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  • 1
    Electronic Resource
    Electronic Resource
    Electron microscopy of pig liver carboxylesterase
    Amsterdam : Elsevier
    FEBS Letters 24 (1972), S. 146-148 
    Details
    ISSN: 0014-5793
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-5793(72)80753-1
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  • 2
    Electronic Resource
    Electronic Resource
    The functional and structural border of the neurohemal region of the median eminence (1978)
    Springer
    Cell & tissue research 192 (1978), S. 327-339 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence (Rat) ; Neurohemal region ; Tanycytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In stressed rats the tanycytes of the ventrolateral wall of the third ventricle exhibit by light microscopic immunohistochemistry a positive staining for neurohormones which is distinctly limited to the distal perivascular end of the tanycyte process. Since by electron microscopic immuncytochemistry the tanycyte cytoplasm does not show any reaction product, the light microscopic reaction most likely results from a labeling of the intercellular space in the direct vicinity of the subendothelial cleft. Whether this subendothelial space is permeable to neurohormones was tested by injection of HRP1. In the region of the arcuate nucleus 30 min after intravenous application, the marker is affixed to the membranes of the perivascular tanycyte processes in the subendothelial cleft of capillaries possessing non-fenestrated endothelia. Occasionally, HRP penetrates for a short distance between the tanycytes. Then the labeling of the intercellular cleft ends abruptly. Here, several parallel ridges of tight junctions between the perivascular distal tanycyte processes are found by the freezeetching technique. Since HRP cannot reach the subendothelial clefts of this region by passing through capillary walls due to the presence of a blood-brain barrier, it is suggested that the marker penetrates from the median eminence this far via the subendothelial extracellular space. It is prevented from spreading further by the tight junctions of the perivascular tanycyte endings. The same way may be taken by the neurohormones. Hence, a border area exists adjacent to the dorsolateral aspect of the neurohemal region of the median eminence where the tanycytes isolate the neuropil from the cerebrospinal fluid not only by their apical tight junctions, but also by basal tight junctions from the subendothelial cleft. This communicates with the perivascular space of the portal vessels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220750
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  • 3
    Electronic Resource
    Electronic Resource
    The rhombencephalic recess in the rat (1978)
    Springer
    Cell & tissue research 189 (1978), S. 479-495 
    Details
    ISSN: 1432-0878
    Keywords: Rhombencephalic recess (rat) ; Ependyma ; Circumventricular organs ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rhombencephalic recess, an ependymal organ, has been studied for the first time by light- and electron microscopy. It is situated mediosagittally on the floor of the rhomboid fossa at the level of the colliculus facialis. The recess and the superimposed tissue are built up by tanycytes, their apices being connected by tight junctions. HRP horseradish-peroxidase , injected into the c.s.f. cerebrospinal fluid , does not penetrate into the intercellular clefts of the recess area. The recess area reveals a certain autonomy regarding its supply with arteries and capillaries. A bloodbrain barrier exists, but shows slight leakage in circumscribed areas as a result of intense transendothelial vesicular transport. The organization of the recess area is compared with that of other ependymal organs, especially circumventricular organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209134
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  • 4
    Electronic Resource
    Electronic Resource
    Differing postnatal development of the somatostatin- and luliberin- systems in the male and female rat (1983)
    Springer
    Cell & tissue research 232 (1983), S. 357-378 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin ; Luliberin (LRF) ; Postnatal development (rat) ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By means of light-microscopic immunohistochemistry the perikarya of the luliberin-(LRF-) and somatostatin systems of neonate rats were found to be in differing stages of development. At a time point when the LRF-producing neurons had obviously attained their final shape and size, the somatostatin-immunoreactive perikarya were still in a postnatal phase of maturation. Whereas the number of the latter perikarya increases with advancing age, the number of LRF-immunoreactive perikarya decreases significantly from postnatal day 7 onward. Both peptide-hormone systems do not project concomitantly and to the same extent to their principal neurohemal regions in the organum vasculosum laminae terminalis (OVLT) and the median eminence (ME). In all presently studied stages of development, despite considerable individual variations in one age group, among the components of the LRFsystem the OVLT displays a