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Biomedical subjects

A K Burroughs

Publications and source records attributed to A K Burroughs.

At least 217 records · Page 12Linked to original sources
PubMed1992

Distal spleno-renal shunt versus endoscopic sclerotherapy in the prevention of variceal rebleeding. A meta-analysis of 4 randomized clinical trials.

Meta-analysis was used to evaluate 4 clinical trials comparing distal spleno-renal shunt (DSRS) with endoscopic sclerotherapy (EVS) in the prevention of variceal rebleeding: the interval between bleeding and therapy ranges from < 14 days to > 100 days. A questionnaire was sent to each author of the published trials concerning methods, definitions and results of the trials in order to obtain more detailed and up-to-date information. The selected end-points for the meta-analysis were: rebleeding, mortality and chronic encephalopathy. Analysis of the results in the questionnaires was made using the method proposed by Collins. The pooled relative risk (i.e. the combined Odds ratio of each trial as an estimate of overall efficacy) of rebleeding was statistically reduced by DSRS (0.16; 95% confidence interval 0.10-0.27). Despite this, the overall risk of death following DSRS was only marginally decreased (0.78; 95% confidence interval 0.47-1.29); the lack of homogeneity in the results does not permit any significant conclusions on this end-point. However, in non-alcoholic patients, the decrease in risk of death was greater, and this without heterogeneity, following DSRS than EVS (0.59; 95% confidence interval 0.23-1.50). The overall risk of chronic encephalopathy was slightly increased after DSRS (1.86; 95% confidence interval 0.90-3.86). In conclusion, DSRS significantly reduced the risk of rebleeding compared to EVS without increasing the risk of chronic hepatic encephalopathy. However, DSRS did not significantly affect the overall death risk. Only in non-alcoholic disease did it seem to show an advantage over EVS.

Brain Diseases↗
PubMed1992

Reversal of extrahepatic membrane cholesterol deposition in patients with chronic liver diseases by S-adenosyl-L-methionine.

1. S-Adenosyl-L-methionine is reported to improve serum liver function tests in chronic liver disease. Because liver disease is complicated by cholesterol deposition in hepatic and extrahepatic membranes, we have assessed whether oral administration of S-adenosyl-L-methionine to patients with hepatic disease can reverse the cholesterol enrichment of their erythrocytes. 2. The mean erythrocyte cholesterol-to-phospholipid molar ratio in 13 jaundiced patients was reduced 2 weeks after oral administration of S-adenosyl-L-methionine (from 0.874 +/- 0.112 to 0.844 +/- 0.102, P < 0.05) with 10 of the patients (77%) showing a decrease. By contrast, only four of 11 untreated patients (36%) had a reduced erythrocyte cholesterol-to-phospholipid molar ratio after 2 weeks and the mean values did not differ. 3. The plasma and erythrocyte cholesterol-to-phospholipid molar ratios remained closely correlated (r = 0.77, P < 0.01) before and after treatment, suggesting that S-adenosyl-L-methionine had not acted directly on the cells but rather had improved their lipoprotein milieu. Further support for this concept was provided by following one patient, who initially failed to respond, during an additional 3 weeks of S-adenosyl-L-methionine administration. The plasma cholesterol-to-phospholipid molar ratio fell steadily from week 1 to week 5 and was accompanied by a progressive decrease in the erythrocyte cholesterol-to-phospholipid molar ratio. Moreover, the initially suppressed acetylcholinesterase activity of the erythrocyte membranes returned towards normal during this period. 4. This preliminary study is the first evidence in jaundiced patients that a drug can help to reverse the deposition of cholesterol in an extrahepatic membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1992

Surveillance for CMV infection in orthotopic liver transplant recipients.

Infection with cytomegalovirus is a major cause of morbidity and mortality following orthotopic liver transplantation. In order that preventive strategies may be devised, a detailed assessment of risk factors for infection and disease is required. We have prospectively assessed 46 orthotopic liver transplant recipients for CMV excretion from multiple sites in order to determine incidence of, and risk factors for, CMV infection and disease. Risk factors for posttransplant CMV infection were donor CMV seropositivity, an increased volume of peritransplant whole-blood transfusion and an increased dose of extra steroid therapy to treat rejection episodes. These findings implicate, respectively, transfer of virus with donor organ, transfer of virus with blood transfusion, and stimulation of reactivation of latent virus in recipients through augmented immunosuppression. The possible ways of preventing or ameliorating these effects are discussed.

