PubMed Health⌕ Search

Biomedical subjects

W D Chey

Publications and source records attributed to W D Chey.

46 records · Page 3Linked to original sources
PubMed1996

One-week therapy for Helicobacter pylori. A randomized trial of two treatment regimens.

In clinical practice, eradication of Helicobacter pylori infection may be difficult due to medication side effects and the need for 2 weeks of therapy. Because therapies of shorter duration may improve patient compliance and reduce treatment side effects, we compared the efficacy and tolerability of two anti-H. pylori treatments of 1 week's duration. Patients with H. pylori infection were randomized to treatment with either (a) short-course triple therapy, composed-of bismuth subsalicylate (Pepto-Bismol, Procter & Gamble, Cincinnati, OH, U.S.A.) two tablets four times daily, amoxicillin 1 g (two 500-mg tablets) twice daily, and metronidazole 500 mg four times daily on days 5-7 or (b) omeprazole 40 mg twice a day with amoxicillin 1 g twice a day for 1 week. At least 4 weeks posttreatment, efficacy was evaluated with either histological evaluation of antral biopsies for H. pylori or 14C urea breath testing. Patients who failed initial therapy were allowed to cross over to the alternative treatment regimen after a minimum "wash-out" period of 5 weeks. Patients completed a diary during therapy to monitor both compliance and side effects. Thirty-four patients completed the study, 10 receiving both treatment regimens. Treatment with the shortcourse triple therapy eradicated H. pylori in 78.3% of treatments compared with 38% with the high-dose omeprazole/ amoxicillin combination (p < 0.05). Patients were highly compliant with both treatments, and mild side effects, such as transient loose stools or abdominal pain, were common in both groups. This is the first report from North America confirming the success of the short-course triple therapy for the eradication of H. pylori. The high-dose omeprazole/ amoxicillin regimen's eradication rate was markedly inferior to that achieved by the short-course triple therapy regimen and should not be used. Comparative studies of the short-course triple therapy regimen with other 7-day anti-H. pylori treatment regimen therapies are indicated.

Amoxicillin↗
PubMed1996

Prolonged effect of omeprazole on the 14C-urea breath test.

OBJECTIVES: We investigated omeprazole's effect on 14C-urea breath testing. We also determined the duration of omeprazole's effect on the breath test. Finally, we studied whether effects on breath testing were dose dependent. METHODS: Fifty-seven employees and outpatients were screened for Helicobactor infection. Those positive for serology, CLO, or histology were asked to undergo baseline breath testing. Those with a positive breath test took omeprazole 20 mg/day for 14 days followed by repeat breath testing, 1, 3, and 5 days after therapy. Subjects with persistently positive breath tests despite omeprazole 20 mg/day were asked to take omeprazole 20 mg b.i.d. for 14 days. Repeat breath tests were performed as above. RESULTS: Thirteen of 57 had HP infection. Ten of 13 underwent a baseline breath test. Eight of 10 with baseline breath test experienced a significant decrease in expired 14CO2 after omeprazole 20 mg/day. Five of 13 with active HP infection developed a negative breath test after omeprazole. All subjects had a positive breath test within 5 days of stopping omeprazole 20 mg/day. Five of eight with persistently positive breath tests despite omeprazole 20 mg/day took omeprazole 40 mg/day. Four of five developed a significant decrease in 14CO2 excretion after omeprazole. All subjects had a positive breath test within 5 days of stopping omeprazole 40 mg/day. CONCLUSIONS: Recent treatment with omeprazole 20 mg/day led to a false-negative breath tests in 38.5%. This effect appeared to be dose dependent and lasted up to 5 days after cessation of omeprazole.

Anti-Bacterial Agents↗
PubMed1995

Hyperglycemia inhibits mechanoreceptor-mediated gastrocolonic responses and colonic peristaltic reflexes in healthy humans.

