, pH and redox potential of solution and a color change from yellow to reddish purple. Hydroxyl groups present in the algal polysaccharides were involved in the gold bioreduction. Metallic gold was detected as microprecipitates on the biomass surface and in colloidal form as nanoparticles in the solution. Bioreduction with F. vesiculosus could be an alternative and environmentally friendly process that can be used for recovering gold from dilute hydrometallurgical solutions and leachates of electronic scraps, and for the synthesis of gold nanoparticles of different size and shape.

Umbilical cord transection in twin-reverse arterial perfusion syndrome with the use of a coaxial bipolar electrode (Versapoint®)

Umbilical-cord occlusion has been proposed for the treatment of twin-reverse arterial perfusion syndrome (TRAP). Transection of the umbilical cord is necessary in patients with monoamniotic or 'pseudomonoamniotic' TRAP to avoid subsequent cord entanglement and demise of the pump twin. We present a case of TRAP in which the umbilical cord was successfully ligated with suture and transected with the Versapoint electrode.

Nanoscopic surface inspection by analyzing the linear polarization degree of the scattered light

We present an optical method for the nanoscopic inspection of surfaces. The method is based on the spectral and polarization analysis of the light scattered by a probe nanoparticle close to the inspected surface. We explore the sensitivity to changes either in the probe-surface distance or in the refractive index of the surface.

Biosorption of cadmium, lead and copper with calcium alginate xerogels and immobilized Fucus vesiculosus

This paper determines the effect of immobilized brown alga Fucus vesiculosus in the biosorption of heavy metals with alginate xerogels. Immobilization increased the kinetic uptakes and intraparticle diffusion rates of the three metals. The Langmuir maximum biosorption capacity increased twofold for cadmium, 10 times for lead, and decreased by half for copper. According to this model, the affinity of the metals for the biomass was as follows: Cu>Pb>Cd without alga and Pb>Cu>Cd with alga. FITR confirmed that carboxyl groups were the main groups involved in the metal uptake. Calcium in the gels was displaced by heavy metals from solution according to the "egg-box" model. The restructured gel matrix became more uniform and organized as shown by scanning electron microscopy (SEM) characterization. F. vesiculosus immobilized in alginate xerogels constitutes an excellent biosorbent for cadmium, lead and copper, sometimes surpassing the biosorption performance of alginate alone and even the free alga.

Optimization of the continuous biosorption of copper with sugar-beet pectin gels

Sugar-beet pectin xerogels obtained from residues of the sugar industry are an adequate material for metal recovery from effluents in continuous systems. The xerogels were used as a biosorbent for copper removal in a fixed-bed column. The performance of the system was evaluated in different experimental conditions: flow rate, bed height, inlet metal concentration and feeding system (drop and reverse). The effect on the biosorption parameters (saturation time, amount of adsorbed and treated metal, column performance and metal uptake) and the shape of the breakthrough curves was determined. The saturation time increased with increasing bed height but decreased with increasing feed flow rate and inlet metal concentration. Preferential flow channels greatly influenced the metal uptake and column performance. Copper was completely desorbed with 0.1M HNO(3). Additionally, the column data fitted both the linear and nonlinear expressions of the Thomas model.

A child presenting with acute renal failure secondary to a high dose of indomethacin: a case report

Introduction

Acute renal failure caused by nonsteroidal anti-inflammatory drugs administered at therapeutic doses is generally mild, non-anuric and transitory. There are no publications on indomethacin toxicity secondary to high doses in children. The aim of this article is to describe acute renal failure secondary to a high dose of indomethacin in a child and to review an error in a supervised drug prescription and administration system.

Case presentation

Due to a medication error, a 20-day-old infant in the postoperative period of surgery for Fallot's tetralogy received a dose of 10 mg/kg of indomethacin, 50 to 100 times higher than the therapeutic dose. The child presented with acute, oligo-anuric renal failure requiring treatment with continuous venovenous renal replacement therapy, achieving complete recovery of renal function with no sequelae.

Conclusion

In order to reduce medication errors in critically ill children, it is necessary to develop a supervised drug prescription and administration system, with controls at various levels.

Extraction of extracellular polymeric substances from the acidophilic bacterium Acidiphilium 3.2Sup(5)

Extraction of extracellular polymeric substances (EPS) from Acidiphilium 3.2Sup(5) was investigated using five methods: EDTA, NaOH, ion exchange resin, heating and centrifugation. The bacterium studied presents promising application in microbial fuel cells (MFCs). The degree of cellular lysis provoked by each method was determined by UV-visible spectroscopy of cultures before and after EPS extraction. In addition, two electron microscopy techniques (TEM and SEM) were employed to determine the degree of attachment and the growth of the biofilm overtime on two solid supports: carbon fibre cloth and graphite rods. The main constituents of the EPS extracted by all methods were proteins and carbohydrates, as confirmed by FT-IR analysis, showing the major presence of carboxylic, hydroxylic and amino groups. The greater extractions of EPS were obtained using EDTA. This method also produced a less degree of cellular lysis. Furthermore, both the amount and the chemical composition of EPS strongly depended on the extraction method used.

Study of cadmium, zinc and lead biosorption by orange wastes using the subsequent addition method

The biosorption of several metals (Cd2+, Zn2+ and Pb2+) by orange wastes has been investigated in binary systems. Multicomponent sorption isotherms were obtained using an original procedure, similar to that proposed by Pagnanelli et al. [Pagnanelli, F., Petrangeli, M.P., Toro, L., Trifoni, M., Veglio, F., 2001a. Biosorption of metal ions on Arthrobacter sp.: biomass characterization and biosorption modelling. Environ. Sci. Technol. 34, 2773-2778] for monoelement systems, known as subsequent addition method (SAM). Experimental sorption data were analysed using an extended multicomponent Langmuir equation. The maximum sorption uptake was approximately 0.25mmol/g for the three binary systems studied. The reliability of the proposed procedure for obtaining the equilibrium data in binary systems was verified by means of a statistical F-test.

