Jon I. Isenberg

HEALING OF DUODENAL ULCER WITH AN ANTACID REGIMEN

To determine whether a large-dose antacid regimen is effective in promoting healing of duodenal ulcer, 74 patients with endoscopically proved duodenal ulcer completed a 28-day double-blind clinical trial comparing such a regimen with an inert placebo. The ulcer healed completely in 28 of the 36 antacid-treated as compared to 17 of the 38 placebo-treated patients (P less than 0.005). The antacid regimen was not more effective than placebo in relieving ulcer symptoms. Presence or absence of symptoms during the fourth treatment week was a poor predictor of presence or absence of an ulcer crater. Ulcers of placebo-treated patients who smoked cigarettes were less likely to heal than those of nonsmokers (P = 0.03). Except for mild diarrhea, no side effects of the antacid regimen were observed. We conclude that a large-dose antacid regimen hastens the healing of duodenal ulcer.

Impaired proximal duodenal mucosal bicarbonate secretion in patients with duodenal ulcer.

The defensive factors that prevent the human duodenal mucosa from acidic and peptic damage have not been fully evaluated. To determine whether duodenal mucosal bicarbonate production was altered in patients with inactive duodenal ulcer, we measured basal and acid-stimulated bicarbonate output from the duodenal bulb and the distal duodenum in healthy subjects and patients with inactive duodenal ulcer. As compared with 16 normal subjects, the 12 patients had significantly less mean (+/- SE) basal proximal duodenal mucosal bicarbonate secretion (185 +/- 13 vs. 107 +/- 18 mumol per centimeter per hour; P less than 0.001). Moreover, in response to a physiologic amount of hydrochloric acid (2 mmol per five minutes) instilled directly into the duodenal bulb, peak proximal duodenal bicarbonate output in the patients was 41 percent of the normal response (263 +/- 65 vs. 642 +/- 77 mumol per centimeter per hour; P less than 0.01). There was little overlap between groups. In contrast, bicarbonate outputs in the distal duodenum were similar in the two groups. We conclude that most patients with duodenal ulcer disease have decreased proximal duodenal mucosal bicarbonate production at rest, in response to hydrochloric acid, and in relation to peak gastric acid secretion. Impaired proximal duodenal mucosal bicarbonate secretion may be an important factor in the development and natural history of duodenal ulcer.

Inhibition of gastric acid secretion by cimetidine in patients with duodenal ulcer.

Cimetidine, a non-thiourea-containing H2-receptor antagonist, was studied in seven patients with duodenal ulcer. Oral doses of 100, 200, and 300 mg were tested. Each dose significantly inhibited basal and meal-stimulated secretion. After 300 mg, basal acid secretion was essentially zero for at least five hours. The meal-stimulated three-hour acid output after the 300-mg dose was reduced by 67%. Cimetidine, 300 mg, decreased meal-stimulated acid secretion significantly more than an optimal effective dose of propantheline bromide (P less than 0.05). Inhibition of meal-stimualted gastric acid secretion showed a significant relation to peak blood cimetidine concentration (r is equal to 0.76, P less than 0.01). Cimetidine did not affect meal-stimulated gastrin release. No toxicity was observed after serial doses given during these tests. Cimetidine may be useful in treatment of acid-peptic diseases provided no important toxicity appears on chronic testing.

Human duodenal mucosal bicarbonate secretion: Evidence for basal secretion and stimulation by hydrochloric acid and a synthetic prostaglandin E1 analogue

The factors responsible for prevention of duodenal mucosal injury are not known. This series of experiments was performed to determine whether the human duodenum secretes bicarbonate that could prevent mucosal damage. To isolate a 4-cm segment of proximal (i.e., the duodenal bulb) or distal duodenum free of contamination from either gastric or pancreaticobiliary secretion, or both, methods were developed using occlusive balloons. The test segment was perfused with NaCl (2 ml/min, 37 degrees C) containing [14C]PEG as a nonabsorbable marker, and bicarbonate output was quantitated. Mean (+/- SE) basal proximal duodenal bicarbonate output was 143 +/- 17 mumol/cm X h. A 5-min infusion of 25, 50, and 100 mM HCl directly into the isolated proximal duodenal test segment increased bicarbonate output to 167 +/- 29, 199 +/- 19, and 278 +/- 49 mumol/cm X h, respectively, during the hour after acidification. Distal duodenal acidification (25, 50, and 100 mM) also increased bicarbonate output from the isolated proximal duodenal test segment. A synthetic prostaglandin E1 analogue, misoprostol (1.67-13.3 micrograms/min), infused directly into proximal or distal test segments significantly stimulated bicarbonate outbreak; peak responses were 644 +/- 35 mumol/cm X h and 171 +/- 20 mumol/cm X h (p less than 0.001), respectively. Thus, in humans, the proximal and distal duodenal mucosa secretes bicarbonate at rest; direct acidification of the proximal duodenum stimulates bicarbonate output; acidification of the distal duodenum beyond the isolated test segment also increased proximal duodenal bicarbonate output; and a synthetic prostaglandin E1 analogue stimulated both proximal and distal bicarbonate output; however, distal duodenal bicarbonate output was significantly less, indicating a proximal-to-distal gradient in bicarbonate secretion.

