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Biomedical subjects

M Classen

Publications and source records attributed to M Classen.

At least 307 records · Page 17Linked to original sources
PubMed1987

Laser and endoluminal 192-iridium radiation.

The combination of laser and endoluminal 192-iridium irradiation for the palliation of malignancies of the esophagus and the cardia was introduced to overcome the short-term effect of laser treatment alone. On the basis of early experience, this method would seem to prolong the effect of laser treatment alone, and is associated with a low risk of complications. However, the initial optimistic results, claiming permanent relief of dysphagia in 80% of the patients, cannot be reproduced under prospective conditions. The combination of laser and 192-iridium irradiation with other palliative methods, such as external radiation treatment and/or chemotherapy is feasible, and remains to be studied in a comparative way.

Brachytherapy↗
PubMed1987

Endoprosthesis and local irradiation in the treatment of biliary malignancies.

Endoscopic biliary drainage by means of a bilio-nasal tube or stent (bilioduodenal endoprosthesis) provides an intermediate or long-term "bridge" for the interrupted bile flow. Insertion procedures are successful in 80-90% of the cases. Percutaneous transhepatic drainage serves as an alternative or complementary procedure to the endoscopic approach. Virtually every patient can be treated in this way when surgery is contraindicated or impossible. Endoscopic stenting is equally effective in relieving jaundice, but has a lower mortality rate and is associated with a shorter hospital stay than biliary surgery. Patients with tumorous obstruction of the liver hilum live significantly less long than those with cancerous occlusion of the hepatocholedochal duct. In the case of bile duct cancer, non-surgical drainage procedures can be combined with endoscopic or transhepatic irradiation employing 192-iridium for intraluminal irradiation; further studies are, however, needed. Endoscopy of the biliary tract (cholangioscopy) is available via the papilla of Vater and through the liver, and may in the future expand our diagnostic and therapeutic possibilities for the treatment of malignant biliary disorders.

Bile Duct Neoplasms↗
PubMed1987

The effects of 75 mg HOE 760, a novel H2-receptor antagonist, on daytime peptone-stimulated and nocturnal gastric acid output in healthy volunteers.

The effects of HOE 760, a highly specific H2-receptor antagonist, on daytime peptone-stimulated and nocturnal gastric acid output were studied (randomized, double-blind crossover) in 10 healthy men. Acid output was monitored at lunch (1200 h to 1400 h) and dinnertime (1800 h to 2000 h) by continuous automatic intragastric titration; from midnight to 0600 h, output was measured by titration of manually aspirated gastric contents. After a 75-mg oral dose (capsule containing HOE 760 granules) at 0800 h peptone-stimulated acid output decreased for at least 12 h. Compared with placebo, significant reductions (p less than 0.05) of 86% and 32% were observed 4-6 h and 10-12 h after drug administration. After another dose of 75 mg at 2100 h nocturnal acid output was significantly reduced (p less than 0.05) by 88%; gastric pH was increased by about 2 units throughout the night. HOE 760 was well tolerated. No adverse reactions occurred; no clinically relevant changes were noted in haematologic, biochemical, urinary, or electrocardiographic variables.

Adult↗
PubMed1987

Computer-aided formulation of physician's reports and storage of ERCP data.

In the 2nd Medical Dept. of the Technical University of Munich, endoscopic retrograde cholangiopancreatography (ERCP) reports are written with the aid of a computer. The doctor doing the examination enters the ERCP data into screen masks. The data are stored at once in a data bank. This data bank system permits immediate error checks of the variables entered, singly and in combination. Errors can be corrected in a loop. Generating of ERCP reports is controlled by a text file, which contains both control statements and standard phrases. A special program for the document generating was developed by the authors and has been used for 15 years in various applications.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1986

Effect of insulin on secretion of bombesin-like immunoreactivity and gastrin from the isolated rat stomach in response to acetylcholine, VIP and leucine-enkephalin.

