Effects of ethanol and acetaldehyde on cultured pre-implantation mouse embryos

Pre-implantation 2-cell stage mouse embryos, obtained from superovulated CF-1 mice, were exposed to ethanol and acetaldehyde through the culture medium for 60 min followed by a 105-h incubation period. Control and ethanol exposed embryos survived equally well in ethanol concentrations as high as 800 mg/100 ml medium and acetaldehyde levels up to 10 mg/100 ml medium.     

Effects of ethanol and acetaldehyde on cultured pre-implantation mouse embryos

Summary Pre-implantation 2-cell stage mouse embryos, obtained from superovulated CF-1 mice, were exposed to ethanol and acetaldehyde through the culture medium for 60 min followed by a 105-h incubation period. Control and ethanol exposed embryos survived equally well in ethanol concentrations as high as 800mg/100 ml medium and acetaldehyde levels up to 10 mg/100 ml medium.     

Effects of streptozotocin on early rat embryos grown in culture

Summary Addition of 1 mg/ml streptozotocin to serum in which 10-day rat embryos are cultured reduces their growth and viability. There is therefore a risk that administration of this drug to pregnant animals to induce diabetes could also have direct, deleterious effects on the embryos.     

Effects of streptozotocin on early rat embryos grown in culture.

Addition of 1 mg/ml streptozotocin to serum in which 10-day rat embryos are cultured reduces their growth and viability. There is therefore a risk that administration of this drug to pregnant animals to induce diabetes could also have direct, deleterious effects on the embryos.     

Inhibitory action of estradiol on testosterone production in rat embryo]

Embryos from Rats given an injection of 0,5-1 mg of oestradiol benzoate on days 17--19 of pregnancy show a 3--4-fold reduction in their testicular testosterone content with respect to the control embryos, 24--48 hrs later. OEstradiol most likely acts by inhibiting LH secretion, which in turn results in a lowered testosterone production.     

Effect of progesterone on male and female sex behavior induced by steroid hormones in adult ovariectomized ewes]

Ovariectomized adult Ewes daily treated with I/M injections of testosterone propionate (10 mg/day) or oestradiol benzoate (200 microgram/day) show male-like sexual behaviour and simultaneously a permanent female receptivity. Additional daily treatment with 100 mg of progresterone results in a rapid decrease in male sexual responses both when Ewes are treated with testosterone and with oestradiol. No effect is observed on the female receptivity. Cyproterone acetate (100 mg/day) given to Ewes in addition to daily injection of testosterone propionate (10 mg/day) has effects similar to those of progesterone. These results show that progesterone has antiandrogen and antioestrogen properties and that this hormone administered at high doses is able to inhibit male activity.     

Plasma testosterone concentration in control and testosterone-treated chick embryos.

After testosterone propionate treatment (1 or 2 mg per embryo), plasma testosterone in chick embryos rises to 500 times higher than in control animals, and then progressively diminishes during the following days of incubation. These drastic changes in hormonal status after the TP treatment entails consequences that may be considered pharmacological rather than physiological.     

Inhibition of cholesterol synthesis ex vivo and in vivo by fluvastatin,a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase

The inhibitory effect of fluvastatin sodium (fluvastatin), a new type of 3-hydroxy-3-methylglutaryl (HMG) coenzyme A inhibitor, on de novo cholesterol synthesis was investigated and compared with that of pravastatin. Fluvastatin at a concentration of 12.5 mg/kg inhibited sterol synthesis ex vivo from [¹⁴C]acetate in rat liver and ileum by 97–99% with respect to the control, while the inhibition in kidney was 55%. The inhibition by fluvastatin in the liver and ileum persisted for approximately 9 h after administration. Significant differences between fluvastatin also had an inhibitory effect on cholesterol synthesis in vivo in various tissues of rats given [¹⁴C]acetate intraperitoneally. Sterol synthesis in the liver, ileum and kidney was inhibited by over 95% 3 h after administration of 6.25 mg/kg of fluvastatin. Significant differences between fluvastatin and pravastatin were found in the liver and ileum. Fluvastatin was more potent than pravastatin in inhibiting both ex vivo and in vivo sterol synthesis in the ileum (but not in kidney) and liver.     