Unusual Effect of Secretin on Serum Gastrin, Serum Calcium, and Gastric acid Secretion in a Patient with Suspected Zollinger-Ellison Syndrome

Previous studies in normal man demonstrated that secretin inhibits pentagastrin-stimulated gastric acid secretion. This report describes a patient with suspected Zollinger-Ellison syndrome (i.e., elevated serum gastrin and hypersecretion of gastric acid) in whom secretin produced significant increases in serum calcium and gastrin, and in gastric acid secretion. The mechanism of this effect is unknown.

Increased sensitivity to stimulation of acid secretion by pentagastrin in duodenal ulcer.

The effect of graded doses of pentagastrin (2.7-6,000 ng/kg times h) on gastric acid secretion was measured in 20 duodenal ulcer (DU) and 20 non-DU subjects. Confirming many previous studies, the mean observed highest response and the mean calculated maximal response were significantly greater in DU than in non-DU subjects. The mean dose (plus or minus SE) in ng/kg times h for half maximal response, calculated from responses corrected for basal secretion and normalized for maximal secretion, was 92.1 plus or minus 1.7 in DU and 246.8 plus or minus 24.6 in non-DU subjects, a significant difference. By parallel line bioassay non-DU subjects required 2.8 times more pentagastrin (95% confidence limits 2.1-3.7) than DU highest response. Thus, this study shows that, compared with non-DU subjects, DU patients not only secrete more acid in response to stimulation by pentagastrin but also are more sensitive to stimulation by pentagastrin, that is, need smaller doses to achieve the same fraction of maximal response.

Patient Acceptance and Effectiveness of a Balanced Lavage Solution (Golytely) Versus the Standard Preparation for Colonoscopy

An oral electrolyte solution containing 125 mM/L sodium, 10 mM/L potassium, 80 mM/L sulfate, 20 mM/L bicarbonate, and 80 mM/L of polyethylene glycol, and associated with little water or electrolyte absorption from the gut was recently described in this journal. To determine the efficacy of this solution (Golytely) for colonoscopy, 20 consecutive patients were randomized to either a standard colonoscopy prep or Golytely. Both preps resulted in a feces-free colon, allowing colonoscopy to the cecum in most cases. Although Golytely produced mild cramps (3 of 12) and transient fullness (6 of 12 vs. 0 of 8 with standard prep, p less than 0.02), 11 of 12 were willing to repeat Golytely vs. 3 of 8 with the standard prep (p less than 0.02). It is concluded that Golytely is an effective prep for colonoscopy and well tolerated by patients. It is especially useful for those requiring repeated examinations because of patient acceptance and efficacy.

Healing of benign gastric ulcer with low-dose antacid or cimetidine. A double-blind, randomized, placebo-controlled trial.

We conducted a 12-week, double-blind, randomized, placebo-controlled trial to determine whether cimetidine (300 mg with meals and at bedtime) or a convenient, liquid aluminum-magnesium antacid regimen (15 ml one hour after meals and at bedtime) would expedite healing or relief of symptoms in patients with benign gastric ulcer. Of the 101 patients who completed the trial according to protocol, 32 received the antacid, 36 cimetidine, and 33 placebo. At 4, 8, and 12 weeks after entry, ulcers had healed in a larger percentage of patients treated with cimetidine than of those treated with placebo: 53, 86, and 89 per cent of the cimetidine group versus 26, 58, and 70 per cent of the placebo group (P = 0.02, 0.01, 0.05), respectively. Healing at the three intervals had occurred in 38, 70, and 84 per cent, respectively, of the antacid-treated patients. Neither cimetidine nor antacid was more effective than placebo in relieving symptoms. The presence or absence of symptoms during the fourth and eighth treatment weeks was a poor predictor of the presence of absence of an ulcer crater. We conclude that cimetidine significantly hastens the healing of benign gastric ulcer.

