Publications (27) View all
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Article: Importance of hepatic fibrosis in cystic fibrosis and the predictive value of liver biopsy.
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ABSTRACT: Cystic fibrosis liver disease (CFLD), which results from progressive hepatobiliary fibrosis, is an important cause of morbidity and mortality, but it is difficult to identify before portal hypertension (PHT) ensues. Clinical signs, serum alanine aminotransferase (ALT) levels, and ultrasound (US) are widely applied, but their value in predicting the presence of cirrhosis, the development of PHT, or adverse outcomes is undetermined. The potential gold standard, liver biopsy, is not standard practice and, notwithstanding sampling error considerations, has not been systematically evaluated. Forty patients with cystic fibrosis (median age = 10.6 years) with abnormal clinical, biochemical, and US findings were subjected to dual-pass percutaneous liver biopsy. Clinical outcomes were recorded over 12 years of follow-up (median = 9.5 years for survivors). Logistic regression and receiver operating characteristic analyses were applied to predict hepatic fibrosis (which was assessed by fibrosis staging and quantitative immunohistochemistry) and the occurrence of PHT. PHT occurred in 17 of 40 patients (42%), including 6 of 7 (17%) who died during follow-up. Clinical examination, serum ALT levels, and US findings failed to predict either the presence of liver fibrosis or the development of PHT. Fibrosis staging on liver biopsy, where the accuracy was improved by dual passes (P = 0.002, nonconcordance = 38%), predicted the development of PHT (P < 0.001), which occurred more frequently and at a younger age in those with severe fibrosis. CONCLUSION: Clinical modalities currently employed to evaluate suspected CFLD help to identify a cohort of children at risk for liver disease and adverse outcomes but do not predict an individual's risk of liver fibrosis or PHT development. Liver fibrosis on biopsy predicts the development of clinically significant liver disease. Dual passes help to address sampling concerns. Liver biopsy has a relevant role in the management of patients with suspected CFLD and deserves more widespread application.Hepatology 01/2011; 53(1):193-201. · 11.66 Impact Factor -
Article: Varying etiologies lead to different molecular changes in Australian and South African hepatocellular carcinomas.
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ABSTRACT: There is significant regional variation in the etiologic agents responsible for hepatocellular carcinoma (HCC), which influences the genetic and epigenetic mechanisms of malignant transformation. The aim of the present study was to investigate the prevalence of allelic imbalance (AI) and CpG island methylation in HCCs from Australia and South Africa. Genomic DNA was extracted from malignant and non-malignant liver from 37 Australian and 24 South African HCCs and histologically normal liver from 20 transplant donors. AI was examined at 1p, 4p, 4q, 8p, 9p, 13q, 16q and 17p, using 23 microsatellite markers. Methylation status of p14, p16, p15, RIZ1, E-cadherin and O6-MGMT was examined using methylation specific PCR, while MINTs 1, 2, 12, 25 and 31 were assessed using combined bisulfite restriction analysis. The highest prevalence of AI was observed at 9p (69%) and 17p (52%). AI was significantly higher in South African HCCs (p<0.05). The prevalence of promoter methylation of the six genes was significantly higher in Australian cases in both malignant and non-malignant liver tissue (p<0.05). MINT assays revealed an increasing degree of CpG island methylation in the progression of hepatocarcinogenesis which was significant for MINTs 1, 12 and 31 (p<0.05). MINT methylation was more prominent in Australian HCCs. These data indicate that methylation is an early event preceding malignant transformation. Methylation was more and AI less prevalent in Australian than South African HCCs. These data suggest that there are different mechanisms of malignant transformation in HCCs from Australia and South Africa.International Journal of Oncology 11/2009; 35(5):1081-9. · 2.40 Impact Factor -
Article: Silencing of O6-methylguanine DNA methyltransferase in the absence of promoter hypermethylation in hepatocellular carcinomas from Australia and South Africa.
