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Biomedical subjects

C J Hawkey

Publications and source records attributed to C J Hawkey.

At least 163 records · Page 9Linked to original sources
PubMed1994

Treatment of inflammatory bowel disease from now to the millennium.

After decades of therapeutic stasis, treatment advances are occurring in inflammatory bowel disease. Recognition that mesalazine was the active moiety of sulphasalazine has led to a number of new methods of delivering mesalazine without sulphapyridine, with improved toxicity ratios. Current attempts to deliver topical steroids directly to the large bowel have yet to be established as therapeutically effective. Immunosuppressive treatment has been used for many years but recent evidence has firmly established its value and cyclosporin has recently been added to the therapeutic armamentarium. Increasing understanding of the basic processes of inflammation has yielded targets for anti-inflammatory treatments aimed both at the processes of immune activation and of attraction by chemotaxis of neutrophils from the circulation to the lamina propria. Some of these novel treatments, which will be assessed in forthcoming years, involve large molecular weight bioengineered peptides and antibodies that are likely to be expensive and difficult to administer. Other treatment, e.g. 5-lipoxygenase or thromboxane synthesis inhibitors or platelet-activating factor antagonists, are conventional lower molecular weight compounds that are easier to produce and are orally active. It is predicted that 5-lipoxygenase inhibitors will be the next therapeutic advance in inflammatory bowel disease. Such a prediction may founder if blanket suppression of multiple inflammatory mechanisms, rather than targeted actions, is required in inflammation.

Adrenal Cortex Hormones↗
PubMed1994

Review article: aspirin and gastrointestinal bleeding.

Many animal and human studies have shown aspirin to cause gastric mucosal erosions and enhanced spontaneous microbleeding. Chronic use is associated with uncomplicated gastric ulcer (but not clearly with uncomplicated duodenal ulcer) and with presentation with haematemesis and melaena. Sub-group analysis suggests that the risks of bleeding duodenal ulcer as well as bleeding gastric ulcer (and possibly non-ulcer bleeding) are increased. These data imply that an anti-haemostatic as well as an ulcerogenic effect contributes to such presentation and acute data support this proposition. A broken mucosa and inhibition of thromboxane synthesis both appear to be necessary for bleeding to occur. Aspirin enhances the bleeding associated with mucosal biopsy analogous to its prolongation of the skin bleeding time. Anti-haemostatic properties could account for the apparent increase in presentation with haematemesis and melaena in patients taking low doses of aspirin for cardiovascular prophylaxis. However, acute studies also show aspirin 300 mg to cause a level of mucosal injury which is substantial, though significantly less than with aspirin 600 mg q.d.s. The risk attached to aspirin consumption needs to be kept in perspective. It can be calculated that aspirin use is associated with approximately 700 bleeds per annum in the UK. The relative risk for upper gastrointestinal bleeding is roughly similar to that for non-aspirin non-steroidal anti-inflammatory drugs but those affected are generally younger, in an age group where death from upper gastrointestinal bleeding is very uncommon. In keeping with this and in contrast to non-aspirin non-steroidal anti-inflammatory drugs, no study has shown increased mortality from aspirin-related upper gastrointestinal complications.

Anemia, Hypochromic↗
PubMed1994

Scintigraphic assessment of the intragastric distribution and gastric emptying of an encapsulated drug: the effect of feeding and of a proton pump inhibitor.

BACKGROUND: Local delivery of therapeutic agents to the stomach may be a useful strategy in the treatment of Helicobacter pylori infection. We aimed to see whether the intragastric distribution and gastric retention of a therapeutic agent could be improved, either by giving omeprazole or by dosing after a meal. METHODS: Twelve healthy volunteers took part in this double-blind placebo-controlled crossover study comparing the effects of omeprazole 20 mg twice daily for 5 days with placebo, and the fasted with the fed state, on the gastric emptying and intragastric distribution of a soluble scintigrapic marker contained in a drug capsule. RESULTS: Dosing after food profoundly prolonged gastric residence of the drug label, prolonging mean time to 50% emptying (T50) from 0.5 +/- 0.1 h in the fasted state to 2.0 +/- 0.2 h when given after food. Food also improved intragastric distribution by increasing delivery to the body and fundus. Omeprazole enhanced the effect of food, prolonging T50 to 2.9 +/- 0.3 h, but had no effect in fasted subjects. CONCLUSIONS: Dosing after food markedly improves the aspects of local drug delivery to the stomach investigated in this study, and omeprazole enhances this effect. Post-prandial dosing may, therefore, be useful for improving delivery of some anti-Helicobacter agents.

