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W Krause

Publications and source records attributed to W Krause.

At least 199 records · Page 11Linked to original sources
PubMed1989

Determination of beta-carboline derivatives in biological samples by high-performance liquid chromatography with fluorescence detection.

An assay procedure for measuring plasma, urine, and feces levels of seven beta-carbolines and possible metabolites is described. The drugs are extracted with diethylether or, alternatively, with a commercially available automated extraction device after adding an appropriate internal standard. Separation from matrix constituents is performed by reversed-phase high-performance liquid chromatography (HPLC) followed by fluorescence detection. The carboxylic acid metabolites of the beta-carbolines have to be esterified before HPLC measurement. The detection limits are 0.2 ng/mL for beta-carbolines and 2 ng/mL for their metabolites. Plasma levels and pharmacokinetic parameters of six different beta-carbolines in healthy male volunteers following iv or po treatment are described. Total clearance ranged from 17 to 52 mL/min/kg and the terminal half-life ranged from 1 to 4 h. The absolute bioavailability exhibited a range from less than 1 to 61%.

Administration, Oral↗
PubMed1989

In vivo effects of terbinafine and ketoconazole on testosterone plasma levels in healthy males.

Ten healthy male volunteers received daily 200 mg of ketoconazole or 500 mg of terbinafine (SF 86-327) for a period of 8 days according to a crossover double-blind design. Between the periods of treatment there was an interval of 3 weeks. Before and during the treatments, on 3 days in all, blood levels of testosterone were determined in the morning at 08.00 and 12.00 h. On the following day in each case, after taking a basal blood sample, 5,000 IU of hCG were injected intravenously and 2 h later a further blood sample for plasma testosterone determination was taken (short-term hCG stimulation test). Prior to treatment, the mean plasma testosterone levels at 12.00 h were slightly below the level at 08.00 h (6.5 +/- 3.5 against 7.2 +/- 3.1 ng/ml). The difference increased and was statistically significant with ketoconazole treatment (4.2 +/- 3.2 against 7.7 +/- 3.0 ng/ml), but did not alter during administration of terbinafine (7.8 +/- 4.4 against 6.8 +/- 3.0 ng/ml). The administration of testosterone levels by hCG stimulated 25.6% prior to treatment. The stimulation was suppressed to zero by ketoconazole but clearly intensified (41.7%) by terbinafine treatment. The results demonstrate once more the well-known effect of ketoconazole on testosterone production and confirm that terbinafine obviously does not have this effect.

Adult↗
PubMed1989

Pharmacokinetics of the antidepressant rolipram in healthy volunteers.

1. The pharmacokinetics of rolipram were studied in healthy male volunteers using 3H-rolipram and a radioimmunoassay for measurement of unchanged drug. 2. Rolipram was rapidly and completely absorbed after an oral dose of 1 mg. Bioavailability was 73%. 3. Plasma levels of the unchanged drug declined with a terminal half-life of 2 h. The total clearance of rolipram was 2 ml/min per kg. 4. Labelled rolipram was excreted rapidly and completely. The main route of elimination was via the urine.

Administration, Oral↗
PubMed1989

[Andrologic indications for in vitro fertilization: is there a true therapeutic gain?].

Andrological indications for human in vitro fertilization (IVF) are assumed if this is not carried out because of gynaecologically conditioned sterility but to overcome poor semen quality. The fertilization rate of human oocytes in IVF is lower when oligo-astheno-terato-zoospermia (OAT syndrome) is present than in the case of normozoospermia, even if it can be guaranteed that the number of spermatozoa incubated is the same in each case. The further development of the fertilized oocyte following embryo transfer, however, does not depend on semen quality. There have been attempts to determine the fertilization ability of spermatozoa prior to their use in IVF in order to enhance the prognosis of the technique. The results of the hamster-oocyte penetration test (HOP test) correlate only poorly with the outcome of human IVF. Testing of the acrosome reaction in vitro is also unsuitable as a predictor of the results of IVF. So far, the "normality" of spermatozoa can only be demonstrated by the direct observation of fertilization of the oocyte. In view of the high costs of IVF, a controlled, randomized study comparing the success rates of IVF in andrological indications and of other treatment procedures is urgently necessary.

