Pancreatic polypeptide and gastrin release during sham feeding in man

Strongyloidiasis: a diagnosis more common than we think

Strongyloides stercoralis is endemic to many tropical regions; however, there is limited knowledge concerning the clinical implication of this helminth, particularly in urban medical centers. We report a case series of strongyloidiasis in our urban medical center in New York City. Patients over the age of 18 years who were examined in our institution from January 1998 to May 2011 were identified by electronic medical record search using International Classification of Diseases, 9th Revision codes. We identified 22 cases of S. stercoralis. Eleven patients were men and 11 were women, with the average age at diagnosis being 62.4 years. Fourteen patients emigrated from the Caribbean, one from Nepal, five were blacks born in the USA, and two did not have their birthplace documented. The main presenting complaints were diarrhea (9/22), abdominal pain (6/22), vomiting (7/22), and weight loss (8/22). Seventeen patients demonstrated eosinophilia. Four patients were positive for human T-lymphotropic virus-1 antibodies, and three patients were infected with HIV. Diagnosis was made with stool examination (19/22), bronchoalveolar lavage (1/22), gastric biopsy (1/22), and duodenal biopsy (3/22). Among six patients who had upper endoscopy performed, the findings commonly included gastritis and gastric and duodenal ulcers. After treatment, 12/22 showed resolution of symptoms. Although a diagnostic approach tends to start with stool collections, consideration of upper endoscopy with biopsy in symptomatic patients is advisable. The absence of eosinophilia should not deter the clinician from seeking a diagnosis. Although often not done, ascertaining HIV and human T-lymphotropic virus-1 status should be part of the work-up.

Endoscopic pyloric injection of botulinum toxin-A for the treatment of postvagotomy gastroparesis

OBJECTIVES

To evaluate the efficacy of botulinum toxin-A in the treatment of postvagotomy gastroparesis.

METHODS

This open-labeled trial identified and recruited 11 subjects who developed symptomatic gastroparesis after a vagotomy (9 fundoplication, 1 trauma, and 1 exploratory laparotomy). Gastroparesis was defined as an abnormal solid-phase gastric emptying test using the standardized 4-hour radionuclide eggbeater meal method and vagotomy was confirmed with a sham meal challenge test. To complete the study, subjects should have completed the 6-month follow-up visit after their pylorus was injected with botulinum toxin-A injection in a 4-quadrant manner. Patients either received 100 (n = 2) or 200 (n = 9) units of botulinum toxin. Questionnaires recorded symptom severity of gastroparesis at baseline and at monthly intervals for 6 months after the therapy was completed by the patients.

RESULTS

Of the 11 subjects initially recruited, 10 finished the 6-month follow-up visit (7 women). Mean age was 51 years (range, 31-84 years). Mean symptom score at baseline was 16 (95% CI 13-19) and showed a numerical decline to 9 (P > 0.05) over the 6-month period after the procedure (95% CI 5-13). Seven (70%) patients observed >30% improvement in the total symptom score. No complications were recorded.

CONCLUSIONS

In conclusion, this open-label study in patients with postvagotomy gastroparesis patients reveals a reduction of gastroparetic symptoms at 1 and 3 months after treatment with pyloric injection of botulinum toxin-A, with return of symptoms by 6 months. Thus, botulinum toxin treatment does not produce a sustained reduction in gastroparetic symptoms in this clinical setting.

Atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli

Acupuncture is known to influence autonomic nervous activity. Acupuncture on Zusanli points has been shown to enhance the regularity of gastric myoelectrical activity and accelerate gastric emptying, partly through the vagal pathway, in dogs. The aim of this study was to evaluate whether atropine-induced autonomic nervous alteration, measured by heart rate variability (HRV), could be amended by electroacupuncture on Zusanli points. HRV measurements were recorded in 15 healthy volunteers before, during and after electroacupuncture. Each subject was studied for three sessions in a randomized sequence, which included electroacupuncture on the Zusanli (St 36) points with or without premedication of atropine and placebo stimulation on a non-acupoint. The analysis of low frequency (LF), high frequency (HF) and LF/HF ratios were compared between different sessions. Serum levels of gastrin, motilin and pancreatic polypeptide (PP) levels were also measured. There was an increase in the LF/HF ratio (indicating increased sympathetic activity) during the post-acupuncture period with 2 Hz of electrical stimulation on the Zusanli acupoints. When IV atropine was used immediately before the electroacupuncture, there was a decrease in the LF power and HF power during the acupuncture and post-acupuncture periods. In addition, there was a significant increase in the LF/HF ratio during the acupuncture and post-acupuncture periods. There was a significant decrease in serum PP in the post-acupuncture period after premedication with IV atropine. In conclusion, atropine-induced HRV change might be mediated via the vagal pathway. However, atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli points.

