Biomedical subjects

P Bauerfeind

Publications and source records attributed to P Bauerfeind.

At least 19 recordsLinked to original sources

PubMed1992

[Percutaneous endoscopic gastrostomy (PEG) for long-term nutrition--comparison of 2 different caliber tubes].

Percutaneous endoscopic gastrostomy (PEG) is often used nowadays for long-term enteral nutrition in patients with swallowing disorders and severely altered esophageal-duodenal transit. The most common indications for gastrostomy tubes were neurological disturbances and malignancies of the oropharynx and esophagus. We compared in a prospective sequential trial PEG-tubes of two different sizes (2.9 mm [CH-9] vs. 4.8 mm [CH-15]) with respect to placement, complications, durability and handling. The tube was successfully placed in 51 of 52 patients (98%). In 1 patient placement was impossible due to missing diaphanoscopy. The mean observation period was 22 weeks for the CH-9-tubes (n = 28) and 14 weeks for the CH-15-tubes (n = 23). The only early complication was 1 case with a hemorrhage at the site of implantation (CH-15). In both groups 2 cases of local infection were noted. In the CH-9-group 2 PEG-tubes disappeared into the stomach and in 1 case a cicatricial granuloma developed. In the CH-15-group a leak occurred 10 days after implantation. All complications were treated conservatively. There was no causal relationship between the size of tube and the complications. The period of implantation was mostly limited by the death due to the underlying disease of the patient and was not related to the type of PEG-tube. We conclude the both PEG-tubes were easy to place, safe and effective means of providing enteral nutrition. We would, however, recommend CH-15-tubes for long-term nutrition, since in our experience they were less frequently obstructed and handling for the nurses was easier.

Adult↗

PubMed1992

A physiological role for cholecystokinin as a regulator of gastrin secretion.

To explore the role of cholecystokinin (CCK) in regulating gastrin secretion in humans, the effect of a CCK antagonist (loxiglumide) on meal-stimulated hormone responses was investigated. Subjects received 500 mL of a liquid test meal in the presence and absence of loxiglumide (22 mumol.kg-1.h-1). In the control experiments, both plasma gastrin and CCK levels increased postprandially. In loxiglumide-treated subjects there was a marked elevation in gastrin (area under the curve, 11,042 +/- 1493/120 min vs. 2156 +/- 281 pg/120 min) and CCK levels compared with the control experiment. These observations were confirmed in experiments with modified sham feeding and gastrin-releasing peptide stimulation in which loxiglumide pretreatment also caused a significant increase in gastrin release compared with saline (P less than 0.05). Further studies with intravenous infusion of gastrin, CCK-8, and CCK-33 with and without loxiglumide showed that the increases in CCK and gastrin during loxiglumide application cannot be explained by alterations in clearance rates. The findings of this study show that postprandial gastrin secretion is influenced by CCK and support the concept of a negative feedback control of gastrin secretion by CCK.

Adult↗

PubMed1992

Oesophageal pH-metry: should meals be standardized?

To assess the effect of a late-evening, high-fat meal on nocturnal supine gastro-oesophageal reflux, eight healthy volunteers (aged 20 to 38 years) underwent two ambulatory oesophageal pH-metry recordings, the first after a standardized light meal at 1930 h and the second after a high-fat meal including peppermint and chocolate, at 2130 h. Between 2300 and 0700 h, when subjects were supine, the median acid exposure time (percentage recording with pH less than 4) increased from 0.0% (range, 0.0-6.8%) after the standardized meal to 7.9% (0.0-17.8%) after the high-fat meal (p = 0.031). Similarly, the median number of reflux episodes increased from 0 (0 to 11) after the standardized meal to 7 (0 to 26) after the high-fat meal (p = 0.031). Reflux occurred after both meals, but, in general, persistent nocturnal reflux was observed only after the high-fat meal. Thus, the analysis of oesophageal pH recordings should consider the effects of meal composition and timing on oesophageal acid exposure.