Embryo Transfer↗
PubMed1988

[Oligoasthenoteratozoospermia in valproic acid therapy].

We report on 2 cases of oligoasthenoteratozoospermia due to therapy with valproic acid, which had been given on account of mal grand epilepsy in both cases. On first examination of the patients, the daily dose of valproic acid amounted to more than 1000 mg. After reduction to 150 mg daily, the sperm parameters returned to normal. One patient succeeded in pregnancy after 5 years of childless marriage.

Adult↗
PubMed1988

Fatigue properties of acrylic bone cement: S-N, P-N, and P-S-N data.

The determination of the fatigue properties of a material is a fundamental criteria in the engineering design process. The fatigue properties are governed by a number of factors, one of which is the inherent scatter in the data. In order to take into account this scatter in the results, the concept of the probability of failure (P) is introduced and interconnected with the well known stress (S) versus number of cycles to failure (N) data. This report determines the S-N curve, P-N curve, and P-S-N contour for the three leading acrylic bone cements: Surgical Simplex P, Zimmer LVC, and Zimmer Regular. Tensile specimens were fabricated according to ASTM D638 specifications and tested in uniaxial, zero-tension fatigue. The resulting stress versus number of cycles to failure data was subjected to a nonlinear least-squares analysis to determine the mathematical expression of the fatigue curve. Statistical analysis showed excellent fit of the data to the predicted curve for estimation of the endurance limit of each cement. The results indicated that Zimmer LVC had the highest endurance limit while the limit of Simplex-P and Zimmer Regular were significantly lower. No significant difference was noted in the endurance limit between Simplex-P and Zimmer Regular. The probability of failure at each stress level was determined with respect to fatigue distribution functions. Using the normal distribution function and previous S-N data, the P-S-N contour was generated for each cement. The P-S-N contour fully describes the fatigue characteristics of the material.

Acrylates↗
PubMed1988

Pharmacokinetics of lisuride after subcutaneous infusion.

Six parkinsonian patients received a constant subcutaneous infusion of 60 micrograms lisuride per hour in the abdominal region for 2 hours. Plasma levels of the unchanged drug were measured by radio-immunoassay. During infusion, a steady state plasma level of 0.78 +/- 0.19 ng/ml was achieved. After discontinuation of the infusion, concentrations declined with a half-life of 1.4 +/- 0.4 hour. The total clearance of lisuride was 20 +/- 6 ml/min/kg. Due to the low interpatient variability of plasma levels, a good control of clinical effects is to be expected.

Administration, Oral↗
PubMed1988

Distribution of vimentin-type intermediate filaments in Sertoli cells of the human testis, normal and pathologic.

The presence, distribution and spatial arrangement of vimentin-type intermediate filaments in Sertoli cells from human testis biopsies, were studied in semithin and ultrathin sections using a polyclonal rabbit antiserum. At the ultrastructural level, vimentin immunoreactivity was seen concentrated around the nuclei, along fibrillary material within the cytoplasm and at the ectoplasmic specializations of the Sertoli cell junctions, as well as throughout the periphery of the Sertoli cell processes. It is therefore well suited as a marker for Sertoli cell configuration. In computer-aided 3D reconstructions of 20 serial sections, Sertoli cells displayed particular configurations of intermediate filaments in the different stages of spermatogenesis. Two basic configurations, named AS (before spermiation, stages V, VI, I and II), and PS (after spermiation, stages III and IV) respectively, could be differentiated. In addition to the reconstruction and morphological analysis of vimentin filaments in Sertoli cells from patients with unaltered spermatogenesis (obstructive azoospermia), pathological specimens (spermatogenetic arrest, Sertoli cells only-syndrome) were studied with respect to vimentin immunohistochemistry. The results indicate that vimentin filaments play an important role in the adaptation of Sertoli cells to the varying configurations of neighbouring cells during spermatogenesis as well as under pathological conditions.

Adult↗
PubMed1988

Prostaglandin E2 output by isolated rat gastric parietal cells and non-parietal epithelial cells.