BACKGROUND/AIMS: The effects of hyperglycemia on colonic motor function are unknown. Therefore, colonic neuromuscular function was tested in normal volunteers as a model for constipation in diabetes. METHODS: Extended (gastrocolonic response) and local (peristaltic reflex) neural responses and colonic muscle contractility were tested under control, hyperglycemic clamp, and euglycemic, hyperinsulinemic clamp conditions with placement of barostat-regulated balloons in the descending colon to measure changes in tone as differences in balloon volume. RESULTS: Hyperglycemic clamping to 274 +/- 3 mg/dL blunted increases in colon tone evoked by gastric distention (gastrocolonic response) (100-300 mL) but did not affect gastric tone. Three descending colonic balloons in series assessed the peristaltic reflex. Inflation of the middle stimulus balloon increased proximal tone, an increase that was blunted by hyperglycemia, but produced distal relaxation followed by increases in tone that were unaffected by hyperglycemia. Euglycemic, hyperinsulinemic clamping had no effect on the gastrocolonic response or peristaltic reflex. Tonic increases evoked by bethanechol (5 mg administered subcutaneously) were unaffected by hyperglycemic clamping. CONCLUSIONS: Hyperglycemia blunts mechanoreceptor-mediated gastrocolonic responses and ascending contractions but not descending components of the peristaltic reflex in humans, effects not caused by hyperinsulinemia or direct muscle actions. These inhibitory effects on long and short neural reflexes that modulate colonic motility may contribute to constipation in diabetes.

Adult↗
PubMed1995

Hyperglycemia alters perception of rectal distention and blunts the rectoanal inhibitory reflex in healthy volunteers.

BACKGROUND/AIMS: Acute hyperglycemia has been shown to alter gastrointestinal motility. The effects of hyperglycemia on rectal afferent neural and anal sphincter function were studied. METHODS: Perception of rectal balloon distention, pressure-volume relationships, volumes necessary to induce reflex internal anal sphincter relaxation, resting anal sphincter pressure, and maximal anal sphincter squeeze pressure were measured under basal, hyperglycemic clamp, and euglycemic, hyperinsulinemic clamp conditions in 9 healthy volunteers. RESULTS: Hyperglycemic clamping (258 +/- 14 mg/dL) significantly blunted threshold perception and the urge to defecate in response to rectal distention without altering perception of maximally tolerated distention. In contrast, euglycemic, hyperinsulinemic clamping had no effect on perception of rectal distention. Rectal pressure-volume relationships after hyperglycemic clamping were unchanged compared with basal conditions. Hyperglycemic clamping caused a significant increase in the distention necessary to induce the rectoanal inhibitory reflex. This effect was not observed under euglycemic, hyperinsulinemic clamp conditions. Hyperglycemia did not significantly affect resting internal anal sphincter pressure or maximal external anal sphincter squeeze pressure. CONCLUSIONS: Acute hyperglycemia but not secondary hyperinsulinemia reduces sensation of rectal distention and blunts the onset of the rectoanal inhibitory reflex, suggesting effects both on visceral afferents projecting to the cortex and intrinsic afferents mediating local reflex activity.

Adult↗
PubMed1995

Possible nizatidine-induced subfulminant hepatic failure.

Subfulminant hepatic failure has not been reported to occur with the histamine-2 receptor antagonists. We report a possible case of nizatidine-induced subfulminant hepatic failure leading to the eventual development of cirrhosis.

Adult↗
PubMed1995

Central cholinergic and alpha-adrenergic mediation of gastric slow wave dysrhythmias evoked during motion sickness.

Motion sickness is associated with gastric slow wave disruption. Animal models of slow wave disturbances show dependence on neural and prostaglandin pathways. Roles of these pathways in circular vection-evoked gastric dysrhythmias and nausea were tested. Eight volunteers with histories of motion sickness underwent vection (60 degrees/s), during which nausea (0 = none to 3 = severe) and electrogastrographic parameters were assessed. Tachygastric activity was expressed as the signal percentage at frequencies of > 4.5 cycles/min. Circular vection induced a maximal nausea score of 2.8 +/- 0 at 513 +/- 66 s. Tachygastric activity increased from 18 +/- 2 to 37 +/- 4% (P < 0.05) and peaked before maximal nausea. Atropine reduced nausea scores to 0 +/- 0 (P < 0.01) with no increase in tachygastric activity (14 +/- 6%). In contrast, the peripheral muscarinic antagonist methscopolamine did not reduce tachygastric activity (46 +/- 4%), nausea (1.8 +/- 0.5), or time to maximal tachygastric activity (504 +/- 80 s) with vection. Phentolamine reduced nausea (1.5 +/- 0.3, P < 0.01) and tachygastric activity, and delayed their onset, whereas propranolol and naloxone had no effect. Pretreatment with oral indomethacin (50 mg) three times daily for 3 days had no effect on vection-evoked tachygastric activity or nausea. To conclude, circular vection evokes gastric dysrhythmias that correlate temporally with maximal nausea and are suppressed by atropine, but not methscopolamine, and are reduced by phentolamine. In contrast to other models of slow wave disruption, endogenous prostaglandins play no role. Thus central cholinergic pathways mediate vection-evoked dysrhythmias with additional modulation by alpha-adrenergic pathways.