Adult↗
PubMed1994

Low dose aspirin: selective inhibition of rectal dialysis thromboxane B2 in healthy volunteers.

AIM: To investigate the degree and selectivity of rectal thromboxane inhibition by low dose aspirin and there by investigate the contribution of platelet thromboxane to rectal thromboxane. METHODS: The study was a randomized double-blind placebo controlled crossover study. Twelve healthy volunteers were studied, each over four separate study periods with two weeks wash-out between each period. Changes in levels of thromboxane (TX) B2, prostaglandin (PG) E2 and leukotriene (LT) B4 in rectal dialysates were measured in response to 5 days oral low dose aspirin therapy in one of three once-daily formulations (plain 75 mg, plain 300 mg or enteric coated 300 mg), and compared to placebo. For each study period, rectal dialysates (4 h duration) were obtained at baseline and twice more after 5 days of aspirin or placebo therapy. Dialysate levels of thromboxane B2, leukotriene B4, prostaglandin E2, and serum thromboxane B2 were measured by radioimmunoassay. RESULTS: Dialysate thromboxane B2 levels were consistently inhibited by low dose aspirin (overall results of all formulations, 75 to 300 mg daily) from 1.06 ng/ml (geometric mean, 95% CI: 0.79-1.43 ng/ml) on placebo, by 29% (95% CI: 11-40%) to 0.75 ng/ml (0.56-1.01 ng/ml) (P = 0.046) on aspirin. In the absence of aspirin the level of prostaglandin E2 was 1.47 ng/ml (0.97-2.23 ng/ml) and in the presence of aspirin was not significantly changed. The dialysate level of leukotriene B4 was 0.45 ng/ml (0.34-0.61 ng/ml) in the absence of aspirin and there was no significant change on low dose aspirin. Serum thromboxane was inhibited by 80% to 20% of placebo values by plain aspirin 75 mg, by 95% by plain aspirin 300 mg, and by 82% by enteric coated aspirin 300 mg, respectively (P < 0.01). These results show that 29% of the rectal thromboxane, but none of the rectal prostaglandin E2 or leukotriene B4 is inhibited by low dose aspirin. We infer that 34% of the rectal thromboxane B2 is platelet-derived in our volunteers. CONCLUSION: Low dose aspirin will selectively inhibit a proportion of rectal thromboxane and may have prophylactic therapeutic potential in inflammatory bowel disease.

Adult↗
PubMed1994

Interobserver variation in assessment of gastroduodenal lesions associated with non-steroidal anti-inflammatory drugs.

Video endoscopic images were used to investigate whether gastroenterologists could agree on the definition of lesions within the stomach seen at endoscopy, with particular reference to those seen in patients taking non-steroidal anti-inflammatory drugs. Seven experienced endoscopists, unaware of the patients' clinical history or drug consumption, recorded their classification for 93 randomised video images of gastric lesions. There was complete agreement in the diagnosis of ulceration for nine images from patients who were not taking non-steroidal anti-inflammatory drugs; eight of nine were classified as deep ulcers, with 86% agreement for this subclassification. By contrast, the overall agreement for lesions in patients taking non-steroidal anti-inflammatory drugs was only 55%. Only nine of 44 ulcers were subclassified as deep, and there was considerable cross classification of non-haemorrhagic erosions and ulcers. In conclusion, ulcers that occur in patients taking non-steroidal anti-inflammatory drugs differ from those in patients who are not taking these drugs in that they are often more superficial and difficult to distinguish from erosions. The prognostic importance of these lesions is, therefore, uncertain.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Healing and prevention of NSAID-induced peptic ulcers.

Non-steroidal anti-inflammatory drug (NSAID) ingestion is associated with erosions, petechiae, type C gastritis, ulceration, interference with ulcer healing, ulcer complications and injury to the small and large intestines. In the UK, NSAIDs can probably be linked to approximately 1200 deaths per year, mainly in the elderly. Inhibition of prostaglandin synthesis plays a major part in NSAID-induced gastric mucosal injury, whilst inhibition of thromboxane synthesis by platelets and impaired platelet aggregation may contribute to ulcer bleeding. There is evidence to show that the impairment of healing of gastric and duodenal ulcer that is associated with concomitant NSAID therapy can be overcome by the use of omeprazole. Acid inhibition has been shown to be effective in prophylaxis of NSAID-induced duodenal lesions. Studies on the prevention of NSAID-associated gastric lesions have indicated that ranitidine is less effective than misoprostol, but that treatment with the latter is associated with a number of side effects, principally in the gastrointestinal tract (e.g. diarrhoea). Whether omeprazole will prevent gastric and duodenal ulceration due to NSAID ingestion is the subject of ongoing research, but studies of acute ulceration have shown efficacy against erosions and microbleeding.

