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R E Pounder

Publications and source records attributed to R E Pounder.

At least 73 records · Page 4Linked to original sources

The beta 3-adrenoceptor agonist CL316243 prevents indomethacin-induced jejunal ulceration in the rat by reversing early villous shortening.

Jejunal villi undergo early histological shortening and vascular injury in indomethacin-induced ulcerative enteropathy in the rat. The protective effects of the beta 3-adrenoceptor agonist CL316243 on this rat model and the mechanism of action were examined using histological techniques. Groups of rats received oral indomethacin (15 mg/kg) and oral CL316243 (0, 0.01-10 mg/kg) 0.5 h beforehand. Jejunal ulceration was assessed 48 h after indomethacin. Other groups received CL316243 either 6 h before or 3 or 6 h after indomethacin. Plasma indomethacin and jejunal prostaglandin E2 levels were determined in groups of rats with and without prior CL316243. CL316243 was a potent dose-dependent inhibitor of jejunal ulceration (> 98 percent inhibition at doses > or = 0.1 mg/kg; ED50 = 0.025 mg/kg) but was not protective when given 6 h after indomethacin. CL316243, 1 mg/kg, reversed early villous shortening and vascular injury. CL316243 did not affect either indomethacin bioavailability or the inhibition of prostaglandin E2. To conclude, the beta 3-adrenoceptor agonist CL316243 is a potent inhibitor of indomethacin-induced jejunal ulceration and the mechanism of protection involves reversal of both villous shortening and vascular injury, which are usefully assessed by histomorphological techniques.

Adrenergic beta-Agonists↗

Direct in situ reverse transcriptase polymerase chain reaction for detection of measles virus.

New methods are described for combined intracellular reverse transcription (RT) and polymerase chain reaction (PCR) using single primer pairs, with direct incorporation of digoxigenin-11-dUTP into amplificants (direct in situ RT/PCR). Routinely used fixatives and minimal pre-treatments were employed. Target sequences of measles virus nucleocapsid (N) and phosphoprotein genes were detected within measles virus infected Vero cells, both in suspension and in formalin-fixed sections, that had been treated by in situ reverse transcription and 30 cycles of direct in situ PCR. Uninfected cells, omission of Taq polymerase, and irrelevant primers were used as controls. Distribution of measles virus within infected cells was determined by in situ hybridisation and immunocytochemistry for measles virus N gene and protein, respectively. Confirmation of amplification within sections was by gel electrophoresis, Southern blotting and sequencing of extracted amplicons. In the majority of cases, measles-infected cells exhibited intense cytoplasmic signal after direct in situ PCR; this was not seen in uninfected cells or infected cells reacted either with irrelevant primers or without Taq polymerase. Unfixed cells in suspension required nested reaction. Measles-specific in situ hybridisation and immunocytochemistry gave an identical signal distribution in sections. Nuclear artifact occurred in some sections and was unpredictable, although it was greatest either in areas of cellular damage, following DNase predigestion, or with vigorous protease pre-treatment. In situ RT-PCR is feasible for measles virus in acutely infected cells both in sections and in suspension. Further work is required to improve the procedure and to eliminate artefactual nuclear signal.

Animals↗

Morning versus evening dosing of lansoprazole 30 mg daily on twenty-four-hour intragastric acidity in healthy subjects.

BACKGROUND: Morning dosing is usually recommended with proton pump inhibitors, but there are few data from 24-h intragastric acidity studies comparing times of dosing. METHODS: A double-blind, placebo-controlled study was performed on the seventh day of dosing to compare the effects of lansoprazole 30 mg given either in the morning or evening on 24-h intragastric acidity in 32 healthy volunteers. RESULTS: The median integrated 24-h intragastric acidity on the seventh day of morning dosing with lansoprazole 30 mg was decreased to 36% of the placebo value, compared with 42% for evening dosing. For each daytime meal-related interval, morning dosing was significantly more effective for controlling acidity, but there was no significant difference between the regimens during the night interval (23.00-08.00 h). CONCLUSIONS: These data favour morning dosing of lansoprazole 30 mg for routine use, but patients with mainly nocturnal symptoms may be best treated by evening dosing.

2-Pyridinylmethylsulfinylbenzimidazoles↗

The safety and efficacy of ranitidine bismuth citrate in combination with antibiotics for the eradication of Helicobacter pylori.