Adult↗
PubMed1995

Octreotide reduces perception of rectal electrical stimulation by spinal afferent pathway inhibition.

Octreotide reduces perception of rectal distension in normal volunteers and irritable bowel patients. To localize octreotide's site of action, perceptual and evoked potential responses to rectal electrical stimulation were tested in seven normal volunteers after double-blind octreotide (100 micrograms 2) or placebo. After octreotide, the currents needed to elicit threshold perception of square-wave impulses delivered to the rectum were 29% higher than after placebo. When electrical stimulation was delivered at constant currents 50% above threshold, rectal perception scores were significantly reduced after octreotide compared with placebo. Rectal electrical stimulation led to characteristic and reproducible cerebral evoked potentials. Octreotide had no effect on latencies, but reduced peak-to-peak amplitudes by 35% compared with placebo. Rectal electrical stimulation also led to characteristic and reproducible spinal evoked potentials. Octreotide had no effect on spinal latencies, but reduced peak-to-peak amplitudes by 51%. In conclusion, octreotide reduces perception of rectal electrical stimulation, which is associated with inhibition of cerebral and spinal evoked potential amplitude, indicating effects on spinal afferent pathways.

Adult↗
PubMed1992

Angiodysplasia and von Willebrand's disease type IIB treated with estrogen/progesterone therapy.

The association between angiodysplasia and von Willebrand's disease was first reported in 1967. The cases reported to date have involved patients with type I and IIA von Willebrand's disease. We report a patient with type IIB von Willebrand's disease who suffered gastrointestinal bleeding attributable to gastric angiodysplasia. The patient underwent endoscopic electrocautery acutely and has been treated long-term with estrogen/progesterone therapy. She has suffered no recurrent gastrointestinal bleeding at over 11 months of follow-up. We suggest hormonal therapy as an alternative to repeated blood product transfusion or extensive surgical resection in patients with von Willebrand's disease and gastrointestinal bleeding from angiodysplasia.

Arteriovenous Malformations↗
PubMedDate not supplied

Gastric emptying characteristics of a novel (13)C-octanoate-labeled muffin meal.

GOALS: Determine the gastric emptying characteristics of a novel, 350-kcal test meal consisting of two muffins, using scintigraphy and the 13C-octanoate breath test (OBT). STUDY: Healthy volunteers underwent three studies on separate days within a 1-week period. On day 1, we measured emptying of the 350-kcal muffin test meal labeled simultaneously with 99mTc sulfur colloid and 13C-octanoate. On day 2, reproducibility of the OBT using a single-labeled 350-kcal test meal was assessed. On day 3, the effect of erythromycin on the 350-kcal OBT was determined. RESULTS: The mean (+/-SD) half-emptying time (T1/2) as measured by scintigraphy was 104 +/- 24 minutes, versus 212 +/- 52 minutes by OBT. There was a strong correlation between T1/2 determined by scintigraphy and the breath test (r = 0.83). Multiple linear regression analysis identified a significant relationship between T1/2 determined by scintigraphy and the 90-and 180-minute breath samples. There was a strong correlation (r = 0.830, slope = 0.732 +/- 0.120 [SE], intercept = 26.4 +/- 12.7) between the T1/2 obtained using the regression equation and the actual T1/2 obtained by scintigraphy. The mean T1/2 (+/-SD) for replicate determinations using the OBT was 209 +/- 52 minutes, compared with 196 +/- 42 minutes on days 1 and 2, respectively (not significant, p = 0.28, paired Student t test). Treatment with erythromycin on day 3 produced a significant decrease in T1/2 (155 +/- 49 minutes, p = 0.002). CONCLUSIONS: The 350-kcal muffin meal OBT provides a convenient, nonscintigraphic way of measuring solid-phase gastric emptying. Multiple linear regression appears promising as a method of analyzing OBT data and may allow for an abbreviated breath test protocol.

Adult↗