Cephalic phase of pancreatic polypeptide release: a valid test of autonomic neuropathy in diabetics?

We investigated pancreatic polypeptide (PP) release by chew and spit sham feeding as a test of autonomic function in 33 patients with diabetes mellitus (DM) and 24 age-matched healthy controls. Plasma samples were taken at nine 5-min time intervals, and PP plasma levels were determined by radioimmunoassay. Autonomic neuropathy (AN) was diagnosed and staged according to four standardized tests of cardiovascular autonomic function. The integrated PP response during sham feeding was decreased in DM patients (1067 + or - 397 vs. 2670 + or - 394 pg/ml/30 min; P < 0.05). The maximum increase of PP plasma levels was significantly different between the DM subgroups with AN (36 + or - 19 pg/ml; n = 13) and without AN (132 + or - 36 pg/ml; n = 20) but varied widely in healthy controls (219 + or - 29 pg/ml; range 20-460 pg/ml). A cutoff of maximum PP increase < 20 pg/ml (specificity 100%) resulted in only 46% sensitivity, while a cutoff < 160 pg/ml (sensitivity 100%) yielded 38% specificity for diagnosis of AN. The diagnostic value of the PP test for identifying individual patients against the variable reference range is therefore limited. Maximum PP increase < 20 pg/ml indicates AN, while maximum PP increase > 160 pg/ml excludes AN in diabetic patients.

Autonomic dysfunction in patients with achalasia

It has been previously shown that patients with achalasia may have motor abnormalities of the stomach, small bowel and biliary system. This study investigates whether a disturbance of extraintestinal autonomic function occurs. Autonomic function studies were performed in 15 patients with achalasia and 15 age- and sex-matched healthy controls. Pupillograms were obtained during darkness, light exposure and after pilocarpine administration. Cardiovascular function studies included determinations of heart rate variation during deep breathing and orthostasis. In addition, we determined blood pressure changes in response to sustained handgrip, cold exposure and orthostasis. Neurohormonal function was investigated by measuring serum pancreatic polypeptide (PP) levels prior to and following sham feeding. Pupillary function did not differ in patients as compared with controls. However, 9 of 15 patients (95% CI: 32-84%) and none of the controls showed at least one abnormal autonomic cardiovascular response. A significant difference between the two groups was observed in sympathetic function (P = 0.023). More patients than controls did not respond to sham feeding with a PP increase. It is concluded that some patients with achalasia exhibit an abnormality of the autonomic nervous system that extends beyond the gastrointestinal tract. These abnormalities mainly concern cardiovascular function but may also involve neurohormonal responses.

The role of pancreatic innervation and cholecystokinin in the intestinal phase of pancreatic polypeptide release in conscious dogs

Besides vagal cholinergic mechanisms, pancreatic polypeptide (PP) secretion is thought to be mediated by hormones. This study was performed to delineate the role of extrinsic pancreatic innervation and cholecystokinin (CCK) in amino acid- and fat-stimulated PP secretion. In ten mongrel dogs, pancreatic denervation was performed by the method of Debas et al. [3]. Total denervation of the pancreas did not alter PP response to intraduodenal application of amino acids (integrated output 24,434 +/- 3260 pmol/1 x 120 min before vs 22,797 +/- 2470 pmol/1 x 120 min after operation) and to intraduodenal fat solution (19,595 +/- 2121 pmol/1 x 120 min vs 19,983 +/- 2031 pmol/1 x 120 min). Also, no significant differences were measured in CCK release (491 +/- 71 pmol/1 x 120 min vs 430 +/- 57 pmol/1 x 120 min for amino acids, 571 = 63 pmol/1 x 120 min vs 563 +/- 89 pmol/1 x 120 min for fat solution). Plasma PP and CCK levels were compared by linear regression analysis. Correlations between PP and CCK were high in the intact pancreas (amino acids, r = 0.92; fat, r = 0.99) as well as in the denervated pancreas (r = 0.93 amino acids and r = 0.98 fat). These results show that extrinsic pancreatic innervation does not influence PP and CCK release after intraduodenal amino acids or fat solution and that PP secretion seems to be mediated to some extent through the release of CCK.