Aged↗
PubMed1993

Nitric oxide synthase activity in ulcerative colitis and Crohn's disease.

Excessive nitric oxide (NO) production by an isoform of NO synthase that can be induced by inflammatory stimuli leads to changes in vascular permeability and to tissue injury. We measured NO synthase activities in mucosa and muscle from the colons of control patients (n = 11) and patients with ulcerative colitis (6) or Crohn's disease (4). NO synthase activity in colonic mucosa of ulcerative colitis patients was 0.55 (median interquartile range 0.32-0.57) nmol/min per g tissue, which was about eightfold higher than the value in control mucosa, with no individual overlap (p < 0.001). With colonic muscle there was no difference in NO synthase activity between ulcerative colitis patients and controls. In the patients with Crohn's disease, mucosal NO synthase activity did not differ from control values and activity in the colonic muscle was low. Thus, induction of colonic NO synthase may be involved in the mucosal vasodilation and increased vascular permeability of active ulcerative colitis, and could also contribute to the impaired motility that accompanies toxic dilation.

Adult↗
PubMed1993

Audit of outcome of long-term enteral nutrition by percutaneous endoscopic gastrostomy.

Percutaneous endoscopic gastrostomy (PEG) is the preferred method for administration of long-term enteral tube feeding. However, most published studies describe only short-term follow-up in any detail. We report the long-term outcome and complication rate after PEG insertion in 49 patients (mean [SE] age 64 [2] years) whose mean length of PEG feeding was 175 days (range 30-560). Data were collected prospectively. PEG insertion was technically successful in all cases, with a procedure-related mortality of 2%. Early (< 30 days) mortality and morbidity were 8% and 22%, respectively. Of 45 patients surviving for more than 30 days, 76% were able to return home and 6 patients were eventually able to revert to oral feeding. There were 27 late complications: 2 site infections, 17 mechanical problems, and 8 episodes of gastrointestinal dysfunction. 51% of patients had no problems at all and 22% had 2 or more complications. 47% of complications required a hospital visit for resolution. Long-term enteral feeding by PEG was safe, effective, and had a low complication rate. Our patients were managed by a specialist nutrition team, a policy that may reduce the complication rate and hospital visits for patients being fed at home, and allow early discharge of dysphagic patients, thereby reducing costs.

Aged↗
PubMed1993

Ileo-caecal ulceration associated with the use of diclofenac slow release.

A 38-year-old man with seropositive arthropathy on long-standing treatment with diclofenac slow release presented with abdominal pain, diarrhoea and anaemia. Upper gastrointestinal endoscopy and barium series were unremarkable. Five months later he presented with a right iliac fossa mass. Investigations revealed discrete ulceration in the terminal ileum and caecum confirmed at laparotomy. Other possible causes of intestinal ulceration were excluded suggesting a diagnosis of non-steroidal anti-inflammatory drug associated intestinal ulceration.

Adult↗
PubMed1993

Ranitidine bismuth citrate and aspirin-induced gastric mucosal injury.

The aim of this study was to investigate the protective action of a new compound, ranitidine bismuth citrate, in the prevention of aspirin-induced acute mucosal injury to the upper gastrointestinal tract of healthy human volunteers. In a double-blind randomized three-way cross-over study 24 male volunteers received placebo, 900 mg aspirin or 900 mg aspirin and 800 mg ranitidine bismuth citrate at 12-h intervals for nine doses with a 2-week wash-out period between each treatment. The median (interquartile range) number of erosions seen at endoscopy when ranitidine bismuth citrate was given with aspirin (1 [0-4]) was significantly lower than aspirin alone (24 [16-32]) (P < 0.001) and not significantly different from either baseline or placebo (0 [0-2]). These findings were similarly reflected in the effects on microbleeding following the ninth dose: 12.1 (7.1-21.0) microL/10 min following aspirin alone compared to levels with placebo of 1.2 (0.4-2.9), and with aspirin and ranitidine bismuth citrate of 1.6 (0.8-2.6) (P < 0.005). Ranitidine bismuth citrate conferred substantial protection from aspirin-induced injury to the gastric and duodenal mucosa as determined by both endoscopic assessment and microbleeding rates, reducing injury to placebo levels.

Adult↗
PubMed1993

Double blind trial of oral fluticasone propionate v prednisolone in the treatment of active ulcerative colitis.

