Effects of H2-receptor antagonists on blood alcohol levels.
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Absorption↗
Biomedical subjects
R E Pounder
Publications and source records attributed to R E Pounder.
Detection of herpesvirus DNA in the large intestine of patients with ulcerative colitis and Crohn's disease using the nested polymerase chain reaction.
The prevalence of herpesvirus DNA was examined in inflammatory bowel disease tissue. DNA was extracted from resection and biopsy specimens of the large intestine from patients with ulcerative colitis (n = 21), patients with Crohn's disease (n = 29), and patients with noninflammatory bowel disease (controls) (n = 21). The nested polymerase chain reaction was used to detect viral DNA using primer pairs specific for either cytomegalovirus (CMV), herpes simplex virus 1 (HSV1), human herpesvirus 6 (HHV6), varicella zoster virus (VZV), or Epstein Barr virus (EBV). HSV1 and VZV DNA were not detected in any of tissue samples. There was a high prevalence of CMV (81%), HHV6 (76%), and EBV (76%) DNA in ulcerative colitis tissue compared to Crohn's disease tissues (CMV 66%, HHV6 45%, EBV 55%). Control tissue had a relatively low frequency of CMV (29%) and EBV (19%) DNA but a prevalence of HHV6 DNA similar to that of ulcerative colitis (86%). However, the simultaneous presence of HHV6 and CMV and/or EBV DNA in ulcerative colitis tissue (76%) was much greater than in either Crohn's disease tissues (38%) or control tissue (29%) (P < 0.05). There was a low prevalence of CMV, HHV6, and EBV DNA in peripheral blood mononuclear cells from all patient groups. CMV and EBV are capable of reactivating HHV6: the high prevalence of coexistent HHV6 infection with either or both of these two viruses in ulcerative colitis tissue suggests that they may play a synergistic role in the pathogenesis of this disease.
Adolescent↗
Neuroendocrine changes in rat stomach during experimental diabetes mellitus.
The effects of 48 days of streptozotocin-induced diabetes mellitus in rats on plasma concentrations of gastrin, somatostatin, pancreatic glucagon, and enteroglucagon have been assessed. In addition, neuroendocrine changes in sections of gastric mucosa were quantified using a computer-assisted morphometric system following immunohistochemical staining with polyclonal antibodies directed against gastrin, PGP 9.5 (a neural protein), and somatostatin. Diabetes resulted in significantly increased fasting plasma concentrations of somatostatin, and entero- and pancreatic glucagon. In contrast, lower plasma gastrin concentrations and decreased antral G-cell density were noted in diabetic rats. Gastric somatostatin and neuronal PGP 9.5 stain densities were unaltered by diabetes. Stomachs of diabetic rats weighed less, but both the jejunum and ileum showed evidence of mucosal hyperplasia. The gastric neuroendocrine atrophy observed in diabetes may be a consequence of elevated plasma somatostatin derived from nongastric sources. The enhanced growth of the intestinal mucosa may be related, directly or indirectly, to raised intraluminal glucose concentration in diabetes.
Animals↗
DNA patterns of Helicobacter pylori isolated from gastric antrum, body, and duodenum.
Biopsy specimens for culture of Helicobacter pylori were obtained from two different sites in the antrum, gastric body, and duodenal cap in 20 patients during endoscopic investigation of dyspepsia. H. pylori was identified in 64 isolates obtained from 15 of the 20 patients. Analysis of chromosomal DNA from these isolates of H. pylori showed that 13 of 15 patients harbored a single strain of H. pylori throughout their stomach and duodenum. Two differing H. pylori types were found in two patients. Unique DNA patterns were shown in each of the 15 patients. The genetic heterogeneity of H. pylori is unexplained but it could be of considerable value for epidemiological studies.
Biopsy↗
A ferret model of acute multifocal gastrointestinal infarction.
