Clonal expansion of hepatocytes with a selective advantage occurs during all stages of chronic hepatitis B virus infection.

Hepatocyte clone size was measured in liver samples of 21 patients in various stages of chronic hepatitis B virus (HBV) infection and from 21 to 76 years of age. Hepatocyte clones containing unique virus-cell DNA junctions formed by the integration of HBV DNA were detected using inverse nested PCR. The maximum hepatocyte clone size tended to increase with age, although there was considerable patient-to-patient variation in each age group. There was an upward trend in maximum clone size with increasing fibrosis, inflammatory activity and with seroconversion from HBV e-antigen (HBeAg)-positive to HBeAg-negative, but these differences did not reach statistical significance. Maximum hepatocyte clone size did not differ between patients with and without a coexisting hepatocellular carcinoma. Thus, large hepatocyte clones containing integrated HBV DNA were detected during all stages of chronic HBV infection. Using laser microdissection, no significant difference in clone size was observed between foci of HBV surface antigen (HBsAg)-positive and HBsAg-negative hepatocytes, suggesting that expression of HBsAg is not a significant factor in clonal expansion. Laser microdissection also revealed that hepatocytes with normal-appearing histology make up a major fraction of the cells undergoing clonal expansion. Thus, preneoplasia does not appear to be a factor in the clonal expansion detected in our assays. Computer simulations suggest that the large hepatocyte clones are not produced by random hepatocyte turnover but have an as-yet-unknown selective advantage that drives increased clonal expansion in the HBV-infected liver.

Adenocarcinoma arising in a gastrocystoplasty.

Gastrocystoplasty is a form of surgical bladder augmentation or neobladder used to restore bladder capacity and compliance in children and in patients with neurogenic bladder. Other forms of bladder augmentation include ileocystoplasty and colocystoplasty. Reported complications of gastrocystoplasty include post-operative bleeding, haematuria, stricture, metabolic alkalosis and rupture of the gastric segment. There are reports of adenocarcinomas arising in the setting of ileocystoplasty and colocystoplasty. However, the first case of adenocarcinoma arising in the setting of a gastrocystoplasty is reported.

Increased parenchymal damage and steatohepatitis in Caucasian non-alcoholic fatty liver disease patients with common IL1B and IL6 polymorphisms.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a complex, multifactorial disease affected by diet, lifestyle and genetics. Proinflammatory cytokines like IL-1ß and IL-6 have been shown to be elevated in non-alcoholic steatohepatitis (NASH). AIM: To investigate the relationship between IL1B and IL6 gene polymorphisms and histological features of NAFLD in the NASH CRN cohort. METHODS: A total of 604 adult (≥18 years) non-Hispanic Caucasians with biopsy-proven NAFLD were genotyped for the following SNPs: IL1B, rs16944, rs1143634; IL6, rs1800795, rs10499563. Logistic regression was used to examine the relationship between genotype and a definitive diagnosis and advanced histological features of NASH after controlling for the following variables selected a priori: age, sex, diabetes, obesity and HOMA-IR level. RESULTS: The IL6 rs10499563 C allele was independently associated with the presence of definitive NASH, and increased ballooning and Mallory bodies. The IL1B rs1143634 TT genotype was associated with advanced fibrosis and increased Mallory bodies. The IL6 rs1800795 C allele was associated with not only increased risk for severe steatosis, >66% but also decreased risk for advanced fibrosis and lobular inflammation and Mallory body formation. CONCLUSIONS: These results suggest that common variants in the IL6 and IL1B genes may increase susceptibility for NASH and confer a higher risk of hepatic parenchymal damage including increased ballooning, increased Mallory bodies, and bridging fibrosis or cirrhosis. In contrast, the IL6 rs1800795 C allele may confer a higher risk for steatosis, but less parenchymal damage. Our findings support the development of therapeutics aimed at IL-1ß and IL-6 suppression.

TGF-ß signaling alters the pattern of liver tumorigenesis induced by Pten inactivation.

Hepatocarcinogenesis results from the accumulation of genetic and epigenetic changes in liver cells. A common mechanism through which these alterations induce liver cancer is by deregulating signaling pathways. A number of signaling pathways, including the PI3K/PTEN/AKT and transforming growth factor ß (TGF-ß) pathways have been implicated in normal liver development as well as in cancer formation. In this study, we assessed the effect of the TGF-ß signaling pathway on liver tumors induced by phosphatase and tensin homolog (Pten) loss. Inactivation of only the TGF-ß receptor type II, Tgfbr2, in the mouse liver (Tgfbr2(LKO)) had no overt phenotype, while inactivation of Pten alone (Pten(LKO)), resulted in the formation of both hepatocellular carcinomas and cholangiocarcinomas (CC). Interestingly, deletion of both Pten and Tgfbr2 (Pten(LKO);Tgfbr2(LKO)) in the mouse liver resulted in a dramatic shift in tumor type to predominantly CC. Assessment of the PI3K/PTEN/AKT pathway revealed increased phosphorylation of AKT and glycogen synthase kinase 3 beta (GSK-3ß) in both the Pten(LKO) and Pten(LKO);Tgfbr2(LKO) mice, suggesting that this pathway is constitutively active regardless of the status of the TGF-ß signaling pathway. However, phosphorylation of p70 S6 kinase was observed in the liver of all three phenotypes (Tgfbr2(LKO), Pten(LKO), Pten(LKO);Tgfbr2(LKO)) indicating that the loss of Tgfbr2 and/or Pten leads to an increase in this signaling pathway. Analysis of markers of liver progenitor/stem cells revealed that the loss of TGF-ß signaling resulted in increased expression of c-Kit and CD133. Furthermore, in addition to increased c-Kit and CD133, Scf and EpCam expression were also increased in the double knock-out mice. These results suggest that the alteration in tumor types between the Pten(LKO) mice and Pten(LKO);Tgfbr2(LKO) mice is secondary to the altered regulation of stem-cell features induced by the loss of TGF-ß signaling.

