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Biomedical subjects

M G Robinson

Publications and source records attributed to M G Robinson.

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

The effect of raw onions on acid reflux and reflux symptoms.

Patients with gastroesophageal reflux often describe heartburn after "spicy meals." One ingredient common to most such meals is onion. We investigated the effects of onion on acid reflux and reflux symptoms in 16 normal subjects and 16 heartburn subjects. Subjects were studied with an esophageal pH probe for 2 h after the ingestion of a plain hamburger and a glass of ice water. The identical meal, with the addition of a slice of onion, was ingested on a counterbalanced day. Variables measured were number of reflux episodes, percentage of the time pH was less than four, heartburn episodes, and belches. Ingestion of onions did not increase any of the reflux variables measured in normals. However, onions significantly increased all measures in heartburn subjects, compared with the no-onion condition, and compared with normals under the onion condition. Onions can be a potent and long-lasting refluxogenic agent in heartburn patients.

Adult↗
PubMed1989

Effect of ranitidine on gastroduodenal mucosal damage induced by nonsteroidal antiinflammatory drugs.

The effect of ranitidine in preventing mucosal damage caused by nonsteroidal antiinflammatory drugs (NSAIDs) was evaluated for eight weeks in a prospective study of 144 patients requiring NSAIDs. Patients with normal endoscopic findings were randomly assigned to receive either ranitidine 150 mg twice daily or placebo for eight weeks, along with either ibuprofen, indomethacin, naproxen, sulindac, or piroxicam. Duodenal damage was significantly less in the ranitidine group compared with the placebo group by weeks 4 and 8 (P less than or equal to 0.01). Duodenal ulcers did not develop in any patients on ranitidine (0/57) compared with 4/49 patients (8%) on placebo (P = 0.02). No significant difference was found between treatment groups with respect to gastric damage; 6/60 (10%) in the ranitidine group compared with 6/50 (12%) in the placebo group developed gastric ulcers. These findings suggest that acid suppression is of greater importance for mucosal protection in the duodenum than in the stomach, where other defense mechanisms may be operative. While ranitidine is an effective prophylaxis for NSAID-induced damage in the duodenum, further studies are needed to define specific risk groups and to assess the potential usefulness of more complete acid suppression in preventing gastric mucosal damage.

Adult↗
PubMed1989

Lower esophageal sphincter pressure, esophageal body motor functioning, and esophageal acid sensitivity.

Esophageal acid sensitivity is believed to develop as a result of esophageal acid exposure, contributing factors being gastroesophageal reflux and delayed esophageal acid clearance. The relationship among lower esophageal sphincter pressure, motor functioning of the body of the esophagus, and esophageal acid sensitivity was examined by comparing the results from 912 patients and normal subjects studied with both esophageal manometric and Bernstein acid infusion tests. Positive acid infusions were statistically more closely associated with hypotensive lower esophageal sphincter pressures than with any motor abnormality in the body of the esophagus. Of the several esophageal body motor abnormalities considered, only feeble peristalsis had significantly more positive Bernstein tests than did normal esophageal body motor functioning. The findings from this study demonstrate that hypotensive lower esophageal sphincter pressure is more closely associated with an acid-sensitive esophagus than is impaired esophageal body motor functioning.

Esophagitis↗
PubMed1989

New oral salicylates in the therapy of chronic idiopathic inflammatory bowel disease.