Bombesin-like immunoreactivity (BLI), a putative peptidergic neurotransmitter of the gastrointestinal intrinsic nervous system is released from the isolated perfused rat stomach in response to the classical neurotransmitter acetylcholine and in response to other putative peptidergic neurotransmitters such as vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI) or growth hormone releasing factor (GRF). The secretion of BLI is modulated not only by gastric factors such as the intragastric pH but also by changes of perfusate glucose concentrations indicating that alterations of carbohydrate metabolism might have an effect on gastric neuroendocrine regulation. Since previous studies have shown that insulin, the major regulatory hormone of glucose metabolism, reduces gastric somatostatin and glucagon secretion it was of interest to determine the effect of insulin on gastric BLI and gastrin secretion. The experiments were performed in the isolated perfused rat stomach model. The addition of porcine insulin to the perfusate at concentrations of 50 and 100 microU/ml had no effect on basal BLI and gastrin secretion. The infusion of acetylcholine (2 X 10(-6)M and 4 X 10(-6)M) elicited a stimulation of BLI and gastrin secretion which was not altered by the addition of insulin (100 microU/ml). On the other hand, significant effects of insulin were observed during administration of the two putative peptidergic neurotransmitters VIP and leu-enkephalin. The infusion of VIP at 10(-11)M and 10(-8)M had no effect on BLI and gastrin secretion in the absence of insulin, however, with the addition of insulin (100 microU/ml) the higher dose of VIP (10(-8)M) elicited a significant stimulation of BLI secretion while both doses of VIP (10(-11)M and 10(-8)M) significantly increased gastrin release. Similar to VIP the infusion of leu-enkephalin at doses of 10(-9)M and 10(-6)M had no effect on BLI and gastrin secretion in the absence of insulin. When insulin was added to the perfusate both doses of leu-enkephalin elicited a significant stimulation of BLI secretion while gastrin remained unchanged. The addition of the specific opiate receptor antagonist naloxone (10(-5)M) did not block the effect of leu-enkephalin in the presence of insulin. In addition the effect of naloxone was also examined during cholinergic stimulation. The addition of naloxone (10(-5)M) during the infusion of acetylcholine abolished the stimulatory effect on BLI secretion in the absence of insulin, whereas in the presence of insulin naloxone did not alter cholinergically-induced BLI secretion.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed1986

Calcium, calmodulin, and cyclic adenosine monophosphate modulate prostaglandin E2 release from isolated human gastric mucosal cells.

We studied prostaglandin E2 (PGE2) release from isolated cells of the human gastric mucosa. Mucosal cells were enzymatically isolated from biopsy specimens of human fundic mucosa. The results from these crude cell preparations were compared to those obtained in fractions with enriched (65-80%) or depleted parietal cell content (3-7%) which were prepared from gastric mucosa obtained at surgery. PGE2 release in the enriched parietal cell fractions exceeded that from crude or parietal cell depleted preparations 3- and 13-fold, respectively. However, despite this quantitative difference, all preparations responded similarly to the test agents. Newly synthesized PGE2 was not stored intracellularly but was released into the incubation medium. Release increased linearly for 30 min. Addition of the calcium ionophore A23187 enhanced PGE2 release 4- to 5-fold. The effect of A23187 required the presence of extracellular Ca2+ (10(-3) mol/liter). Assuming that A23187 alters Ca2+ flux in gastric cells as it does in other cell systems our data indicate that increased Ca2+ influx enhances PGE2 release. Since calmodulin is of importance for intracellular Ca2+ action, the calmodulin antagonists trifluoperazine and W7 were tested. Both antagonists inhibited PGE2 release by 65-85%, trifluoperazine being slightly more effective. Activation of the adenylate cyclase system by forskolin or direct addition of (Bu)2cAMP, a stable cAMP-analog, also inhibited PGE2 release. We conclude that PGE2 is released from parietal and from nonparietal cells of the human gastric mucosa, although the major quantity is released from the light density fraction that is enriched in parietal cells. In parietal and nonparietal cells Ca2+ is of importance in the regulation of gastric mucosal PGE2 release and calmodulin seems to mediate this intracellular action of Ca2+. cAMP inhibits PGE2-release from gastric cells.

Bucladesine↗
PubMed1986

Modulatory glucose effect on bombesin-like immunoreactivity and gastrin secretion from isolated perfused rat stomach.

Previous studies have demonstrated mostly inhibitory effects of elevated plasma glucose levels on gastric exo- and endocrine as well as motor functions. Because increased plasma glucose levels reduce vagal activity via the central nervous system, it remains unclear if glucose exerts a direct effect on gastric functions. Therefore, our study was designed to determine the effect of acute changes in glucose concentrations on the release of gastrin and bombesin-like immunoreactivity (BLI) from the isolated perfused rat stomach. Acute elevations of perfusate glucose from 100 to 200 mg/dl or from 100 to 300 mg/dl augmented BLI secretion significantly without affecting gastrin release. During an acute decrease from 200 to 30 mg/dl, the secretion of both peptides remained unchanged. When acetylcholine was administered to stimulate BLI and gastrin secretion, the elevation of perfusate glucose to 200 mg/dl and the decrease to 30 mg/dl attenuated BLI secretion, whereas gastrin secretion remained unchanged compared with the control experiments at 100 mg/dl glucose. On the other hand, the perfusion of vasoactive intestinal peptide (VIP) and Leu-enkephalin had no effect on BLI and gastrin secretion during 100 mg/dl glucose perfusion, but both peptides elicited a significant stimulatory effect on BLI secretion during a perfusate glucose concentration of 200 mg/dl without affecting gastrin secretion. In conclusion, our study demonstrates first that an acute increase of glucose augments basal BLI secretion. Second, cholinergically induced BLI secretion is attenuated by hypo- and hyperglycemia. Third, hyperglycemia augments BLI secretion in response to the neuropeptides VIP and Leu-enkephalin. Fourth, basal and stimulated gastrin secretion remains unchanged during acute alterations of perfusate glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1986

