Search PubMed⌕ Search

Biomedical subjects

B Liedtke

Publications and source records attributed to B Liedtke.

33 records · Page 2Linked to original sources
PubMed1977

[Metabolism of Etozolin in rat, dog and man].

Investigations on the metabolism of the new diuretic ethyl (Z)-(3-methyl-4-oxo-5-piperidino-thiazolidin-2-ylidene) acetate (Gö 687, etozolin, Elkapin) were carried out with urine of rat, dog and man as well as rat bile after enteral administration of the 14C-labelled substance. Seven metabolites were isolated with either the aid of high-pressure liquid chromatography (HPLC) or extraction and thin-layer chromatography. Mass spectroscopy was applied to determine the structures of the metabolites, partly by use of authentic reference substances. Because of the instability of most of the metabolites, some of them showing strong polarity, the described investigations on the metabolic profiles and the enrichment and purification of some metabolites could only be carried out with the HPLC-radioactivity detector system, which requires no clean-up for the samples. The metabolisation process of etozolin is qualitatively equal in rat, dog and man; it is characterized by 3 steps: 1. enzymatic cleavage of the ester group, which leads to the also diuretically active main metabolite (metabolite I) in the plasma of all 3 species; 2. glucuronidation of the resulting metabolite I, leading to metabolites II and III, which are diastereoisomeric esters of the two enantiomeric forms of metabolite I with beta-D-glucuronic acid. 50--60% of the urinary radioactivity can be described with these two metabolisation steps in all 3 species; 3. Oxidation of the piperidine moiety to metabolites IV--VII.

Acetates↗
PubMed1976

[Comparison of lipid concentrations in lung homogenates of newborns with and without hyaline membrane disease (author's transl)].

Quantitative and qualitative studies on lipids of the lungs were performed in babies who died during the perinatal period. The lungs were divided into organs with and without hyaline membranes respectively. Total lipids, phospholipids, neutral lipids, lecithins and sphingomyelins were determined. The fatty acid composition of total phospholipids and of lecithins is reported. A multivariate analysis of variance was used for the verification of significant differences in lipid content and in fatty acid composition with regard to the histological diagnosis. Taking at least two parameters (total phospholipids and C: 14-fatty acid or lecithin and C: 14-fatty acid into account, the two groups (lungs with and without hyaline membranes) were significantly different at the 5% level. The results are compared as well with the lipid content and composition of fatty acids of normal neonatal lung tissue as with observations regarding the lipids in amniotic fluid. The data obtained are discussed with regard to the development of lung maturity.

Amniotic Fluid↗
PubMed1976

[Comparison of serum lipid concentrations in umbilical artery, umbilical vein and maternal vein blood (author's transl)].

Maternal serum lipids and lipids in umbilical artery and umbilical vein blood were examined immediately after delivery in order to relate maternal and fetal lipid metabolism. Total lipids, phospholipids, triglycerides, total cholesterol, cholesterol esters and free cholesterol were determined. The comparison of arterial and venous umbilical lipid levels showed a significantly higher concentration of phospholipids in the umbilical vein, indicating an enhanced flux of phospholipids from the placenta to the fetus. A positive correlation is established for the amounts of total lipids (p less than 0,05), triglycerides (p less than 0,01), phospholipids (p less than 0,05) and free cholesterol (p less than 0,005) between maternal and umbilical vein blood. It is suggested that free cholesterol passes the placental barrier unchanged. The other correlations are discussed as the expression of a factor influencing simultaneously the maternal and fetal lipid metabolism.

Cholesterol↗
PubMed1976

[Lipid composition in placental homogenates of mature, premature and small for gestational age newborns (author's transl)].

Total lipids, phospholipids, and neutral lipids were determined in the placentas of mature, premature and small for gestational age babies. In addition the phospholipids and neutral lipids were calculated as percentage of total lipids. The distribution of fatty acids in placental phospholipids is reported. The difference found in the concentration of placental lipids is statistically significant at the 5% level between the groups of premature and small for gestational age babies. The increase of neutral lipids and the reduced content of phospholipids in placentas of small for gestational age babies are discussed as a possible sign of placental insufficiency.

Birth Weight↗
PubMed1975

[First experiences with prenatal affection of infantile lung maturation by betamethason (author's transl)].