Adult↗

PubMed1992

[Differential diagnostic value of occult blood in stool in hookworm infection in the Third World. Study from Papua New Guinea].

In 633 persons of the Madang province in Papua-New Guinea hookworm-infection, blood hemoglobin and the presence of blood in stools were studied. 60% of the subjects were infected with hookworm (Necator americanus). There was a significant linear correlation between the intensity of hookworm infection and blood haemoglobin level. The Colo-Rectal test gave positive results in 17% of the cases without worm-infection. In infected persons, the Colo-Rectal test gave an increasing rate of positive results as the parasite infection increased: 24% for subjects with low levels of infection, and 57% and 67% for moderate and high levels, respectively. The mean blood-haemoglobin level was lower in persons with positive Colo-Rectal-Test and hookworm infection (11.8 g%) than among those with negative Colo-Rectal-Test and hookworm infection (15.0 g%, p < 0.01). In young populations with a known high prevalence of hookworm infection, Colo-Rectal test is therefore suitable for the detection of moderate or severe hookworm infections. It may serve as a simple and useful method to work up anaemia is such populations.

Adolescent↗

PubMed1991

The ion sensitive field effect transistor (ISFET) pH electrode: a new sensor for long term ambulatory pH monitoring.

Intraluminal pH monitoring in man should be performed with disposable multichannel assemblies that allow recordings at multiple sites and prevent transmission of infection. Currently available glass electrodes are unsuitable for this purpose because of their size and price. We have thus constructed and tested a small, combined ion sensitive field effect transistor (ISFET) pH electrode incorporating an integral reference electrode. In vitro studies showed that both ISFET and glass electrodes (440-M4, Ingold, Switzerland) have a linear response over the pH range 1.3-8.0 and that they are comparable with regard to response time and 24 hour drift. Twenty one hour intragastric pH recordings were performed simultaneously in eight healthy volunteers using a glass electrode and an ISFET electrode, placed no more than 2 mm apart in a combined assembly. This was located in the gastric corpus under fluoroscopic control. The 21 hour pH curves recorded by each electrode type showed identical patterns: an early morning rise in pH with three meal-associated pH peaks lasting for about two to three hours. The means of the 21 hour pH medians were 2.09 and 2.07 as measured by the glass and the ISFET electrodes respectively. Thus, ISFETs are suitable for the construction of inexpensive and hence disposable multichannel pH monitoring assemblies of small diameter. Provided that they can be produced in large numbers with appropriate technical support, ISFETs have the potential to replace glass electrodes for long term monitoring of gastrointestinal luminal acidity.

Evaluation Studies as Topic↗

PubMed1991

[Collagen colitis--a clinical entity of relevance].

Collagenous colitis is a clinical and pathological entity characterized by chronic watery diarrhea and deposition of collagen beneath the surface epithelium of the large intestine. By colonoscopy and barium enema the colon appears normal. The laboratory tests give usually normal results. 75% of the patients are middle-aged women with a mean age around 50 years. The etiology of the disease is still unknown. An association with various autoimmune diseases has been suggested, but was never proven. Up to now, it is not clear whether the collagenous colitis is a distinct entity or only an epi-phenomenon of another disease which leads to thickening of the collagen layer. Collagenous colitis is diagnosed if all other diseases with chronic watery diarrhea are excluded. A specific treatment is not known. Symptomatic treatment with bulk and antidiarrheal drugs improves the symptoms of most of the patients.

Colitis↗

PubMed1990

Fate of antacid gel in the stomach. Site of action and interaction with food.