Based on the demonstration of mural granulomatous vasculitis in Crohn's disease, it was hypothesized that this vasculitis may account for the discontinuous pattern of lesions in this condition. Accordingly, the present study investigated the histological changes produced by interruption of the submucosal and mucosal microcirculation in the ferret midgut. Two techniques were used. First, up to 30 adjacent vasa recta were ligated using microsurgical techniques; this produced no evidence of ischemic damage. Second, interruption of the submucosal collateral plexus by the intra-arterial injection of styrene microspheres (27-, 50-, or 90-microns diameter) produced acute intestinal mucosal damage. A combination of 27- and 90-microns spheres resulted in focal mucosal inflammation, necrosis, and ulceration. "Summit" lesions with normal adjacent mucosa were observed 48 hours after embolization, with evidence of regeneration of the mucosa overlying the occluded vessels at 72 hours. This model shows that focal gastrointestinal infarction with normal adjacent mucosa can be produced by acute occlusion of submucosal and mucosal arteries.
Acute Disease↗
Transmucosal penetration of bismuth particles in the human stomach.
Electron microscopic examination of upper gastrointestinal biopsies with x-ray microanalysis was used to detect electron-dense particles of bismuth in the mucosa of the upper gastrointestinal tract, 30-60 minutes after oral dosing with either tripotassium dicitrato bismuthate [De-Noltab; Brocades (Great Britain) Ltd., Weybridge, UK; five patients] or bismuth salicylate (Pepto-Bismol; Richardson Vicks Ltd., Egham, UK; five patients), or without dosing (two patients). Transmucosal penetration of bismuth particles was observed in the gastric antral mucosa of all patients who had been dosed with tripotassium dicitrato bismuthate, but there was no penetration after oral dosing with bismuth salicylate. Persorption of bismuth particles through the gastric mucosa to the vascular endothelium provides an explanation for the rapid rise of plasma bismuth concentration observed only after oral dosing with tripotassium dicitrato bismuthate.
Adult↗
Evidence for activation of coagulation in Crohn's disease.
Haemostatic changes in 16 patients with Crohn's disease were studied from active disease into clinical remission and beyond. Elevated concentrations of fibrinopeptide A (FpA) and prothrombin fragments F1 + 2 (F1 + 2) were found at times of both active (FpA median 3.2, range [0.3-40] ng/ml and F1 + 2 median 2.3, range [0.3-18] nm/l) and inactive disease (FpA median 2, range [0.4-40] ng/ml and F1 + 2 median 1.3, range [0.2-20) nm/l]. We also measured the physiological inhibitors of coagulation and fibrinolysis; there was no significant difference in the levels of antithrombin III, protein C or the Exner ratio between active and inactive disease. Free protein S levels were significantly lower in active disease (median 34, range 9-54 U/dl) than in remission (median 40, range 12-65 U/dl). Plasminogen activator inhibitor type 1 (PAI-1) was significantly raised in remission (median 11, range 3-32 ng/ml) when compared to active disease (median 7, range 3-42 ng/ml). The D-dimer correlated significantly with fibrinopeptide A (P < 0.001), suggesting reactive fibrinolysis in some patients. Most (35/52, 67%) samples showed evidence of persistent haemostatic activation (elevated FpA and/or F1 + 2) during phases of apparent clinical remission in Crohn's disease, a factor that is not reflected by clinical activity scores. This study supports the hypothesis that coagulation is activated in the mesenteric vasculature of patients with Crohn's disease.
Adolescent↗
The long-term management of duodenal ulceration using an H2-antagonist: symptomatic self-care compared with maintenance treatment.
In a 48-week study of 319 duodenal ulcer patients, symptomatic self-care with an histamine H2-receptor antagonist (flexible self-chosen dosing with cimetidine 0, 400 or 800 mg/day) was compared with maintenance treatment (cimetidine 400 mg nocte). The rate of withdrawal from the study was similar in both groups. The mean consumption of cimetidine 400 mg tablets was significantly higher in the maintenance group (7.2 vs. 5.4 tablets/week; P less than 0.0001), but the mean cumulative number of days with ulcer symptoms was higher in the symptomatic self-care group (47.2 vs. 29.1 days in 48 weeks). The estimated number of days of work-loss due to ulcer symptoms was similar in both groups (approximately 4 days in the 48 weeks of observation). It is concluded that symptomatic self-care using an H2-antagonist can provide not only an economic but also an effective strategy for the long-term management of uncomplicated duodenal ulceration.