Sulfasalazine has been the mainstay of therapy for ulcerative colitis and Crohn's disease of the colon. More recently, it has become clear that 5-ASA is the active moiety of the compound and that the sulfapyridine component is responsible for most of the adverse responses to sulfasalazine. The modes of action of sulfasalazine and 5-ASA have not been determined despite active investigations. There has been great current emphasis on the development of delivery systems to allow maximum concentration of therapeutically active 5-ASA in the colon or other gastrointestinal mucosal locations. Olsalazine accomplishes this goal by creatively coupling two molecules of 5-ASA to each other by a diazo bond. Bacterial azoreductases uncouple the parent drug and deliver 5-ASA to the colonic mucosa. Several pharmaceutical manufacturers have devised variations in mesalamine (5-ASA) coatings designed to release in pH and time-related manners. Oral Rowasa, Claversal, and Asacol accomplish distal delivery with acrylic coating of tablets. Oral Pentasa seems unique in distributing 5-ASA throughout the small bowel as well as the colon by utilization of small ethylcellulose-coated microgranules. For this reason, Pentasa may be particularly useful in the treatment of small bowel Crohn's disease. There are no data to suggest that patients unresponsive to oral sulfasalazine will respond to 5-ASA in any form, although it is possible that better toleration of the 5-ASA formulations will allow more effective dosage levels to be delivered. There are also preliminary data supporting synergism between oral and topical rectal 5-ASA in certain patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

Anorectal functioning in fecal incontinence.

Manometric testing was performed on three groups of subjects: 14 patients complaining of fecal incontinence, 14 age- and sex-matched continent patients, and 14 sex-matched younger normal controls. The younger group displayed significantly stronger contractions of the external anal sphincter and puborectalis than the two patient groups, which did not differ. No differences were found in the relaxation of the internal and sphincter. The incontinent group required a significantly larger stimulus in order to detect rectal distension compared to either the continent patients or the younger normals. An additional group of unmatched normals and incontinent patients demonstrated significant differences in their ability to retain rectally infused saline. The patients leaked sooner and retained less; however, the performance of the normals was considerably reduced from that reported in previous studies. The aging process seems to result in weakening of the striated muscles of the anal canal, although fecal incontinence need not occur. The afferent limb of the anorectal sensorimotor mechanism does not necessarily deteriorate with aging. A lower threshold for sensation of rectal distension among continent individuals apparently helps them to avoid incontinent episodes, even though maximum contractile pressures in their anal canal are no different from a comparable group of incontinent individuals.

Adult↗
PubMed1988

Esophageal acid clearance during sleep in patients with Barrett's esophagus.

Sleep-related gastroesophageal reflux and esophageal acid clearance have been shown to be important components in the pathogenesis of reflux esophageal disease. Previous studies have suggested that patients with more severe esophagitis are distinguished by an accumulation of acid mucosal contact time during sleep. These data would suggest that patients with Barrett's esophagus should have particularly severe impairment of acid clearance, most notable during sleep. To address this issue, 16 asymptomatic healthy volunteers and 13 patients with Barrett's esophagus were studied. Acid clearance was assessed by timing the reestablishment of an esophageal pH of 4 following the infusion of 15 ml 0.1 N HCl. Sleep was polygraphically monitored in order to objectively determine sleep and waking. The results indicated that while patients with Barrett's esophagus had a marked increase in the frequency of spontaneous gastroesophageal reflux during sleep, they unexpectedly demonstrated faster acid clearance times during both waking and sleep. A greater percentage of arousal responses to acid infusion during sleep was noted in the Barrett's group. It is concluded from these results that patients with Barrett's esophagus can adequately clear acid from the distal esophagus but experience considerable acid mucosal contact through repeated episodes of spontaneous reflux during sleep.

Adult↗
PubMed1988

Water swallows versus food ingestion as manometric tests for esophageal dysfunction.

Data from 100 consecutive patients with chest pain or dysphagia, or both, who underwent esophageal testing with standard water swallows and upright food ingestion were retrospectively evaluated. In addition to having manometric patterns monitored, patients were asked to relate symptoms during testing. Of 77 patients with a history of dysphagia, significantly more had abnormal manometry during the test meal than with water swallows (79 vs. 43%, p less than 0.005). Additionally, dysphagia, although reported in only 8% of these patients during standard testing, occurred in 47% during the test meal (p less than 0.001). Of 60 patients with chest pain, symptoms were rarely reported (5%) with water or with food ingestion. We conclude that manometry with food ingestion should be used as a provocative test in anatomically normal patients with dysphagia.

Adult↗
PubMed1988

Dose--response effect of famotidine on patterns of gastro-oesophageal reflux.