more intense immunoreactivity than the ME. The somatostatin system, however, projects to the OVLT with a conspicuous temporal delay compared to the ME, and, furthermore, in the OVLT the pattern of immunoreactivity characteristic of adult rats is not yet attained at postnatal day 21. Evidence for differences in the immunoreactivity between male and female animals was restricted to the LRF-system. Finally, the results obtained on the stria terminalis speak in favour of the fact that the long-range extrahypothalamic projections of the somatostatin system also undergo postnatal maturation. In the stria terminalis, somatostatin-immunoreactive fibers can be demonstrated initially on postnatal day 7. They attain their full immunoreactivity on postnatal day 21. Furthermore, in the bed nucleus of the stria terminalis an intermittent cytoplasmic immunoreactivity is observed, which is limited to the animals of postnatal day 7 and disappears completely during the further course of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213793
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  • 5
    Electronic Resource
    Electronic Resource
    Demonstration of a somatostatin-like activity in retinal cells of the rat (1979)
    Springer
    Cell & tissue research 204 (1979), S. 127-140 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin-like activity ; Retina ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A somatostatin-like substance is demonstrated by light microscopic immunohistochemistry (PAP-method) in perikarya and cell processes of the retina of adult and infant rats. These perikarya are identified according to their size, arrangement and distribution. Each of the first two neuronal orders (receptors, bipolar cells, ganglionic cells) of the visual pathway can be associated with retinal cells reacting positively with anti-somatostatin. In the adult rat, perikarya and processes of (i) horizontal cells, (ii) amacrine cells and (iii) large neurons in the ganglionic layer are specifically labeled. The staining of middle-sized and small ganglion cells is probably caused by the close attachment of labeled fibers to non-reacting cells. Postnatally, the immunoreactive elements develop in parallel to the differentiation of the corresponding retinal layers. It is discussed whether the three types of retinal cells containing a somatostatin-like substance provide an inhibitory system to each of the two orders of retinal neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235169
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  • 6
    Electronic Resource
    Electronic Resource
    An intermittent somatostatin-immunoreactivity in the cortex and basal ganglia of the rat (1980)
    Springer
    Cell & tissue research 205 (1980), S. 327-331 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin ; Cortical cells and fibers ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using light microscopic immunohistochemistry, somatostatinpositive structures were observed in the cortex of the rat. These structures, including cells and fibers, are widely distributed in all cortical laminae and are also found in the basal ganglia. The positive results were obtained exclusively in two groups of animals sacrificed during two different months of two subsequent years. The reason for this variability in the immunocytochemical stainability of cortical structures remains enigmatic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234691
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  • 7
    Electronic Resource
    Electronic Resource
    Luliberin and somatostatin fiber-terminals in the subfornical organ of the rat (1980)
    Springer
    Cell & tissue research 210 (1980), S. 33-45 
    Details
    ISSN: 1432-0878
    Keywords: Luliberin (LRF)-terminals ; Somatostatin-terminals ; Subfornical organ ; Neurohemal regions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the aid of light- and electron- microscopic immunocytochemistry, somatostatin- and luliberin (LRF)-positive fibers can be demonstrated in the rat subfornical organ (SFO). Each of the neurohormones has a specific location: LRF in the lateral parts of the organ, and somatostatin in the center of the posterior zone. Common to both neurohormone-containing fibers is the pattern in which they reach the organ as well as the fact that their terminals are located in the perivascular spaces of fenestrated vessels, i.e., within the limited neurohemal regions of the organ. Since injection of India ink of different colors demonstrates that the capillary bed of the SFO is connected with the central capillaries of the choroid plexus, the question arises as to whether the neurohormones released in the area of the SFO influence the choroid plexus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232139
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  • 8
    Electronic Resource
    Electronic Resource
    Neurohormones in the intercellular clefts and in glia-like cells of the rat brain (1980)
    Springer
