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  • Springer  (105)
  • 2015-2019
  • 1970-1974  (105)
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  • 1
    ISSN: 1432-072X
    Keywords: Adenosinephosphate System ; Energy Charge ; Acanthamoeba ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Konzentration von Adenosintri-, Adenosindi- und Adenosinmonophosphat wurde in Acanthamoeba castellanii währed der logarithmischen Wachstumsphase und der stationären Wachstumsphase, in deren Verlauf sich Trophozoiten zu Cysten entwickeln, bestimmt. Der Entwicklungsprozess wurde durch drei verschiedene Methoden hervorgerufen: Durch Wachstum im Nährmedium zu großer Zelldichte, durch Überführen von Amöben der logarithmischen Wachstumsphase in ein nährstoffreies Salzmedium und durch Versetzen logarithmisch wachsender Amöben mit Äthidiumbromid. In allen Fällen wird der Adenosinphosphat-Gehalt in den Zellen im Laufe der Entwicklung um etwa 85% reduziert, wozu besonders die Abnahme des ATP-Gehaltes beiträgt. Die Adenosinphosphat-“energy charge” beträgt in logarithmisch wachsenden Amöben 0,83. Im Laufe der Entwicklung wird sie je nach Encystierungsbedingungen auf unterschiedlichen Werten stabilisiert (zwischen 0,58 und 0,81). Die Möglichkeit eines Zusammenhanges von Konzentrationsveränderungen der Adenosinphosphate und entwicklungsspezifischen Prozessen wird diskutiert.
    Notes: Abstract The concentration of adenosine tri-, adenosine di-, and adenosine monophosphate in cells of Acanthamoeba castellanii was measured during the logarithmic growth phase and the stationary growth phase in which trophozoites were transformed into cysts. This developmental process was induced in three ways: by growth in nutrient medium to high cell density, by transferring cells in the logarithmic phase into a nutrient-free medium, and by mixing logarithmically growing cells with ethidium bromide. In all cases, encystment is accompanied with a reduction of total adenosine phosphate content to about 85%, mainly because of a depletion of cellular ATP. The value of the adenosine phosphate energy charge in logarithmically growing amoebae is 0.83. During development the energy charge becomes stabilized at different values (between 0.58 and 0.81), characteristic to the mode of encystation. A possible functional relationship between changes of the adenosine phosphate concentration and developmental processes of the amoeba is discussed.
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  • 2
    ISSN: 1432-1106
    Keywords: Striate cortex ; Receptive field ; Development ; Single units ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The responses of rabbit striate cortex neurons to light or optic nerve shock were tested in 633 units in 54 rabbit pups 3–25 days of age. Units were driven by optic nerve shock at the youngest ages tested, but could not be driven by light until postnatal day eight. It was found that the symmetric receptive field types (concentric, uniform, motion) were present at or near the time of eye opening (10–11 days), while the asymmetric types (directional, simple, complex, oriented-directional) did not appear until several days later. All adult receptive field types were first seen at day 18. Until about day 20, cells with indefinite response properties were much more numerous than in the adult, and it is suggested thab cells with asymmetric receptive fields may differentiate out of the indefinite group. Development of visual response in the striate cortex is markedly retarded when compared to that in the superior colliculus.
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  • 3
    ISSN: 1432-0568
    Keywords: X zone ; Electron microscopy ; Development ; Adrenal ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal development and involution of the X zone in the mouse adrenal cortex of both sexes were examined using the light and electron microscopes. At 0–5 days of age, no special cell group could be distinguished for the developing X zone in the inner cortex. The inner cortical cells contained spherical or ellipsoidal mitochondria with vesiculotubular cristae, vesiculotubular smooth endoplasmic reticulum (sER) and electron-lucent lipid droplets. The first sign of the developing X zone was the appearance of small groups of cells in juxtamedullary region differing from the cells in other part of inner cortex at 8 days. The electron microscopy showed that such cells contained nuclei of somewhat irregular outline and some parallel stacks of flattened sER. At 10–11 days, a thin layer of small eosinophilic cells were clearly identified as the developing X zone light microscopically in both sexes. Electron microscopically, the X zone cells showed a much dense cytoplas, which contained abundant sER, many mitochondria and numerous ribosomes. The typical X zone cells were characterized by the formation of peculiar mitochondrial complexes and whorled pattern of the sER. Mitoses were often found in the X zone, where mitotic cells even contained the whorled sER and bizarre mitochondria characteristic of the typical X zone cells. In the male the X zone rapidly involuted and might disappear by 30 days of age, whereas in the female X zone persisted as a thicker layer with the earlist sign of fatty degeneration. The origin of the X zone cell and the process of formation of its characteristic organelles are discussed.