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ABSTRACT: The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) is involved in cellular defences against alkylating agents. Alterations in the MGMT gene may result in an increase in the mutation rate and risk of malignant transformation. We have previously shown that MGMT is implicated in colorectal carcinogenesis particularly in cancers which display microsatellite instability, a marker of impaired DNA repair. The aims of the current study were to assess the roles of MGMT and microsatellite instability in hepatocellular carcinomas (HCCs) from Australia and South Africa. DNA was extracted from malignant and non-malignant liver tissue from 37 Australian and 24 South African patients, and histologically normal liver from 20 transplant donors. MGMT promoter hypermethylation and MGMT protein expression were assessed using methylation specific PCR and immunohistochemistry. Microsatellite instability was examined using a panel of 23 microsatellite markers previously used to detect allelic imbalance and two specific markers for the detection of low levels of microsatellite instability. Methylation specific PCR did not detect any methylation of the MGMT promoter in Australian and South African HCCs. Similarly, no hypermethylation of MGMT was observed in the adjacent non-malignant liver or histologically normal liver. MGMT staining was predominantly nuclear with some cytoplasmic staining. Overexpression of MGMT protein was detected in 14 (39%) HCCs, while a reduction in protein expression was evident in 14 (39%) HCCs. In the remaining 8 cases the expression of MGMT was comparable in HCCs and adjacent non-malignant tissue. Interestingly, MGMT expression decreased relative to adjacent non-malignant liver tissue in patients who had aetiologies other than viral hepatitis for their underlying liver diseases (p<0.02). No microsatellite instability was detected in this series of 61 HCCs. This suggests that epigenetic silencing of MGMT and microsatellite instability does not play an important role in this series of HCCs derived from different populations.Oncology Reports 04/2007; 17(4):817-22. · 1.84 Impact Factor -
Article: Plasma delipidation process induces rapid regression of atherosclerosis and mobilisation of adipose tissue
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ABSTRACT: Cholesterol is a major component of atherosclerotic plaques. Cholesterol accumulation within the arterial intima and atherosclerotic plaques is determined by the difference of cellular cholesterol synthesis and/or influx from apo B–containing lipoproteins and cholesterol efflux. In humans, apo A-1 Milano infusion has led to rapid regression of atherosclerosis in coronary arteries. We hypothesised that a multifunctional plasma delipidation process (PDP) would lead to rapid regression of experimental atherosclerosis and probably impact on adipose tissue lipids. In hyperlipidemic animals, the plasma concentrations of cholesterol, triglyceride and phospholipid were, respectively, 6-, 157-, and 18-fold higher than control animals, which consequently resulted in atherosclerosis. PDP consisted of delipidation of plasma with a mixture of butanol-diisopropyl ether (DIPE). PDP removed considerably more lipid from the hyperlipidemic animals than in normolipidemic animals. PDP treatment of hyperlipidemic animals markedly reduced intensity of lipid staining materials in the arterial wall and led to dramatic reduction of lipid in the adipose tissue. Five PDP treatments increased apolipoprotein A1 concentrations in all animals. Biochemical and hematological parameters were unaffected during PDP treatment. These results show that five PDP treatments led to marked reduction in avian atherosclerosis and removal of lipid from adipose tissue. PDP is a highly effective method for rapid regression of atherosclerosis. J. Clin. Apheresis © 2005 Wiley-Liss, Inc.Journal of Clinical Apheresis 09/2005; 20(3):143 - 153. · 1.93 Impact Factor -
Article: Serum markers of hepatic fibrogenesis in cystic fibrosis liver disease.
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ABSTRACT: Hepatic fibrosis contributes to adverse outcome in cystic fibrosis (CF). Early detection of CF liver disease (CFLD) may identify patients at risk of significant complications. To evaluate the utility of serum markers to detect hepatic fibrosis in children with CFLD vs. CF patients without liver disease (CFnoLD) and controls. Sera from 36 CFLD, 30 CFnoLD and 39 controls were assessed for tissue inhibitor of matrix metalloproteinase (MMP) (TIMP)-1, collagen (CL)-IV, MMP-2, hyaluronic acid (HA) and prolyl hydroxylase (PH) by enzyme immunoassay and were correlated with hepatic fibrosis score in CFLD. TIMP-1, PH and CL-IV were increased in CFLD vs. CFnoLD and controls. Fibrosis score was negatively correlated with TIMP-1 (r=-0.34, P=0.06) and PH (r=-0.48, P=0.008). Receiver-operating characteristics analysis showed CL-IV (AUC 0.785, P<0.0001) and TIMP-1 (AUC 0.765, P<0.0001) differentiated CFLD from CFnoLD and controls, while PH (AUC 0.814, P<0.0001) predicted early fibrogenesis. Diagnostic accuracy improved using logistic regression combining (i) CL-IV, TIMP-1, PH to identify CFLD (AUC 0.831, P<0.0001) and (ii) TIMP-1, PH to identify CFLD patients with no fibrosis (AUC 0.852, P<0.02). Elevated TIMP-1, CL-IV, PH may be indicators of hepatic fibrogenesis in CF. Increased TIMP-1, PH may be early markers of CFLD.Journal of Hepatology 11/2004; 41(4):576-83. · 9.26 Impact Factor