Because of premature labour, probability of fetal retardation, discrepance at term of delivery, Rh-incompatibility or EPH-gestosis 185 patients were hospitalized. 76 pregnant women received twice 1.5 ml Celestan Depot i.m. (4.5 betamethasone acetate and 6mg betamethasome dinatrium phosphate per injection) within an interval of 24 hours. It was necessary to maintain a tocolysis for at least 48 hours as a minimum after the first injection of Celestan Depot. The other 109 patients without treatment of glucocorticoids were considered as a controlgroup. We could show that antepartum application of betamethasone before the 38. week of gestation was associated with a reduction of RDS in our premature infants. Only one baby of the betamethasone-treated infants died of hyaline membrane disease during the first 7 days of life compared with 11 of the control group. In 11 patients patients amniocentesis was performed before the first injection of glucocorticoids and was repeated 2 to 7 days later. The amniotid fluid lecithin phosphorus concentration was determined. In the same period of pregnancy and the same iterval the lecithin phosphours level of amniotic fluid was analysed in 11 other patients who were not rreated with glucocorticoids. The difference between amniotic fluid lecithin phosphorus concentration in the first and second anslysis was found significant by a level of significance of alpha = 5%. There was no evidence of an influence of the therapy with Celestan Depot on this increase. The excretion of oestorgens in the urine of 24 hours was analysed in 22 gradidae before and 7 days after the treatment with betamethasone. The oestogen values of the day before application of betamethasone served as baseline figures. All patients showed a market fall in urinary oestrogens excretion, especially after the second day of therapy. After day 2 the values returned rapidly to baseline values. There were no differences between treated and control groups in Apgar scores at birth or in the incidence of icterus neonatroum (bilirubine level is greater that 10 mg% in the serum). The results of our study support the hypothesis that in humans glucocorticoid administration to the fetus accelerates lung maturation. Relatively brief intrauterine exposure of human infants to pharmacological doses of betamethasone was associated with a substantial reduction in the incidense of RDS.

Amniotic Fluid↗
PubMedDate not supplied

Metabolism of thymoxamine. I. Studies with 14C-thymoxamine in rats.

Thymoxamine is rapidly and completely absorbed in rats. It is a prodrug which does not enter the systemic circulation in its unchanged form. After either oral or intravenous administration it undergoes rapid and intense metabolism involving four biotransformation reactions: Enzymatic hydrolysis to the corresponding phenol (metabolite I), Monodemethylation to metabolite II, Sulfate conjugation of I and II (metabolites III and IV) and Conjugation of I and II with glucuronic acid (metabolites V and VI). With these 6 metabolites identified approximately 95% of the radioactivity can be accounted for in plasma, urine and bile. Whereas the systemic availability of I and II is low, III and IV show high bioavailability. Metabolites I to IV are pharmacologically active, while III and IV are less potent than I and II. The radioactivity distribution in tissues is different after oral and intravenous administration consistent with the higher portion of unconjugated metabolites in the body after administration by parenteral route. Although 60% of the labelled compounds is eliminated via bile, the radioactive compounds are almost completely excreted in the urine after both routes of administration. This demonstrates complete reabsorption of the biliary metabolites. Secondary peaks of radioactivity in plasma and organs at 4 hours are explained by the participation of the metabolites in the enterohepatic circulation.

Animals↗
PubMedDate not supplied

[Changes in erythrocyte P50 and its effect on O2 transport in intravenous tocolysis with fenoterol (Partusisten)].

Fenoterol (Partusisten), which has a considerable influence on glucose metabolism in addition to its well-known cardiac side-effects, does not appear to have any direct influence on the P50 of the maternal erythrocytes in in-vitro experiments. In incubation experiments with fresh erythrocytes, fluctuations in the P50 with an amplitude of 2-5 mmHg were measured at +37 degrees C; these fluctuations depend on the storage age of the erythrocytes and the glucose content of the incubation medium. Fenoterol has no effect on the amplitude, nor on the frequency of this P50 fluctuation. The glycolytic activity of the erythrocytes, relative to the 2,3-DPG and ATP content, also remains uninfluenced under Fenoterol. The addition of progesterone or cortisone to the incubation medium has no influence on the P50 of the maternal erythrocytes. In-vivo studies of the blood of pregnant women indicate changes of the P50 with maximal "shift to the left" after 6 hours and compensatory "shift to the right" after 20 hours under tokolysis. No fluctuations of the pH value were observed in our patients. The intraerythrocytic 2,3-DPG concentration changes simultaneously with the P50. Venous pO2 increases by approx. 12 mmHg in the first 3 hours following the start of tokolysis. However, the changes in the venous pO2 are not simultaneous with the changes in the P50. It can be stated that the progesterone level has no influence on the release of O2 from the maternal blood.(ABSTRACT TRUNCATED AT 250 WORDS)

2,3-Diphosphoglycerate↗
PubMedDate not supplied

[Doppler studies of arterial blood flow in the uterus during labor].

By the pulsed doppler method the arterial uterine blood velocity was studied in 19 patients with contractions before and during labour. It is shown, that uterine contractions reduce blood velocity significantly. Normally there is a low resistance in uterine arteries, so that the diastolic flow is nearly as high as the systolic flow. In uterine contractions the vascular resistance increases. Systolic flow is reduced slightly and diastolic flow severely or completely. But a complete zero-flow couldn't observed in any studied uterine contraction.

Arteries↗