Comparison of the results for three automated immunoassay systems in determining serum HBV markers

BACKGROUND: Automated immunoassay analyzers are used to identify hepatitis B virus (HBV) serum markers. In regions with high prevalence of HBV, it is imperative to compare test results from different immunoassay analyzers. METHODS: Samples from 496 subjects were collected and HBV markers were determined (double-blind, parallel manner) using Abbott AxSYM, Roche Modular Analytics E170, and Abbott Architect i2000). RESULTS: Concurrence between AxSYM and E170 was 97.78% for HBsAg, 91.13% for anti-HBs, 98.79% for anti-HBc, 98.39% for HBeAg, and 88.91% for anti-HBe. Positive rates of anti-HBs and anti-HBe from AxSYM were lower than E170 (P<0.01). Concurrence between AxSYM and Architect i2000 was 98.79% for HBsAg, 91.33% for anti-HBs, 95.97% for anti-HBc, 98.39% for HBeAg, and 95.77% for anti-HBe. Positive anti-HBs rates from AxSYM were lower than Architect i2000 (P<0.01). Concurrence between E170 and Architect i2000 was 97.38% for HBsAg, 94.15% for anti-HBs, 95.56% for anti-HBc, 99.60% for HBeAg, and 88.10% for anti-HBe. Positive anti-HBe rates using Architect i2000 were lower than E170 (P<0.01). Overall, the greatest differences were observed in samples with low-level serum HBV markers. CONCLUSION: Significant discrepancies were observed among results for the 3 automated immunoassay analyzers, especially for low-level anti-HBs and anti-HBe results.     

Molecular diagnostics of genetic eye diseases

Eye diseases can be simple or complex, and mostly of heterogeneous molecular genetics. Some eye diseases are caused by mutations in a single gene, but some diseases, such as primary open angle glaucoma, can be due to sequence variations in multiple genes. In some diseases, both genetic and epigenetic mechanisms are involved, as was recently revealed in the mechanism of retinoblastoma. Disease causative mutations and phenotypes may vary by ethnicity and geography. To date, more than a hundred candidate genes for eye diseases are known, although less than 20 have definite disease-causing mutations. The three common genetic eye diseases, primary open angle glaucoma, age-related macular degeneration, and retinitis pigmentosa, all have known gene mutations, but these account for only a portion of the patients. While the search for eye disease genes and mutations still goes on, known mutations have been utilized for diagnosis. Genetic markers for pre-symptomatic and pre-natal diagnosis are available for specific diseases such as primary open angle glaucoma and retinoblastoma. This paper reviews the molecular basis of common genetic eye diseases and the available genetic markers for clinical diagnosis. Difficulties and challenges in molecular investigation of some eye diseases are discussed. Establishment of ethnic-specific disease databases that contain both clinical and genetic information for identification of genetic markers with diagnostic, prognostic, or pharmacological value is strongly advocated.     

Massive Hematochezia from Acute Hemorrhagic Rectal Ulcer in Patients with Severe Comorbid Illness: Rapid Control of Bleeding by Per Anal Suturing of Bleeder Using Anoretractor

Purpose Massive hematochezia from acute hemorrhagic rectal ulcer can arise in patients with severe comorbid illness who are bedridden for long periods. If the bleeder is not found and treated immediately, the bleeding will cause deterioration of health and even threaten life. The results of the current study show how quickly and safely per anal suturing can treat acute hemorrhagic rectal ulcer. Methods From January 2003 to December 2003, the records of 26 patients who underwent per anal suturing of acute hemorrhagic rectal ulcer were retrospectively reviewed. The identification of acute hemorrhagic rectal ulcer was confirmed by clinical and anoscopic examination. Results Most of these patients were elderly and bedridden (14 men; median age 69 years). Main comorbid illnesses existed in all patients and included liver cirrhosis (8 patients, 31 percent), sepsis (13 patients, 50 percent), cerebral vascular accident (15 patients, 58 percent), respiratory failure (13 patients, 50 percent), and malignancy (7 patients, 27 percent). Effective hemostasis was achieved in all patients by direct suture of bleeding ulcer. No complications developed relative to the per anal suturing procedure among any patients. Although 11 patients developed recurrent hematochezia, 9 patients responded to repeated therapy. The risk factors associated with recurrent bleeding were severity of disease and abnormal coagulation. Conclusions When massive hematochezia occurs in bedridden patients with severe comorbid illness, it is essential to investigate the lower rectum, which often is affected by acute hemorrhagic rectal ulcer. Recognition of this clinical presentation will result in early identification and therapy. Per anal suturing of a bleeder at the bedside provides a quick, safe, and successful management of acute hemorrhagic rectal ulcer.     

