In vitro release of bovine serum albumin from alginate/HPMC hydrogel beads

In recent years, the use of swelling polymeric matrices for the encapsulation and controlled release of protein drugs has received significant attention. The purpose of the present study was to investigate the release of albumin, a model protein from alginate/hydroxypropyl-methylcellulose (HPMC) gel beads. A hydrogel system comprised of two natural, hydrophilic polymers; sodium alginate and HPMC was studied as a carrier of bovine serum albumin (BSA) which was used as a model protein. The morphology, bead size and the swelling ratio were studied in different physical states; fully swollen, dried and reswollen using scanning electron microscopy and image analysis. Finally the effect of different alginate/HPMC ratios on the BSA release profile in physiological saline solution was investigated. Swelling experiments revealed that the bead diameter increases with the viscosity of the alginate solution while the addition of HPMC resulted in a significant increase of the swelling ratio. The BSA release patterns showed that the addition of HPMC increased the protein-release rate while the release mechanism fitted the Peppas model. Alginate/HPMC beads prepared using the ionic gelation exhibited high BSA loading efficiency for all formulations. The presence of HPMC increased the swelling ability of the alginate beads while the particle size remained unaffected. Incorporation of HPMC in the alginate gels also resulted in improved BSA release in physiological saline solution. All formulations presented a non-Fickian release mechanism described by the Peppas model. In addition, the implementation of non-parametric tests showed significant differences in the release patterns between the alginate/HPMC and the pure alginate beads, respectively.

Accelerated apoptosis in SLE neutrophils cultured with anti-dsDNA antibody isolated from SLE patient serum: a pilot study.

Increased numbers of apoptotic neutrophils are found in SLE, related to disease activity and levels of anti-dsDNA antibody. The mechanism of increased apoptosis is not clear, but anti-dsDNA antibody has been shown to induce apoptosis in neutrophils from normal subjects and in certain cell lines. In this study, polyclonal anti-dsDNA antibody was isolated from the serum of a patient with active SLE, and was shown to substantially accelerate apoptosis in neutrophils from SLE patients as compared with neutrophils from healthy control or rheumatoid arthritis subjects.

Level of renal function and serum erythropoietin levels independently predict anaemia post-renal transplantation

Background. Post-renal transplant anaemia is a potentially reversible cardiovascular risk factor. Graft function, immunosuppressive agents and inhibition of the renin-angiotensin system have been implicated in its aetiology. The evaluation of erythropoietin (EPO) levels may contribute to understanding the relative contributions of these factors. Methods. Two-hundred and seven renal transplant recipients attending the Belfast City Hospital were studied. Clinical and laboratory data were extracted from the medical records and laboratory systems. Results. Of the 207 patients (126 male), 47 (22.7%) were found to be anaemic (males, haemoglobin (Hb) <12 g/dl, females Hb <11g/dl). The anaemic group had a significantly higher mean serum creatinine level (162.8 µmol/l vs 131.0 µmol/l, P <0.001) and lower mean estimated glomerular filtration rate (eGFR) (41.5 ml/min vs 54.9 ml/min, P <0.001) than the non-anaemic group. Individual immunosuppressive regimens were comparable between those with and those without anaemia. Angiotensin converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) administration was not more prevalent in those with anaemia compared with those without (36.2 vs 38.8, P = 0.88). There was a significant inverse correlation between Hb levels and serum EPO levels (R = -0.29, P <0.001), but not between EPO levels and eGFR (R = 0.02, P = 0.74). Higher EPO levels were predictive of anaemia, independent of eGFR in multivariate analysis. Conclusion. Anaemia is common in post-renal transplant patients. The levels of renal function and serum EPO and not immunosuppressive regimens or ACE-I/ARB use, are strong and independent predictors of anaemia. © The Author [2007]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.