The site of action of a high-power Al-Mg antacid gel (buffering capacity 70 meq/10 ml) and its interaction with food was examined in 10 healthy volunteers. Combined pH-metries in antrum and corpus were performed in each volunteer on four occasions. In a randomized study design, antacid or placebo were given 1 hr after either a protein or a carbohydrate pancake, of which only the former had any acid-buffering capacity. Before the meal, pH was higher in the antrum than in the corpus (median antrum: 3.2, corpus 1.5). In the corpus, a protein pancake but not a carbohydrate pancake raised the pH (median pH after protein pancake: 3.5; after carbohydrate pancake: 1.4). In the antrum, the protein pancake had no effect, but the carbohydrate pancake decreased the pH (median pH after protein pancake: 3.1; after carbohydrate pancake: 2.0). The antacid had no effect in the corpus after either pancake. It raised intraluminal pH markedly in the antrum after a carbohydrate pancake (median antral pH before antacid: 2.0; after antacid: 3.3), whereas its effect in the antrum was weak after a protein pancake. In vitro experiments were conducted to explain the in vivo results: in contrast to a carbohydrate pancake, a protein pancake reduced the buffering capacity of the antacid by direct interaction. In conclusion, the effect of an antacid gel on intragastric pH is predominantly localized in the antrum and is attenuated in the presence of proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

[Pathogenic heterogeneity of Barrett's ulcers. Apropos of 38 case reports].

Barrett's ulcer is thought to develop in the columnar epithelium of Barrett's esophagus. In our series there is evidence that at least some Barrett's ulcers develop in squamous epithelium which may correspond to islets within Barrett's esophagus; in other cases Barrett's mucosa may surround a preexisting reflux-induced ulcer and thus transform it into Barrett's ulcer. In some individual cases of Barrett's ulcer development of the ulcer primarily in the columnar epithelium could not be ruled out. These ulcers may be produced by local acid secretion, by acid or alkaline gastroesophageal reflux in patients with reduced resistance of the columnar epithelium. Exceptionally, Barrett's ulcer may result from local irritation by medication (pill-induced ulcer) or by nasogastric intubation.

Adult↗

PubMed1989

Combined esophageal and gastric pH-metry in healthy volunteers. Influence of cable through LES and effect of misoprostol.

In order to evaluate whether combined esophageal and gastric pH-metry is feasible without interference due to the transcardial cable, four 24-hr ambulatory esophageal pH-metries were carried out in seven healthy volunteers in a randomized order. In two studies only one glass electrode was used. It was placed 5 cm above the lower esophageal sphincter. In the two other studies an additional electrode was placed in the corpus region 10 cm below the lower esophageal sphincter. In order to obtain a wide range of pH values, misoprostol (400 micrograms) was given at 9 AM and 9:15 PM in two studies. In the two other studies placebo was given. Misoprostol exerted only a weak and short-lasting effect on gastric acidity. The four measuring conditions did not differ with respect to medians of esophageal reflux time and duration of single reflux episodes, Kendall's coefficient of concordance yielded a high reproducibility for both variables (P less than 0.0025). Thus, combined esophageal and gastric pH-metry is feasible and highly reproducible.

Adult↗

PubMed1989

Luminal acid reduces gastric mucosal blood flow in the ischemic stomach.

Luminal gastric acid is essential for the formation of acute gastric mucosal lesions during ischemia. The mechanism by which luminal acid promotes gastric injury is, however, unclear. We investigated the effect of exogenous luminal acid on gastric mucosal blood flow using the radiolabeled microsphere technique. In rats with intact gastric blood supply application of exogenous luminal acid increased blood flow to the mucosa of the corpus and antrum. However, after ligation of the left gastric artery, which compromised mucosal blood flow to the corpus, application of luminal exogenous acid further decreased blood flow to the corpus. This indicates that the ability of the normal stomach to respond to luminal acidification with an increase in blood flow, which is thought to support clearance of back diffusing H+, is reversed in the ischemic stomach. The exposure to high luminal H+ concentrations may therefore promote gross injury in the ischemic stomach by further compromising nutritional mucosal blood flow.

Animals↗

PubMed1989

Early dinner reduces nocturnal gastric acidity.