Modulating effects of cholesterol feeding and simvastatin treatment on platelet-activating factor acetylhydrolase activity and lysophosphatidylcholine concentration

BACKGROUND: Platelet-activating factor acetylhydrolyse (PAF-AH) is an enzyme that degrades PAF and bioactive oxidized lipids. However, it has been reported to be a risk factor for coronary heart disease. The present study examined the effects of cholesterol feeding and simvastatin treatment on plasma PAF-AH activity. METHODS: Japanese White rabbits (n=22) were fed a diet containing 0.3% cholesterol and 3% corn oil for 1 month, and then divided into two groups that continued to receive this diet with (treated) or without (control) treatment with simvastatin (0.01%) for another 2 months. RESULTS: Cholesterol feeding increased and simvastatin treatment decreased apolipoprotein (apo) B-containing lipoprotein subfractions as characterized by capillary isotachophoresis, serum levels of total cholesterol, phospholipids, LDL-C, apoE, plasma and LDL-associated PAF-AH (LDL-PAF-AH) activities, and plasma lyso-PC concentration. Cholesterol feeding also increased apoB levels but decreased the LDL-PAF-AH/LDL-C ratio and did not change the plasma PAF-AH/lyso-PC ratio. Simvastatin treatment did not affect apoB levels and only slightly increased the LDL-PAF-AH/LDL-C ratio. Secretion of PAF-AH activity from monocyte-derived macrophages was increased by cholesterol feeding but not affected by simvastatin treatment. These results indicate that PAF-AH activity is increased by cholesterol feeding due to increased secretion of PAF-AH activity from macrophages and that PAF-AH activity is decreased by simvastatin due to increased removal of lipid and enzyme contents of LDL particles. CONCLUSION: Cholesterol elevation by cholesterol feeding and cholesterol-lowering by simvastatin modulate plasma PAF-AH activity by different mechanisms.     

High doses of tyrosine kinase inhibitor PTK787 enhance the efficacy of ischemic hypoxia for the treatment of hepatocellular carcinoma: dual effects on cancer cell and angiogenesis

The present study aimed to investigate the therapeutic efficacy of combining vascular endothelial growth factor (VEGF) receptor blockade using tyrosine kinase inhibitor PTK787 with hypoxia for the treatment of hepatocellular carcinoma (HCC). The in vivo effects of the treatments were determined in a rat orthotopic HCC model, in which hypoxia was generated by hepatic artery ligation (HAL). Compared with HAL alone, PTK787 combined with HAL significantly prolonged the animal survival, reduced the tumor size, induced more tumor tissue necrosis and apoptosis, and down-regulated the expression of von Willebrand factor. The mechanism was explored in vitro using murine HCC and endothelial cell lines, respectively. PTK787 combined with hypoxia decreased the expression of VEGF and VEGF receptors in both cell lines and suppressed the cell viability by induction of cell cycle arrest and promotion of apoptosis. Up-regulation of cleaved form caspase-9 and down-regulation of Bcl-2 and cyclin D1 were detected with the combined treatment. Hypoxia sensitized endothelial cells to the inhibitory effect of PTK787 on forming tubular-like structure. The motility of tumor cells was inhibited by hypoxia and the combined approach, with down-regulation of Rac1, Rho, and phosphorylated Akt expression. However, in the endothelial cells, the combined treatment inhibited the hypoxia-enhanced cell motility, with suppressed Rac1, Rho, and phosphorylated Akt expression. In conclusion, PTK787 combined with hypoxia achieved a better therapeutic efficacy than hypoxia alone through enhancing hypoxia-induced antitumor cell effect and preventing the activation of angiogenic process.     

Human embryonic stem cells have a unique epigenetic signature

Human embryonic stem (hES) cells originate during an embryonic period of active epigenetic remodeling. DNA methylation patterns are likely to be critical for their self-renewal and pluripotence. We compared the DNA methylation status of 1536 CpG sites (from 371 genes) in 14 independently isolated hES cell lines with five other cell types: 24 cancer cell lines, four adult stem cell populations, four lymphoblastoid cell lines, five normal human tissues, and an embryonal carcinoma cell line. We found that the DNA methylation profile clearly distinguished the hES cells from all of the other cell types. A subset of 49 CpG sites from 40 genes contributed most to the differences among cell types. Another set of 25 sites from 23 genes distinguished hES cells from normal differentiated cells and can be used as biomarkers to monitor differentiation. Our results indicate that hES cells have a unique epigenetic signature that may contribute to their developmental potential.