Renal polycystosis in the rat induced by prednisolone tertiary butyl acetate

Summary A single i.m. injection of 66 mg/kg prednisolone tertiary butyl acetate given on the 1st day of life produced glomerular degeneration and collecting duct and proximal tubule cysts in rat kidneys. There was evidence of delayed nephrogenesis leading to persistance of the neogenic zone.     

Action of various progestational hormones on the electric activity of the rat myometrium in pregnancy after biovariectomy

8-day-pregnant rats were ovariectomized, then injected im with progestagens and estrogens while their uterine motility and electrical activity were being recorded simultaneously with a strain gauge and 2 bipolar electrodes. The injections, known to maintain pregnancy after ovariectomy, were progesterone 50 mg/kg, progesterone with estradiol 5 mcg/kg, or medroxyprogesterone acetate 25 mg/kg. Base line recordings for 20 minutes showed the normal pregnant state of brief periods of synchromous electrical and mechanical activity. After ovariectomy, untreated controls exhibited increased duration of synchronized mechanical and electrical activity and height of contractions. When any of the 3 progestagen treatments coincided with ovariectomy, synchrony was decreased and the intervening interval lasted longer. These procedures demonstrated how quickly the hormonal deficit due to ovariectomy is compensated for when ablation is performed before placental progesterone synthesis has begun.     

Plasma testosterone concentration in control and testosterone-treated chick embryos

Summary After testosterone propionate treatment (1 or 2 mg per embryo), plasma testosterone in chick embryos rises to 500 times higher than in control animals, and then progressively diminishes during the following days of incubation. These drastic changes in hormonal status after the IP treatment entails consequences that may be considered pharmacological rather than physiological.Acknowledgment. We would like to thank Mrs N. Jeanguyot (UNCEIA, Laboratoire d'hormonologie, Maisons Alfort, France) for her excellent technical assistance in the RIA procedure.     

A procedure for the rapid freezing of whole embryos.

A procedure for the rapid freezing of whole chick embryos for histochemical treatment is described. The problems of deformation during preparation for quenching and orientation for sectioning have been largely overcome by placing embryos inside lengths of chicken trachea. The subsequent disorientation of tissues that follows cracking and shattering due to the rapid freezing of whole embryos is avoided. The method permitted a more precise identification of the position and time of appearance of formaldehyde-induced fluorescence and myosin antibody immunofluorescence in serially sectioned embryos.     

Sea urchin embryo as a model for analysis of the signaling pathways linking DNA damage checkpoint,DNA repair and apoptosis

DNA integrity checkpoint control was studied in the sea urchin early embryo. Treatment of the embryos with genotoxic agents such as methyl methanesulfonate (MMS) or bleomycin induced the activation of a cell cycle checkpoint as evidenced by the occurrence of a delay or an arrest in the division of the embryos and an inhibition of CDK1/cyclin B activating dephosphorylation. The genotoxic treatment was shown to induce DNA damage that depended on the genotoxic concentration and was correlated with the observed cell cycle delay. At low genotoxic concentrations, embryos were able to repair the DNA damage and recover from checkpoint arrest, whereas at high doses they underwent morphological and biochemical changes characteristic of apoptosis. Finally, extracts prepared from embryos were found to be capable of supporting DNA repair in vitro upon incubation with oligonucleotides mimicking damage. Taken together, our results demonstrate that sea urchin early embryos contain fully functional and activatable DNA damage checkpoints. Sea urchin embryos are discussed as a promising model to study the signaling pathways of cell cycle checkpoint, DNA repair and apoptosis, which upon deregulation play a significant role in the origin of cancer. Received 10 April 2007; accepted 23 April 2007     

Abortive effect of autologous anti-alpha-fetoprotein antibodies in the rat]

Female Commentry Rats 80--85 days old, were immunized by 5 intramuscular injections of Mouse alphafetoprotein (AFP) and then mated. After fertilization a supplementary injections was administered. The animals were bled at different times and killed immediately after the last bleeding on the 19 or 20th day of gestation. Titers of AFP and of autologous anti-AFP antibodies in the maternal blood were determined as well as the AFP concentration in the pooled amniotic fluids from live embryos of each litter. Compared to non-immunized control series, the total of live and dead embryos per litter in animals immunized with Mouse AFP showed no difference. However, the number of live embryos was on the average 50% lower than that in the control series. The serum titers of AFP and of antibodies to autologous AFP in immunized pregnant Rats bearing dead embryos decreased concomitantly with the number of live embryos. The results reported herein demonstrate that the presence of anti-autologous AFP antibodies in pregnant Rats correlates with the interruption of development in a significant proportions of embryos. This suggests that certain spontaneous abortions in the Rat and perhaps in other mammals can be explained by the rupture of immunological tolerance to autologous AFP.     

