Biomedical subjects
D C Carter
Publications and source records attributed to D C Carter.
Prophylactic treatment of patients with esophageal varices: is it ever indicated?
The prognosis of patients who bleed from esophageal varices is dismal. Prophylactic treatment of the varix or the elevated portal venous pressure offers a possibility of improving the outlook for these patients. However, as only approximately one-third of patients with varices bleed during their lifetime, correct identification of high-risk patients is vital before embarking on prophylaxis. At present, neither European or Japanese selection criteria are perfect in this respect. The documented incidence of initial variceal bleeding varies between 27% and 48%, and most bleeding episodes occur within the first year after varices are diagnosed. Data from six randomized controlled trials comparing prophylactic beta-blockers with placebo demonstrated a decreased incidence of bleeding in propranolol-treated patients, which in large measure may depend on patient compliance and did not significantly affect survival in all but one study. Early randomized studies of prophylactic sclerotherapy have shown significant reductions in both the incidence of bleeding and mortality, but this promise has not been sustained by subsequent trials, and indeed sclerotherapy was detrimental in two studies. The impressive results in highly selected patients treated in Japan by prophylactic surgery are unlikely to be repeated in a Western setting, involving patient populations that consist predominantly of alcoholic cirrhotics. At present prophylaxis with beta-blockade seems to offer the best therapeutic option, but the future may lie in the development of new interventional techniques such as transjugular intrahepatic portosystemic stent shunting (TIPS) or variceal banding, and ultimately with hepatic transplantation.
The role of selective visceral angiography in the management of pancreatic and periampullary cancer.
A prospective study was undertaken to evaluate selective visceral angiography (SVA) in the management of patients with pancreatic and periampullary cancer. Over a 30-month period 52 patients with potentially resectable pancreatic or periampullary cancer underwent SVA; 4 patients had obvious angiographic evidence of widely disseminated disease and were not subjected to laparotomy while 2 further patients were eventually considered too frail for resection. The remaining 46 patients (median age 58 years, range 37-73 years, males 26, females 20) had no evidence of disseminated disease on ultrasonography and/or CT scanning and had both SVA and surgery and form the basis of this study. Vascular anomalies were detected in 16/46 (35%) patients. Hepatic metastases were wrongly diagnosed by angiography in 7 out of 9 patients (77%). SVA correctly predicted resectability or irresectability in 28/46 patients (overall predictive value 61%). Of the 27 patients who proved to have irresectable disease at operation, 11 were correctly identified by SVA (sensitivity 41%). Of the 13 patients reported to have irresectable disease, 2 underwent resection (false-positive rate 15%). Of the 33 patients reported to have resectable disease, 16 were irresectable (false-negative rate 48%). Overall there was a poor relationship between resectability and the angiographic features. On the basis of these data, SVA cannot be considered a sufficiently accurate means of assessing resectability. Its use for this purpose in patients with pancreatic and periampullary cancer is not justified.
The effects of an anabolic steroid and peripherally administered intravenous nutrition in the early postoperative period.
Sixty patients undergoing colorectal surgery for malignancy were randomized to receive the anabolic steroid stanozolol (n = 30) or to a control group (n = 30). Patients were further randomized to receive on the first 4 postoperative days a) a standard dextrose-saline regimen (DS), b) an amino acid regimen (AA), or c) a glucose-amino acid-fat regimen (GAF) via a peripheral vein. Fat and carbohydrate oxidation rates were calculated pre- and postoperatively using indirect calorimetry. Postoperative nitrogen balance (NB) in patients receiving amino acids was significantly improved (p less than 0.02) by the administration of stanozolol. Fat and carbohydrate oxidation rates were not significantly affected by stanozolol. Patients in the stanozolol and control AA groups showed a fall in carbohydrate oxidation (p less than 0.01) and a rise in fat oxidation (p less than 0.05) postoperatively, whereas no significant changes in fat and carbohydrate oxidation occurred in the two DS and two GAF groups. Cumulative NB for the first 4 postoperative days was significantly better (p less than 0.01) in the two AA groups than in the two DS groups, due to an improved NB in the two AA groups on the 1st and 2nd days only. Cumulative NB in the two GAF groups was significantly better (p less than 0.01) than in all the other groups. This study shows that stanozolol improves postoperative NB in patients receiving amino acids alone, whereas the provision of a more complete nutritional regimen containing glucose, amino acids, and fat results in a positive NB unaffected by stanozolol.
Chemotherapy in advanced gastric cancer.
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Clinical features and management of carcinoma of the pancreas.
Carcinoma of the pancreas remains a disease of uncertain aetiology, late presentation and appalling prognosis. This article reviews the clinical presentation of the disease and the role of surgical and non-surgical methods of management.
An open-label phase I/II dose escalation study of the treatment of pancreatic cancer using lithium gammalinolenate.
There are currently no satisfactory treatments for inoperable pancreatic cancer. Median survivals for untreated patients are of the order of 100 days and, with one exception, no chemotherapy or radiotherapy regime has been found to produce a worthwhile extension of life with reasonably tolerable side effects. Gamma-linolenic acid (GLA) has been found to kill about 40 different human cancer cell lines in vitro without harming normal cells. The lithium salt of GLA (LiGLA) can be administered intravenously and a dose escalation study of a 10 day infusion followed by oral therapy in patients with inoperable pancreatic cancer was carried out in 48 patients in two centres. Peripheral venous infusion caused thrombophlebitis but this could be avoided by infusing via a central vein with appropriate heparinisation. Too rapid infusion caused haemolysis which could be avoided by slow dose escalation in the first few days and maintenance of plasma lithium below 0.8 mmol/l. Doses ranged from 7 to 77g/patient cumulatively delivered over 2-12 days. Other than the above described events there were no important side effects and patients felt well during the infusions. A Kaplan-Meier analysis showed that survival was not significantly influenced by which centre the patients were treated in, the sex of the patients or the presence or absence of histological confirmation. The presence or absence of liver metastases, the patients' Karnofsky scores and the-dose of LiGLA had significant effects on survival from treatment. A Cox proportional hazards model revealed similar results: in both centres, in both sexes, and in patients with and without liver metastases according to the model the highest doses of LiGLA were associated with longer survival times as compared with the lowest doses. LiGLA deserves investigation in a randomised prospective study.