This study examines whether eating food at different times has differential effects on intragastric pH. Experiments were done in 23 healthy volunteers (12 men). Intragastric acidity was monitored by ambulatory 22 hour pH-metry. Composition of meals was standardised: breakfast and lunch at 7 am and 12 noon respectively, and dinner at 6 or 9 pm, in random order. The time of going to bed and getting up was also standardised. With early dinner nocturnal pH was higher, than with late dinner (pH median: 1.67 and 1.39, p less than 0.001). During the remaining time periods, pH values were similar. Thus early dinner may be helpful in conditions where low intragastric acidity is desirable.

Adult↗

PubMed1989

Effects of hCGRP I and II on gastric blood flow and acid secretion in anesthetized rabbits.

Effects of intravenously administered human calcitonin gene-related peptides (hCGRP) I and II on regional blood flow and gastric acid secretion were examined in barbiturate-anesthetized rabbits. Blood flow was measured by injection of radioactively labeled microspheres at 0, 10, 20, 30, and 60 min. hCGRP I and II and vehicle were infused intravenously in five rabbits in rising doses of 0.01 (0-10th min), 0.03 (11-20th min), and 0.1 microgram.kg-1.min-1 (21-30th min). hCGRP I and II increased gastric blood flow dose dependently. Moreover, hCGRP I raised regional conductance (inverse of vascular resistance) in the stomach, duodenum, heart, brain, and skeletal muscle. As a result of the increased total peripheral conductance the mean arterial pressure was reduced, but the cardiac output remained unchanged. hCGRP II increased blood flow and conductance selectively in the stomach and the pancreas. The total peripheral conductance and mean arterial pressure remained unchanged. Apparently, hCGRP II exerts a more localized effect on the stomach than hCGRP I. hCGRP I and II did not affect basal gastric acid secretion. Pentagastrin-stimulated acid secretion was increased by 28% with hCGRP I (0.025 micrograms.kg-1.min-1) and decreased by 27% with hCGRP II (0.025 micrograms.kg-1.min-1). The inverse effect of hCGRP I and II and the parallel stimulation of blood flow brought about with hCGRP I and II indicate a different mode of action of the peptides on gastric blood flow and gastric acid secretion.

Animals↗

PubMed1989

[Is the measurement of carcinoembryonic antigen still indicated in digestive cancers?].

Carcinoembryonic antigen (CEA) is not useful for detecting asymptomatic cancer. Its sensitivity and specificity are not high. For some cancers, antigen levels at the time of diagnosis provide more precise prognosis than staging alone. Regular determination of CEA is useful as a method of surveillance after surgery for cancer in the colon and in the rectum. Unfortunately the clinical gain of detecting postoperative relapses is low since curative surgical treatment is usually impossible.

Carcinoembryonic Antigen↗

PubMed1989

[Screening for colorectal tumors using fecal occult blood studies].

Guaiac tests such as Hemoccult are widely used but are affected by several factors. Occult blood testing does uncover subclinical colorectal cancer often at early stage, but a favorable effect on survival remains to be proven. The sensitivity for the detection of malignancies is from moderate to good, but it is poor for benign polyps. Predictive value of a positive test for cancer ist about 8-12%. Thus, most of the individuals with a positive test would not need colonic investigations. Recommendations relating to the testing for of occult blood could change rapidly with the new immunologic techniques or with new data on mortality coming from controlled clinical trial now being conducted.

Colorectal Neoplasms↗

PubMed1989

Direct cytotoxic effect of oxygen radicals on the gastric mucosa.

