Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0300-9629
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Tissue distribution and developmental expression of fetuin were studied in the sheep fetus from embryonic day (E) 30 to adult (gestational period is 150 days). The presence of fetuin was demonstrated immunocytochemically using anti-fetuin antibodies; in situ hybridisation using short anti-sense oligonucleotide probes labelled with digoxigenin was used to study the ability of the developing tissue to synthesise fetuin, and reverse transcription-polymerase chain reaction (RT-PCR) was used to estimate the level of fetuin mRNA in selected tissues. Tissue distribution of fetuin was widespread in the younger fetuses (E30 to E40). The most prominent presence due to in situ synthesis was demonstrated in the liver, central nervous system (CNS) including anterior horn cells, dorsal root ganglia and in skeletal muscle cells. Other developing tissues and organs that showed evidence of fetuin synthesis and presence of the protein included mesenchyme, kidney, adrenal, developing bone, gut, lung and heart. In the immature liver (E30–40) there was a strong signal for fetuin mRNA in hepatocytes and also in numerous haemopoietic cells; the proportion of these latter cells that was positive for fetuin mRNA increased between E30 and E40. Only some hepatocytes and a proportion of the haemopoietic stem cells were immunoreactive for fetuin itself at E30–40; immunoreactive hepatocytes were more frequently observed in the more mature outer regions of the developing liver. Lung and gut contained scattered fetuin-positive epithelial cells, especially at E30; a weak fetuin mRNA signal could be detected above background in many of these cells up to E40, but not at E60–E115 or in the adult. Particularly at E30 to E40, mesenchymal tissue both within organs such as the gut and lung and around forming bone and skeletal muscle contained cells that were positive for fetuin mRNA. Mesenchyme at these ages was also very strongly stained for fetuin protein, much of which may reflect fetuin in tissue extracellular spaces and be derived from the high concentration in plasma. By E80 fetuin mRNA was mainly present in the liver and the CNS; staining of the muscle tissue was becoming less pronounced. However in developing bone tissue, staining of chondrocytes for fetuin mRNA was still prominent in older (E80) fetuses; there was also fetuin protein staining of chondrocytes at the growing surfaces of bones and in bone marrow at this age. In the adult, weak immunocytochemical staining for fetuin itself was present in hepatocytes, but the mRNA signal was barely above the threshold limit of detection. Other tissues in the adult were generally negative for both fetuin mRNA and fetuin, except that fetuin could generally be detected immunocytochemically in precipitated plasma within vessels in many tissues and in their interstitial spaces. The highest levels of fetuin mRNA, as demonstrated by RT-PCR, were detected in E40 and E60 liver followed by E40 muscle. The very low level of fetuin mRNA in adult liver, evident from in situ hybridisation, was confirmed by RT-PCR (about 0.1% of that at E60). These results show that in many tissues in which fetuin could be demonstrated immunocytochemically, its presence is likely to be due to synthesis in situ. However in some instances (e.g. gut and mesenchymal tissue) fetuin probably originates predominantly by uptake from plasma or extracellular fluid. The functional significance of the presence of fetuin in different tissues during their development is considered.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A histochemical and ultrastructural study was carried out on subcommissura organs from 42 human embryos and fetuses in order to characterize some “large granules” Typical “granules” make their appearance in the rostral hypendymal region of the subcommissural organ (SCO) in fetuses of about 50 mm CRL. Although they appear in other SCO-regions later, the highest number of “granules” is always located towards the pineal gland. Typical “granules” are of spherical shape with a diameter of about 2 microns. The various histochemical reactions reveal a reactivity which differentiates the shell of the “granules” from the “granule” interior. Nucleoproteins are present in the shell together with phospholipids and/or lipoproteins. The interior of the “granules” can contain different materials such as glycogen or lipid or “neurosecretory substance”. Ultrastructural observations show that a “granule” consists of whorls of endoplasmic reticulum sparsely studded with ribosomes surrounding an interior containing either lipid or lipoprotein inclusions, large amounts of glycogen or simply cytoplasm. It is suggested that the concentric lamellar organelle (CLO) is a morphological entity that might be involved in secretory processes rather than being the secretory granules themselves.