Adolescent↗
Short report: twenty-four-hour hyperpepsinogenaemia in Helicobacter pylori-positive subjects is abolished by eradication of the infection.
Twenty-four-hour plasma pepsinogen I and II concentrations were determined in 8 healthy subjects with antibody to Helicobacter pylori, before and after treatment with tripotassium dicitrato bismuthate, amoxycillin and metronidazole, Therapy was successful in the 5 subjects with active H. pylori infection. In these subjects, median integrated 24-h plasma pepsinogen I and II concentrations significantly decreased from 2288 and 357 micrograms.h/L before treatment, respectively, to 1811 and 171 micrograms.h/L at 4-6 weeks after treatment, and 1643 and 150 micrograms.h/L at 20-24 weeks. By contrast, in the 3 subjects without evidence of active H. pylori infection, pre-treatment plasma pepsinogen I and II concentrations were similar to values found in the H. pylori-infected subjects after successful therapy, and they did not change significantly in response to therapy. H. pylori infection is associated with reversible hyperpepsinogenaemia.
Adult↗
Short report: the effect of ranitidine on the post-prandial absorption of a low dose of alcohol.
Twenty healthy male subjects were studied twice using a double-blind, randomized placebo controlled, cross-over study design. Alcohol absorption (integrated 2-h plasma alcohol concentration, peak plasma alcohol concentration, and time to reach peak concentration) was measured after 8 daily doses of either placebo or 300 mg ranitidine. They were given alcohol, 0.15 g/kg of body weight by month after an evening meal. Compared with placebo, there was a trend towards higher integrated 2-h plasma alcohol concentrations (3.17 and 3.89 mg. h/dL, respectively, P = 0.07), and a statistically significant increase in mean peak plasma alcohol concentration after dosing with ranitidine (4.92 and 6.47 mg/dL, respectively, P = 0.05).
Adult↗
Comparison of one-day oral dosing with three bismuth compounds for the suppression of Helicobacter pylori assessed by the 13C-urea breath test.
Assessment of intragastric urease activity by the 13C-urea breath test was performed before and after one day of dosing with either De-Noltabs (tripotassium dicitrato bismuthate, one tablet 1 q.d.s.), Pepto-Bismol liquid (bismuth salicylate 30 ml q.d.s.), or Roter tablets (bismuth subnitrate, one tablet q.d.s.) in twelve Helicobacter pylori-positive patient volunteers. There was a significant decrease in the excess of 13CO2 after one day of dosing with each of the three bismuth compounds, but analysis of variance could detect no difference between the effects of the three compounds. Systemic absorption of bismuth following oral dosing with either Pepto-Bismol or Roter is minimal, yet both compounds have a suppressive effect on H. pylori similar to that of De-Noltab. This study suggests that the action of all three bismuth compounds is within the gastric lumen, and that systemic absorption of bismuth is not necessary for activity against H. pylori.
Adult↗
Ranitidine, cimetidine, famotidine have no effect on post-prandial absorption of ethanol 0.8 g/kg taken after an evening meal.
Forty-seven healthy male subjects were studied twice using a randomized, placebo-controlled design. Each subject took an 8-day course of two of the following four regimens; 300 mg ranitidine, 800 mg cimetidine, 40 mg famotidine or placebo (identical either to 300 mg ranitidine or 800 mg cimetidine). The systemic bioavailability of ethanol (integrated 6-h plasma ethanol concentration, peak plasma ethanol concentration, and the time to peak plasma ethanol concentration) was measured after the oral ingestion of 0.8 g of ethanol per kg body weight, given one hour after an evening meal on Day 8 of each regimen. There was no significant difference of integrated 6-h plasma ethanol concentration, peak ethanol concentration, or time to reach peak ethanol concentration after dosing with either ranitidine, cimetidine or famotidine or placebo.
