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C Krüger

Publications and source records attributed to C Krüger.

At least 73 records · Page 4Linked to original sources
PubMed1987

Determination of the polychlorinated biphenyl substitute Ugilec (tetrachlorobenzyltoluenes) in fish.

A method is presented for the determination of tetrachlorobenzyltoluenes (TCBTs) in fish. TCBTs represent the major constituents of Ugilec, which is commonly used as a substitute for polychlorinated biphenyls (PCBs) in underground mining. The compounds are extracted from the freeze-dried material together with fat and other lipophilic substances. Gel chromatography on Bio-Beads S-X3 is used for removal of fat followed by adsorption chromatography on silica gel (1.5% water). Combined gas chromatography-mass spectrometry employing an ion trap detector is used for the separation and detection of the compounds. The developed procedure provides identification and determination of TCBTs even in the presence of an excess amount of PCBs. The application of the procedure to the investigation of fish caught in rivers from areas with extensive mining indicates that Ugilec has already found its way into the food chain.

Animals↗
PubMed1987

[Levels of the PCB-substitute Ugilec (tetrachlorobenzyltoluene) in fish from areas of extensive mining].

Tetrachlorobenzyltoluenes, which represent the major constituent of the PCB substitutes Ugilec 141 and Ugilec T, have been widely used in the last few years as hydraulic fluids in underground mining. Their use has been termed a "closed application", but there are obviously considerable losses. Tetrachlorobenzyltoluenes released underground can enter the environment vit pia water, mine outputs or ventilation systems and as a consequence they can contaminate the food-chain, especially in fish. In fish from areas where there is extensive mining concentrations of tetrachlorobenzyltoluenes in edible portions ranged up to 25 mg/kg. The compounds were extracted from the freeze-dried material with petroleum ether. Gel chromatography on Bio-Beads S-X3 was chosen for the removal of fat followed by adsorption chromatography on silica gel according to the method of Specht and Tillkes. A combination of gas chromatography/mass spectrometry employing an ion trap detector was used for the separation and detection of the compounds. The great selectivity of mass selective detection combined with the high resolving power of capillary gas chromatography made it possible to determine and confirm the presence of Ugilec in fish down to a level of 0.02 mg/kg, even if there was a large PCB surplus.

Animals↗
PubMed1987

Studies on the embryotoxic risk of exposure to caffeine and ethanol during the preimplantation period in the mouse.

Pregnant mice were exposed before implantation to caffeine and ethanol to determine the dose-response relation for embryolethality during the preimplantation period. For risk estimation the embryotoxicity was evaluated at term and also 24 h after implantation. For ethanol no embryotoxic risk could be detected. Caffeine unexpectedly exhibited a high risk for embryoethality when compared to the maternal LD50. However, when taking into account realistic exposure levels an embryotoxic risk in early pregnancy can be excluded in humans for both caffeine and ethanol.

Animals↗
PubMed1986

Studies on the embryotoxic risk of drug treatment during the preimplantation period in the mouse.

For risk evaluation of exposure to drugs in early pregnancy the dose-response relationship for embryotoxicity was determined in mice during the preimplantation period using cytotoxic drugs (cyclophosphamide, mitomycin, vinblastine) and therapeutic drugs which are embryotoxic in laboratory animals or in humans during organogenesis (diazepam, doxycycline, phenobarbital, rifamycin, tolbutamide). No malformations but only signs of retardation and a dose related increase in the resorption rate could be detected after treatment with some of the drugs at term even at dose levels close to the maternal LD50 (MLD50). A comparison of the embryolethal dose during the preimplantation period (ELD50) with the MLD50 revealed no risk for the therapeutic drugs, a slight risk for mytomycin and vinblastine and an unusually high risk for cyclophosphamide. The ELD50 for all drugs in this study was higher than the embryotoxic doses during organogenesis which is routinely determined for all drugs. It is concluded that for therapeutic drugs additional testing for embryotoxicity during early pregnancy is not required.

Animals↗
PubMed1985

[Digitalis therapy: prescription frequency, serum concentrations and withdrawal trials].