BACKGROUND: Ranitidine bismuth citrate is a novel salt of ranitidine and a bismuth citrate complex. It has intrinsic antisecretory and anti-Helicobacter pylori activity, but monotherapy rarely eradicates H. pylori infection in man. AIM: A pilot study to investigate rates of H. pylori eradication achieved by co-prescription of ranitidine bismuth citrate with antibiotics, and to identify several regimens which would merit further investigation. METHOD: One hundred dyspeptic patients infected with H. pylori were randomly allocated to treatment with ranitidine bismuth citrate 800 mg b.d. plus either amoxycillin, metronidazole, clarithromycin, cefuroxime axetil, tetracycline, tetracycline plus metronidazole or clarithromycin plus tetracycline for 14 days. Eradication of infection was assessed using the 13C-urea breath test 4 weeks after the end of treatment. RESULTS: In a per protocol analysis eradication of H. pylori ranged between 22 and 100%; the intention-to-treat eradication rates ranged between 15 and 92%. No adverse events were specifically attributed to ranitidine bismuth citrate. CONCLUSION: Co-prescription therapy, using ranitidine bismuth citrate and one or more antibiotics, is suitable for further investigation in large-scale clinical trials in patients infected with H. pylori.

Adult↗

A survey of dyspepsia in Great Britain.

OBJECTIVES: To determine the prevalence of dyspepsia in the adult population of Great Britain and to describe the clinical features, treatment, effect of dyspepsia on daily lives and perceptions of peptic ulcer disease. DESIGN: Cross-sectional survey of the adult population using structured questionnaires. SETTING: Subjects interviewed at more than 150 sampling points in England, Scotland and Wales in November 1994. SUBJECTS: A representative sample of the adult population comprising 2112 subjects, aged 16 years or more. MAIN OUTCOME MEASURES: The prevalence of dyspepsia in the adult population and the frequency of various characteristics in dyspeptic subjects. RESULTS: The prevalence of dyspepsia was 40%. Upper abdominal pain and heartburn were the most frequently reported symptoms. Solitary symptoms were uncommon and there was frequent overlap between 'ulcer-like' and 'reflux-like' dyspepsia. Forty-six per cent of dyspeptic subjects reported moderate or severe symptoms. More than half of symptomatic subjects took medication and 22% had visited their GP during the previous year. Overall, 2% of the survey sample had been absent from work due to dyspepsia. Awareness of the factors precipitating or aggravating peptic ulcer disease was poor, particularly in relation to anti-inflammatory drugs. CONCLUSIONS: The present study emphasizes the magnitude of the problem of dyspepsia in the adult population of Great Britain. The survey also shows that the public in general, and patients in particular, require more information if they are to avoid factors known to damage the upper alimentary tract.

Adolescent↗

Thrombotic vascular risk factors in inflammatory bowel disease.

BACKGROUND: Thrombosis may be an important effector mechanism in the pathogenesis of Crohn's disease. METHODS: This study therefore investigated the prevalence of independent thrombotic risk factors (factor VII coagulant activity, lipoprotein (a), fibrinogen, plasma triglycerides, and smoking) in patients with Crohn's disease, ulcerative colitis, and normal controls. RESULTS: In Crohn's disease (n = 75), the mean plasma VII:C, lipoprotein (a) and fibrinogen concentrations were significantly greater than in the normal population (n = 85). In ulcerative colitis (n = 35), only the mean factor VII:C concentration was significantly higher than normal. Ninety three per cent of patients with Crohn's disease and 86% of those with ulcerative colitis had at least one risk factor for thrombotic vascular disease, compared with 61% of the normal population (p < 0.001). CONCLUSIONS: In many young patients with inflammatory bowel disease, plasma concentrations of these prothrombotic factors were in excess of the limits that are regarded as posing an increased risk for the development of occlusive vascular disease.

Adult↗

Gastric mucosal contraction and vascular injury induced by indomethacin precede neutrophil infiltration in the rat.

BACKGROUND: In contrast with earlier reports that neutrophils play a primary part in non-steroidal anti-inflammatory drug (NSAID) injury to the stomach, recent evidence suggests only a secondary role for these cells. AIM: To examine whether early microscopic changes induced by indomethacin in the gastric corpus of fasted rats and the antrum of fasted-refed rats involve neutrophil infiltration. METHODS: Oral indomethacin 30 mg/kg or vehicle was given to six groups of fasted rats that were killed five, 15, and 30 minutes after dosing. Subcutaneous indomethacin 30 mg/kg was also given to six groups of fasted-refed rats that were killed one, two, and four hours later. Haematoxylin and eosin and reticulin stained sections were examined to identify mucosal architectural changes. The gastric mucosa was also examined immunohistochemically for actin, fibrin, and neutrophils. RESULTS: In both the corpus and antrum, indomethacin caused an early phase of mucosal injury that occurred prior to mucosal neutrophil infiltration. Within the superficial corpus mucosa, this phase preceded coagulative necrosis and included surface epithelial expulsion, mucosal contraction with capillary aggregation and distortion, intravascular vascular fibrin deposition, and capillary congestion. The antrum showed similar early changes except that full thickness mucosal coagulative necrosis was a predominant early finding. CONCLUSIONS: In two experimental models of NSAID gastric ulceration the mucosa undergoes early contraction, vascular fibrin deposition, and necrosis prior to neutrophil infiltration. These findings support a primary, neutrophil independent, ischaemic pathogenesis for NSAID gastric ulceration.