Mucins secreted by cell lines derived from colorectal mucinous carcinoma and adenocarcinoma.

Mucinous (colloid) carcinoma and well- to moderately-differentiated adenocarcinoma of the colon differ in the pattern and the amount of mucin secretion and perhaps in their behaviour and clinical outcome. To ascertain why these differences exist and to elucidate the mechanisms of tumour progression, we examined two model human cell lines derived from colorectal mucinous carcinoma (C1a) and moderately differentiated adenocarcinoma (HM3) which show typical pathological and mucin staining patterns of the respective type of carcinomas to nude mouse tumour xenografts. Specifically, we sought to determine if there were quantitative and qualitative differences in mucin synthesis, in mucin gene expression and in biological properties between the two model cell lines. Northern blot analysis showed that MUC2 mRNA levels were significantly higher in C1a cells compared with HM3 cells, while those of MUC3, -5 and -6 mRNA were lower. C1a cells secreted approximately five times more radiolabelled apomucin and 1.5 times more glycosylated apomucin than HM3 cells. When the carbohydrate side-chain length of secreted mucins by these cell lines were examined by beta-elimination followed by P4 column chromatography, C1a mucins had mostly short carbohydrate side-chains, while HM3 cells had predominantly longer side-chains. Western blot analysis of the cell homogenate showed higher expression of MUC2 apomucin and mucin-associated carbohydrate antigens, such as T, Tn and sialyl Tn, with decreased sialyl Le(x) expression in C1a cells compared with HM3. Immunohistochemical analysis of 35 colorectal adenocarcinoma and 25 mucinous colorectal carcinoma tissues also demonstrated increased MUC2 apomucin, T, Tn and sialyl Tn antigens in the mucinous cancer specimens. Examination of the biological properties of these cell lines showed that C1a cells had significantly higher in vitro invasive activity in assays of invasion and collagenase activity and significantly lower E-selectin binding and liver colonisation activities in nude mice. These results indicate that colorectal mucinous carcinoma cells differ considerably from colorectal adenocarcinoma cells, both qualitatively and quantitatively, in the pattern of mucin gene expression and in the synthesis and secretion of mucin. In addition, biological studies showed that mucinous carcinoma cells have a greater degree of invasiveness, but less liver colonising activity. These results suggest that the biological and mucin characteristics of mucinous carcinoma cells contribute to extensive local invasion through tissue stroma as the predominant mechanism of tumour progression, while the biological and mucin characteristics of well- to moderately-differentiated colorectal adenocarcinoma contribute to progression via distant metastasis formation.

Theoretical and experimental analysis of air cooling for intracavitary microwave hyperthermia applicators.

An intracavitary microwave antenna array system has been developed and tested for the hyperthermia treatment of prostate cancer at Thayer School of Engineering and Dartmouth-Hitchcock Medical Center. The antenna array consists of a choked dipole antenna inserted into the urethra and a choked dipole antenna eccentrically embedded in a Teflon obturator inserted into the rectum. To prevent unnecessary heating of the healthy tissue that surrounds each applicator, an air cooling system has been incorporated into the rectal applicator. The air cooling system was designed and modeled theoretically using a numerical solution of heat and momentum equations within the applicator, and an analytical solution of the Pennes bioheat equation in tissue surrounding the applicator. The 3-D temperature distribution produced by the air-cooled rectal applicator was measured in a perfused canine prostate.

Quantifying physician teaching productivity using clinical relative value units.

OBJECTIVE: To design and test a customizable system for calculating physician teaching productivity based on clinical relative value units (RVUs). SETTING/PARTICIPANTS: A 550-bed community teaching hospital with 11 part-time faculty general internists. DESIGN: Academic year 1997-98 educational activities were analyzed with an RVU-based system using teaching value multipliers (TVMs). The TVM is the ratio of the value of a unit of time spent teaching to the equivalent time spent in clinical practice. We assigned TVMs to teaching tasks based on their educational value and complexity. The RVUs of a teaching activity would be equal to its TVM multiplied by its duration and by the regional median clinical RVU production rate. MEASUREMENTS: The faculty members' total annual RVUs for teaching were calculated and compared with the RVUs they would have earned had they spent the same proportion of time in clinical practice. MAIN RESULTS: For the same proportion of time, the faculty physicians would have generated 29,806 RVUs through teaching or 27, 137 RVUs through clinical practice (Absolute difference = 2,669 RVUs; Relative excess = 9.8%). CONCLUSIONS: We describe an easily customizable method of quantifying physician teaching productivity in terms of clinical RVUs. This system allows equitable recognition of physician efforts in both the educational and clinical arenas.