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Background/aims: Mutations in hepatitis B virus (HBV) to lamivudine resistance that arise during prolonged treatment frequently cause amino acid substitutions in the YMDD motif of HBV DNA polymerase. Current methods of detecting such variants are time-consuming, labor intensive, and unsuitable for screening large numbers of samples. Here, we describe the development of a matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) genotyping assay suitable for detecting HBV variants in a sensitive and specific manner., Methods: The assay is based on PCR amplification and mass measurement of oligonucleotides containing sites of mutation of the YMDD motif., Results: The MALDI-TOF MS-based genotyping assay is sufficiently sensitive to detect as few as 100 copies of HBV genome per millilitre of serum, with superior specificity for determining mixtures of wild-type and variant viruses. When sera from 40 patients were analyzed, the MALDI-TOF MS-based assay correctly identified known viral variants and additional viral quasi-species not detected by previous methods, as well as their relative abundance., Conclusions: The sensitivity, accuracy and amenability to high-throughput analysis makes the MALDI-TOF MS-based assay suitable for mass screening of HBV infected patients receiving lamivudine, and can help provide further understanding of disease progression and response to therapy.

Gastric volvulus occurs when the stomach rotates about its longitudinal axis (organo-axial volvulus), or about an axis joining the lesser and greater curvatures (mesentero-axial volvulus). Primary gastric volvulus, making up one third of cases, occurs when the stabilizing ligaments are too lax as a result of congenital or acquired causes. Secondary gastric volvulus, making up the remainder of cases, occurs in association with a paraesophageal hernia or other congenital or acquired diaphragmatic defects. While gastric volvulus may occur acutely, especially in children, it may not be clinically apparent and discovered incidentally. The authors present a case of chronic organo-axial volvulus of the stomach secondary to left hemidiaphragmatic eventration with a review of the relevant literature.

Among 92 surgically resected human hepatocellular carcinomas (HCCs) < or = 3 cm in diameter, 23 tumors (25%) grossly showed a nodule-in-nodule appearance indicating stepwise progression of HCC. The central nodules showed destructive growth of HCC, which was less differentiated than the surrounding area histologically, while the surrounding area showed growth of very-well-differentiated HCC with no, or only minimal, destruction of the underlying liver structures. Previously, we proposed the term "early HCC" for HCCs without definite destructive growth, and the nodule-in-nodule lesions described here are considered to be in the transitional stage from early HCC to advanced HCC, and are therefore named early advanced HCC (eAd HCC). DNA cytophotometry was performed in 12 cases of eAd HCC, in which the early HCC component, advanced HCC component and non-tumorous liver tissue showing chronic hepatitis or cirrhosis were analyzed separately. The early HCC component showed a diploid pattern in eight of the 12 cases. The advanced HCC component showed an aneuploid peak in seven cases, and in three of these the peak was detected only in the advanced HCC component and not in the early HCC component. The mean nuclear DNA content was significantly increased from non-tumorous liver to the early HCC component and from the early HCC component to the advanced HCC component. Polyploid cells containing more than 4.8C DNA were exceptional in non-tumorous liver, but were detectable in the early HCC component and increased in number in the advanced HCC component. These findings suggest that DNA instability may have an important role to play in the subclonal progression of human HCC.