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Biomedical subjects

U Leuschner

Publications and source records attributed to U Leuschner.

At least 73 records · Page 4Linked to original sources
PubMed1989

Pigment gallstone dissolution in vitro. Solubilization of brown bilirubinate and black polybilirubinate stone material by buffered solvents containing ethylenediaminetetraacetic acid, bile salts, and reducing thiols.

The efficacy of a buffered 1% ethylenediaminetetraacetic acid (EDTA)-2Na solution (pH 9.2) in solubilizing carefully pulverized material from brown bilirubinate and black polybilirubinate pigment stones can be intensified stepwise by admixtures of detergents and mucolytic active thiols. Solubilization effects were quantified either photometrically by measuring the dissolved calcium bilirubinate or gravimetrically by measuring the total weight loss of solids after a defined incubation period. Maximum effects were achieved when using a buffered solvent with 1 g/dl disodium-EDTA, 1 g/dl sodium taurocholate (NaTCA), and 2 g/dl N-acetylcysteine (NAC). Whereas admixtures of NAC enhanced the solubilization of brown bilirubinate stone material additionally by an average of 21.3% (related to the effect of an EDTA/NaTCA-containing solvent), black polybilirubinate material responded rather poorly and inconsistently to NAC (mean, 8.4 +/- 11.7%).

Bile Acids and Salts↗
PubMed1989

[Bile acid binding by antacids in a "quasi-natural" reflux milieu].

In a "quasi-physiological" reflux mixture obtained from non-stimulated gastric juice and hepatic bile the bile acid adsorption of 7 antacids is investigated with an newly developed HPLC method. The antacids produce pH values varying from 3.7 to 7.6. With increasing pH and increasing polarity of bile acids the bile acid binding to antacids decreases. The theoretically desirable combination of high pH and good bile acid binding is difficult to achieve. The relatively good total bile acid binding (over 60%) by Trigastril at a high pH (7.53) contrast with better bile acid adsorption by Maaloxan and Aludrox (about 90%) at a lower pH (4.5-4.9). Interestingly, toxic nonpolar bile acids are particularly well adsorbed by antacids.

Antacids↗
PubMed1988

[Percutaneous transhepatic lysis of gallstones using methyl tert-butyl ether. Report on 15 patients].

In 15 patients (13 women and two men) with cholesterol stones in the gall-bladder a special (Thistle) catheter was introduced into the gall-bladder under local anaesthesia by percutaneous transhepatic puncture. Methyl-tert-butyl ether, 2-15 ml, was injected via the catheter and removed again after 2 min. The number of stones per gall-bladder averaged 6.3 (1-20), size of stones 1.7 cm (0.5-2.8 cm), and duration of treatment 11.9 h (5-24 h). The stones dissolved in 13 patients (87%). In three patients stone débris remained: in one it was ultimately sucked out after reduction of the amount of débris with an EDTA-containing solution. The side effects of treatment--nausea and vomiting--were minor. In one patient there was a leak of bile from the gall-bladder after the procedure; a cholecystectomy was uneventfully performed. Another patient developed haemobilia which responded to conservative treatment. MTBE treatment has thus proved to be a successful and cheap method, low in side effects, in the treatment of patients with gall-stones.

Adult↗
PubMed1988

Dissolution of gall stones with an ursodeoxycholic acid menthol preparation: a controlled prospective double blind trial.

In a controlled prospective double blind trial patients with cholesterol gall bladder stones are treated with ursodeoxy-cholic acid (group A: UDCA 11.1 mg/kg per day; n = 16) and Ursomenth respectively (group B: a mixture of UDCA/menthol: 4.75 mg/kg per day each; n = 17). With same stone number and size (10-12 mm) there is a complete dissolution rate in group A of 38%, and of 53% in group B within 15-16.9 months. The response rate (complete + partial dissolution) amounted to 75% and 76% respectively. In group A there is one case of stone calcification, in group B none. Both preparations are free of unwanted effects. This suggests that the cyclic monoterpene menthol enhances the effect of UDCA and is of comparable effect to a mixture of six different terpenes used in former times.

Adult↗
PubMed1988

Dissolution of calcified cholesterol stones and of brown and black pigment stones of the gallbladder.

The influence of different solvents on cholesterol and pigment stones was investigated in vitro. Stone analysis was performed chemically, with infrared spectroscopy (IRS), scanning electron microscopy, energy-dispersive X-microanalysis (EDXA) and wave-length-dispersive X-microanalysis (WDXA). Each set of stones came from one source: eight human calcified cholesterol stones (CHS), eight fragments of bovine radiopaque Ca-bilirubinate stones (BBIL), and two complete BBIL. CHS and BBIL fragments were treated with (1) a buffered, alkaline 1% ethylenediamine tetraacetate solution (BA-EDTA; pH 9.5); (2) with BA-EDTA and monooctanoin preparation (GMOC) alternately; (3) with GMOC alone, and (4) with methyl-tert-butyl ether (MTBE). The complete BBIL were treated with BA-EDTA and MTBE. Furthermore, two human black pigment stones (BPS) were incubated in BA-EDTA. Calcified cholesterol stones are not dissolved by GMOC alone, nor by alternating treatment with BA-EDTA. They are dissolved by MTBE. MTBE is unsuitable for complete Ca-bilirubinate stones but MTBE, GMOC and GMOC/BA-EDTA alternately disaggregate stone fragments. This means that stone fragments behave differently from complete Ca-bilirubinate stones, which is important for further in vitro investigations. Ca-bilirubinate and black pigment stones are disaggregated in BA-EDTA. These results were confirmed with six CHS, 12 BBIL and 12 BPS from 5 further patients, incubated in the most eligible solvent for any individual stone type.

