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Biomedical subjects

R Arendt

Publications and source records attributed to R Arendt.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Pathophysiologic and clinical relevance of atrial natriuretic factor in patients with cirrhosis of the liver].

Defects of the ANF system in cirrhosis have not been demonstrated in terms of absolute deficiency of plasma levels or by evidence of major abnormalities of processing in patients with cirrhosis. In the present study, the responsiveness of the ANF system to acute volume stimulation by water immersion and the diuretic and natriuretic effects of ANF infusion were examined. Stimulation of ANF release by 1-h immersion was significantly blunted in ten cirrhotic patients with ascites (increase of plasma ANF by 46 +/- 18%), whereas 11 cirrhotics without ascites showed a 104 +/- 16% increase, similar to the 117 +/- 29% stimulation in 25 healthy controls. Immersion increased urinary volume by 3.6 +/- 0.6/2.0 +/- 0.8/0.7 +/- 0.4 ml/min and urinary sodium excretion by 146 +/- 38/75 +/- 43/43 +/- 19 mumol/min in controls/cirrhotics without/cirrhotics with ascites. Infusion of ANF for 30 min prompted an increase in diuresis and natriuresis in seven cirrhotic patients, which was less marked in patients with ascites, as compared to patients without ascites. Thus, the stimulus response coupling for ANF may be impaired in patients with cirrhosis and ascites.

Ascites↗
PubMed1988

[Effect of an antacid on duodenal pH in severe excretory pancreatic insufficiency].

pH was measured continuously in the lower duodenum before and 90 min after a standard meal in 15 controls and 13 patient with severe pancreatic insufficiency (PI); gastric acid secretion was unimpaired in all of them. 7 out of the 13 pat. with PI received additionally 30 ml of an A-Mg-silicate preparation (MegalacR) 45 min after the meal. Mean pH dropped after the meal from 6.9 to 6.2 in the controls and from 7.1 to 4.9 in the pat. with PI. The overall time of pH-values below 5 amounted to 0.5% of the measuring period in the controls, in PI-pat. to 35%. In pat. with PI there were additionally pH-values below 4 during 11% of the postcibal period. Antacid administration increased duodenal pH significantly but only over 15 min; this transient effect had, however, no significant influence on the overall time of the pH-values below 5 and 4. Al-Mg-silicate has obviously no relevant effect on the postcibal duodenal pH in pat. with PI and can therefore not be regarded as a means to prevent inactivation of pancreatic enzymes in the duodenum.

Aluminum Compounds↗
PubMed1987

Diffuse gastric antral vascular ectasia: cause of chronic gastrointestinal blood loss.

In a patient with long-standing iron deficiency anemia, diffuse gastric antral vascular ectasia was found endoscopically. Diagnostic problems were the misinterpretation of the macroscopic finding as hemorrhagic inflammation and the microscopic confirmation of the diagnosis from small biopsy particles. Resection of the antrum resulted in a persistent normalization of hematologic parameters. Focal ischemia due to microthrombi in mucosal vessels might be the cause of the tendency of this vascular malformation to bleed.

Adult↗
PubMed1987

[Interdigestive and postprandial duodenal pH in healthy probands, in patients with ulcer and in chronic pancreatitis].

In patients with chronic pancreatitis (48), gastric ulcer (6), duodenal ulcer (6) and controls (12) duodenal pH was measured continuously by a glass electrode before and 90 minutes after a standard meal. The capacity of the stomach to secrete acid was known in all test persons, the degree of exocrine pancreatic insufficiency was determined according to the results of the S-CCK-test: 6 had no, 29 moderate and 13 severe pancreatic insufficiency. There were no significant differences between the mean interdigestive duodenal pH of the groups. After a meal, however, even patients with a normal pancreatic function but with hyperchlorhydria had a significantly lower pH (mean pH 5.5) than those with normo-chlorhydria (mean pH 6.1) and hypochlorhydria (mean pH 6.5). In patients with severe pancreatic insufficiency and normo-/hyperchlorhydria duodenal pH was much lower (mean pH 4.2) in some cases to pH 3.5, thus well below a level known as inactivating pancreatic enzymes. The total duration of the pH being less than 4.5 amounted to 12% of the postprandial measuring time (11 of 90 min). If, however, severe pancreatic insufficiency was combined with a-/hypochlorhydria duodenal pH did not differ from controls. Thus, reduced acid secretion of the stomach exerts beneficial effect on duodenal pH in patients with severe pancreatic insufficiency.

Acid-Base Equilibrium↗
PubMed1986

[Pure human pancreatic juice. Methodologic aspects of pancreatic juice collection and interpretation of findings].

A procedure to collect pure pancreatic juice endoscopically is described which allows an instant estimation of the protein content of the secretion by measuring its absorption at 280 nm. By this the kinetics of protein secretion can already be read from a curve during the collecting procedure, thus avoiding a multitude of small fractions otherwise necessary. Timing and size of the samples are adjusted individually according to the course of protein secretion and not to a rigid regimen. The method described is especially apt to investigations of pancreatic proteins and substances the secretion of which parallels that of protein; e. g. trypsinogen, calcium and zinc, however not sodium and potassium.

Cholecystokinin↗
PubMed1986

[Endoscopic perfusion manometry of the common bile duct in the post-cholecystectomy syndrome].