The frequency of therapy with digitalis glycosides was determined in 4.143 patients on their first visit at a medical outpatient clinic. 508 (12.3%) patients said to take digitalis. Of 480 (94.5%) patients, a digoxin serum concentration was obtained. It was in 229 (47.7%) patients below, in 31 (6.5%) above, and in 220 (45.8%) within the therapeutic range (0.8-2.0 ng/ml). From the 251 patients with a serum digoxin concentration greater than or equal to 0.8 ng/ml, 220 (87.7%) were not included in a withdrawal trial on the basis of predetermined criteria, mainly because of cardiac diseases (52%). Digitalis therapy was withdrawn in 31 patients. 5 patients started to take the drug again on their own; they were considered drop-outs. In the remaining 26 patients, no symptoms of heart failure appeared during a 3-month observation period; in 2 patients, however, atrial fibrillation requiring intervention occurred. Our results confirm the frequent use of digitalis therapy in Germany, but also the frequent presence of subtherapeutic serum digoxin concentrations. Withdrawal should be considered in patients with a questionable indication for this therapy; the occasional occurrence of supraventricular arrhythmias, and not so much of heart failure, should be anticipated.

Aged↗
PubMed1985

Abnormal chromosome behavior in human oocytes which remained unfertilized during human in vitro fertilization.

Chromosomal abnormalities and abnormal embryonic development have previously been observed after human in vitro fertilization (IVF). Chromosomal abnormalities may arise not only after fertilization but even earlier during meiotic maturation of human oocytes in culture. Since chromosomal analysis is simple in oocytes during meiotic maturation, the chromosomal status was analyzed in oocytes which remained unfertilized in a human in vitro fertilization program. In 50 fertilization attempts the chromosomes of 62 unfertilized oocytes could be analyzed; 45 of them were in the process of meiotic maturation. In three oocytes two small polar bodies were observed 16-18 hr after insemination in the absence of fertilization. In one oocyte abnormal chromosome behavior was found during the first meiotic division, and in four oocytes during metaphase of the second meiotic division. These data suggest that chromosomal analysis of unfertilized oocytes in human IVF may improve the understanding human oocyte maturation and fertilization.

Chromosome Aberrations↗
PubMed1985

Development and sister chromatid exchange of mouse morulae and blastocysts cultured in rat serum containing active metabolites of cyclophosphamide.

To establish an in vitro test system in which sera from animals treated with various chemicals can be tested for embryotoxic effects during the preimplantation period, mouse morulae and blastocysts were cultured in the presence of rat serum (RS) from animals which had been treated with cyclophosphamide (CPA). Development during in vitro culture for 96 h, cell number, chromosomal aberrations and sister chromatid exchange (SCE) were the end-points tested in exposed embryos. SCE frequency was the most sensitive parameter, indicating embryotoxic effects in preimplantation mouse embryos after only 1 h of exposure to RS-CPA.

Animals↗
PubMed1985

[Tobacco-alcohol amblyopia. Clinical course in 33 patients].

The clinical data of 33 patients with tobacco-alcohol-amblyopia are described. Usually, the visual disturbance concerned both eyes and was not associated neither with headache nor with painful eye movements. The fundus was very often normal. In the static perimetry mostly relative or absolute central scotomas were found, sometimes centrocoecal scotomas and very seldom paracentral scotomas. The colour vision was very often disturbed, usually the red-green discrimination. In the rule the amplitudes of the visual evoked potentials were diminished, the P-100 latency was delayed in 39%. A follow-up of 25 patients revealed that the visus and the results of the static perimetry improved in 72% during vitamin substitution (B1, B2, B6, B12, folic acid). In a few cases this improvement could be observed even though the alcohol drinking was not ceased. In most cases the disturbance of the colour vision and the pathologic visual evoked potentials, however, did not change.

Adult↗
PubMed1985

[In-vitro-fertilization: chromosome analysis of unfertilized human oocytes].

