Search PubMed⌕ Search

Biomedical subjects

C W Venables

Publications and source records attributed to C W Venables.

At least 37 records · Page 2Linked to original sources
PubMed1990

The adherent gastric mucus gel barrier in man and changes in peptic ulceration.

The mucus barrier is a layer of water-insoluble gel adherent to the gastroduodenal epithelium. In man most previous studies have focused on luminal mucus or histological assessment of presecreted, intracellular mucus--neither of which can be directly correlated with the protective capacity of the adherent mucus barrier. We here describe direct observation of adherent mucus thickness in man, and changes in peptic ulceration. Adherent mucus gel on human antral mucosa is a continuous homogeneous layer of variable thickness, in the range 50-450 microns (median 180 microns), comprising 67% polymeric mucin. In gastric ulcer patients, adherent antral mucus is significantly increased in thickness (median 240 microns), but is very heterogeneous and structurally a substantially weaker gel, comprising only 35% polymeric mucin. Adherent antral mucus from duodenal ulcer patients is homogeneous, significantly thinner (median 110 microns), and structurally a weaker gel, comprising 50% polymeric mucin. The adherent mucus layer from patients with gastric carcinoma resembled that from subjects with gastric ulcer in that it was very heterogeneous, of significantly increased thickness (median 240 microns) and structurally a very weak gel (23% polymeric mucin). These results are discussed in the context of gastroduodenal mucosal protection against acid and pepsin in the gastric juice.

Duodenal Ulcer↗
PubMed1989

In vitro study of human skeletal muscle strips: effect of nonesterified fatty acid supply on glucose storage.

To examine the effect of increased nonesterified fatty acid concentration on glucose storage in human muscle, an in vitro method for study of glycogen synthesis in this tissue has been established. Muscle strips obtained from rectus abdominus during elective abdominal surgery were clamped at resting length, and adenosine triphosphate/total adenosine nucleotide ratios remained constant for 3 hours ex vivo. Leakage of enzyme markers of muscle damage was minimal, and electron microscopy showed preserved myofibril ultrastructure. Insulin stimulation brought about a dose-dependent increase in rates of glycogen synthesis with a half-maximal effect at 9 x 10(-10) mol/L insulin. In 15 consecutive studies, basal rates of glycogen synthesis were 4.1 +/- 0.5, 3.2 +/- 0.7, and 3.0 +/- 0.3 nmol glucose/25 mg/h in the absence of palmitate, with 1.4 mmol/L and 2.8 mmol/L palmitate, respectively. Insulin-stimulated rates of glycogen synthesis were 8.6 +/- 1.2, 6.0 +/- 1.8, and 5.8 +/- 0.8 nmol glucose/25 mg/h. Thus, increasing fatty acid concentrations decreased rates of glycogen synthesis both basally and with insulin stimulation. The insulin signal itself was not affected as the percentage stimulation over basal rates remained approximately constant in the presence or absence of fatty acid (2.1-, 1.9- and 1.9-fold, respectively). Insulin sensitivity in vivo is usually expressed as absolute rates of glucose uptake during euglycemic hyperinsulinemia, and if plasma fatty acid elevation were to be studied in vivo an erroneous conclusion may be reached of resistance to hormone action per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Treatment of Crohn's disease in relapse with cyclosporin A.

It has been suggested that cyclosporin A might be of some benefit to patients with Crohn's disease. The clinical response and side-effects of cyclosporin A in Crohn's disease are described in a series of 13 adults. The majority of patients had ileal disease and all but one were started on an initial oral dose of 15 mg/kg per day. Duration of treatment ranged from 3 to 42 weeks. Of the 13 patients, 6 showed a response to therapy; the remainder showed no response or deteriorated. The commonest side-effect was hyperaesthesia, but one patient developed nephrotoxicity and one developed hepatotoxicity. Significant drug malabsorption occurred in one case. The side-effects were dose dependent and reversible. Cyclosporin A may have a part to play in the treatment of resistant Crohn's disease, and in our hands has been associated with a 46 per cent response rate; however, the precise role of cyclosporin A in the management of Crohn's disease awaits further study.

Adult↗
PubMed1988

Three computer models for the calculation of prevalence of peptic ulcer disease during long-term treatment.

At present the effects of maintenance treatment for peptic ulcer disease are usually calculated by using 'life-table' analyses. Whilst these accurately demonstrate the speed with which an initial relapse occurs they make no allowance for the fact that, in clinical practice, a relapse often responds to a further course of full-dose treatment and the patient then returns to maintenance therapy. A further compounding factor is that, in any long-term study, patients will be lost to follow-up for a variety of reasons not all related to failure of the treatment. In this paper we describe the use of 'prevalence rates' to better reflect the outcome of peptic ulcer management. Three 'computer models', which have been developed to address the problems of patients leaving the study for any reason during such a long time-period, are also described, as are the underlying assumptions made. Using the results from a long-term study of continuous treatment with cimetidine, the 'prevalence rates' of ulcer disease over 6 years were calculated. Observed relapse rates appeared to fall with time (from 2.7% for duodenal ulcer (DU) and 2.5% for gastric ulcer (GU) to 1% and 2% respectively). However, on applying the models to the data, prevalence rates tended to rise slowly with time for the first 3 years in each of the models tested. At 6 years, two of the models suggested that the prevalence rate for DU would be about 8%; this is not very different to the reported recurrence rate after surgical treatment by truncal vagotomy and pyloroplasty. It is concluded that 'prevalence rates' should be used to assess long-term medical treatments for ulcer disease. Similar methods could also be used to examine the medical treatment of any other disease where multiple relapses, capable of responding to re-treatment, occur. The use of models proved beneficial in compensating for patients lost during the study.