Gastric Acid Secretion is Abnormally Sensitive to Endogenous Gastrin Released after Peptone Test Meals in Duodenal Ulcer Patients

We studied 25 duodenal ulcer patients and 14 age- and sex-matched normal controls to determine whether gastric acid secretion in duodenal ulcer patients is abnormally sensitive to stimulation by gastrin endogenously released in response to meals. Acid response to saline and to 0.5, 1.0, 2.0, 4.0, and 8.0% peptone infused into the stomach was measured by 30 min intragastric titration. Total serum gastrin (G-total) and serum heptadecapeptide gastrin (G17), fasting and 30 min after each test meal, were measured by specific radioimmunoassays. In 19 ulcer patients and 11 normal subjects (controls), acid response to graded doses (11, 33, 100, and 300 pmol kg(-1) h(-1)) of G17-I were also measured. Mean acid output in response to each dose of peptone was significantly higher in duodenal ulcer patients than in the controls. Gastrin levels in ulcer patients and controls were not significantly different. Within individual patients and controls, both G-total and G17 were significantly correlated with meal-stimulated acid output regardless of whether the absolute, basal-corrected, or distention-corrected values for acid output were examined (median r ranged from 0.82 to 0.94, P < 0.001). From the individual regression lines, the gastrin concentrations corresponding to half of the highest observed meal-stimulated acid response (D(50m)) were calculated. Mean D(50m) for G-total and G17 were significantly lower in duodenal ulcer patients than in controls both in the overall group and in pairs of ulcer patients and controls matched on the basis of highest observed meal-stimulated acid responses, or on the basis of maximal acid output in response to synthetic human G17. The dose of exogenously administered G17 required for half maximal G17 acid response mean D(50g), was significantly less in patients than in control subjects. In both ulcer and control subjects, D(50g) correlated significantly with D(50m). This and the significant correlation between meal-stimulated G17 and acid response strongly suggest that the endogenously released gastrin was responsible for most, if not all, of the postpeptone acid output.We conclude that after peptone test meals, gastric acid secretion in duodenal ulcer patients was abnormally sensitive to stimulation by endogenously released gastrin.

Clearance and acid-stimulating action of human big and little gastrins in duodenal ulcer subjects.

Acid-stimulating action and clearance of pure natural human big gastriin (HG-34-I) and little gastrin (HG-17-I) were assessed in four male subjects with inactive duodenal ulcer (DU) disease. Disappearance half-times for HG-17-I after intravenous infusion (5.2 min) or rapid intravenous injection (6.4 min) were six to eight times shorter than those for HG-34-I (41.5 and 37.8 min, respectively). Studies of clearance of synthetic human little gastrin (HG-17-I) were performed in three of these same four DU subjects, eight additional male DU subjects, and eleven normal male subjects. The disappearance halftime of synthetic HG-17-I averaged 6.2 min in both the DU subjects and the normal subjects. These data suggest that clearance of exogenous gastrin is not altered in patients with DU. Acid secretion in response to rapid intravenous injection of HG-34-I reached a higher peak and lasted longer than in response to an equimolar dose of HG-17-I; the total response to HG-34-I was about three times that to HG-17-I. During constant intravenous infusion, acid responses to equimolar exogenous doses of the two peptides were similar but the increment in molar concentration of circulating gastrin was six to eight times greater with HG-34-I than with HG-17-I. Chromatography of serum obtained during infusions of HG-34-I revealed no evidence of conversion to HG-17-I, nor was there any increase in circulating G-34 activity during infusions of HG-17-I. The increment in serum gastrin concentration required to produce half-maximal stimulation of gastric acid secretion (D50) was estimated in each subject for each gastrin from curves relating acid secretion to change in serum gastrin concentration produced by infusion of these peptides. After instilling peptone solution into the stomach, acid secretion was measured by intragastric titration, and increases in circulating G-17 and G-34 were determined by chromatography and radioimmunoassay of serum. Increases in circulating G-17 and G-34 in response to the peptone meal, taken together, were equivalent to 1.5 times the D50 determined from infusions of G-34 and G-17. Acid secretion during the same time period averaged 55% of maximal rates. Although G-34 comprised approximately three-fourths of the total molar concentration of circulating gastrin after stimulation, it was estimated to contribute less than half of the acid-stimulating activity.