The present study attempts to assess the alteration in patterns of gastro-oesophageal reflux as assessed by 24-h oesophageal pH monitoring by varying degrees of H2-receptor blockade with famotidine. Subjects were 12 patients with complaints of daily heartburn who demonstrated at least 6% of acid mucosal contact time by 24-h ambulatory oesophageal pH monitoring. All subjects had a positive Bernstein test, and nine of the 12 subjects had erosive oesophagitis. The study was conducted as a double-blind crossover design utilizing 40 mg nocte, 20 mg b.d., and 40 mg b.d. and placebo treatments. Results indicated that all treatments significantly reduced the 24-h percentage acid contact time (P less than 0.05) compared to placebo. The two b.d. treatment regimens also significantly (P less than 0.05) reduced the number of episodes lasting longer than 5 min. Only the b.d. regimens successfully lowered the percentage of upright acid exposure. All treatments significantly (P less than 0.01) reduced the percentage of supine acid contact time, as well as the number of episodes lasting more than 5 min. It is concluded that gastro-oesophageal reflux disease may well require a b.d. dosing regimen with famotidine in order to achieve optimal mucosal healing and day time symptom control.

Adult↗
PubMed1988

The timing of evening meal and ranitidine administration--effects on patterns of 24 hour intragastric acidity.

Intragastric pH-metry was utilized to assess the effect of the time of meal ingestion and ranitidine administration on 24-h intragastric acidity. Twelve volunteers with a documented history of duodenal ulcer were studied in a four-way crossover design. Subjects randomly received ranitidine at 18.00 and 22.00 hours, with and without food. Serial blood samples were collected and analysed for ranitidine by high pressure liquid chromatography. Over the interval of 18.00-0.700 hours, the mean hydrogen-ion activity was significantly lower with the 18.00 hour dose than with the 22.00 hour dose (P less than or equal to 0.05). There were no differences between the four treatments in median pH or mean hydrogen-ion activity over the 23-h study interval. There were no differences between treatments in peak ranitidine concentrations, time to peak concentration, area under the serum-concentration time curve or elimination half-life.

Adult↗
PubMed1988

Validation of an ambulatory esophageal pH monitoring system.

The present study documents the accuracy of a commercially available ambulatory esophageal pH instrument. The distal esophagus of five subjects with daily heartburn was monitored for 24 h in the laboratory via an antimony pH electrode. The computer output from the ambulatory unit was compared to the on-line recording in terms of all events in which the pH dropped below four. A signal detection model was used, with an on-line pH tracing serving as the criterion response. The events noted as true positives (80%) were an accurate representation by the computer output of the events of pH less than four displayed by the on-line recording. The processing done by this particular ambulatory system tends to actually "ignore" transient pH drops (18% false negatives) and, may, in fact, provide more physiologically meaningful information than hardwired analog techniques for 24-h pH monitoring. The results confirm that ambulatory pH monitoring can produce meaningful and reliable physiological data concerning gastroesophageal reflux.

Adult↗
PubMed1987

Salmonella newport infections transmitted by fiberoptic colonoscopy.

During a 2-week period following the colonoscopy and biopsy of a patient with acute Salmonella newport gastroenteritis, S. newport was recovered from colonic aspirates or fecal specimens of eight of 28 patients from whom specimens were cultured during or after colonoscopy. Two of the eight persons from whom S. newport was isolated developed acute gastroenteritis, two had asymptomatic infections, and four had positive aspirates collected through a colonoscope but did not become infected. Although S. newport was never recovered from the four colonoscopes used during the outbreak, cultures of one of the colonic biopsy forceps grew S. newport. Contamination of the equipment most likely occurred during colonoscopy of the index patient. Inadequate disinfection of the equipment allowed the organism to survive and possibly to cross-contaminate other colonoscopes, and the organism was then transmitted to other patients by use of the contaminated colonoscopes or the contaminated biopsy forceps. Implemented control measures terminated the outbreak.

Adult↗
PubMed1987

Effect of smoking in a controlled study of ranitidine treatment in gastroesophageal reflux disease.