Animals↗

Is measles vaccination a risk factor for inflammatory bowel disease?

Measles virus may persist in intestinal tissue, particularly that affected by Crohn's disease, and early exposure to measles may be a risk factor for the development of Crohn's disease. Crohn's disease and ulcerative colitis occur in the same families and may share a common aetiology. In view of the rising incidence of inflammatory bowel disease (Crohn's disease and ulcerative colitis), we examined the impact of measles vaccination upon these conditions. Prevalences of Crohn's disease, ulcerative colitis, coeliac disease, and peptic ulceration were determined in 3545 people who had received live measles vaccine in 1964 as part of a measles vaccine trial. A longitudinal birth cohort of 11,407 subjects was one unvaccinated comparison cohort, and 2541 partners of those vaccinated was another. Compared with the birth cohort, the relative risk of developing Crohn's disease in the vaccinated group was 3.01 (95% CI 1.45-6.23) and of developing ulcerative colitis was 2.53 (1.15-5.58). There was no significant difference between these two groups in coeliac disease prevalence. Increased prevalence of inflammatory bowel disease, but not coeliac disease or peptic ulceration, was found in the vaccinated cohort compared with their partners. These findings suggest that measles virus may play a part in the development not only of Crohn's disease but also of ulcerative colitis.

Adult↗

Is proximal demarcation of ulcerative colitis determined by the territory of the inferior mesenteric artery?

The sharp demarcation between diseased and normal mucosa often observed in ulcerative colitis remains unexplained by current hypotheses of disease pathogenesis. To investigate whether this demarcation occurs at the watershed of vascular territories, the colonic arterial anatomy of 10 patients with ulcerative colitis was studied by in-vitro angiography and macroscopic and histological examination of total colectomy specimens. Of the 10 perfusion-fixed colectomy specimens studied, 7 had pancolitis associated with a complete marginal artery (Arteria marginalis coli) that spanned the entire length of the large bowel. 3 specimens had sharply demarcated disease in which the marginal artery arose from the inferior mesenteric artery and ended abruptly at the point of mucosal demarcation. The colon proximal to this point was histologically normal. These findings suggest that the proximal extent of colitis is determined by the limit of the marginal artery. We suggest that some characteristic of the mucosal microvasculature in the territory of the inferior mesenteric artery, possibly embryological in origin, predisposes the dependent colon to develop ulcerative colitis.

Adult↗

The intracellular polymerase chain reaction for small CMV genomic sequences within heavily infected cellular sections.

The indirect intracellular polymerase chain reaction (in situ PCR) combines the potential sensitivity of the polymerase chain reaction (PCR) with the high specificity and morphological preservation of in situ hybridization (ISH). This study describes a method for the amplification of small, specific cytomegalovirus (CMV) genomic sequences [100 base pairs (bp)] within large formalin-fixed, paraffin-embedded tissue sections. A heat-resistant glue surrounds the section, creating a well which contains a relatively large volume of isotonic reaction solution without a covering mineral oil layer; this optimizes morphological preservation, permits the evaluation of large sections, and allows both denaturation steps and up to 40 cycles of in situ PCR to be performed, whilst progressively concentrating the reaction solution by evaporation during thermal cycling. ISH was performed using a non-isotopic DNA probe with specificity for CMV, with or without prior in situ PCR amplification, both for samples on slides (fibroblasts and lung) and in suspension (fibroblasts). Samples on slides were evaluated by both blinded studies and image analysis, comparing the intensity of signal (P < 0.003) and the numbers of positive cells detected (P < 0.007), with or without intracellular amplification. Cells in suspension were analysed by blinded studies on cytospins and by gel electrophoresis of cell lysates. Successful intracellular amplification was achieved in this high copy model.

Base Sequence↗

Serum concentrations of von Willebrand factor and soluble thrombomodulin indicate alteration of endothelial function in inflammatory bowel diseases.

Serum concentrations of immunoreactive von Willebrand factor (vWF) and soluble thrombomodulin (TM), and vWF multimer patterns were measured to assess endothelial function in patients with inflammatory intestinal diseases. In Crohn's disease and acute infective diarrhea, vWF concentrations were significantly higher than in normal controls. In all patient groups, multimeric analysis of vWF and the concentration of serum TM were not different from normal controls. The results indicate alteration of endothelial function in inflammatory intestinal disorders. They may be compatible with the presence of localized vasculitis, but indicate that systemic endothelial destruction does not occur in inflammatory bowel disease.