A procedure for the rapid freezing of whole embryos

Summary A procedure for the rapid freezing of whole chick embryos for histochemical treatment is described. The problems of deformation during preparation for quenching and orientation for sectioning have been largely overcome by placing embryos inside lengths of chicken trachea. The subsequenct disorientation of tissues that follows cracking and shattering due to the rapid freezing of whole embryos is avoided. The method permitted a more precise identification of the position and time of appearance of formaldehyde-induced fluorescence and myosin antibody immunofluorescence in serially sectioned embryos.We gratefully thank Dr Ute Gröschel-Stewart for preparing sections for immunofluorescence.     

Existence of cholinergic receptors in the very young chick embryo]

The injection of certain cholinergic agents in the yolk sac of young Chick embryos (40 to 48 hrs. of incubation) gives rise to a twisting of the cervical notochord and spinal cord and contraction of the cervical somites. These morphogenetic changes result in spinal column malformations in older embryos. The effects of the cholinergic agents are inhibited by simultaneous treatments with a cholinergic agonist and an antagonist or a cholinergic receptor ligand. The results lead to the assumption that the early embryos already possess cholinergic receptors, probably located in the notochord.     

Scanning electron microscopy of cells from hydroxyurea-arrested blastulae ofXenopus laevis

Summary Cells fromXenopus embryos blocked at the blastula stage by treatment with hydroxyurea have been isolated and cultured in vitro. The morphology of these cells has been compared with that of cells from normal embryos using scanning electron microscopy. Cells from such hydroxyurea-blocked embryos do not show the features, or changes in features, in culture shown by cells from normal embryos.Acknowledgments. We wish to thank Mr C. Veltkamp for his help with the electron microscopy, and Mrs J. Clumpus for technical assistance.     

On induced fragmentation of ovarian oocytes

Summary Fragmentation of oocytes was induced in the ovary, via ovulation suppression, by administration of dehydro-epiandrosterone acetate (DHA-Ac) to mature cycling rats. The maximal fragmentation ratio, 15.0±3.2%, was obtained by 10 mg/100 g b.wt/day for 7-day administration of DHA-Ac. The relationship of fragmentation to the first stage of meiosis is also discussed.Acknowledgments. The author would like to thank Professor T. Matsuda in the Department of Anatomy I for his valuable advices and Proff. E. Nishida and K. Akasofu in the Department of Obstetrics and Gynecology, Kanazawa University, for instructive suggestions and for kindly supplying DHA-Ac.     

Effects of retinoic acid on embryonic development of mice in culture

The effects of all-trans-retinoic acid (RA) (tretinoin) on the craniofacial development of mouse embryos were examined using whole embryo culture. In day 8 embryos cultured for 48 h, embryonic growth was inhibited concentration-dependently by all-trans-RA treatment. Most of the treated embryos exhibited hypoplasia of the primary palatal processes and a reduction in the development of the first visceral arches. In day 10 embryos cultured for 48 h, although embryonic growth was not inhibited at any concentrations of all-trans-RA, median cleft lip (93%), hypoplasia of the primary palatal processes (37%) and limb reduction deformities (48%) occurred commonly. Furthermore, RA treatment greatly reduced the size of the secondary palatal processes. The incorporation of 3H-thymidine in the treated maxillary processes was decreased to 65% of the control value at 1.0 x 10(-7) M all-trans-RA. These findings indicate that all-trans-RA is teratogenic in mouse whole embryo culture.     

La localisation extra-embryonnaire des cellules germinales chez l'embryon de Lézard vivipare (Lacerta vivipara Jacquin)

Summary The surgical ablation of an extra-embryonic posterior cresent that directly encloses the caudal end of young embryos, reduces to a few gonocytes the germinal stock in the genital ridges. The same operation performed upon embryos of 10 somites is without any action. The presence of some gonocytes in the genital ridges of the operated embryos is discussed.