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Biomedical subjects

M V Singer

Publications and source records attributed to M V Singer.

At least 73 records · Page 4Linked to original sources
PubMed1997

Pancreatic exocrine studies in intact animals: historic and current methods.

This report presents a review of the historic and current methods for performing pancreatic exocrine studies in intact animals. Special emphasis is given to the various surgical procedures--pancreatic fistulas, duodenal pouches, and duodenal fistulas--and practice of collecting pancreatic secretion in dogs. Procedures in other animal species--rat, cat, pig, rabbit, cattle, sheep, and horse--also are specified. The advantages and disadvantages, as well as the indications and limitations of the distinct methods, are discussed.

Animal Diseases↗
PubMed1997

[Postoperative follow-up in patients with partial Whipple duodenopancreatectomy for chronic pancreatitis].

BACKGROUND AND AIM: Physicians and surgeons essentially agree today that chronic pancreatitis must primarily be treated conservatively. The aim of surgery in chronic pancreatitis is the treatment of symptoms. Surgical treatment cannot be a causal therapy for chronic pancreatitis. If surgery is indicated at all. Whipple's operation is considered to be the gold standard. PATIENTS AND METHODS: Between 1973 and 1992, out of a total of 700 patients referred to the surgery University Department in Mannheim with the express purpose of having an operation for chronic pancreatitis, duodenopancreatectomy (Whipple's operation) was performed in 110 cases. 58 of these patients were followed up postoperatively and the results have been compared with preoperative findings. RESULTS: All patients returned to full or only slightly impaired activity. 60% took up work again, 40% retired after the operation with a mean age of 49 years. 38 patients (66%) were totally free of pain, 13 patients (22%) had less pain than preoperatively and only seven (12%) often need analgesics postoperatively because of abdominal pain. Preoperatively there has been a history of long-standing excessive alcohol use in 32 (55%) patients, in the postoperative period there was a significant reduction to only three (5%) patients. 40 patients clinically examined were in a sufficient nutritional condition. Exocrine function of the pancreas (stool chymotrypsin and fluorescein dilaurate test) showed an insufficiency in 20 (71%) of 28 cases. The preoperative exocrine function of the pancreas was not examined in most cases. Examination of endocrine function showed diabetes mellitus treated with insulin occurring preoperatively in six (10%) patients and in 21 (36%) patients postoperatively. CONCLUSION: As chronic pancreatitis very often is concentrated in the head of the pancreas, Whipple's operation seems to be a good procedure for pain relief and concerning late results of life quality and socioeconomic situation.

Adult↗
PubMed1996

Effect of beer, yeast-fermented glucose, and ethanol on pancreatic enzyme secretion in healthy human subjects.

The effect of beer, ethanol (4% v/v), and corresponding volumetric (water), caloric (glucose 5.76% w/v), and osmotic (glucose 11.5% w/v) control solutions on pancreatic enzyme output and release of gastrin and cholecystokinin (CCK) were studied in six healthy human subjects. As a simpler model of beer, yeast-fermented glucose solution (11.5% w/v) was also studied and compared with unfermented glucose (11.5% w/v). Among the control solutions, the two glucose solutions, but not water, significantly (P < 0.05) increased the 150-min integrated trypsin and amylase output over basal levels. Beer and fermented glucose caused a significantly higher increase in trypsin and amylase output compared to water or glucose. Ethanol (4% v/v) failed to stimulate pancreatic enzyme output. Fermented glucose and beer, but not the control solutions, significantly increased plasma gastrin levels above basal values. Isotonic and hypertonic glucose, beer, and fermented glucose significantly increased plasma levels of cholecystokinin (CCK), but the effect was significantly higher after hypertonic glucose than after isotonic glucose, beer, or fermented glucose. Ethanol and water had no effect on plasma levels of gastrin and CCK. We conclude that: (1) in the doses studied intragastric beer and fermented glucose but not ethanol (4% v/v) stimulate pancreatic enzyme output and release of gastrin and CCK; (2) the lack of effect of ethanol indicates that nonalcoholic ingredients of beer and fermented glucose are responsible for this stimulatory effect; and (3) CCK could be one of the major mediators of the stimulation of pancreatic enzyme output after ingestion of beer and fermented glucose.

Adult↗
PubMed1996

Inhibition of canine exocrine pancreatic secretion by peptide YY is mediated by PYY-preferring Y2 receptors.

