Fertilized egg

Beneficial effects have also been attributed to PAF. In reproduction, PAF secreted by the fertilized egg is instrumental in the implantation of the egg in the uterine wall. PAF is produced in significant quantities in the lungs of the fetus late in pregnancy and may stimulate the production of fetal lung surfactant, a protein-lipid complex that prevents collapse of the lungs in a newborn infant. 

As under most circumstances progesterone action will hold primacy over estrogenic effects, the cervical mucus, endometrium, and probably the fallopian tubes reflect progestational stimulation. The cervical mucus becomes thick and viscous and thus impervious to spermatozoa. The endometrium is in a state that is not receptive for implantation of a fertilized egg. Probably, the progestational impact on the secretory activity and peristalsis in the fallopian tubes also assists the general contraceptive effect. It is difficult, however, to assess the relative contribution of the various effects to the... 

The device prevents uterine pregnancy but it does not prevent ovulation or ectopic (implantation of the fertilized egg outside of the uterus) pregnancy. 

It is possible to observe effects of organotin(lV) compounds exposure such as inhibition of cleavage of fertilized eggs, interference with the formation of the mitotic spindle, damages affecting chromosome structure, and electron-dense precipitate formation in organelles. 

No spermatozoa are seen on the egg surface or on the vitelline coat. After 5 h of treatment with 10 M TBTCl, a few spermatozoa, with very anomalous heads, have been detected. The absence of spermatozoa on the egg surface or on the vitelline coat could be explained by the absence of the follicle cells, which, in S. plicata, primarily play an attracting function. It was previously shown that TBTCl solution, either 10 or 10 M, induces anomalies in spermatozoa, unfertilized, and fertilized eggs of Ascidia malaca. In particular, the follicle cells detach from eggs and the test cells show anomalies in their nucleus and granules. Moreover, damaged spermatozoa are observed in the vitelline coat, but never in... 

Although suppression of FSH and LH is the primary mechanism by which combined oral contraceptives prevent ovulation, there are other mechanisms by which these hormones work to prevent pregnancy. Other mechanisms include reduced penetration of the egg by sperm, reduced implantation of fertilized eggs, thickening of cervical mucus to prevent sperm penetration into the upper genital tract, and slowed tubal motility, which may delay transport of sperm.1 Thus, in... 

Reik We don t know, but we would expect them to. The way the androgenetic embryos are made is to take the pronucleus out of the fertilized egg after demethylation. 

The first cell cycle of the mouse embryo differs in many respects from the second and the following cell cycles. It is characterized by a long Gl phase that starts after the penetration of the spermatozoon or artificial activation of the oocyte. During this period the chromatin of the oocyte completes the second meiotic division and forms the female pronucleus. At the same time, in the fertilized egg, the highly condensed chromatin of the sperm nucleus decondenses and sperm-specific proteins, protamines, are replaced by histones. After the initial sperm chromatin... 

Goncpy In the normally fertilized egg there is a centrosome. However, you are saying that the spindle is assembled using a non-centrosomal pathway in the onecell stage mouse embryo. This seems surprising to me in light of Rebecca Heald s work, which shows that the centrosomal pathway of spindle assembly is dominant over the non-centrosomal one (Heald et al 1997). 

Viral particles destined for use as vaccines are generally propagated in a suitable animal cell culture system. Although true cell culture systems are sometimes employed, many viral particles are grown in fertilized eggs or cultures of chick embryo tissue (Table 13.7). 

Okubo, K. and T. Okubo. 1962. Study on the bioassay method for the evaluation of water pollution — II. Use of the fertilized eggs of sea urchin and bivalves. Bull. Tokai Reg. Fish. Res. Lab. 32 131-140. 

Common carp, Cyprinus carpio recently-fertilized eggs exposed to 25-186 pg/L at pH 7.5 or 5.6 Lake trout, Salvelinus namaycush At pH 7.5, lead increased heart rate and decreased body movements. At pH 5.6 there was a dose-dependent reduction in survival and increase in spinal cord deformities 42... 

Amphibians Toad, Bufo arenarum Newly-fertilized eggs held in 120 pg/L-32 mg Pb/L as lead nitrate for 72 h 120 pg/L Normal development 49... 

TCDD concentrations in eggs of seven species after exposure as fertilized eggs to nominal concentrations of 9-285 ng 2,3,7,8-TCDD/L for up to 540 h. Lowest observed effect concentration (LOEC) in ng/kg FW associated with adverse effects on su rvival or growth 32 days post exposure vs. no observed effect concentration (NOEC) in ng/kg FW Lake herring, Coregonus artedi 270 vs. 175 Fathead minnow, Pimephales promelas ... 

Lake trout, Salvelinus namaycush Fertilized eggs were exposed for 48 h to graded concentrations (0, 0.1, 1, 10, or 100 ng 2,3,7,8-TCDD/L) to achieve egg concentrations of 0, <15, 40, or 400 ng 2,3,7,8-TCDD/kg FW egg. Eggs were then transferred to flowing uncontaminated media through hatch... 

Spitsbergen, J.M., M.K. Walker, J.R. Olson, and R.E. Peterson. 1991. Pathologic alterations in early life stages of lake trout, Salvelinus namaycush, exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin as fertilized eggs. Aquat. Toxicol. 19 41-72. 

Fertilized eggs exposed on day 3 of incubation for 0.5 min at room temperature Oil solutions... 

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