Adult↗
PubMed1992

Medical management of bleeding esophageal varices.

Vasoactive drug therapy is the only therapy that can be administered immediately to patients with suspected variceal bleeding. The optimal agent is not yet available, but somatostatin or octreotide, glypressin and vasopressin and nitroglycerin are the best candidates. Somatostatin and octreotide have the best therapeutic index as they have very few side effects. They compare well to the other agents in comparative randomized trials. In addition to being used prior to sclerotherapy, vasoactive agents may show benefit when used in combination with endoscopic methods and in the immediate interval thereafter in order to prevent early re-bleeding. This remains to be tested in clinical trials.

Drug Therapy, Combination↗
PubMed1992

Acute management of bleeding oesophageal varices.

The goals of therapy in acute variceal bleeding are to arrest haemorrhage and to prevent deterioration of liver function and complications related to bleeding. The measures used to stop acute bleeding should, ideally, also prevent the very early rebleeding that is frequently seen with bleeding varices. Variceal bleeding should be managed by a gastrointestinal bleeding team with intensive nursing care. Diagnostic endoscopy is mandatory once initial resuscitation has been achieved, and allows immediate injection sclerotherapy of varices. Drug therapy can be used as the first treatment in patients admitted with variceal bleeding since it can be given immediately. Of the available drugs, somatostatin has the least side effects and is as effective as vasopressin, terlipressin and the combination of vasopressin and an organic nitrate vasodilator. The role of drugs needs to be studied in combination with sclerotherapy. Sclerotherapy remains the mainstay of management as it achieves the twin goals of stopping active bleeding and preventing early rebleeding. Injection of tissue adhesive and endoscopic ligation or 'banding' are new endoscopic techniques that have shown promise in preliminary trials and are currently being assessed more widely. Balloon tamponade is a temporary measure used to prevent exsanguination. Surgery should be reserved for those patients in whom sclerotherapy is unsuccessful or cannot be carried out. Oesophageal staple transection is the most used operation. The new interventional radiological technique of transjugular intrahepatic portosystemic shunting will probably replace surgery in the future, but its role in acute variceal bleeding has yet to be fully defined.

Acute Disease↗
PubMed1992

Prevention of variceal rebleeding.

Recurrent variceal hemorrhage occurs in 50% to 80% of cirrhotic patients who survive a variceal bleeding episode. The aim of preventing rebleeding is to improve survival by reducing the mortality associated with rebleeding; however, although shunt surgery is the most effective treatment to prevent recurrent bleeding, it does not increase survival and is associated with an increased incidence of chronic portosystemic encephalopathy. The distal splenorenal shunt is associated with a reduced incidence of encephalopathy, compared with nonselective shunts, but the true magnitude and longevity of this effect is still controversial. beta-Blockers reduce the incidence of rebleeding, but the effect is modest, and there is little or no effect on mortality when compared with no treatment. Injection sclerotherapy reduces the incidence of rebleeding and improves survival when a schedule of both emergency and long-term injection is compared with no sclerotherapy. No technical variation of injection sclerotherapy has been shown to be superior to another. Endoscopic variceal banding may result in fewer complications but the efficacy is similar to that of injection sclerotherapy. Trials of long-term sclerotherapy versus beta-blockers show very similar mortality and rebleeding rates. Addition of beta-blockade to sclerotherapy does not confer any advantages when compared with sclerotherapy alone. Improvements in pharmacologic therapy, such as the addition of isosorbide mononitrate to propranolol, may in the future make drug therapy the first treatment option to prevent rebleeding. Shunt surgery is superior to sclerotherapy in preventing rebleeding and has a similar mortality; however, liver transplantation is technically more difficult in shunted patients, but shunts do not adversely affect overall survival after transplantation. There are few data to allow optimal selection of a particular therapy or sequence of therapies to prevent variceal rebleeding for any individual patient. This will need to be studied in large trials and is a major issue in the current clinical management of cirrhotics who have bled from varices.

