Search results for "Embryonic and Fetal Development"
showing 9 items of 29 documents
Dithiothreitol prevents age-associated decrease in oocyte/conceptus viability in vitro.
1998
The present study was designed to ascertain whether the negative effects on reproductive potential of post-ovulatory ageing in vitro of oocytes can be prevented by antioxidant therapy. Mouse metaphase II (MII) oocytes were aged in vitro for 12 h prior to insemination in the presence of varying concentrations of L-ascorbic acid, 6-methoxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), L-cystine dihydrochloride, ethylenediaminetetraacetic acid (EDTA), beta-mercaptoethanol and DL-dithiothreitol (DTT). In-vitro ageing of oocytes was associated with lower fertilization rate, higher proportion of concepti exhibiting cellular fragmentation at 24 h post-insemination and lower percentage of…
Do human concepti have the potential to enter into diapause?
1999
Although there is no direct evidence as to whether human concepti have the potential to enter into diapause before implantation, the possibility that human concepti may be capable of following this developmental pathway if exposed to an appropriate environment cannot be ruled out. Direct evidence remains elusive because of the ethical restraints associated with research activities within this area of knowledge. If conceptus diapause has evolved in primates and persists at the present time despite its apparent limited or no adaptive advantage, artificial induction of diapause in humans may have clinical implications for increasing: (i) the viability of concepti after biopsy, freezing-thawing…
Distribution of osteonectin mRNA and protein during human embryonic and fetal development.
1992
We investigated the temporal and spatial distribution of osteonectin during human embryonic and fetal development, using in situ hybridization and immunohistochemistry. Osteonectin gene expression was generally found in cells exhibiting high rates of matrix production/proliferation. In mineralized tissue, a strong signal was obtained in osteoblasts, odontoblasts, and chondrocytes of the upper hypertrophic and proliferative zones. Chondrocytes of the mineralized zone showed no expression throughout the different stages of development. Strong osteonectin expression was found in odontoblasts of developing teeth. In addition, osteonectin mRNA and protein were detected in several non-mineralize…
Vitrification of zona-free rabbit expanded or hatching blastocysts: a possible model for human blastocysts.
2003
BACKGROUND: The purpose of this study was to test the effectiveness of one two-step (A) and two one-step (B1 and B2) vitrification procedures on denuded expanded or hatching rabbit blastocysts held in standard sealed plastic straws as a possible model for human blastocysts. The effect of blastocyst size was also studied on the basis of three size categories (I: diameter <200 μm; II: diameter 200-299 μm; III: diameter ≥300 μm). METHODS: Rabbit expanded or hatching blastocysts were vitrified at day 4 or 5. Before vitrification, the zona pellucida was removed using acidic phosphate buffered saline. For the two-step procedure, prior to vitrification, blastocysts were pre-equilibrated in a solut…
Transient expression of synaptogyrin in the ganglionic eminence of the human fetal brain
2000
Summary The ganglionic eminence (GE) representing a conspicuous bulb-like elevation of the telencephalic proliferative zone has recently been shown to be involved in the establishment of cortical connections. This study demonstrates the presence of synaptogyrin-immunoreactivity in a large number of cell bodies of the human GE between 12 and 20 weeks of gestation. From the 20 th week onwards synaptogyrin expression sharply declines. No immunoreactive structures are detectable in the 23 rd week or later. As the GE persists nearly throughout the entire fetal period these results show that its neurochemical features change distinctly in the course of development. The synaptogyrin-immunoreactive…
M-cadherin and its sisters in development of striated muscle
1999
Cadherins are calcium-dependent, transmembrane intercellular adhesion proteins with morphoregulatory functions in the development and maintenance of tissues. In the development of striated muscle, the expression and function of mainly M-, N-, and R-cadherin has been studied so far. While these three cadherins are expressed in skeletal muscle cells, of these only N-cadherin is expressed in cardiac muscle. In this review, M-, N-, and R-cadherin are discussed as important players in the terminal differentiation and possibly also in the commitment of skeletal muscle cells. Furthermore, reports are described which evaluate the essential role of N-cadherin in the formation of heart tissue.
Long-term prediction of birth weight
1993
On the basis of the hypothesis that undisturbed individual growth in fetal life keeps a constant proportional difference with the standard population 50th percentile, birth weight can be predicted with a single sonographic exploration after the 16th week of pregnancy. Data on 135 singleton pregnancies with accurate dates and delivery at term were used. Sonography was performed between the 17th and 36th weeks of pregnancy, in every case at least 4 weeks before delivery. The observed measurements of BPD, FL, and AC were used for the prediction of their values on the day of delivery, applying the Hadlock equation for the estimation of birth weight. The mean error of birth weight predictions wa…
Identification of Insulin in Chick Embryo Retina During Development and Its Inhibitory Effect on DNA Synthesis
1992
Incubation of chick embryo retinal explants with insulin resulted in a pronounced inhibition of thymidine uptake and incorporation into trichloroacetic acid-insoluble fraction. The inhibitory effect was highest with explants from embryos at day 7 and day 8, and thereafter it declined markedly with the age of embryos until day 11. A time-course study of the effect revealed that the inhibition occurred after a lag time; both thymidine uptake and incorporation were not altered significantly after 2-6 h of incubation with insulin, but began to decrease thereafter, reaching the maximum after 16 h. The effect was also dose dependent. After 16 h of incubation, the maximal inhibition (65%) was foun…
Developmental expression of human cartilage matrix protein.
1994
Cartilage matrix protein (CMP) is a non-collagenous component of cartilage with a yet unknown function. In this study we used in situ hybridization to investigate the temporal and sptial distribution of CMP transcripts during human embryonic and early fetal development, and compared it to the pattern of expression observed for collagen types I, II, X, and decorin. The distribution of CMP and collagen type II transcripts followed a similar pattern in the embryonic bone anlage, the fetal growth plate, and the developing vertebral column. Expression was highest in the upper hypertrophic and lower proliferative zone, whereas calcified cartilage was negative throughout the different stages of bo…