Prostaglandins have acid antisecretory and cytoprotective effects in gastric mucosa when given exogenously. This study's purpose was to isolate preparations of parietal and non-parietal cells from rat stomachs and to compare prostaglandin output by these cells. Gastric epithelial cells were isolated from rat stomachs using pronase. Cells from different incubation times were collected separately and enriched by discontinuous Percoll gradient. Cell types were identified by hematoxylin and eosin stain, succinic dehydrogenase activity (parietal cells), periodic acid Schiff staining (mucous cells), Bowie staining (chief cells) and electron microscopy. Prostaglandin E2 activity was measured by radio-immunoassay. Parietal cells were purified to over 90% while the non-parietal preparation contained 67% chief cells and over 31% mucous cells. By electron-microscopy, cell integrity was seen to be maintained. The parietal cell enriched fraction contained two and one-half times the amount of prostaglandin E2 that the non-parietal chief cell enriched fraction did, p less than 0.01. These results raise the question as to whether output of PGE2 by parietal cells could play a role in modulating gastric acid secretion directly by parietal cells as well as in protecting the deeper layers of gastric mucosa against damaging agents in-vivo.

Animals↗
PubMed1988

[Computerized automatic analysis of the cardiotocogram (results of an international multicenter study].

By means of an international multicentre study (SU, Socialist Republic of Poland, Socialist Republic of Czechoslovakia, GDR) 403 patients with computerized CTG-analysis and 393 patients with visual CTG-analysis in labour were investigated in relation to course of labour and neonatal outcome. The following results were fixed: The computerized CTG-analysis by help of the equipment "robotron-NATALI" is equal the statement of high qualified perinatologists. The computerized CTG-analysis led significantly more frequently in various stages of labour to the diagnosis "prepathological" CTG-pattern (warn signs) in relation to visual CTG-analysis with a significantly higher rate of fetal pH-measurements. That means, that the sensitivity of this method is greater. The safety in frame of electronic supervision of labour is improved. The number of "acut-tocolysis" in various stages of labour for both collectives wasn't significantly too. The rate of caesarean section and the rate of operative vaginally deliveries (forceps, vacuum-extraction) showed in both collectives no significantly differences. The neonatal morbidity (APGAR score, pHUA) matured analogous results in the collective with and without computerized CTG-analysis. A decline of "acidotic" morbidity in the collective with computerized CTG-analysis wasn't mentioned. One stillbirth was found in the collective with visual CTG-analysis. In spite of that computerized CTG-analysis showed no better results in perinatological centres in relation to visual CTG-analysis this method is the basis for very important perinatological aims how computer controlled infusion in connection with termination of labour as well as computer steered tocolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Apgar Score↗
PubMed1988

Pharmacokinetics of rolipram in the rhesus and cynomolgus monkeys, the rat and the rabbit. Studies on species differences.

1. The pharmacokinetics of rolipram were studied in rat, rabbit, rhesus monkey and cynomolgus monkey using 14C- or 3H-labelled rolipram and a radioimmunoassay for measurement of unchanged drug. 2. Rolipram was rapidly and completely absorbed after oral doses of up to 50 mg/kg. Bioavailability was 0.1% in rhesus monkey, 3.7% in cynomolgus monkey, 3.6% in rabbit, 35% in rat, and 75% in man. 3. Rolipram was able to pass the blood-brain barrier achieving concentrations in brain twice those in plasma. 4. Plasma levels of the unchanged drug declined with a similar half-life of 1-3 h in all species investigated. In the rat, there were indications for a different clearance of the two rolipram enantiomers. 5. Labelled rolipram was excreted rapidly and completely. The main route of elimination was via the urine.

Animals↗
PubMed1988

Pharmacokinetics of proterguride in rat and cynomolgus monkey.

1. The pharmacokinetics of proterguride were studied in rat and cynomolgus monkey using 3H- and 14C-labelled drug and a radioimmunoassay for concentration measurements of unchanged drug. 2. Proterguride was rapidly and completely absorbed at low doses but not completely at higher dose levels, especially in rat. 3. Bioavailability was 18% in the monkey (low and high doses) and 79% (low doses) and 38% (high dose), respectively, in the rat. 4. Proterguride was able to pass the blood-brain barrier achieving concentrations in brain similar to those in plasma. 5. Excretion of labelled compounds was mainly in the faeces in rat, but in monkey elimination was equal in faeces and urine.

Animals↗