Adrenergic beta-Antagonists↗
PubMed1992

Octreotide inhibits the meal-induced increases in the portal venous pressure of cirrhotic patients with portal hypertension: a double-blind, placebo-controlled study.

The aim of this study was to determine the effects of the long-acting somatostatin analog, octreotide, on portal venous pressure and collateral blood flow in cirrhotic patients with portal hypertension during fasting and postprandial states. In a double-blind, placebo-controlled study, we investigated the effects of octreotide on the hepatic venous pressures and azygos blood flow of 21 patients before and after a standard liquid meal containing 40 gm of protein in 250 ml. Octreotide significantly reduced azygos blood flow from a mean of 499 +/- 65 ml/min to a mean of 355 +/- 47 ml/min (p < 0.01), but it had no effect on the hepatic venous pressure gradient. The hepatic venous pressure gradient of patients in the placebo group increased significantly, from a fasting mean of 16.4 +/- 1.6 mm Hg to a mean of 20.0 +/- 1.7 mm Hg 30 min after the meal (p < 0.01). In a second protocol hepatic venous pressures were measured in 20 patients at 30-min intervals for 2 hr after ingestion of the mixed meal. Again the placebo group showed a significant increase in the hepatic venous pressure gradient 30 min after the meal (20.4 +/- 1.5 mm Hg vs. 18.2 +/- 1.2 mm Hg; p < 0.05), but the group receiving octreotide showed no significant changes during the 2 hr of observation. We conclude that octreotide significantly reduces azygos blood flow, with little effect on portal venous pressure, and that it appears to inhibit postprandial increases in portal pressure in cirrhotic patients with portal hypertension.

Blood Flow Velocity↗
PubMed1991

Staple-line erosion: a common source of recurrent bleeding following stapled oesophageal transection.

Recurrent bleeding after stapled oesophageal transection was studied in 73 patients with cirrhosis transected for acute variceal bleeding. The most frequent source of bleeding was partial or total circumferential oesophageal erosion at the transection: staple-line erosion. This lesion occurred in 36 (49 per cent) patients and was the source of rebleeding in 29 (40 per cent) patients with 54 episodes. Rebleeding in 22 (30 per cent) patients was due to varices in nine (12 per cent), peptic ulcer in six (8 per cent), gastric erosions in two (3 per cent) and unknown sources in five (7 per cent), accounting for 33 episodes. The mean(s.e.m.) blood transfusion requirement for bleeding from staple-line erosions were 1.5 (0.25) units per bleed versus other sources, 6.5(1.0) units per bleed (P less than 0.001). Staple-line erosion was present at the first postoperative endoscopy in 11 (15 per cent) patients but the time to appearance varied widely. The lesion was more common in patients with Pugh's grade A liver disease at the time of transection, reflecting the increased survival rate of these patients. Staple-line erosion is a common source of minor recurrent bleeding following stapled oesophageal transection.

Acute Disease↗
PubMed1991

The intra-operative use of trasylol (aprotinin) in liver transplantation.

Aprotinin has been reported to reduce blood loss in difficult cases requiring cardiopulmonary bypass surgery and more recently in liver transplantation. Over a 9-month period we compared the effects of an intra-operative infusion of aprotinin on transfusion requirements and coagulation profiles in 12 patients undergoing liver transplantation for end-stage cirrhosis with an equal number of consecutive transplants in patients with similar pathology who did not receive aprotinin. Transfusion of blood and blood products was reduced to one-third in the aprotinin-treated group. Operative time was also significantly reduced, as was ICU stay post-operatively. Aprotinin profoundly inhibits fibrinolysis and this is likely to be the major effect by which blood loss is reduced. Thromboelastography revealed severe fibrinolytic changes in the anhepatic stage in 4 of 6 controlled patients; this accelerated in 3 following reperfusion of the new graft. By contrast, only 1 patient of 12 in the aprotinin-treated group showed fibrinolytic activity in the anhepatic period, and none showed evidence of fibrinolysis following reperfusion of the new graft.

Aprotinin↗
PubMed1991

Qualitative assessment of von Willebrand factor (vWF) in cirrhotics following repeated doses of desmopressin acetate.