Fluticasone propionate is a corticosteroid with the potential for topical treatment of ulcerative colitis because of low systemic bioavailability. The drug was compared with prednisolone in the management of active left sided or total ulcerative colitis. Two hundred and five patients were studied in the multicentre four week double blind study. Prednisolone was given in a dose of 40 mg daily orally, reducing over four weeks to 10 or 20 mg. Fluticasone propionate was given in an oral daily dose of 20 mg. The primary end point was the investigator's overall assessment of response. Patient's assessment, sigmoidoscopic appearance, and histology were also studied. Patients improved more rapidly with prednisolone. Differences between the two groups were significant at two weeks. At four weeks differences were not significant, but there was a trend in favour of prednisolone. Corticosteroid side effects were minimal in the fluticasone propionate group, and there was minimal suppression of the hypothalamic pituitary adrenal axis. Fluticasone propionate 20 mg daily is not as effective in the treatment of active ulcerative colitis as prednisolone tapering from 40 mg daily to 10 or 20 mg. The complete absence of suppression of the corticoadrenal axis by fluticasone propionate was encouraging, however, and a higher dosage schedule should be assessed.

Adolescent↗
PubMed1993

Improved symptom relief and duodenal ulcer healing with lansoprazole, a new proton pump inhibitor, compared with ranitidine.

The purpose of this study was to compare duodenal ulcer healing, symptom relief, and safety of lansoprazole (a new proton pump inhibitor) given at doses of 30 mg and 60 mg, in the morning with ranitidine 300 mg at bedtime. Two hundred and eighty nine patients were enrolled over a 20 month period in a double blind randomised parallel group comparative study set in outpatient endoscopy units of six United Kingdom medical centres. Patients were randomised to receive lansoprazole 30 mg in the morning (n = 95), 60 mg in the morning (n = 96), or ranitidine 300 mg at bedtime (n = 98) for four weeks. Efficacy was assessed by gastroscopy at study entry and after two and four weeks of treatment. Symptom relief was monitored by patient diaries and physician review at two and four weeks. Both doses of lansoprazole resulted in significantly greater ulcer healing than ranitidine after two and four weeks. Respective healing rates on lansoprazole 30 mg, 60 mg, and ranitidine 300 mg were 78%, 80%, and 60% after two weeks and 93%, 97%, and 81% after four weeks. Patients on lansoprazole 30 mg (p = 0.002) and lansoprazole 60 mg (p = 0.026) also recorded greater relief of night time pain in the diary cards during the first seven days of treatment than those on ranitidine. Patients on lansoprazole 60 mg reported significantly better pain relief at their two week visit compared with those receiving ranitidine (p = 0.007). There were no differences between treatment groups in the occurrence or pattern of adverse drug reactions during the trial. It is concluded that for patients with duodenal ulcer, lansoprazole 30 mg or 60 mg is associated with faster ulcer healing and better symptom relief than ranitidine 300 mg at bedtime. There were no significant differences between lansoprazole 30 mg and 60 mg. These data indicate that lansoprazole should be used at a once daily dose of 30 mg for the treatment of duodenal ulcer.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1993

Enhanced gastric mucosal leukotriene B4 synthesis in patients taking non-steroidal anti-inflammatory drugs.

The effects of longstanding non-steroidal anti-inflammatory drug (NSAID) treatment on gastric mucosal synthesis of leukotriene B4 (LTB4), leukotriene C4 (LTC4), and prostaglandin E2 (PGE2) was studied. Gastric antral biopsies in 65 patients with arthritis taking NSAIDs and 23 control patients were taken and eicosanoid concentrations, stimulated by vortex mixing or calcium ionophore, were measured by radioimmunoassay. Median gastric mucosal synthesis of LTB4 was increased in patients taking NSAIDs compared with non-users: (0.9(0.2-2.5) pg/mg v 0 (0-0.6) pg/mg (p < 0.001)). These differences persisted when subgroups of patients were analysed according to Helicobacter pylori colonisation or degree of mucosal injury. Synthesis of LTB4 was strongly associated with the presence of type C (chemical) gastritis. Increased synthesis of LTC4 was associated with Helicobacter pylori colonisation but not NSAID use. Synthesis of PGE2 was decreased in patients taking NSAIDs compared with control patients (p < 0.001). Enhanced gastric mucosal synthesis of LTB4 in patients taking NSAIDs may represent a primary effect of these drugs and could be implicated in the pathogenesis of gastritis and ulceration associated with NSAIDs.

Anti-Inflammatory Agents, Non-Steroidal↗