Cephalic stimulation of gastrointestinal secretory and motor responses in humans

The present study was designed (a) to investigate the cephalic phase of gastropancreatic secretion, antroduodenal motility, and regulatory peptide release in six healthy young men and (b) to assess its regulation by the cholinergic system and endogenous cholecystokinin. Sham feeding performed for 15 minutes induced a concurrent stimulation of gastropancreatic secretion, antroduodenal motility, and pancreatic polypeptide release that lasted for 30 minutes. Reappearance of interdigestive phases III was retarded in the post-sham-fed state. Atropine abolished secretory, motor, and pancreatic polypeptide responses to sham feeding and enhanced gastrin release. The cholecystokinin receptor antagonist loxiglumide did not attenuate pancreatic enzyme response but diminished antral motor response by 72% (P less than 0.05) and release of pancreatic polypeptide by 91% (P less than 0.05); it enhanced gastrin release and abolished retardation of reappearance of phase III with sham feeding. It is concluded that (a) there is a distinct cephalic phase of gastropancreatic secretion, antroduodenal motility, and pancreatic polypeptide release in humans that is primarily under cholinergic control and that (b) endogenous cholecystokinin is involved in antral motor, gastrin, and pancreatic polypeptide responses to sham feeding.

Role of circulating catecholamines in the control of pancreatic polypeptide and gastrin release

The influence of circulating catecholamines on the release of pancreatic polypeptide (PP) and gastrin was studied in volunteers. Physical exercise increased plasma epinephrine by 374 +/- 123% and plasma norepinephrine by 167 +/- 30%, but plasma PP concentrations remained unchanged during standardized bicycle ergometry. Immediately after cessation of exercise catecholamine levels decreased rapidly, whereas PP concentrations increased by 55%. In a second series, epinephrine infusion (5, 25, and 75 ng.kg-1.min-1) increased epinephrine levels by 38 +/- 12, 331 +/- 69, and 1229 +/- 131%, respectively, whilst norepinephrine was unaffected. Neither during nor after catecholamine infusion PP secretion was affected. Gastrin release increased by a maximum of 85 +/- 38% (at epinephrine 75 ng.kg-1.min-1). It is concluded, that (1) changes in circulating adrenaline do not significantly influence PP secretion in man; (2) the PP increase immediately following physical exercise cannot be attributed to a rapid fall of catecholamine levels; (3) endogenous catecholamines are of minor importance in the control of gastrin secretion.

Plasma prolactin, sex steroids and gastrin in human volunteers treated for 2 weeks with therapeutic doses of cimetidine or the new histamine H2-receptor antagonist ramixotidine (CM 57755A)

Three groups of eight healthy male volunteers received placebo for 2 days, then daily morning doses either of cimetidine 800 mg, ramixotidine 750 mg (CM 57755A), or placebo, for 14 days, and then were all returned to placebo for one more day. Plasma levels of prolactin, testosterone and 17 beta-estradiol were measured on Days 2, 3, 16 and 17 in blood samples taken 30 and 15 min before and 0, 60, 120, 180, 240 and 300 min after treatment. Gastrin was assayed in blood collected on the same days 180 min after treatment. Mean pre- and post-treatment areas under the time-concentration curves of the first three hormones were not significantly different in the three groups on any test day, or within the same group throughout the four test days. Mean plasma gastrin levels ranged between 27 and 42 pg/ml, respectively, in the placebo and cimetidine treated groups on test day 3, and intermediate values were found in the group receiving CM 57755A. There was no statistically significant difference in gastrin level between the groups on any test day or within the same group throughout the four test days. No subjective side-effects attributable to the treatments were reported, and there were no abnormalities in blood pressure, heart rate or standard laboratory tests.

Effect of the prokinetic drug cisapride on gastrointestinal hormone release

The influence of the prokinetic drug cisapride on the release of gastrointestinal hormones was studied in volunteers. First, acute effects of single doses of cisapride compared with saline were investigated. Cisapride at doses of 8 mg and 20 mg intravenously significantly increased plasma concentrations of pancreatic polypeptide (hPP) by 145% and 146%, respectively. Cholecystokinin (CCK) levels were increased by 176% at 8 mg cisapride, whereas gastrin and insulin levels remained unchanged. Enhancement of PP and CCK secretion was almost completely abolished by pretreatment with 1 mg atropine. Carbachol (250 micrograms subcutaneously) increased PP release by 62% but did not affect the other hormones. Second, the influence of a 1-week treatment (10 mg three times daily, given orally) on plasma hormone levels was studied. After 1 week the postprandial CCK release was diminished by 58%. Basal levels and postprandial responses of gastrin, PP, and insulin were not altered by prolonged cisapride administration. It is concluded that acute application of cisapride stimulates secretion of PP and CCK via atropine-sensitive mechanisms and that chronic treatment with cisapride diminishes CCK release by an unknown mechanism.