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  • 1
    Electronic Resource
    Electronic Resource
    Intercellular barriers to and transcellular transfer of albumin in the fetal sheep brain (1997)
    Springer
    Anatomy and embryology 195 (1997), S. 229-236 
    Details
    ISSN: 1432-0568
    Keywords: Key words Blood-brain barrier ; Cerebrospinal fluid ; Fetus ; Protein transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The nature of the barriers that keep proteins out of the developing brain has been studied in tissues obtained from fetal sheep in experiments conducted under controlled physiological conditions. In anaesthetised pregnant ewes, 60 day gestation fetuses (term is 150 days) were exposed to human albumin injected intravenously for periods up to 6 h. The immunocytochemical distribution of exogenous human albumin was compared with that of endogenous sheep albumin at both the light and electron-microscopical level. Immunogold labelling of ultracryosections suggests that a tubulocisternal endoplasmic reticulum system in immature choroid-plexus epithelial cells is the route by which albumin crosses from blood to cerebrospinal fluid (CSF) in the developing brain. The integrity of the blood-brain barrier, the blood-cerebrospinal fluid barrier and the cerebrospinal fluid-brain barrier to protein, was confirmed. In addition, at the outer surface of the developing brain there also appears to be a restriction on the passage of albumin from CSF into the brain. These observations support earlier proposals that the immature brain develops within an internal environment from which proteins in plasma and CSF are largely excluded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050042
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The early development of the pars distalis of human foetal pituitary gland (1971)
    Springer
    Anatomy and embryology 135 (1971), S. 117-138 
    Details
    ISSN: 1432-0568
    Keywords: Embryology ; Human adenohypophysis ; Progenitor cell and canaliculi ; Follicular structures ; Histocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histochemical and ultrastructural investigation of the early development of the adenohypophysis was carried out on a human material. Special attention was paid to an accumulation of hyaluronic acid and chondroitin-4-and/or-6-sulfate in the mesenchyma; its role in morphogenesis of the Rathke's pouch is discussed. The role of the vessels as a “critical factor” in the budding of the parenchyma and in the differentiation of secretory cells is discussed. Canalicular extensions from the original lumen of the pouch into the core of parenchymal buds, which migrate into the mesenchyma, is a new observation. The participation of canaliculi in formation of follicular structures of pars distalis is described and discussed. The primitive cell type lining the pouch is also found in the wall of canaliculi and follicular structures. The cell type is described and its role as the real progenitor cell of the adenohypophysis is discussed. Three types of colloid are noticed in pars distalis: 1. In the follicular structures, 2. in the slits or clefts caused by partial occlusion of the lumen of the pouch, and 3. mesenchymal extravasal colloid presumably representing material squeezed out from the aforementioned clefts or slits. It is concluded that the colloid contains material secreted from different types of granulated cells as well as material from the surface coat of the luminal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00525197
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Concordance between morphological and biochemical estimates of fluid spaces in rat brain cortex slices (1974)
    Springer
    Experimental brain research 21 (1974), S. 299-314 
    Details
    ISSN: 1432-1106
    Keywords: Brain cortex slices ; Ultrastructure ; Fluid spaces ; Swelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A comparison was made between morphological and biochemical estimates of extracellular and intracellular fluid spaces in rat brain cortex slices incubated under different conditions. By light microscopy the periphery of the slices was found to be more swollen than the center; this regional difference was verified biochemically in unfixed tissue. The electronmicroscopic evaluation of intra- and extracellular fluid spaces was accordingly based upon findings in a preselected area. Due to intracellular penetration of inulin in rat brain cortex slices the biochemically, determined extracellular and intracellular spaces were obtained by compartmental analysis of the inulin space. The concordance between the biochemical and the morphological findings was good: Both methods showed that the extracellular space increased during the incubation to a considerable magnitude after one hr. and that this extracellular space was reduced by excess potassium, glutamate, anoxia or incubation at 0°. Under the same conditions the biochemically determined intracellular space was increased. This cellular swelling was confirmed morphologically and found to comprise mainly glia cells after exposure to excess potassium, predominantly neurons after incubation at 0° and both cell types after anoxia or addition of glutamate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235749
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    A fetuin-related glycoprotein (α2HS) in human embryonic and fetal development (1987)
    Springer
    Cell & tissue research 248 (1987), S. 33-41 
    Details
    ISSN: 1432-0878
    Keywords: Brain, vertebrate ; Development, ontogenetic ; Proteins, plasma ; Cerebrospinal fluid ; Fetuin ; α2HS glycoprotein ; Human ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The human plasma protein, α2HS glycoprotein, has an amino acid composition very similar to that of fetuin, the major protein in fetal calf and lamb serum. Immunohistochemical studies of human fetuses (6–33 weeks gestation) showed that α2HS glycoprotein and fetuin have similar distributions in developing brain and several other tissues, e.g., bone, kidney, gonads, gastrointestinal tract, respiratory and cardiovascular systems. There were notable differences in the liver and thymus in the distribution of the two proteins. Fetuin and α2HS glycoprotein are present in plasma and cerebrospinal fluid of both human and sheep fetuses; their concentrations are reciprocally related: in human plasma and cerebrospinal fluid α2HS glycoprotein concentration is high and fetuin low; the reverse is the case in sheep fetuses. Estimates of the concentration of α2HS glycoprotein in human fetal cerebrospinal fluid and plasma were obtained. It is suggested that α2HS glycoprotein may play a role in developing tissues, especially in the human fetus, similar to that of fetuin in other species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239959
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    Paper (German National Licenses)
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