Smoking has been shown to be a factor in acid peptic disease. A recent U.S. multicenter trial investigating use of ranitidine in the treatment of gastroesophageal reflux disease provided an opportunity to compare smokers and nonsmokers with regard to demographic features, manifestations of disease, and symptomatic response to treatment. A comparison of characteristics of smokers and nonsmokers revealed similar pretrial clinical findings. No significant differences between groups were found with regard to previous complications or recent symptoms of gastroesophageal reflux disease. There were also no significant differences in the way smokers and nonsmokers responded to treatment. Subjects on ranitidine, regardless of their smoking status, showed significantly greater improvement in heartburn symptoms and consumed less antacid than subjects who received placebo. Results of these analyses indicate that smoking as an independent variable was not related to symptomatic response or esophageal healing and that ranitidine was similarly effective in decreasing heartburn symptoms in smokers and nonsmokers.

Adult↗
PubMed1987

Comparison of calcium channel blocking agents and an anticholinergic agent on oesophageal function.

The effects of oral doses of three calcium blockers and an anticholinergic drug on oesophageal function were compared. Nifedipine (20 mg) and hyoscyamine (0.25 mg) significantly reduced lower oesophageal sphincter (LES) pressure and oesophageal contractile pressure. Verapamil (120 mg) and diltiazem (60 mg) had no significant effect on any of the oesophageal variables measured. Oesophageal transit time and oesophageal contractile duration were not affected significantly by any of the agents. Only hyoscyamine significantly prolonged acid clearance time. The combination of nifedipine and hyoscyamine was no more effective in decreasing LES pressure or oesophageal contractile pressure than either agent alone. Either nifedipine or hyoscyamine would appear to be potentially effective for the treatment of oesophago-spastic and other hypertensive motor disorders, but hyoscyamine may lead to prolongation of acid clearance from the oesophagus.

Adult↗
PubMed1987

Do endoscopic findings influence response to H2 antagonist therapy for gastroesophageal reflux disease?

As part of a multicenter trial evaluating ranitidine in the treatment of gastroesophageal reflux disease, the therapeutic responses of patients with and without abnormal endoscopic findings were evaluated. All patients were randomized to either placebo or ranitidine (150 mg bid) treatment groups. The treatment interval was 6 wk. Thirty-seven percent of 283 patients enrolled in the trial had normal baseline endoscopy. Compared to the placebo group, 147 evaluable ranitidine patients with abnormal endoscopy displayed a marked and rapid symptom reduction which was sustained throughout the last 4 wk of therapy. Despite randomization of endoscopically normal patients, those treated with ranitidine had significantly more heartburn at baseline. However, the 89 evaluable ranitidine-treated patients with normal endoscopy also experienced a marked and rapid reduction in heartburn at the end of 1 wk. The symptomatic improvement in the endoscopically abnormal ranitidine patients was significantly greater (p less than 0.05) than that observed in the endoscopically normal ranitidine group. Since both groups fared better on ranitidine than placebo, the results of this study indicate that ranitidine is an effective treatment for patients with heartburn symptoms and documented esophageal acid sensitivity whether or not endoscopic parameters for esophagitis are present.

Adolescent↗
PubMed1985

The effects of swallowing frequency and transdermal scopolamine on esophageal acid clearance.

Fourteen volunteers were studied on two occasions to assess the effect of swallowing frequency on acid clearance time. The experimental protocol consisted of two trials of infusion of 15 ml of 0.1 N HCl into the distal esophagus. One trial required swallowing every 30 s for 10 min. The other trial involved an initial rapid swallowing rate (seven swallows in the 1st min) with a gradual predetermined decline in rate. This procedure was repeated 12 h after application of a transdermal scopolamine patch. Baseline clearance times for rapid and slow swallowing were not significantly different. The anticholinergic drug significantly prolonged the clearance times for both rapid and slow swallowing. Under baseline conditions, sequential swallows (after the first three to four swallows) produced a significant rise in pH until the clearance criterion of pH 4.0 was reached. This effect was abolished with the anticholinergic drug. These results support a two-stage model of acid clearance with initial volume clearance and subsequent salivary buffering of residual intraesophageal acid.

Administration, Topical↗