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Traditionally, patients are starved of food and fluid for several hours before being given a general anaesthesia. However, in the early days of anaesthesia a drink was often recommended before [...]

Background & Aims: Acute hepatitis B is a highly dynamic human viral infection during which the hepatitis B virus can generate many genetic variants. Methods: We analyzed the evolution of the hepatitis B virus genome in sequential serum samples from a unique cohort of patients with acute infection acquired from a single source. Results: We showed that most mutations were nonsynonymous, that genetic diversity was greatest at the peak of viremia, and that patients who resolved their infection (''resolvers'') showed a significantly higher level of diversity in the core, surface, and polymerase genes compared with those who progressed to chronic infection. Overall, the core gene showed the greatest genetic diversity. In resolvers who possessed an HLA-A*0201 haplotype, the emergence of mutants in the immunodominant HLA-A*0201-restricted core 18-27 epitope was observed. Functional studies showed that these mutants were less able to stimulate interferon-@c release from core 18-27 specific CD8^+ T-cell lines. However, they appeared only as a transient low-abundance species and were rapidly displaced by wild-type sequences before resolution of infection, and their overall significance is uncertain. Conclusions: Overall, genetic evolution of the hepatitis B virus differs at early time points between patients who experience acute resolving hepatitis B and those who progress to chronicity. These observations suggest that the rapid development of broadly reactive host immune responses leads to clearance of hepatitis B virus, even in the presence of possible CD8^+ T-cell immune escape variants.

Background & Aims: Cytotoxic T cells have been suggested to be responsible for lysis of hepatitis B virus (HBV)-infected hepatocytes and control of virus infection. The frequency, kinetics, phenotype, and capacity for clonal expansion of circulating HBV-specific CD8 cells were analyzed directly in patients with acute HBV infection to clarify their pathogenetic role. Methods: Three HLA-A2 peptide tetramers able to visualize HBV core, envelope, and polymerase epitope-specific cytotoxic T lymphocytes were synthesized and used for flow cytometric analysis of antigen-specific populations. Results: Tetramer-positive cells specific for the core 18-27 epitope were found at a higher frequency than those specific for polymerase 575-583 and envelope 335-343 epitopes in most patients with acute HBV. The number of HBV-specific CD8 cells was highest during the clinically acute stage of infection and decreased after recovery. These cells expressed an activated phenotype and had an impaired capacity to expand in vitro and to display cytolytic activity in response to peptide stimulation. Recovery of these functions was observed when the frequency of specific CD8 cells decreased, coincident with a progressive decrease in their expression of activation markers. Conclusions: This study provides the first ex vivo evidence that the highest frequency of circulating HBV-specific CD8 cells coincides with the clinically acute phase of hepatitis B. These cells exhibit an activated phenotype with limited further proliferative capacity that is restored during recovery. GASTROENTEROLOGY 1999;117:1386-1396

Background: The traditional fluid fast prior to endoscopy is unnecessary. We have previously shown that drinking water prior to endoscopy does not affect either the quality of mucosal views or residual gastric fluid volumes when compared to patients undergoing endoscopy after a standard fast. The present study was designed to establish whether milk, which may delay gastric emptying, could also be drunk prior to endoscopy without adverse effect. Methods: Forty-eight patients (mean age 48 years, range 20 to 79) undergoing routine upper gastrointestinal endoscopy after overnight fast were randomized to drink 200 ml of either still mineral water or full fat milk. Endoscopy was performed 90 minutes later, when all residual gastric fluid was aspirated via the endoscope. Volume and pH of gastric aspirate were measured and the quality of the mucosal view at endoscopy recorded as poor, adequate, or excellent. Results: No difference was shown between water (n = 27) and milk (n = 21) drinkers in residual gastric volume (mean +/- SEM, water vs milk) (16.0 ml +/- 1.5 vs 18.9 ml +/- 2.9) or pH (2.23 +/- 0.14 vs 2.48 +/- 0.14). Of those patients with poor, adequate, or excellent views, 4 of 4, 11 of 12, and 6 of 32 patients, respectively, were milk drinkers (chi-squared test for trend = 21.7, df = 1, p < 0.001), indicating significantly worse mucosal views in the group drinking milk. Conclusion: Drinking water up to 90 minutes prior to endoscopy is safe, but milk should be discouraged because of suboptimal mucosal views. (Gastrointest Endosc 1997;45:406-8.)