In 14 cholecystectomized patients with recurrent attacks of pain endoscopic manometry of the c.b.d. was carried through after thorough exclusion of organic diseases. Two different conspicuous types of pressure behaviour became evident: In 8 pat. the pressure in the c. b. d. increased steadily during perfusion and finally triggered pain, identical to the spontaneous one according to localization and character. In 6 pat. even after prolonged perfusion no pain emerged and the c. b. d.-pressure remained unchanged. As the increase in c. b. d.-pressure connected with provocation of pain was reproducible, perfusion manometry in the c. b. d. seems to be a mean of delimitating and objectifying functional disturbances of the bile duct.

Cholecystectomy↗
PubMed1985

[Transpapillary bile duct endoprostheses in obstructive jaundice].

12 patients were treated with endoscopic transpapillary biliary endoprosthesis. The indication for biliary drainage was malignant obstructive jaundice in 10 and benign obstructive jaundice in 2 cases. The effectiveness of drainage is indicated by the disappearance of jaundice. The lifetime of the endoprosthesis was maximal 4 months and the survival of the tumor patients maximal 6 months. If the endoprosthesis is occluded replacement by a new one is necessary. Nonsurgical biliary drainage is an alternative method to palliative operation and should be preferred in general inoperability and in patients with irresectable tumors.

Ampulla of Vater↗
PubMed1984

Time-series analysis of stereotyped movements: relationship of body-rocking to cardiac activity.

The pathological stereotypies frequently observed among severely mentally retarded and autistic persons are highly rhythmical in nature. Most attempts to quantify such behavior, however, have not analyzed stereotypy in terms of its cyclical properties. In the present paper we have detailed a method for electronically transducing stereotyped body-rocking and analyzing its frequency and amplitude characteristics with a standard polygraph and microprocessor. The relationship between stereotyped body-rocking and cardiac activity was also described using time-series analysis. The method described should provide a sensitive index of various experimental manipulations and treatment effects.

Adult↗
PubMed1983

[Endoscopic papillotomy in East Germany].

Through a survey 751 patients, in whom an endoscopic papillotomy (EPT) had been tried, were registered to the end of 1981. EPT was technically successful in 695 cases (92,5%). Control investigations were available for 650 patients, the aim of therapy being achieved in 594 cases (91,4%). The main indication was choledocholithiasis, 90,2%--among them 10% with gallbladder in situ--followed by benign papillary stenosis without stones (5,9%), carcinoma of the Vaterian papilla (3,2%) and rare indications such as ascaridiasis, choledochocele and stones of the pancreatic duct (0,7%). 53 patients suffered from more serious complications (7,6%), 18 had to be operated on (2,6%), and 7 patients died due to EPT (1%). The results are in agreement with those of other statistics from various countries.

Ampulla of Vater↗
PubMed1982

Electron capture GLC analysis of the thienodiazepine clotiazepam. Preliminary pharmacokinetic studies.

Plasma concentrations of 5-(2-chlorophenyl)-7-ethyl-1,3-dihydro-1-methyl-2H-thieno[2,3-e][1,4]diazepin-2 -one (clotiazepam, CTZ, Trecalmo), a thienodiazepine anti-anxiety agent, and two of its metabolites (hydroxy- and desmethyl-clotiazepam) are reliably quantified by electron capture GLC. After addition of diazepam as internal standard, 1-ml plasma samples are extracted with benzene-isoamyl alcohol (98.5:1.5). The organic extract is evaporated to dryness, reconstituted, and directly chromatographed using a 3% SP-2250 liquid phase at 260 degrees C. Sensitivity limits are 1-3 ng of each of the 3 compounds per ml of plasma. The method is applicable to clinical pharmacokinetic studies in humans. After p.o. ingestion of a single 5-mg dose of clotiazepam by three healthy volunteers the drug was rapidly absorbed. Values of elimination half-life were 6.5, 7.0, and 17.8 h, respectively. The two metabolites appeared and disappeared approximately in parallel with the parent compound. Clotiazepam was more than 99% bound to plasma protein.

Adult↗
PubMed1982

[Pancreatic findings after ductal occlusion in rats. A histological and biochemical study].

By histological examination of the exocrine pancreas a triphasic reaction was proven in 46 rats of a wistar strain 1 hour up to 8 weeks after a transduodenal intraductal instillation of an alcoholic amino acid solution (Ethibloc). The first phase, due to both the incorporated substance by itself and an acutely increased intraductal pressure, consists in an interstitial edema with transition into a perilobular pancreatitis, a cytotoxic damage of the acinar and ductal epithelium with focal necrosis of parenchyma and fat-tissue, a sialangiitis and foreign body granulomas. In a second phase, produced by the occlusion of the duct system, a cystofibrosis of the lobuli developed within 7 to 14 days after a preceding hyperplasia and ectasia of intercalated ducts and an atrophy of acini. In a third phase of pancreas injury, starting at the 14th day of experiment, in non-atrophied lobuli a progressive intralobular, supposed autoimmunological, pancreatitis developed. Changes in the activity of serum lipase and -amylase correlated strongly with the morphological findings. The results suggest that at last a nearly complete burnout of the normal rat pancreas is possible by duct occlusion. But for the clinical application the danger of provocation of an acute relapse of chronic pancreatitis might be given by the presence of a secreting parenchyma.

Amylases↗
PubMed1982

[A new procedure for the revision and reposition of functionless peritoneal dialysis catheters].

The most important requirement for satisfactory transperitoneal dialysis is faultless functioning of the Tenckhoff catheter. Suddenly occurring functional disturbances are often caused by wrong positioning and by envelopment of the catheter by tissue, which require surgical correction. A technique for successfully locating and replacing a transperitoneal catheter by means of an operation laparoscope is described.

Adult↗