Absorption↗
Mucosal capillary thrombi in rectal biopsies.
We studied the initial rectal biopsy from 46 patients in whom subsequent follow-up established the diagnosis of either self-limited colitis or inflammatory bowel disease. An additional 12 non-inflamed rectal biopsies were also studied. There was between 2 and 8 years of follow-up in each of these cases. Staining for fibrin (MSB, fibrinogen), platelets (factor XIIIA, Y2/51), and capillary basement membrane (reticulin, collagen 4) was performed to identify thrombotic material within capillaries. Mucosal capillary thrombi were best identified by staining for factor XIIIA; thrombi were observed in 8/13 cases of ulcerative colitis, 4/10 cases of Crohn's disease, 1/3 cases of unspecified inflammatory bowel disease and 5/20 cases of self-limited colitis. The presence of capillary thrombi was not related to the severity of inflammation, but none of the control biopsies showed capillary thrombi. Their presence seems of little diagnostic value in distinguishing inflammatory bowel disease from self-limited colitis. The pathogenetic significance of these mucosal capillary thrombi is uncertain.
Adult↗
DNA fingerprints of Helicobacter pylori before and after treatment with omeprazole.
AIMS: To test whether a hypoacidic environment may potentially "stress" Helicobacter pylori DNA, encouraging the emergence of strain variation. METHODS: This hypothesis was tested by inducing prolonged hypoacidity with omeprazole, a potent antisecretory drug. The genomic DNA of H pylori was studied by electrophoretic separation of restriction endonuclease fragments followed by rRNA gene hybridisation in seven patients infected with H pylori before and after treatment with omeprazole 20-40 mg daily for six to eight weeks. DNA was isolated and purified using the guanidium thiocyanate reagent method. DNA samples were digested with Hae III, electrophoresed, vacublotted, and hybridised using a biotinylated cDNA probe prepared from 16S and 23S rRNA from H pylori NCTC 11638. Isolates were compared using their ribopatterns (DNA fingerprints). RESULTS: A total of 26 isolates were obtained; all DNA isolates were cut by Hae III, which was the enzyme that gave the best resolved hybridisation patterns for analysis. No two patients harboured the same strain. The isolates from two patients showed evidence of subtypic variation; one patient had two distinct strains and four patients had their own indistinguishable strains before and after treatment with omeprazole. For each patient, the paired ribopatterns of H pylori DNA were not affected by treatment with omeprazole for six to eight weeks. CONCLUSION: The H pylori genome is relatively stable when exposed to the conditions of prolonged hypoacidity that result from treatment with omeprazole.
DNA Fingerprinting↗
Gastric epithelial cell proliferation and histological damage after hypertonic sodium chloride: the effect of variation in the strain of rat.
Two strains of rat, Sprague-Dawley and inbred Piebald Virol Glaxo pigmented (PVG) strain, were dosed orally with hypertonic sodium chloride at a dose of 0.25, 0.5, 1.0 or 1.33 g/kg. Gastric epithelial cell proliferation was compared 16 hours after a single dose. The rats were given intraperitoneal bromodeoxyuridine (20 mg/kg) 1 hour before sacrifice, and cells undergoing DNA synthesis (S-phase) were assessed using a monoclonal antibody to bromodeoxyuridine. The number of labelled cells per gastric gland was counted using video image analysis, assessing ten low-power fields (160-180 gastric glands) per rat. Tissue injury was graded for submucosal oedema, inflammation and necrosis; it was minimal after dosing with 0.25 and 0.5 g/kg of sodium chloride. The PVG rats were more susceptible to tissue injury after dosing with 1.0 or 1.33 g/kg of sodium chloride: submucosal oedema, 80% in the PVG and 10% in the Sprague-Dawley; inflammation, 70% compared with 10%; necrosis, 70% compared with 20%. The number of labelled cells per fundic gland increased with increasing dose concentration of sodium chloride and the response was similar for both strains of rat. Plasma gastrin concentration at the time of sacrifice was significantly higher in the PVG rat for the 0.5, 1.0 and 1.33 g/kg doses. These strain differences may be useful in the further evaluation of the mechanisms of sodium chloride-induced tissue damage and repair.
