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Biomedical subjects

G J Webster

Publications and source records attributed to G J Webster.

6 recordsLinked to original sources
PubMed1999

Infection and hemostasis in decompensated cirrhosis: a prospective study using thrombelastography.

Bacterial infections are common complications in decompensated cirrhosis, but their relationship with hemostasis has not been studied. We prospectively assessed whether infection affects hemostasis in cirrhosis using routine hemostasis tests and thrombelastography (TEG), a global test of hemostatic function. Eighty-four cirrhotic patients (Child-Pugh B: 26; C: 58) without overt bleeding or blood-product transfusion were prospectively evaluated with routine hemostasis tests and TEG on admission and/or the first day with signs of infection and 5 days later. There were 30 patients with infection; 15 had infection on admission, and 15 developed infection in hospital. In the patients who developed infection in hospital, there was a significant deterioration in all routine hemostasis tests except platelet count (PLT) and in all TEG parameters, on the first day of infection compared with 7 +/- 3 days previously. The same parameters significantly improved from the first day of infection to day 5 and after (P <.02) only in the 22 patients whose infection resolved, while the r, k, and alpha TEG parameters significantly worsened in the 8 patients with persistent infection. In those who developed infection in hospital and were cured (n = 11), the 5-day parameters did not differ from their preinfection values. In conclusion, bacterial infections frequently impair hemostasis in decompensated cirrhotic patients. Successful treatment of infection usually restores hemostasis parameters to preinfection levels in 5 days. Thus, infection may have a role in the bleeding diathesis of cirrhosis.

Adult↗
PubMed1999

Direct ex vivo analysis of hepatitis B virus-specific CD8(+) T cells associated with the control of infection.

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.

Adult↗
PubMed1997

Drinking before endoscopy: milk or water?

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.

Animals↗
PubMed1996

Assessment of residual gastric volume and thirst in patients who drink before gastroscopy.

BACKGROUND: Before endoscopy patients undergo an uncomfortable fluid fast to reduce the risk of gastric acid aspiration and to ensure good endoscopic views are obtained. However, fluids rapidly leave the stomach and thus a long fluid fast before endoscopy may not be required. AIMS: The object of this study was to establish whether drinking before endoscopy is safe and relieves patients' symptoms of thirst. PATIENTS AND METHODS: 88 patients with American Society of Anaesthesiologists classification of physical status grades I and II were recruited in a controlled randomised single blind trial. The volume and pH of gastric aspirate obtained at gastroscopy was assessed in patients who drank 330 ml of water a minimum 90 minutes before their endoscopy and compared with values in patients who starved overnight. RESULTS: 44 patients who drank ('drinkers') 330 ml of water a mean 117 minutes before their morning gastroscopy had a similar volume and pH of gastric aspirate compared with 44 patients starved overnight ('starvers'); median volume 12.5 ml versus 10 ml, median pH 2.0 versus 2.0; 'drinkers' versus 'starvers' (NS). Before endoscopy patients were asked to score their thirst and hunger ratings as either none, mild, moderate or severe. Ratings for moderate and severe thirst were grouped together for analysis. The percentage of drinkers compared with starvers in each group with no thirst, mild thirst, and moderate severe thirst was 63%, 46%, and 37% respectively (chi 2 test for trend p < 0.05). Hunger ratings were similar in the two groups. CONCLUSIONS: It is safe for elective day cases to drink a significant volume of water two hours before endoscopy and this alleviates symptoms of thirst.

Adult↗
PubMed1991

Streptozotocin-induced diabetes in rats causes neuronal deficits in tyrosine hydroxylase and 5-hydroxytryptamine specific to mesenteric perivascular sympathetic nerves and without loss of nerve fibers.

The aim of this study was to investigate the possibility that inadequate venous return to the heart in diabetes is the result of a neuropathy which affects autonomic nerves supplying the splanchnic vasculature. Mesenteric veins from rats with streptozotocin-induced diabetes were markedly dilated in vivo compared to veins from control animals. Dilation appeared to be the result of loss of muscle tone rather than hypertrophy or hyperplasia of the vessel wall. Using quantification by image analysis and double-labeling immunohistochemistry on mesenteric veins, significant reductions in the density of nerve plexuses staining for 5-hydroxytryptamine (5-HT) and tyrosine hydroxylase (TH) were shown in vessels from diabetic rats compared to controls. No reductions were observed in the density of nerve plexuses stained for the neuronal marker, PGP 9.5, or for substance P (SP), a marker for afferent nerve fibers. These results indicate neurochemical deficits in experimentally induced diabetes which are specific to perivascular noradrenergic nerves and which, within the time-scale of our experiments, do not involve loss of nerve fibers. These deficits may contribute to an increase in venous pooling of blood in the splanchnic vasculature of diabetic rats and thus to inadequate venous return to the heart.

Animals↗