    Cell & tissue research 211 (1980), S. 251-268 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin ; Luliberin (LRF) ; Intercellular clefts (brain) ; Immunoreactive glia-like cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the aid of electron microscopic immunocytochemistry following the application of antisera against somatostatin and luliberin (LRF), a labeling of the intercellular clefts in different areas of the brain was observed. This labeling is especially conspicuous near the basal pole of the cuboidal ependymal cells, but is also generally present in all regions containing neurohormone-producing perikarya or their processes (for example, the preoptic area, the basal ganglia and the cortex). Furthermore, in all these regions displaying labeled intercellular clefts, glialike cells and sparsely ciliated ependymal cells are found, the secondary lysosomes of which exhibit an immunoreactivity resembling that observed in the intercellular clefts. As sources of the immunoreactive material the following possibilities are discussed: (i) perikarya producing somatostatin or LRF, situated in the wall of the third ventricle and sending fibers between the cuboidal ependymal cells, (ii) hypothalamic and extrahypothalamic projections of both peptidergic systems, and (iii) in the case of somatostatin, immunoreactive perikarya in the cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236448
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  • 9
    Electronic Resource
    Electronic Resource
    The functional and structural border between the CSF-and blood-milieu in the circumventricular organs (organum vasculosum laminae terminalis, subfornical organ, area postrema) of the rat (1978)
    Springer
    Cell & tissue research 195 (1978), S. 485-497 
    Details
    ISSN: 1432-0878
    Keywords: Circumventricular organs (rat) ; Tanycytes ; Tight junctions ; CSF ; blood-milieu
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study continues a previous investigation on the median eminence (EM) (Krisch et al., 1978). In rats with high levels of neurohormones (LHRH, vasopressin) a limited immunohistochemical labeling of perivascular tanycyte processes can be observed surrounding capillaries in the marginal region of the organum vasculosum laminae terminalis (OVLT) and in the inner part of the subfornical organ (SFO). This labeling extends from the perivascular space a short distance along the tanycyte processes. By conventional electron microscopy and by freeze-etching, tight junctions are demonstrated at a distance from the capillary lumen which corresponds to the borderline of the immunohistochemical labeling of perivascular tanycyte processes in light microscopic preparations. The tight junctions are arranged in several parallel and helical rows and correspond to those found in the median eminence. Consequently, the immunohistochemical labeling in the OVLT and in the SFO marks the intercellular cleft. In the circumventricular organs the immunostaining labels the extension of the perivascular space characterized by the hemal milieu. The perivascular space is separated off by tight junctions from the CSF-milieu of the adjacent neuropil. Furthermore, the present study demonstrates tight junctions in the marginal region of the area postrema (AP) between the perivascular processes of the tanycytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233891
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  • 10
    Electronic Resource
    Electronic Resource
    Lipids in the proximal convoluted tubule of the cat kidney and the reabsorption of cholesterol (1977)
    Springer
    Cell & tissue research 177 (1977), S. 523-538 
    Details
    ISSN: 1432-0878
    Keywords: Cat kidney ; Lipids ; Cholesterol ; Reabsorption ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid deposits in the cat kidney are mainly located in the epithelium of the proximal tubuli contorti, particularly in the pars contorta. As the amount of fatty acids in the blood of renal arteries is higher than in renal veins, the lipid inclusions are likely to be formed in the proximal convoluted tubule. Whether fat occurring in the urine has been released from the nephron epithelium and the mode of this release remains obscure. The structural equivalent of lipid extrusion into the tubules has not been observed. Components of the tubular lipids include triglycerides, phosphoglycerides and cholesterol. The results of the digitonin-cholesterol reaction favour the assumption that cholesterol is eliminated in the glomeruli and pinocytotically reabsorbed by the brush border cells, this process possibly serving recycling of this compound. The dilated basal labyrinth and intercellular space contain perpendicularly oriented lipid accumulations that reach the basal lamina. The ultrastructure of the lipid storing cells of pars contorta reacting positively for phosphoglyceride and cholesterol is characterised mainly by bodies with marginal plates. As far as can be judged from their morphology, these bodies are interpreted as large peroxisomes. A special feature of the pars recta are dumbbell shaped bodies and elongated or cup-like mitochondria concentrically surrounding cytoplasmic areas, as well as a well-developed smooth ER. In what way the organelles of the brush border cells are involved in catabolic and anabolic processes as far as renal lipid metabolism is concerned remains to be answered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220612
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