(n.) A more or less spherical and transparent mass of granular protoplasm, which by a process of multiplication and growth develops into a mass of cells, constituting a new individual like the parent; an egg, spore, germ, or germ cell. See Illust. of Mycropyle.
(n.) One of the series of egg-shaped ornaments into which the ovolo is often carved.
Example Sentences:
(1) A specimen of a very early ovum, 4 to 6 days old, shown in the luminal form of imbedding before any hemorrhage has taken place, confirms that the luminal form of imbedding does occur.
(2) The results indicate that the sperm swelling test and the zona-free hamster ovum penetration assay are evaluating different functional qualities of sperm that are apparently not associated with each other.
(3) This study documents a molecular change in the murine ovum related to its exposure to oviductal fluid.
(4) The OCI-related membrane appeared a cause of OCI interference with fimbrial ovum capture by preventing the contact between the fimbrial cilia and the cumulus oophorus.
(5) Also, for determination of the fertilizing capacity of the semen, a zona-free hamster ovum penetration test was done in 49 men, while 14 men were studied by determination of the fertilization of human oocytes in vitro.
(6) The antiprogesterone RU 486 was utilized to evaluate the possible role of progesterone in ovum maturation, ovulation, fertilization, and embryo cleavage.
(7) It is suggested that the beta inhibitory activity of the uterus and the alpha excitatory activity of the rest of the oviduct are involved in the regulation of ovum transport.
(8) Among antigens possible unique to the reproductive process, sperm antigens, antigens of seminal plasma and of the ovum, antigens of placental hormones and of placenta specific proteins appear suitable targets of the production of fertility regulating vaccines.
(9) The preovulatory surge of gonadotropins activates a cascade of proteolytic enzymes resulting in the rupture of the follicular wall and the release of a fertilizable ovum during ovulation.
(10) The development of vaginal ultrasound transducers has facilitated ovum pick-up (OPU) by providing higher precision and less trauma than are found with laparoscopy and other ultrasound-assisted techniques.
(11) In Johnson v. Calvert, a surrogate mother in California failed to gain custody of the child she bore after gestating an embryo from the ovum and sperm of the couple who hired her.
(12) Risk factors that may theoretically alter ovum quality or the hormonal environment include ovulation induction, fertilization in vitro, delayed ovulation, and transperitoneal ovum migration.
(13) Thus, spermatozoa deposited in the vicinity of the USHG immediately following oviposition (to simulate a release of spermatozoa from this region) can be transported to the infundibulum and effectively fertilize the next ovum ovulated.
(14) However, they do not as yet permit a judgment as to the degree that ovum pickup through a fistula was impaired.
(15) We evaluated the differences between this group and those patients presenting either with a blighted ovum or beyond the first trimester, as well as the outcome of those patients with spotting early in gestation.
(16) It is too soon to learn whether this method will be reversible, but use of silastic should prevent adhesions while providing another mechanical barrier between ovum and sperm.
(17) Indomethacin was effective in preventing follicular rupture and ovum extrusion when administered simultaneously with gonadotropin.
(18) A 33% clinical pregnancy rate per ovum pick-up was achieved with the Buserelin-hMG treatment.
(19) The pregnancy rates were higher than a matched IVF series in the male factor and female ASAB groups and reached statistical significance for the ovum donation group.
(20) Lamellar structures, therefore, are considered to be storage material chiefly used in the second half of the cleavage for developmental processes in the rat ovum.
Polyspermy
Definition:
(n.) Fullness of sperm, or seed; the passage of more than one spermatozoon into the vitellus in the impregnation of the ovum.
Example Sentences:
(1) The relation of these layers to the movements of the spermatozoon, to the activation of the egg, to the block to polyspermy, and to each other are discussed.
(2) The incidence of polyspermy, which did not exceed 5% in Series I and reached 58% in Series II, was dependent on the genotype of both gametes.
(3) Microscopic examinations of eggs stained with aceto-orcein or the DNA fluorochrome bisbenzimide and direct observations on isolated sperm aster complexes show that halothane induces polyspermy (multiple sperm entry) when present at fertilization.
(4) The purine inhibits the detachment of the vitelline layer from the sea-urchin egg plasma membrane after fertilization and this effect leads to polyspermy.
(5) The eggs of the surf clam Spisula solidissima have a built-in mechanism that prevents polyspermy: the eggs show a 70 percent decrease in sperm receptivity 5 seconds after fertilization, and become completely resistant to sperm by 15 seconds.
(6) When inseminated with sperm of the newt, Cynops pyrrhogaster, mature Bufo oocytes exhibited polyspermy accompanied by a gradual hyperpolarization and a slowly developing positive plateau, without the fast spike that occurs in self-species fertilization.
(7) The zona pellucida block to polyspermy is very effective since only one sperm penetrated the zona pellucida in 72.8% of the 876 fertilized eggs examined.
(8) The fertilizing capacity of sperm was evaluated after 0, 24, and 30 h of incubation by adding oocytes to the culture and determining the incidences of fertilization and polyspermy.
(9) Thus, universal roles of zona hardening in the block to polyspermy and in oviductal interaction with embryos have been discounted.
(10) The change in distribution of labelled macromolecules on the zona surface may be a prerequisite for successful sperm-zona binding and the specific association of labelled glycoconjugates in the region of the egg plasma membrane may be involved in the preparation of the egg surface for sperm-egg interactions involving cortical granule exocytosis and the block to polyspermy.
(11) Correction of polyspermy through pronucleus extraction in the absence of membrane relaxants was applied to 25 polyspermic human zygotes.
(12) The present study was undertaken to determine what type(s) of block(s) to polyspermy exist in Chaetopterus.
(13) As a step toward defining in molecular terms the sperm-triggered block to polyspermy reaction established by the egg at fertilization, vitelline (VE) and fertilization (FE) envelopes were isolated from eggs of the Sounth African clawed toad Xenopus laevis and some of their physicochemical properties determined.
(14) In A. callosa, fertilization in low Na+ SW causes a 60% decline in enzyme release and a similar increase in the number of sperm remaining on the VC at 4 min as well as a great increase in polyspermy.
(15) It is proposed that the hyperpolarization of the egg membrane in response to fertilization constitutes a long-lasting electrical block to polyspermy in crab eggs.
(16) The consequences of interactions between porcine sperm, eggs, and oviduct cells before and during fertilization in vitro (IVF) has been examined with particular reference to the block to polyspermy.
(17) This block to polyspermy is inactivated by GlcNAc (2mM) or 150 mM-Na+ (choline substituted) SW.
(18) Zona cutting was associated with a low loss of oocytes (less than 1%), no increase in polyspermy and normal development in vitro and in vivo after fertilization.
(19) Comparisons with data from animals, and measures aimed at preventing polyspermy are suggested.
(20) Polyspermy increased significantly with 10 mM GR in oocyte incubation medium.