It is still unclear, which receptor subtype, Y1 and/or Y2, mediates the inhibitory action of PYY on exocrine pancreatic secretion. The present study was undertaken to characterize functionally the Y receptor subtype that mediates the inhibition of exocrine pancreatic secretion by peptide YY (PYY). In eight conscious dogs with chronic gastric and pancreatic fistulas, we compared the action of intravenous infusion of 200 and 400 pmol/kg/h of the Y receptor agonists PYY 1-36, PYY 3-36, PYY 13-36, Pro34PYY 1-36, and NPY 1-36 on the pancreatic secretory response to secretin (20.5 pmol/kg/h) and cerulein (29.6 pmol/kg/h). PYY 13-36, Pro34PYY 1-36, and NPY 1-36 were also studied by giving a fivefold dose (1,000 and 2,000 pmol/kg/h). PYY 1-36 and the Y2 receptor agonist PYY 3-36 significantly inhibited pancreatic secretory responses to secretin and cerulein, whereas inhibition by NPY 1-36 and the Y2 receptor agonist PYY 13-36 was attainable only at doses of 1,000 and 2,000 pmol/kg/h. The Y1 receptor agonist Pro34PYY 1-36 was without effect on pancreatic secretion. We conclude that in dogs the inhibition of exocrine pancreatic secretion by PYY is mediated via Y2 receptors of a PYY-preferring subtype.

Animals↗
PubMed1996

Comparison of the effects of the M1-receptor antagonist telenzepine and the CCK-receptor antagonist loxiglumide on the pancreatic secretory response to intraduodenal tryptophan in dogs.

In six conscious dogs with chronic gastric and pancreatic fistulas we compared the action of different doses (20.25 to 81.0 nmol/kg/h) of the muscarinic M1-receptor antagonist telenzepine, the cholecystokinin (CCK) antagonist loxiglumide (2.5 to 10.0 mg/kg/h) and several combinations of both drugs on the pancreatic secretory response to intraduodenal perfusion of graded loads of tryptophan (0.37-10.0 mmol/h) given against a background of secretin (20.5 pmol/kg/h i.v.). Except for 20.25 nmol/kg/h telenzepine, all tested doses of telenzepine and/or loxiglumide decreased the 180-min integrated bicarbonate response to tryptophan by 55 to 119%. Except of 20.25 nmol/kg/h telenzepine and/or 2.5 mg/kg/h loxiglumide, all tested doses of telezepine and/or loxiglumide inhibited the tryptophan stimulated integrated pancreatic protein responses by 54 to 88%. While telenzepine mainly inhibited the bicarbonate and protein response to the lower loads of tryptophan (0.37-1.1 mmol/h), loxiglumide decreased the response to all loads of tryptophan. The inhibition evoked by the combinations of telenzepine and loxiglumide was not significantly greater than that by single infusion of either drug. The CCK plasma levels basally and in response to tryptophan were not significantly altered by telenzepine and/or loxiglumide. These findings indicate that (1) both enteropancreatic cholinergic reflexes and the hormone CCK are mediators of the protein response to intraduodenal trytophan (2) enteropancreatic cholinergic reflexes are probably the dominant mediators of the response to low amounts of tryptophan, whereas CCK is the major mediator of the response to high loads of tryptophan, (3) the two mediators seem to act independently of each other, and (4) the release of CCK by intestinal trytophan is not influenced by telenzepine or loxiglumide.

Animals↗
PubMed1996

Comparison of the effects of two cholecystokinin-receptor antagonists, loxiglumide and L-364,718, on the pancreatic secretory response to intraduodenal tryptophan in dogs.

BACKGROUND: The aim of the study was to compare the effects of the cholecystokinin (CCK)-receptor antagonists loxiglumide and L-364, 718 on the endogenously stimulated pancreatic exocrine secretion. METHODS: In six conscious dogs with chronic gastric and pancreatic fistulas we compared the action of different doses of loxiglumide (2.5 to 10.0 mg/kg/h) and L-364, 718 (0.025 to 0.1 mg/kg/h) on the pancreatic secretory response to intraduodenal perfusion of graded loads of tryptophan (0.37-10.0 mmol/ h), given against a background of secretin (20.5 pmol/kg/h intravenously). RESULTS: Both loxiglumide and L-364, 718 inhibited the secretin-stimulated pancreatic bicarbonate output by up to 47% and 48%, respectively. The pancreatic protein output during secretin was significantly inhibited by all doses of L-364,718 (by 65% to 82%) but not by loxiglumide. All doses of loxiglumide and L-364, 718 abolished the 180-min integrated bicarbonate response to tryptophan. The two higher doses of loxiglumide (5.0-10.0 mg/kg/h) and L-364,718 (0.05-0.1 mg/kg/h) significantly decreased the 180-min integrated response to tryptophan by 59% and 79% (loxiglumide) and by 72% and 97% (L-364, 718). The plasma CCK-like immunoreactivity basally and in response to tryptophan was not significantly altered by loxiglumide or L-364, 718. CONCLUSIONS: These findings indicate that in dogs 1) the pancreatic bicarbonate response to secretin is augmented by the hormone CCK; 2) L-364, 718 but not loxiglumide decreases pancreatic protein output during secretin; 3) endogenous released CCK is involved in the pancreatic bicarbonate response and is a major mediator of pancreatic protein response to intraduodenal tryptophan; and 4) the release of CCK by intraduodenal tryptophan is not influenced by loxiglumide and L-364, 718.

Animals↗
PubMed1996

[Neurohormonal control of gallbladder motility by intra-ileal and intracolonic nutrients--a review].

