Biomedical subjects
Publications and source records attributed to U Claussen.
A new method has been developed to abridge the time between amniocentesis and chromosome analysis in prenatal diagnosis. With this method cells in metaphase are separated from the clones by a micropipette with the help of a micromanipulator and then prepared.
The possible derivation of a small supernumerary marker chromosome was investigated by means of different staining techniques and the frequency of satellite associations. It could be demonstrated that the marker chromosome participates at satellite association more than randomly. The marker chromosome is supposed to derive from 2 of chromosomes 13, 14, 21, or 22.
Hyperthermia was induced in pregnant rabbits (day 9 of gestation) by placing them in an incubator at 45 degrees C. The rabbits were killed on day 29 of gestation, the fetuses were inspected for organ malformations macroscopically and for skeleton malformations microscopically. The results were compared with those of control animals (without hyperthermia). The rise in temperature up to 3 degrees C above the normal value resulted in a significant higher malformation and resorption rate. These findings are in contrast to previous experiments having shown that virally induced fever (day 9 of gestation) results in no anomalies of development.
On the 9th day of gestation of rabbits the embryotoxic effects of cyclophosphamide were tested in vivo by i.v. injection (20, 40 and 80 mg/kg) and by injection into the yolk sac of rabbit embryos (20 micrograms, 80 micrograms 320 micrograms/blastoderm; yolk-sac-method). Furthermore pharmacological studies were undertaken to investigate cyclophosphamide and its metabolism in the blastoderm (york sac fluid and embryo). When applied by i.v. injection, cyclophosphamide was embryolethal and teratogenic in a dose-dependent manner. No embryotoxic effects could be observed by injection of unchanged cyclophosphamide into the yolk sac of rabbit embryos. Pharmacokinetic studies did not show any metabolism in the blastoderm by injection or unchanged cyclophosphamide into the yolk sac. The embryotoxicity of unchanged cyclophosphamide is discussed.
On the 9th day of gestation the embryotoxic effects of acrolein were tested in vivo by i.v. injection in rabbits (3, 4.5 and 6 mg/kg) and by injection into the yolk sac of rabbits embryos (10, 20 and 40 microliter/blastoderm of an 0.84% acrolein solution: yolk-sac method). After i.v. injection acrolein caused mainly embryolethal effects in a dose-dependent manner. After direct injection into the rabbit embryos acrolein led to an increase of resorption and malformation rate in a dose-dependent manner. The highest dose in both investigations showed that by i.v. injection acrolein acts as an embryotoxic agent in a 50-60 times lower concentration. As acrolein plays an important role in the metabolism of cyclophosphamide the results are discussed in relation to the embryotoxicity of cyclophosphamide.
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Amniotic fluid testosterone measured by radioimmunoassay (RIA) without chromatography (immunoreactive testosterone) seems not to be a definitive test for prenatal sex determination in all cases. In this study testosterone (T) levels measured by RIA with chromatography of the amniotic fluid samples were compared with immunoreactive testosterone (iT) values, to determine the predictive accuracy of the two methods. In 111 amniotic fluid samples between 15 and 19 weeks of gestation iT and T were measured parallelly. There are significant differences between iT- and T-means of both sexes (p less than 0.001). 95%-condifence limits of iT-values of the male and female fetuses are largely overlapping. In contrast, the overlap of 95%-confidence limits of the T-values is only minor. The measurement of testosterone with chromatography of the amniotic fluid samples shows for prenatal sex determination in over 90% accuracy. This result is due to the elimination of sex-specific differences in crossreacting steroids within the amniotic fluid of both sexes.
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The empirical coefficient of correlation and the empirical coefficient of regression were evaluated in New Zealand White rabbits between birth weight and crown-rump on the one hand and number of implantations and litter size on the other. The average birth weight decreases with increasing litter size (P = 0.01). The decreased supply of blood to the single fetus in big litters might be responsible for this result. As no definite correlation between crown-rump and litter size could be proved, the conclusion may be drawn that the crown-rump is more determined by genetic factors than is the birth weight.
Pregnant rabbits were injected ip with 5 mg/kg 6-ANA at day 10, 11, 12 or 12.5 respectively of gestation. Embryos removed at day 13 of gestation had reduced DNA and RNA concentrations. The differences (DNA: 14 percent; RNA: 22.4 percent) were significant in the group treated on the twelfth day. Some possible mechanisms are discussed.
The horseshoe kidney is a not so rare fusion anomaly of the urinary tract system. Clinical and genetic aspects of this phenomenon are shown in a case of familiar occurrence. Genetic consultation of the family must consider various inheritable possibilities and sources of this disease. The difficulty of an exact genealogical tree analysis is pointed out.
In contrast to former opinions detection of genetic disorders in early multiple pregnancy is possible by advanced techniques of amniocentesis Prenatal diagnosis has been performed in a twin pregnancy of an 41 years old patient by two ultrasonically guided amniocenteses. Injection of Indigo carmin after the first puncture showed two separate amnion cavities. Postpartal findings proved prenatal diagnosis.
A technique was developed for injecting agents into the yolk sac of rabbits to study their teratogenic effects. On the 9th day of gestation the rabbits were laparotomized during ether-oxygen narcosis. The test substance was injected into the yolk sacs in one horn of the uterus, and as control the corresponding solvent was injected into the other horn. On the 28th day of gestation the rabbits were killed, resorptions counted, and fetuses examined for malformations. Three series of studies were made: physiological saline; polyvinylpyrrolidone; and doxycycline dissolved in polyvinylpyrrolidone (DIP). The rate of resorptions and malformations significantly increased after injection of Vibravenos. As polyvinylpyrrolidone was not teratogenic it is concluded that the teratogenic effects of DIP were probably caused by doxycycline.
A method is described by which the embryotoxic and teratogenic effects of substances can be examined through their application into the yolk-sac. On the ninth day of gestation rabbits (white New Zealand) were laparatomised and the uterus bicornis together with the blastoderms were treated in 3 different experiments. The results show that after application of physiological saline into the yolk-sac the high rate of malformations and resorptions are caused mainly by an avoidable venous obstruction and by postoperative inflammations and infections.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.