Colitis, Ulcerative↗

Inherited disorders of coagulation appear to protect against inflammatory bowel disease.

BACKGROUND/AIMS: Crohn's disease and ulcerative colitis seem to be rarely associated with inherited diseases of coagulation. Histological and hematologic studies suggest that thrombotic mesenteric microvascular occlusion is involved in the pathogenesis of inflammatory bowel disease. The aim of this study was to perform a national survey to determine the prevalence of inflammatory bowel disease among patients with inherited disorders of coagulation. METHODS: Using a postal and telephone questionnaire survey sent to directors of all 129 hemophilia centers in the United Kingdom, the number of patients with inflammatory bowel disease and either hemophilia or von Willebrand's disease was determined. The expected number of cases of inflammatory bowel disease in this population was estimated using published data. RESULTS: Of 6433 patients with hemophilia and 3129 patients with von Willebrand's disease, 4 cases of Crohn's disease were reported compared with expected 11.97-16.58 cases (standardized morbidity ratio, 0.33-0.24; 95% confidence interval, 0.90-0.01; P < 0.05). Ulcerative colitis also occurred significantly less frequently than expected: 9 observed cases in comparison with expected 19.43-31.35 cases (standardized morbidity ratio, 0.46-0.29; 95% confidence interval, 0.91-0.01; P < 0.025). CONCLUSIONS: This epidemiological study provides further evidence that thrombosis and vascular occlusion may be important in the pathogenesis of inflammatory bowel disease.

Adolescent↗

Crohn's disease: pathogenesis and persistent measles virus infection.

The Inflammatory Bowel Disease Study Group at the Royal Free Hospital School of Medicine has tested the hypothesis that the primary pathological abnormality in Crohn's disease is in the mesenteric blood supply. Early morphological studies involved arterial perfusion-fixation and either resin casting and scanning electron microscopy or vascular immunostaining of resected intestine affected by Crohn's disease. Granulomatous and lymphocytic damage to intramural blood vessels, even in macroscopically normal areas, was observed. We put forward possible mechanisms by which a chronic ischemic process might account for many of the idiosyncracies of Crohn's disease. It was proposed that persistent viral infection of the mesenteric microvascular endothelium might underly this vasculitic process; based on certain behavioral characteristics of measles virus, including its tropism for the submucosal endothelium of the intestine, this agent was investigated further. This report reviews the preliminary evidence from both epidemiological and basic scientific data for persistent measles virus in the intestine of patients with Crohn's disease. Possible mechanisms for virus persistence and subsequent reactivation are discussed. In conclusion, we believe that Crohn's disease may be a chronic granulomatous vasculitis in reaction to a persistent infection with measles virus within the vascular endothelium. This granulomatous inflammation, perhaps aggravated by either a hypercoagulable state or mechanical stress, results in the clinical features of Crohn's disease.

Colon↗

Intestinal site-dependent susceptibility to chronic indomethacin in the rat: a morphological and biochemical study.

BACKGROUND: The cyclo-oxygenase inhibitor indomethacin induces a pattern of gastrointestinal injury in the rat that is site-dependent. This study compared the extent of injury to different regions of the rat intestine (small intestine, caecum and colon) with the corresponding changes in arachidonic acid metabolism in these areas, following long-term, low-dose indomethachin. METHODS: Rats (eight per group) received either indomethacin (3 mg.kg/day) or control diet for either 6 or 12 weeks. At termination animals were bled, examined both macroscopically and microscopically for ulcers, and assayed for blood thromboxane B2, intestinal tissue prostaglandin E2 content and production of leukotriene B4. In a further eight animals luminal indomethacin concentrations from the small intestine, caecum and colon were measured following 6 weeks of chronic drug ingestion. RESULTS: At 6 weeks, macroscopic ulcers were observed in 2/8 (small intestine), 3/8 (caecum) and 1/8 (colon) animals. The corresponding ratios at 12 weeks were 5/8, 8/8 and 0/8. In control animals, a site-dependent gradient of the prostaglandin E2 concentration was found. In indomethacin-dosed animals the intestinal prostaglandin E2 content was reduced significantly in the caecum at 6 weeks, and in all tissues at 12 weeks. An increased leukotriene B4 production was observed in the caecum only, at 12 weeks (P < 0.01), and the blood thromboxane B2 was reduced at both time points (P < 0.05). CONCLUSION: There is a site-dependent gradient of the prostaglandin E2 concentration in the rat intestine. The rat caecum is particularly sensitive to long-term low-dose indomethacin, both in terms of chronic intestinal inflammation and changes in prostanoid metabolism. This site-dependent degree of injury may be associated with a local cyclo-oxygenase inhibition.

Animals↗