Oxygen radical release has been proposed as a pathogenetic factor in the formation of acute gastric mucosal injury. We assessed the ability of the naturally occurring oxygen radical generating system hypoxanthine/xanthine oxidase (HX/XO) to cause gross gastric mucosal injury and measured the effect on regional mucosal blood flow. Local intra-arterial infusion of HX/XO into the vascular network of the stomach caused marked gross mucosal injury in the antrum and corpus. This injury occurred even in the absence of exogenous luminal acid and was aggravated by luminal acidification with 1 ml of 0.1N HCl. The selective oxygen radical scavenger superoxide dismutase (SOD) prevented mucosal injury caused by HX/XO. The effects of HX/XO and SOD were not mediated by alterations in regional gastric mucosal blood flow, as measured by the radiolabeled microspheres and reference sample method. These findings suggest that oxygen radicals are capable of causing substantial gastric mucosal injury by a direct cytotoxic effect independent of luminal acid or mucosal blood supply and give support to the concept that oxygen radical release may be a major primary pathogenetic factor in the development of acute gastric mucosal injury.

Animals↗

PubMed1988

Intragastric behavior and absorption kinetics of a normal and "floating" modified-release capsule of isradipine under fasted and fed conditions.

From measurements of drug levels in both gastric juice and plasma, we investigated whether or not a prolonged gastric residence time (GRT) is responsible for the slow absorption kinetics of a "floating" modified-release (MR) capsule of isradipine [isopropyl methyl (+/-)-4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3,5- pyridinedicarboxylate], a lipophilic dihydropyridine calcium channel blocker. The effects of a "high-fat" breakfast on the intragastric behavior and absorption kinetics were also assessed. In an open crossover design, five healthy subjects ingested either a normal or MR capsule of isradipine under fasted conditions. Serial samples of gastric juice (obtained via an indwelling nasogastric tube) and plasma were collected up to 24 h after drug intake, and were analyzed for isradipine by GC and RIA methods, respectively. The pH and titratable acid, protein, and pepsin concentrations of the gastric juice samples were also determined. Four additional subjects were similarly studied after ingesting the capsules following a high-fat breakfast. Under fasted conditions, gastric juice drug levels of the normal and MR capsules indicated a median GRT of less than 1.5 h in both cases. Plasma levels indicated a rapid absorption for the normal capsule (less than 2 h), but a remarkably slow absorption for the MR capsule, lasting 24 h or more. Under fed conditions, gastric juice and plasma profiles of the normal capsule were similar to those for the fasted case. In contrast, the MR capsule had an increased GRT (approximately 2.4 to 4.8 h) that was associated with a delayed and more extensive intragastric drug release. The corresponding plasma profiles showed a rapid absorption phase which correlated closely with the intragastric release kinetics. The influence of a high-fat meal on the release kinetics of the MR capsule did not appear related to the intragastric pH, or acid, protein, or pepsin concentrations. From these results we conclude that: (1) a prolonged GRT is not responsible for the slow absorption achieved with a "floating" MR capsule; (2) the presence or absence of food, rather than buoyancy, is the principal determinant of the GRT of the MR capsule; (3) the release and absorption of a lipophilic drug from a "floating" MR capsule may be affected by intragastric interaction with the lipid phase of meal; and (4) the major portion of drug release from the MR capsule takes place in the colon, rather than in the stomach.

Adult↗

PubMed1988

Effect of a slow-release formula of trimoprostil on intragastric acidity in healthy volunteers.

We investigated the effect of a slow-release formula of trimoprostil, a prostaglandin E2 analogue, at a dose of 3 mg b.d. on circadian intragastric acidity in nine healthy volunteers using ambulatory pH-metry in a placebo-controlled study. The effect of trimoprostil was long lasting (8 hours during the night). However, it lowered gastric pH on average only by 0.4 pH units. In four of the six women severe side-effects occurred in the form of abdominal cramping, metrorrhagia, and/or diarrhoea. These disadvantages may limit the clinical use of this drug.

Adult↗

PubMed1988

Microsphere estimates of blood flow: methodological considerations.

The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study we have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 X 10(6) microspheres (15 microns) each time. The effects of excessive numbers of microspheres (13 million), pentobarbital sodium anesthesia (30 mg/kg), and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. We conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period.

Animals↗