Exception for the zero-forward-scattering theory

Studies on single scattering of electromagnetic waves by magnetic particles were reported in the 1980s by Kerker et al. [J. Opt. Soc. Am.73, 765 (1983)]. They obtained that very small spherical particles with electric permittivity and magnetic permeability values such that epsilon=(4-mu)/(2mu+1) do not produce forward scattering. We show here that this condition contains an interesting exception at (epsilon=-2, mu=-2) when electric and magnetic resonances are present and around which the scattered field distribution is computed and described showing a polarization-insensitive behavior at the point (epsilon=-2, mu=-2).

Characterization of the biosorption of cadmium, lead and copper with the brown alga Fucus vesiculosus

The recovery of cadmium, lead and copper with the brown alga Fucus vesiculosus was characterized and quantified. The biosorption data fitted the pseudo-second order and Langmuir isotherm models, but did not adjust to the intraparticle diffusion model. The metal uptakes deduced from the pseudo-second order kinetic model and the Langmuir isotherm model followed a similar sequence: Cu>Cd approximately Pb. The Langmuir maximum metal uptakes were: 0.9626 mmol/g, Pb 1.02 mmol/g, and Cu 1.66 mmol/g. According to the equilibrium constants of this isotherm model, the affinity of metals for the biomass followed this order: Pb>Cu>Cd. Biosorption was accomplished by ion exchange between metals in solution and algal protons, calcium and other light metals, and by complexation of the adsorbed metals with algal carboxyl groups. FTIR spectra showed a shift in the bands of carboxyl, hydroxyl and sulfonate groups.

[Gorlin syndrome (nevoid basal cell carcinoma syndrome)]

CLINICAL CASE

A 77 year-old male patient with Parkinson's disease and senile dementia had many facial basal cell carcinomas and an ectropion of the left eye. When he experienced respiratory difficulty he was diagnosed to have an ameloblastoma in left nostril requiring surgery.

DISCUSSION

Gorlin syndrome is an autosomal dominant condition characterized by basal cell carcinomas, and skeletal and neurological anomalies. The presence of multiple basal cell carcinomas on the eyelids in a child or in a young patient should alert ophthalmologists to the possibility of this syndrome.

Biosorption with Algae: A Statistical Review

The state of the art in the field of biosorption using algae as biomass is reviewed. The available data of maximum sorption uptake (qmax) and biomass-metal affinity (b) for Cd2 +, Cu2 +, Ni2 +, Pb2 + and Zn2 + were statistically analyzed using 37 different algae (20 brown algae, 9 red algae and 8 green algae). Metal biosorption research with algae has used mainly brown algae in pursuit of treatments, which improve its sorption uptake. The information available in connection with multimetallic systems is very poor. Values of qmax were close to 1 mmol/g for copper and lead and smaller for the other metals. Metal recovery performance was worse for nickel and zinc, but the number of samples for zinc was very small. All the metals except lead present a similar affinity for brown algae. The difference in the behavior of lead may be due to a different uptake mechanism. Brown algae stand out as very good biosorbents of heavy metals. The best performer for metal biosorption is lead.

Interaction of nanoparticles with substrates: effects on the dipolar behaviour of the particles

In this work, we present a numerical analysis of the surface electric field of a metallic nanoparticle (either 2D or 3D) interacting with a flat substrate underneath. The influence of the distance to the substrate, particle size, the surrounding media and the substrate optical properties is analyzed as a function of the incident wavelength. We show that these are crucial factors that change the field distribution associated to the dipolar behavior of the particle. A useful parameter for illustrating the changes in the angular distribution is theta(max), the angle at which the maximum of the surface electric field is located.

Surface inspection by monitoring spectral shifts of localized plasmon resonances

We present a numerical study of the spectral variations of localized surface plasmon resonances (LSPR) in a 3D-probe metallic nanoparticle scanned over an inhomoegeneous dielectric surface. The possibilities for both, index monitoring and lateral resolution at nanoscale level are explored, with special attention paid to the shape of the probe and the profile of the near field underneath.

Biosorption of heavy metals by Fucus spiralis

The sorption uptake of cadmium, nickel, zinc, copper and lead by marine brown alga Fucus spiralis was investigated in bimetallic, trimetallic and multimetallic solutions. The experimental data fitted very well to Langmuir model. In bimetallic systems, the affinity of biomass for lead and copper increased and the sorption uptake of these metals was not affected by increasing concentrations of cadmium, nickel or zinc. However, in solutions with both metals there was a significant mutual decrease of their sorption levels at high concentrations of the other metal. The sorption uptake of cadmium, nickel and copper was investigated in trimetallic aqueous systems. Based on the kinetic parameter b, the affinity of F. spiralis for copper was considerably higher than for cadmium or nickel: bCd=6.39, bNi=1.82 and bCu=17.89. In all tests, the maximum sorption uptake remained practically constant around 1 mmol/g, indicating that the number of active sites on the biomass was limited. Tests with four and five metals showed that copper was preferentially adsorbed. The differences between the experimental sorption data and those given by the chemical speciation program PHREEQCI were negligible. In general, the software used provided satisfactory estimated data for each metal and hence can be a useful tool to predict or simulate the real process.