Computer Simulation↗
PubMed1988

Surgery in the management of the gastric side-effects of NSAIDs.

It is now accepted that the administration of non-steroidal anti-inflammatory drugs (NSAIDs) can result in peptic ulceration. Not infrequently, the first presentation of the ulcer is as a life-threatening complication such as a perforation or gastrointestinal bleed. Surgeons often become involved in management when one of these complications occurs. This paper discusses the ways in which NSAID-induced peptic ulceration may present to the surgeon and the special features that distinguish patients with NSAID-induced ulcers from the remainder of patients with peptic ulcer disease. It is pointed out how little has been written on the surgical management of this group of patients. The importance of the overall assessment of these patients, with the correction of nutritional deficiencies and the use of appropriate prophylactic therapeutic measures in their surgical management, is stressed. The criteria for determining what surgical procedure is used and results are described.

Adult↗
PubMed1987

An initial appraisal of the value of serum carbohydrate antigenic determinant (CA 19-9) levels in patients with pancreatic cancer.

Serum CA 19-9 levels have been determined in 20 patients with pancreatic cancer, 18 patients with primary hepatocellular cancer, 15 patients with metastatic liver disease and 10 patients with colorectal cancer. Market elevations 3 times the upper limit of normal were found in all 20 patients with pancreatic cancer, 10 out of 15 with metastatic liver disease and 7 out of 18 with hepatoma. As serum AFP and CEA levels are normal in those with pancreatic cancer, the serum CA 19-9 level provides a sensitive and specific test for this malignancy.

Aged↗
PubMed1987

A randomised, prospective study comparing two contrast media in ERCP.

A randomised, prospective, stratified, double blind study comparing two contrast media in endoscopic retrograde cholangio-pancreatography (ERCP) was undertaken. Forty-six patients received Meglumine/Sodium Ioxaglate (Hexabrix 320) and forty-eight received Meglumine/Sodium Diatrizoate (Urografin 310). The two groups were evenly matched for age, sex and diagnosis. Radiographs were examined independently by two radiologists. There were no differences in radiograph quality with either type of contrast medium. More patients developed pancreatitis following Urografin, suggesting that Hexabrix is a safer contrast medium for ERCP.

Adult↗
PubMed1986

Postvagotomy diarrhoea put into perspective.

Truncal vagotomy and drainage is still the commonest operation for duodenal ulcer in the United Kingdom, despite its known association with diarrhoea. The frequency and severity of diarrhoea were compared in 102 randomly selected men 10 or more years after truncal vagotomy and pyloroplasty (TVP) and a control group of 62 men taking long-term maintenance cimetidine treatment 2 or more years after healing of duodenal ulcer. 53% of the TVP group still had diarrhoea attacks compared with only 7% of the cimetidine group (p less than 0.001). Of the TVP patients, 11% had continuous diarrhoea and a further 22% at least one attack a week. 24% were displeased with the change in bowel function, and 8% complained that diarrhoea still seriously affected their lives. This side-effect is unacceptable and truncal vagotomy should now be avoided whenever possible.

Adult↗
PubMed1986

Use of ERCP to identify the site of traumatic injuries of the main pancreatic duct in children.

Major pancreatic injuries in children are uncommon but potentially very serious. They usually occur in active young boys following characteristic accidents. Despite this they frequently go unrecognized for prolonged periods. Four patients with delayed recognition of blunt pancreatic trauma are described. The presence of pancreatic injury was identified by hyperamylasaemia in every case. Ultrasound and CT scanning were helpful in identifying pseudocysts but accurate pre-operative diagnosis of main duct disruption required endoscopic retrograde cholangiopancreatography (ERCP). Surgical treatment involved a full exploration of the lesser sac with drainage of the cyst contents and identification of the site of extravasation. Two patients with proximal duct lacerations were treated by internal drainage into a Roux-en-Y loop with the addition of a distal pancreaticojejunostomy in one case. Two patients with distal lacerations were treated by distal pancreatectomy and oversewing of the remnant. All four patients recovered and were well at follow-up. Early ERCP is the only reliable method of identifying duct injuries which require urgent surgery. It should be considered in all children with blunt pancreatic trauma.

Adolescent↗
PubMed1985

Duodenitis.

"Duodenitis" remains a controversial area in clinical medicine. This review discusses the various methods of diagnosis (histology, radiology, endoscopy) and concludes that "endoscopic duodenitis" is a definite clinical entity. Studies are presented on the changes in duodenitis in relation to peptic ulcer disease, and it is concluded that "endoscopic duodenitis" is unlikely to be the cause of symptoms unless accompanied by a peptic ulcer.

Cimetidine↗
PubMed1984

Gallstones presenting as mental and physical debility in the elderly.

Within 1 year six elderly patients (aged 80-89 years) were admitted because of non-specific deterioration in mental or physical well-being. In no instance was hepatobiliary disease suspected at the time of hospital admission. One patient presented with intermittent confusion only. The other five were referred with "falls" or having "gone off legs", with malaise, confusion, or incontinence. All had raised alkaline phosphatase levels of 159-1230 IU/l, which led to investigation of the biliary tree. At endoscopic retrograde cholangiopancreatography all were shown to have biliary disease (three common duct stones, one gallbladder calculus, one an abscess, and one a widely dilated common bileduct ). With appropriate treatment (endoscopic sphincterotomy for two, surgery for two, and antibiotics alone for two), all showed a gratifying return of mobility and mental function. Biliary disease is a treatable cause of chronic ill health in the elderly and should be excluded, even in the absence of "classical" symptoms, when there is abnormal liver function.

Aged↗