Biomedical subjects

M Rössle

Publications and source records attributed to M Rössle.

78 records · Page 5Linked to original sources

PubMed1983

[Tryptophan loading test as a function parameter in liver diseases].

Because of its specific hepatic degradation tryptophan was orally administered (50 mg/kg) to patients with various chronic liver diseases (n = 30) and to healthy volunteers (n = 8) as a test for hepatic function. The plasma half life of tryptophan was determined between 4 and 8 h after the amino acid load. It was found that in patients with cirrhosis (n = 25) the half life of tryptophan was prolonged to 4.7 +/- 0.4 h (means +/- SD), compared to 2.0 +/- 0.1 h in the controls. The tryptophan half life also correlated with the plasma concentration of albumin, bilirubin, cholinesterase and prothrombin time in these patients. In addition a significant correlation was observed with the galactose elimination capacity and the 45 min retention of BSP. Thus, the oral tryptophan loading test may be suitable for a more specific determination of functional impairment of the liver in chronic liver disease. In decompensated cirrhotic patients alterations of the tryptophan metabolism seen to be related to indicators of hepatic encephalopathy. The test may therefore be used to assess the degree and risk of hepatic encephalopathy in such patients.

Adult↗

PubMed1982

[Therapy of hepatic encephalopathy. Changes in the cerebrospinal fluid concentration of catecholamine neurotransmitters, ammonia and amino acids in the course of an infusion treatment with branched-chain amino acids].

Infusions containing branched-chain amino acids have recently been used for the therapy of hepatic coma. Their mode of action was attributed to a reduction in the intracerebral concentrations of the aromatic amino acids with resultant normalization of the neurotransmitters noradrenaline, dopamine and serotonin, synthesized from these amino acids. In order to further clarify this therapeutic mechanism an infusion solution consisting of branched-chain amino acids and ammonia-reducing amino acids was administered to patients with porto-systemic encephalopathy. The amino acid pattern, the ammonia in plasma and liquor, and the neurotransmitters noradrenaline, adrenaline and dopamine, in the liquor were determined before and after the course of treatment. Our studies show that the therapeutic effect of branched-chain amino acids in the therapy of hepatic encephalopathy is based on an effective intracerebral reduction of the ammonia concentration by 61%. The actual concentrations of the neurotransmitters were not significantly modified by the therapy. This opens to question the hypothesis that the neurotransmitters are responsible for the development of hepatic encephalopathy.

Amino Acids↗

PubMed1981

Acetyl coenzyme A and coenzyme a contents of growing clostridium kluyveri as determined by isotope assays.

CoASH and some of its acyl derivatives, especially acetyl-SCoA, occupy a central position in the energy metabolism of the anaerobic Clostridium kluyveri, both as intermediates and as regulatory effectors. The steady state concentrations of these compounds were determined in growing cultures of this organism using an anaerobic and fast deproteinization technique and radio isotope assays. Acetyl-SCoA was determined as [1-14C]citrate formed in the presence of [4-14C]oxaloacetate and citrate synthase; 0.49 mumol/g cell wet wt. were found. CoASH, CoAS-SCoA after borohydride reduction, and total acyl derivatives of coenzyme A after hydrolysis of the thiol esters were converted to thioethers with [2,3-14C]N-ethylmaleimide and brought to radiochemical purity by chromatographic methods. While disulfides of coenzyme A were undetectable, 0.13 mumol CoASH and 1.17 mumol of total acyl-SCoA per g wet wt. were found. These data are consistent with the regulatory scheme of the energy metabolism of C. kluyveri previously proposed.

Acetyl Coenzyme A↗

PubMedDate not supplied

Structural processes during starch granule hydration by synchrotron radiation microdiffraction.

Starch granule hydration has been examined on the level of a single potato starch granule by static and dynamic synchrotron radiation (SR) microdiffraction techniques. A cryofrozen, hydrated granule was mapped through a 5 microm SR-beam in order to investigate its internal organization. The edge of the granule showed fiber texture scattering due to radially oriented amylopectin helices. The variation of fiber texture across the granule center supports the model of concentric shells. The crystalline phase appears, however, to increase strongly toward the granule center due to a random amylopectin fraction, which could be related to crystallization of short-range ordered amylopectin during hydration. During gelatinization, the shell structure breaks down and remaining fiber-textured amylopectin domains belong probably to the swollen starch granule envelope. Hydration of a granule was initiated by a microdrop generator and followed in situ by SR-microdiffraction. A fast hydration process with a half time of about 7 s seems to reflect the porous nature of starch granules. The size of the hydrated domains suggests that this process is limited to the level of amylopectin side chain clusters. Longer hydration times are assumed to involve remaining short-range ordered amylopectin and results in larger domains.

Kinetics↗

PubMedDate not supplied

Helicobacter pylori infection does not correlate with plasma ammonia concentration and hepatic encephalopathy in patients with cirrhosis.

BACKGROUND/AIMS: In patients with cirrhosis, infection of the stomach with Helicobacter pylori may increase ammonia production and, consequently, the incidence of hepatic encephalopathy. To test this hypothesis a retrospective analysis was performed in patients with a transjugular intrahepatic portosystemic shunt. These patients are regarded to be ideal candidates for such a study since they have a high bioavailability of gut-derived ammonia and many of them develop spontaneous hepatic encephalopathy. METHODOLOGY: In 132 patients (Child-Pugh class A: 24%, B: 49%, C: 27%) with stable transjugular intrahepatic portosystemic shunt function for more than 3 months (mean follow-up: 15.5 +/- 10.8 months) the diagnosis of H. pylori infection was established by a specific and sensitive immunoblot assay for IgG- and IgA-antibodies. During follow-up, hepatic encephalopathy was assessed by clinical examination and a structured questionnaire. Venous plasma ammonia concentration was measured at the time of antibody determination (end of study period). RESULTS: Eighty-four patients (64%) had negative and 48 patients (36%) had positive immunoblots for H. pylori. The groups were comparable with respect to age, gender, etiology of cirrhosis, Child-Pugh class, follow-up after transjugular intrahepatic portosystemic shunt, and shunt function. The ammonia concentrations of the patients without (group 1) and with antibodies against H. pylori (group 2) were 73 +/- 27 and 69 +/- 28 mumol/L (mean +/- SD), respectively. Hepatic encephalopathy occurred in 23 of 84 patients (27%) of group 1 and in 11 of 48 patients (23%) of group 2. CONCLUSIONS: A positive immunoblot for H. pylori antibodies neither correlates with plasma ammonia concentration nor with the incidence of hepatic encephalopathy in patients with cirrhosis of the liver and portosystemic shunt.

Adult↗

PubMedDate not supplied

The role of TIPS for the treatment of portal hypertension: effects and efficacy.

In patients with variceal bleedings TIPS is effective even if the portal pressure is reduced only partially and the reduction does not reach the threshold of 12 mmHg. Since the post-TIPS pressure gradient is closely correlated to the incidence of hepatic encephalopathy, higher gradients should be favoured in patients with a higher risk of hepatic encephalopathy, e.g. patients > age 65 years, Child-class C patients, and active alcoholics. An 8 mm diameter-shunt is probably the adequate size for most of these patients. Regarding patients with ascites, the effect of TIPS is partially due to an improvement of renal blood flow and function. The reasons for this are unknown. The systemic hemodynamic effects of the TIPS are probably not the cause since the shunt did not result in an improvement of the arterial filling and peripheral resistance. The experimentally proven hepatorenal baro-reflex may be an explanation.

Aged↗