Animals↗
Smoking, the oral contraceptive pill, and Crohn's disease.
Both cigarette smoking and the oral contraceptive pill have been implicated as aggravating factors in Crohn's disease. Based upon the recent demonstration of multifocal gastrointestinal infarction in Crohn's disease, a possible pathogenic mechanism for this condition, we propose how smoking and the oral contraceptive pill may potentiate a tendency for focal thrombosis and hence exacerbate the activity of Crohn's disease.
Blood Coagulation↗
Nocturnal intragastric acidity during and after a period of dosing with either ranitidine or omeprazole.
The magnitude and duration of changes in nocturnal intragastric acidity caused by 25 days of dosing with the antisecretory drugs ranitidine and omeprazole were investigated in a double-blind study of 22 healthy subjects. Nocturnal intragastric acidity was studied before (twice), during (on day 25), and after (every 3 days for 21 days) dosing with either 300 mg ranitidine at night or 40 mg omeprazole every morning. Three and six days after withdrawal of dosing with ranitidine, median integrated nocturnal intragastric acidity was increased significantly (17% and 14%, P = 0.01 and P = 0.05, respectively) compared with before dosing. Three days after withdrawal of dosing with omeprazole, median integrated nocturnal intragastric acidity was decreased significantly (-23%, P = 0.003). Compared with before dosing, no significant differences were seen in the ranitidine group between days 9 and 21 or the omeprazole group between days 6 and 21 after cessation of dosing. Fasting plasma gastrin concentration was measured on the morning of each study; compared with before treatment, the only significant elevations occurred on the last day of dosing with omeprazole (before, 4 pmol/L; during, 7 pmol/L). It is concluded that rebound intragastric hyperacidity after dosing with 300 mg ranitidine at night or sustained hypoacidity after dosing with 40 mg omeprazole every morning reflect transient disturbances of gastric function that are unlikely to be of clinical importance.
Adult↗
The effect of histamine H2-receptor blockade on bismuth absorption from three ulcer-healing compounds.
Twelve healthy male subjects were dosed with six regimens: ranitidine and De-Noltab (tripotassium dicitrato bismuthate; Gist-Brocades Ltd., Weybridge, England), placebo and De-Noltab, ranitidine and Pepto-Bismol liquid [bismuth salicylate; Procter & Gamble (Health and Beauty Care) Ltd., Egham, England], placebo and Pepto-Bismol, ranitidine and Roter tablets (bismuth subnitrate; Roter Pharma Ltd., Ashford, England), and placebo and Roter. Ranitidine, 300 mg, or placebo was administered at 10 PM (night before) and at 7 AM; at 9 AM, the oral dose of bismuth was either 2 De-Noltabs, 3 30-mL doses of Pepto-Bismol liquid, or 2 Roter tablets. When predosed with placebo, the median integrated 8-hour plasma bismuth concentration was significantly greater after dosing with De-Noltabs than after dosing with either Pepto-Bismol or Roter (61, 8, and 8 ng.h/mL, respectively), with a similar trend for 8-hour median urinary bismuth excretion (213, 40, and 6 micrograms, respectively). When predosed with ranitidine, only after De-Noltab administration were there significant increases in the 8-hour plasma bismuth concentration (147 ng.h/mL), and 8-hour urinary bismuth excretion (686 micrograms). Eliminating intragastric acidity may enhance bismuth absorption after oral dosing with De-Noltabs by maintaining intragastric tripotassium dicitrato bismuthate as a colloidal suspension.
Adult↗