Benign lesions of the upper GI tract by means of endoscopic ultrasonography.

In contrast to conventional ultrasound tomography endoscopic ultrasonography (EUS) allows an exact evaluation of the wall of the upper GI tract. The gastric and esophageal walls give a typical five-layer image presumably corresponding to the mucosa (two inner layers), submucosa (middle echogenic layer), muscularis propria (outer echo-poor layer), and serosa (outer echogenic layer). A thickening of the mucosa may be demonstrated in Ménétrier's disease. In patients with gastric antrum ulcers there is considerable thickening of the gastric wall, especially of the submucosa and muscularis. Benign gastric and esophageal submucosal tumors are easily localized between the different layers. They are easily distinguished from malignant processes by means of EUS. In patients with polypoid endoscopic aspect due to an impression from outside, a tumor can be easily excluded.

Endoscopy↗
PubMed1986

Endosonographic diagnosis of benign pancreatic and biliary lesions.

The transduodenal and transgastric route provides good access to the pancreas and to large parts of the biliary tract, and endosonography (ES) creates images of high-detail resolution. Of 87 patients examined, 33 had benign lesions of the pancreas and biliary tract. All of 12 patients with chronic calcifying pancreatitis were correctly diagnosed, and ES in addition displayed minute cysts that were missed with conventional imaging modalities. Two of three apudomas were seen with ES, and seven of eight common bile duct (CBD) stones could be identified. Adenomyosis of the papilla of Vater was missed in all of three cases. Although minor alterations of the gallbladder can be displayed by ES, benign lesions of this organ are at present not indications for ES, whereas changes in the terminal portion of the CBD are rewarding for ES examination. ES proved to be a useful morphological technique in the diagnosis of minor benign alterations of the pancreas and prepapillary stones.

Adult↗
PubMed1986

A rare source of occult gastrointestinal bleeding: jejunal filiae secondary to metastatic lung carcinoma.

A case of occult gastrointestinal bleeding due to jejunal metastases of a primary lung carcinoma in a 53-year-old man is reported. When after healing of a large gastric ulcer melena persisted, a subsequently performed double contrast enema of the small bowel revealed evidence of several jejunal tumors. This was confirmed by angiography of the superior mesenteric artery and computed tomography of the abdomen. After resection of the tumor-bearing jejunal loop, histological evaluation revealed metastases secondary to a large-cell bronchogenic carcinoma which had been resected 1 year previously.

Carcinoma, Bronchogenic↗
PubMed1986

Electronic endoscopy--fibres or chips?

The video endoscope represents a new generation of endoscopic instruments. The main feature is an intragastric CCD-chip transforming the optical impulses into electronic signals. The latter are transmitted without any optical fibre bundle, transformed by a video processor and visualized on a television screen. The present experience show drawbacks in respect to mechanical properties of the endoscopes, to reproduction of colors (esp. red) and photographic documentation. On the other hand the excellent image quality guarantees convenient handling for investigator, information for attending persons (doctors, nurses, students), improved conditions for documentation and control of quality. Although the video-endoscope is not replacing fibre endoscopes at present, further improvement will promote its general acceptance.

Endoscopes↗
PubMed1986

[New observations in a case of Cronkhite-Canada syndrome].

We report about a 76 years old patient with Cronkhite-Canada syndrome. The diagnosis has been found with the following clinical symptoms: diarrhea, anorexia, alopecia, and onychotrophia. Laboratory values: severe hypoproteinemia (total serum protein 4.3 g/dl, albumin 2.4 g/dl); endoscopical and radiological findings: a generalized polyposis which involved the whole intestine except the oesophagus. As far as we saw in our literature-overview of 55 patients with Cronkhite-Canada syndrome, this patient had for the first time a carcinoma of the urinary bladder and a Bricker operation 17 years before the onset of his disease. Further we remarked a lack in the resorption of the enterally administered thyroidal hormones. The progress was fatal despite a parenteral hyperalimentation and a treatment with antibiotics and glucocorticoids.

Aged↗