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A technique is described for enhancing the reaction product of the staining reaction for iron in paraffin-embedded tissue from central nervous system (CNS). After amplification of the Prussian Blue staining reaction with 3,3′-diaminobenzidine (DAB), the reaction product was further intensified using a stepwise treatment with silver methenamine, gold chloride and uranyl nitrate (post-DAB treatment). Following the Prussian Blue-DAB staining reaction, iron was seen only in glial cells and choroid plexus epithelial cells, whereas the post-DAB treatment revealed that neurons and endothelial cells of the brain capillaries were also positively stained. The post-DAB treatment resulted additionally in an increased intensity of the reaction product within choroid plexus epithelial cells compared to that obtained in sections subjected only to the Prussian Blue-DAB reaction. The reliability of the method was evaluated using liver sections as positive controls. Furthermore the higher sensitivity of the method was assessed using nitrocellulose filters containing serially diluted iron-saturated transferrin. The post-DAB method is simple and can easily be applied to formalin- or glutaraldehyde fixed, paraffin-embedded nervous and non-nervous tissue.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The specificity of Alcian blue staining has been investigated on a material comprising the adenohypophysis from 26 human foetuses. Two distinct types of alcianophilic cells were observed. The first cell type appears about 28 mm CRL forming small groups at the epithelial-mesenchymal junction and beneath the anlage of the fibrous capsule. Besides its alcianophilic property the cell shows a pronounced maltase-resistant PAS-positivity. The alcianophilia is due to carboxylgroups — probably of proteins as no sialic acid could be detected. By the performic acid — Alcian blue method the cell seems to show a high content of SH and S-S groups. The second type of cell appears about 70 mm CRL and is mostly located singly. It shows a pronounced alcianophilia — probably due to sulphate groups and to some extent to carboxyl groups. The role of the alcianophilic properties of the cells in typing definite cells of the foetal adenohypophysis was discussed. — Finally the pitfalls caused by different fixatives and by the use of the general polychrome staining methods for the typing of pituitary parenchymal cells were discussed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    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
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract An immunohistochemical study was undertaken, in an attempt to identify the acidic glycoprotein(s) present in colloid and in parenchymal cells in human fetal pituitary gland. As the colloid has been proposed to represent disintegrating cells, a series of antibodies against plasma glycoproteins and plasma proteins was applied; their presence intracellularly would generally be an indicator of plasma membrane leakage in dying parenchymal cells. In tissue sections from 9- to 20-week-old fetuses, the colloid showed prominent staining with an antibody to human fetuin/α2 HS glycoprotein. Anti-α2-HS glycoprotein labelled parenchymal cells in pars anterior and intermedia. Apart from a minor immunoreactivity for α1 β glycoprotein, no other plasma glycoprotein was seen in colloid or parenchymal cells. An antibody against bovine fetuin showed staining of the colloid and of some parenchymal cells in pars distalis and intermedia; the plasma and stroma of the pituitary gland were unstained. In contrast, the anti-human plasma protein antibodies all stained the stroma. The presence of α2 HS glycoprotein in parenchymal cells and absence of other plasma glycoproteins imply integrity of the parenchymal cell plasma membrane. Thus, α2 HS glycoprotein is either synthesized locally or taken up specifically in the parenchymal cells, which are proposed to participate in the formation of colloid. It is suggested that α2 HS glycoprotein is part of a homeostatic system, which controls remodelling and physiological cell death during development.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    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
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-0568
    Keywords: NCAM ; Thy-1 ; Immunocytochemistry ; Organs of special sense ; Mouse embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of the neural cell adhesion molecule (NCAM) and Thy-1 in the olfactory mucosa and olfactory bulb, the eye and the inner ear was examined with immunocytochemistry in mouse embryos from embryonic day 12 (E 12) to embryonic day 19 (E 19). In general, neurons are completely outlined with NCAM, whereas Thy-1 outlines only dendrites and axons. A variable cytoplasmic staining for Thy-1 is present in the perikarya. Neurons directly associated with special sense organs express NCAM and Thy-1 already from the earliest stage and throughout the period investigated, apart from the olfactory neurons in which Thy-1 disappears at E 19. The mitral cells in the olfactory bulb show Thy-1 but no NCAM reactivity. In the eye, lens fibers express Thy-1 and the pigmented layer expresses NCAM; neither of the two molecules can be detected at E 19. In the inner ear, hair cells express NCAM at E 19. Based on the distribution during the developmental period studied and on the cellular localisation of reaction products, it is suggested that the NCAM adhesion function could be of a more general nature by keeping appropriate cell membranes in close contact and thereby allowing more specific molecular interactions to take place. Thy-1, which is located on dendrites and axons, could be such a specific factor and function as recognition molecule in the developing nervous system.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    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
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...