Chromosomal abnormalities and abnormal embryonic development have been observed after human in vitro fertilisation (IVF). Such investigations are not permitted according to the ethical guidelines approved by the IVF team in Berlin ("Berliner Modell"). However, the chromosomal status was studied in oocytes which remained unfertilised in a human IVF programme. In 50 fertilisation attempts the chromosomes of 62 oocytes could be analysed. 45 of the oocytes were in the process of meiotic maturation. One of these showed abnormalities in the first meiotic division and seven during the second meiotic division. After fertilisation in addition to normal embryos, all of which were transferred to the mother, three embryos were triploid and six oocytes were fragmented. The results prove that in human IVF chromosome abnormalities can occur in oocytes already before fertilisation. The importance of the results for later stages of embryonic development is discussed.

Chromosome Aberrations↗
PubMed1985

Tobacco-alcohol amblyopia neuro-ophthalmological findings and clinical course.

The clinical picture of 40 patients with tobacco-alcohol amblyopia (TAA) is described. In 15 patients the course of the disease was studied longitudinally over a period of 31 months. In addition in six patients the acute development of the disease was studied during a period of four weeks in-patient treatment. TAA is characterised by distinct bilateral visual disturbances, symmetric scotomas, acquired disturbances of colour vision and mostly normal fundi. Visual acuity is usually grossly diminished. Central scotomas were present in 80% of the cases while the centrocecal from prevailed in the rest. The acquired disturbances of colour vision usually concerned the red-green sense (84%). The amplitudes of the visual evoked potentials were always reduced and deformed. In 33% we could not detect a P-100. In 5% the latency of the P-100 was prolonged. Full field stimulation was the best method of defining the P-100. By foveal stimulation the deformations of the amplitudes were more evident. The prognosis of the visual disturbances was unpredictable. The abnormalities improved in one half of the patients, but complete recovery was never reached despite substitution with vitamins.

Alcoholism↗
PubMed1983

[Orotracheobronchial aspiration for bacteriologic and cytologic diagnosis].

A presently described new method for obtaining tracheal and bronchial secretions does not only represent an alternative to established methods, but also enlarges, due to its simple bedside performance, the indication for an invasive procedure, e. g. in pneumonias. Despite a transoral approach to trachea and bronchi bacterial contamination was excluded. Bacteriologic and cytologic results of orotracheobronchial aspiration in 25 patients with bronchopulmonary infections and one patient with eosinophilic pneumonia represented a valuable help for the correct diagnosis and thus for treatment.

Bronchi↗
PubMed1981

In vitro translation of Drosophila heat-shock and non--heat-shock mRNAs in heterologous and homologous cell-free systems.

Upon heat shock, Drosophila Kc cells still contain normal cellular messenger RNAs in the cytoplasm. The distribution of these 25 degrees C mRNAs between polysomes and the postpolysomal fraction of heat-shocked cells appears unaltered as compared with control cells. The translatability of these normal cellular messages isolated from heat-shocked and non--heat-shocked Kc cells is unaltered when analyzed by in vitro translation in the rabbit reticulocyte lysate. In contrast, homologous cell-free translation systems obtained from Kc cells effectively discriminate between the in vitro translation of normal cellular messages and heat-shock--specific mRNAs. In particular, a cell-free system from heat-shocked Drosophila Kc cells almost completely shuts down the translation of 25 degrees C messenger RNA species, whereas the translatability of heat-shock--specific messenger RNA appears to be unaffected.

Animals↗
PubMed1981

[Chemotherapy with fosfomycin, cefoxitin, and cefotaxime in experimental E. coli-pleuropneumonia (author's transl)].

Two models of pneumonia--the experimental E. coli-pleuropneumonia and "intrapulmonary" E. coli-pneumonia--were employed in these studies. Only fosfomycin was effective in both models even at the low dosage of 100 mg/kg/d. The comparative drugs cefotaxime and cefoxitin, however, were not able to reduce the bacteria in both lungs even at very high dosages of 900 mg/kg and 300 mg/kg per day respectively over 6 days.

Animals↗