The duodenum controls gallbladder motility mainly via stimulatory mechanisms, whereas intraileal and intracolonic nutrients have mainly inhibitory effects on postprandial as well as interdigestive gallbladder motility, which are described in particular. Possible mechanisms for the neurohormonal mediation of the effects of intraileal and intracolonic nutrients on gallbladder motility as well as the possible physiological importance of these effects are discussed.

Animals↗
PubMed1995

Effect of repeated boluses of intravenous omeprazole and primed infusions of ranitidine on 24-hour intragastric pH in healthy human subjects.

The aim of this study was to identify dosage regimens using intravenous omeprazole and ranitidine that would elevate and consistently maintain intragastric pH > 6 in the first 24 hr of therapy. In 19 healthy, fasting human subjects using continuous 24-hr gastric pH-metry, we studied two dosages of primed infusions of ranitidine (50 mg bolus followed by infusion of either 3 or 6 mg/kg body wt/24 hr) and six regimens of intravenous omeprazole (80-200 mg in 24 hr in two to five boluses). Only the two ranitidine infusions and high doses of omeprazole (> or = 160 mg/day as four or five boluses) raised the intragastric median pH above 5.4. There was no significant difference in the median intragastric pH after high dose ranitidine and high doses of omeprazole. Considerable interindividual variation in intragastric pH was observed after omeprazole therapy. The percentage of intragastric pH > 6.0 during the 24-hr study was lower after omeprazole (35-42%) than after high-dose ranitidine (58%). We conclude that it is possible to raise intragastric pH > 6.0 by use of either primed ranitidine infusion or by repeated boluses of omeprazole. However, maintenance of this high pH in the first 24 hr is difficult with both, more so with omeprazole.

Adult↗
PubMed1995

Comparison of two dose-response techniques to study the pancreatic secretory response to intraduodenal tryptophan in the absence and presence of the M1-receptor antagonist telenzepine.

To answer the questions if the type of continuous dose-response technique influences the pancreatic secretory response to intraduodenal tryptophan and if the M1-receptor antagonist telenzepine influences the intestinal absorption of tryptophan, we determined, in 12 conscious dogs with chronic gastric and duodenal fistulas, pancreatic bicarbonate and protein secretion and tryptophan plasma concentrations following intraduodenal tryptophan perfusion using two dose-response techniques. With an ascending continuous dose-response technique (aDRT), tryptophan was perfused in loads ranging from 0.12 to 10.0 mmol h-1, starting with the lowest load and tripling it every 45 min. With the descending continuous dose-response technique (dDRT), the order of tryptophan loads was reversed, with the highest load being given first. All studies were done on a fixed background of intravenous secretin (20.5 pmol kg-1 h-1) and repeated in the presence of the anticholinergic M1-receptor antagonist telenzepine (243 nmol kg-1 h-1). The bicarbonate and protein response as well as tryptophan plasma concentrations to the same loads of tryptophan did not differ significantly between the two techniques. Using both techniques, telenzepine significantly (p < 0.05) inhibited the overall pancreatic protein response by 65% (dDRT) to 81% (aDRT). The overall bicarbonate response was only numerically, and not statistically significantly, inhibited by telezepine. Tryptophan plasma concentrations after duodenal perfusion with tryptophan were neither influenced by the order of tryptophan loads nor altered by telenzepine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Acceptability of high colonoscopy using different premedication--a comparison of the effect of midazolam versus midazolam and pethidine from the viewpoint of the patient and the physician].

Invasive endoscopic procedures such as total colonoscopy result in a better patient acceptance, the less discomfort they cause. Therefore a premedication for total colonoscopy is often required. In a prospective, double-blind, placebo-controlled clinical study of 132 patients examined by one experienced endoscopist we compared two premedication schedules: midazolam (mean 5.2 mg i.v.) versus midazolam (mean 4.8 mg) plus pethidin (50 mg). We found that the combination midazolam plus pethidin provides a deeper and more reliable sedation and analgesia than midazolam alone. The combination of both drugs caused also more anterograde amnesia. It was also shown, that the endoscopist scored a higher degree of patient's pain during the examination than the patient did himself. No more negative side-effects such as decrease of arterial partial pressure of oxygen or cardiopulmonary complications were found using the combination of both drugs; they provided to be safe without added risk of hypoxia. Thus, the combination of both drugs can be given as premedication for total colonoscopy.

Adolescent↗
PubMed1995

[Neurohormonal control of exocrine pancreas secretions by intra-ileal and intracolonic nutrients].

While the duodenum controls pancreatic exocrine secretion mainly via stimulatory mechanisms, intraileal and intracolonic nutrients have mainly inhibitory effects on the postprandial and interdigestive pancreatic secretion, which are described in particular. The inconsistent findings in dogs in contrast to other species (cat, rat, human) referring to the effects of intraileal nutrients are discussed. Possible mechanisms for the neurohormonal mediation of the effects of intraileal and intracolonic nutrients on the pancreatic secretion as well as the possible physiological importance of these effects are discussed.

Animals↗