Robert J. White

Changes with age in the structure of fibromodulin in human articular cartilage

An anti-peptide antibody was raised in a rabbit against the carboxy terminal region of the human fibromodulin core protein. The antibody was purified from other components of the resulting antiserum by affinity chromatography using the immobilized peptide, and was used to study the structural heterogeneity of fibromodulin extracted from human articular cartilage of different ages by the use of immunoblotting following sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the extracted macromolecules. In the fetus and neonate, fibromodulin was visualized as a diffuse component with a relative molecular weight of 70-110 kDa, whereas in the mature adult a more discrete component of smaller size was apparent with a relative molecular weight of 67 kDa. The size of the fibromodulin from mature adult cartilage could not be altered by pretreatment of the samples with keratanase II or endo-beta-galactosidase before analysis. In contrast, the size of the fibromodulin from younger cartilage could be decreased with both glycosidases, with the endo-beta-galactosidase yielding a smaller product than the keratanase. The size of the product resulting from endo-beta-galactosidase treatment of the fibromodulin from young cartilage was the same as that of the intact fibromodulin from mature adult cartilage. Thus, fibromodulin is present in human articular cartilage at all ages, but the extracted molecules only appear to exist in a proteoglycan form possessing keratan sulfate chains in the juvenile and young adult, and the size of these chains decreases with age. In the mature adult the fibromodulin does not possess either keratan sulfate or non-sulfated polylactosamine chains, though it appears to possess the same number of N-linked oligosaccharides as its counterparts from the younger tissue, but they are not modified further. The majority of the fibromodulin extracted from arthritic cartilage is of the same size as that found in the normal mature adult, although there is evidence for proteolytic processing. The degree of such processing is greater for the fibromodulin obtained from the cartilage of rheumatoid arthritic joints than osteoarthritic joints.

The use of caesium sulphate density gradient centrifugatin to analyse proteoglycans from human articular cartilages of different ages

Proteoglycan subunits from human articular cartilage were fractionated by caesium sulphate density gradient centrifugation. A single heterogeneous population of molecules was produced whose average density decreased with increasing age of the individual from which they were obtained. At no density did the carbohydrate composition of any adult fraction resemble that of any newborn fraction, although there was considerable overlap in density. However, there was a similarity in amino acid composition between the most dense proteoglycans from the adult and those of least density from the newborn. The carbohydrate content of a 2-year-old proteoglycan was intermediate in composition, with high density fractions resembling the newborn and low density fractions resembling the adult. In addition, the proteoglycans of lowest density in both the newborn and two year preparations showed additional bands on agarose/polyacrylamide gel electrophoresis resembling the adult material. These results indicate that while a core protein of adult composition may occur in the juvenile proteoglycan it need not necessarily be glycosylated in an adult manner, suggesting that glycosylation is to some extent independent of the origin of core protein heterogeneity.

M1887 The Gain in Quality-Adjusted Life Years By Switching to Esomeprazole in Those with Persistent GERD Symptoms in Primary Care: EncomPASS - a Cluster-Randomized Trial

INTRODUCTION: An increasing number of case reports have identified acute kidney injury (AKI) secondary to acute interstitial nephritis (AIN) provoked by Proton Pump Inhibitor (PPI) therapy. The present collaborative study identifies experience from a major UK renal unit. AIMS & METHODS: All cases of biopsy-proven AIN between Jan 1st 2007 and October 1st 2008 presenting to the regional renal centre (serving a population of 1.1 million), were identified. The notes of all patients (pts) with a diagnosis of AIN and a history of PPI were analysed. Pre-PPI treatment, diagnosis and most recent plasma creatinine and estimated glomerular filtration rate (eGFR) were obtained. Pts were deemed likely to have PPI-associated AKI if a deterioration in kidney function was identified after starting PPI therapy in the absence of a history of any other medications associated with AIN and other renal or systemic causes. RESULTS: 210 kidney biopsy reports were analysed of which 27 reported AIN due to a multitude of causes. Of these, 6 cases of AIN were found to be strongly associated with PPI therapy. PPIs were the most common drug class associated with AIN. Male : Female 1 : 5. The median age at diagnosis was 66 yrs (range 60-86). All pts presented with nonspecific malaise and tiredness. 5 cases were due to omeprazole & 1 pt esomeprazole. Mean ± SD duration of PPI therapy was 7.7 ± 5.6 months, (range 5-18). Mean ± SD pre-PPI creatinine was 73 ± 30 μmol/L (range 45-103); eGFR 69 ± 23 ml/min/1.73m2 (range 4590). At diagnosis, mean ± SD creatinine was 269 ± 217 μmol/L (range 141-697) and eGFR 24 ± 16 ml/min/1.73m2 (range 5-52), representing a mean decline in eGFR of 65%. The PPI was immediately stopped in all pts. 1 pt required temporary renal replacement therapy. 5 pts were treated with steroids. The mean ± SD most recent creatinine post diagnosis was 129.5 ± 36.5 μmol/L (range 94-196) and eGFR 41 ± 11 ml/min/1.73m2 (range=23-52). Although kidney function improved following cessation of PPI and/or treatment with steroids, there was a net decline in kidney function from pre-PPI exposure levels. CONCLUSION: PPI related AIN is an important iatrogenic cause of potentially reversible AKI and is likely to be significantly underestimated. Kidney function should be assessed in patients receiving PPI therapy presenting with non specific malaise or tiredness. AIN should be considered in patients with deteriorating kidney function when receiving PPI therapy. Prompt identification of PPI induced AIN is important as our study suggests (in line with the established literature) that cessation of therapy can at least partially reverse decline in renal function inmost patients.

The cost-effectiveness of alternative strategies to manage patients with uninvestigated dyspepsia: comparing the CanDys approach to antisecretory therapy and prompt endoscopy

The cost-effectiveness of alternative strategies to manage patients with uninvestigated dyspepsia: comparing the CanDys approach to antisecretory therapy and prompt endoscopy