Implantation and Early Stages of Fetal Development

High levels of estrogen secretion is a characteristic of steroidogenesis in the pig testis in both the adult and newborn male. We have now examined the ability of fetal gonads to secrete estrogens, and compared it with testosterone secretion during prenatal development. Fetuses were recovered from sows (N=33) at 27–114 (term) days of gestation. Gonads were removed for organ culture in TC-199 medium, or used as minced tissues or free cell preparations when taken later in development. Organ cultures were maintained for 96 h with luteinizing hormone added for the last 72 h for one gonad of each pair. Estrone, estradiol-17β and testosterone were measured by radioimmunoassay in media samples. Trace amounts of estrone were detected almost as early as testosterone secretion commenced, but quantities sufficient for confirmation by radioimmunoassay after chromatography were not seen until day 35 of gestation. Estrogen production increased to >0.37 nmol·gonad−1·4 h−1 at term. Testosterone secretion in organ culture was increased by luteinizing hormone but no effect was seen on estrone levels for the first half of pregnancy. Thus, estrogen secretion is a feature of steroidogenesis in the porcine testes even in the early stages of fetal development.

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Ghrelin endocrine cells in the human stomach during prenatal and early postnatal development

Archives of Biological Sciences ◽

10.2298/abs1101021m ◽

2011 ◽

Vol 63 (1) ◽

pp. 21-28 ◽

Cited By ~ 2

Author(s):

Olivera Mitrovic ◽

Mileva Micic ◽

Vera Todorovic ◽

G. Radenkovic ◽

Sanja Vignjevic ◽

...

Keyword(s):

Postnatal Development ◽

Fetal Development ◽

Endocrine Cells ◽

Prenatal Development ◽

Human Stomach ◽

Early Postnatal Development ◽

Early Stages

The aim of this study was to investigate the appearance, localization and density of ghrelin cells in the human stomach during prenatal development. For this purpose the antrum and corpus of embryos, fetuses and infants are stained immunohistochemically by the streptavidin-biotin technique. The presence of P/D1 cells at 11 weeks of fetal development, their highest density during the first detection and higher density in the corpus than in antrum, and their localization in the glandular base of stomach gland, all suggest that ghrelin plays a major role in the early stages of the developing stomach.

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Identification of prenatal behavioral patterns of the gross motor movements within the early stages of fetal development

Infant and Child Development ◽

10.1002/icd.2012 ◽

2016 ◽

Vol 26 (5) ◽

pp. e2012 ◽

Cited By ~ 1

Author(s):

Elisabeth J.J.M. van Merendonk ◽

Jeroen J.W.M. Brouwers ◽

Luc De Catte ◽

Danielle Hasaerts ◽

Maria W.G. Nijhuis-van der Sanden ◽

...

Keyword(s):

Fetal Development ◽

Behavioral Patterns ◽

Gross Motor ◽

Early Stages ◽

Motor Movements

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Cytochemical localization of peroxisomes in rat hepatocytes at early stages of fetal development

Ultramicroscopy ◽

10.1016/0304-3991(83)90376-5 ◽

1983 ◽

Vol 12 (1-2) ◽

pp. 123-124

Author(s):

S. Stefanini ◽

M.P. CerùArgento

Keyword(s):

Fetal Development ◽

Rat Hepatocytes ◽

Cytochemical Localization ◽

Early Stages

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Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076263 ◽

1983 ◽

Vol 41 ◽

pp. 518-519

Author(s):

George G. Cocks ◽

Louis Leibovitz ◽

DoSuk D. Lee

Keyword(s):

Crystal Structure ◽

Crassostrea Virginica ◽

Crystal Orientation ◽

Developmental Changes ◽

Gastrula Stage ◽

Orthorhombic Crystal ◽

Orthorhombic Crystal Structure ◽

Stages Of Growth ◽

Early Stages ◽

Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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Formation of Dislocation Channels in Neutron Irradiated Molybdenum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096618 ◽

1972 ◽

Vol 30 ◽

pp. 672-673

Author(s):

S. Mahajan

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Ambient Temperature ◽

Room Temperature ◽

Channel Formation ◽

Early Stages ◽

Transmission Electron ◽

Three Stages ◽

Two Stages ◽

Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

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