Qualitative abnormalities in von Willebrand Factor (vWF) in patients with cirrhosis have been little studied with contrasting results. We used crossed immunoelectrophoresis (2-DIE) and multimeric analysis of vWF in eight patients with stable hepatic cirrhosis to evaluate abnormalities in vWF before and 1 h following intravenous administration of three doses of desmopressin acetate (0.3 micrograms/kg) given at baseline, 4 and 24 h. We thought that qualitative abnormalities might be more easily detected following desmopressin as this is known to release vWF from storage sites. There was an increased electrophoretic mobility on 2-DIE in all patients with no change following desmopressin. The multimeric analysis did not show an increase in lower molecular weight multimers, but showed a statistically significant increase in higher molecular weight multimers following desmopressin (P less than 0.02). These results suggest that the vWF of cirrhotics has an abnormal charge (not altered by release following desmopressin) which would explain the increased electrophoretic mobility on 2-DIE with a normal pattern of lower molecular weight multimers using multimeric analysis.

Deamino Arginine Vasopressin↗
PubMed1991

Somatostatin and octreotide in gastroenterology.

Somatostatin and octreotide have a definitive role in the management of symptomatic gut neuroendocrine tumours, particularly VIPomas and carcinoid. They probably also have a role in variceal bleeding, but this needs further confirmatory randomized trials. At present there is a potential role in the management of short bowel syndrome, dumping syndrome and gastrointestinal fistulae, but randomized clinical studies are needed. Possibly there is a role in AIDS-related diarrhoea and 'idiopathic' secretory diarrhoea, but more evidence is required. They have no role in acute pancreatitis and peptic ulcer bleeding. Irritable bowel syndrome remains unexplored but unlikely to benefit.

Animals↗
PubMed1991

Hepatocellular ballooning after liver transplantation: a light and electronmicroscopic study with clinicopathological correlation.

The histopathological features of orthotopic liver grafts were studied in 107 serial specimens from 25 patients, to assess the prevalence, possible pathogenesis and prognostic implications of hepatocellular ballooning. Ballooned hepatocytes were found in 46 (54%) of 85 biopsies taken five or more days after transplantation from 16 patients. They were not found in any of the protocol biopsies taken at the time of the operation. Ballooning usually appeared in the second week after transplantation, and in most patients persisted to the time of the latest biopsy studied. The affected cells were always found in acinar zone 3, and sometimes also in other zones. Forty-four of the 46 biopsies with ballooning were taken during a period of clinical and biochemical cholestasis. In 13 of the 16 patients the degree of ballooning paralleled the severity of the cholestasis. Electronmicroscopy of affected hepatocytes showed conspicuous dilatation of the cisternae of the rough endoplasmic reticulum rather than the classical features of cholestasis. It was therefore concluded that ballooning was associated with but not directly caused by bile retention. There was no obvious association between ballooning and cellular rejection, sepsis, immunosuppressive therapy or parenteral nutrition. The most severe early ballooning was associated with serum transaminase levels over 1000 IU/l within 48 h of transplantation, suggesting that ischaemia was one of the pathogenetic factors. Hepatocellular ballooning did not in itself appear to have sinister short-term prognostic implications.

Adolescent↗
PubMed1991

Congestive gastropathy and Helicobacter pylori: an endoscopic and morphometric study.

Congestive gastropathy is a frequent cause of upper gastrointestinal haemorrhage in patients with portal hypertension. The pathogenesis is thought to involve venous congestion with gastric mucosal capillary dilatation. We studied the relation between gastric mucosal capillary dilatation, measured morphometrically, and endoscopic appearances in 74 patients with portal hypertension and 20 control subjects. We also investigated the frequency of gastric colonisation with Helicobacter pylori. Mucosal capillaries in patients were significantly dilated compared with control subjects (p less than 0.001) but the degree of dilatation was not related to the severity of the endoscopic appearances. H pylori was identified in 19 of 74 (26%) patients but was not related to the severity of the endoscopic appearances. These results suggest that other factors in addition to mucosal venous and capillary congestion are important in the pathogenesis of endoscopic congestive gastropathy and that gastric colonisation with H pylori is unlikely to be one of these factors.

Adolescent↗