Animals↗
PubMed1988

Antral mucosal bile acids in two types of chronic atrophic gastritis.

Bile acids may damage the gastric mucosa, and they are cocarcinogenic in experimental colonic and gastric cancer. Chronic atrophic gastritis (CAG) and chronic atrophic gastritis with intestinal metaplasia (CAGIM) are associated with gastric carcinoma. We, therefore, analysed bile acids in the antral mucosa in controls (n = 10), in patients with CAG (n = 12) and CAGIM (n = 20). In both forms of chronic antral gastritis, total mucosal bile acid concentrations drop, caused mainly by lower primary bile acids. The proportions of secondary bile acids rise, in particular of toxic lithocholic acid. This is probably caused by bacterial activity in the stomach. Whether secondary bile acids, especially lithocholic acid, alone or in combination with other bacterial degradation products, influence gastric carcinogenesis remains to be elucidated in further studies.

Adult↗
PubMed1988

Differing effect of chenodeoxycholic acid and ursodeoxycholic acid on bile acids in rat colonic wall and contents.

Bile acids may promote experimental colonic cancer. Many studies correlate fecal bile acids and colorectal carcinomas. Little is known on bile acids in the colonic mucosa and their relation to luminal bile acids. We, therefore, studied bile acids in colonic wall and contents of normal female Wistar rats and after 14 days' administration of chenodeoxycholic acid or ursodeoxycholic acid (90 mg/kg daily), two bile acids used in medicamentous cholelitholysis. Both regimens increase total bile acids in colonic contents, ursodeoxycholic acid produces a higher rise in toxic lithocholic acid. In the colonic wall, only ursodeoxycholic acid causes an increase of most nonsulfated bile acids including lithocholic acid. Bile acid patterns do not correlate in colonic wall and contents. We conclude that increased colonic wall bile acids after ursodeoxycholic acid administration warrant control in man. In future colorectal carcinoma studies, not only fecal, but also mucosal bile acid concentrations should be correlated to carcinogenesis.

Animals↗
PubMed1988

Endoscopy of the gallbladder as control of gallstone therapy with methyl-tert-butyl ether.

We report on a 36-yr-old woman with six gallstones measuring 2.1 cm each. Within 21 h of methyl-tert-butyl ether (MTBE) treatment, the stones had dissolved to a small amount of residue. As could be seen from cholesterol concentrations of samples of aspirated gallbladder bile and MTBE fractions, the dissolution process was slow to begin with, and gained momentum during hours 6-11, after which it decelerated. We discontinued treatment after 20 h, since the stone residue showed no change. Cholecystoscopy performed with an Edwards angioscope via a catheter showed that there were no stone remnants, but that there were flat polyps on the gallbladder wall. One hour later, we stopped the therapy. Cholecystoscopy is a useful method of assessing the results of MTBE treatment.

Adult↗
PubMed1987

Prostaglandin E2 directly protects isolated rat gastric surface cell membranes against bile salts.

Rat gastric surface cell membranes were prepared and the effect of taurocholic acid assessed by ESR spectroscopy using the 16-doxylstearic acid spin label. Taurocholic acid increased the polar part of the spectra, indicating an augmented amount of spin label molecules with a polar environment. Concomitantly, mobility of the spin label molecule was augmented. The effect of taurocholic acid was completely prevented by the previous addition of prostaglandin E2. This suggests a direct protective efficiency of prostaglandin E2 on rat gastric surface cell membranes without the metabolic participation of intact cells.

Animals↗
PubMed1987

Absolute bioavailability of metoclopramide given orally or by enema in patients with normal liver function or with cirrhosis of the liver.

Single dose studies were performed with three different dosage forms of metoclopramide (0.25 mg/kg body weight) in patients with normal liver function (i.v. (Paspertin): n = 4, oral liquid preparation: n = 4, rectal micro-enema n = 4) and patients with histologically confirmed cirrhosis of the liver (i.v.: n = 6, oral liquid preparation n = 4, rectal micro-enema: n = 8). Drug plasma-concentrations were measured over 8 h by a specific gas chromatographic method. The median areas under the plasma concentration-time curves (AUC0-8) after i.v. and rectal administration were similar in both groups. In contrast, the median oral bioavailability was considerably higher in patients with cirrhosis of the liver (82%) than in patients with normal liver function (60%). It can be concluded from this study, that dosage adjustments may be necessary in oral treatment of patients with cirrhosis of the liver, especially if prolonged therapy is required.

Administration, Oral↗