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  • 4
    ISSN: 1432-0568
    Keywords: Sympathetic ganglion ; Carotid body ; Adrenergic innervation ; Development ; Neurochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The adrenergic nerve connections and the catecholamine-containing cells of the carotid body in postnatal rats of different ages were studied using the formaldehydeinduced fluorescence (FIF) method. The main findings are summarized as follows: 1) An intensely fluorescent nerve trunk was seen to reach the carotid body, 2) a specific adrenergic periglandular nerve plexus was formed around the carotid body, 3) a distinct decrease of the fluorescence intensity was observed in the carotid body during the first two postnatal weeks, 4) aberrant cells or cell cords, showing the same fluorescence characteristics as those in the carotid body, were often seen beside or inside the fluorescent nerve trunks emerging from the superior cervical ganglion, 5) the carotid body fluorescent cells often seemed to send processes, which were hard to separate from the varicose parenchymal adrenergic nerves in the carotid body. A functionally active adrenergic sympathetic innervation of the carotid body during the postnatal period is suggested. Correlations with the physiological observations are discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 143 (1974), S. 159-183 
    ISSN: 1432-0568
    Keywords: Bone ; Femur ; Development ; Gravity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The significance of similitude principles for the postnatal development of the cross-sectional area at midlength of the human and rat femur has been subjected to an investigation based both on theory and on observation. Cross sections were taken from 69 femora of female Sprague-Dawley rats 34, 72, 102, and 840 days old and from the right human femora of 94 males and 58 females ranging from 1 day to 89 years of age. The regression of the square-root of the cross-sectional area divided by π on femur length is linear in the rats. The empirical regression line estimated by the method of least squares from the measurements and the theoretical curve calculated on the assumption of adaptive allometric growth and centrically applied loads are more or less alike in slope and elevation. The corresponding empirical relationship in the human femora turned out statistically nonlinear in the males and linear in the females. Comparing the empirical regression functions with five theoretical curves, it has been revealed that the observations are best approximated by two curves calculated on the assumption of centrically or eccentrically applied loads and adaptive allometric growth of the cross-sectional diameter. It was further uncovered that the cross-sectional diameters at midlength of the femur are not changed isometrically with femur length both in rats and in man. Considering a simple model of the human body in the stance phase of slow walking gait on the scale of a neonate and an adult male, the hypothesis was advanced that the stresses at midlength of the femur are not altered much while the femur grows from neonate to adult size, because the outer and inner radii of the femur actually change during growth in such a way that the effects due to scale are appropriately compensated.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 143 (1974), S. 185-203 
    ISSN: 1432-0568
    Keywords: Basement membrane labyrinths ; Cerebral ventricles ; Development ; Rat ; Light and Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Gehirne embryonaler und neugeborener Ratten wurden im Hinblick auf die frühe Entstehung der Basalmembranlabyrinthe licht- und elektronenmikroskopisch untersucht. 1. An den Hirngefäßen embryonaler Ratten der 2. und 3. Fetalwoche kommen zwar bereits Basalmembranen vor, sub- oder interependymale Basalmembranlabyrinthe fehlen aber noch. 2. Basalmembranlabyrinthe werden mit der Perjodsäure-Bisulfit-Aldehydthionin-Methode lichtmikroskopisch ab dem 20. Tag an umschriebenen Stellen des Ventrikelsystems gefunden; elektronenmikroskopisch treten die ersten Basalmembranlabyrinthe am 12. postnatalen Tag auf. 3. Die ersten interependymalen Labyrinthe erscheinen in Erweiterung der interependymalen Spalten in der Nähe von ausgedehnten Golgifeldern. Der Labyrinthinhalt besteht aus einer feinflockigen Substanz. Diese liegt wolkenartig angehäuft gegenüber bogenförmigen Ausbuchtungen lokal verbreiterter Zellmembranen. In Ausbildung begriffene Labyrinthe zeigen eine lamelläre Gliederung. 4. Ab dem 12. postnatalen Tag treten auch an den Basalmembranen der pericapillären Zellen, in denen lichtmikroskopisch Glykoproteide nachweisbar sind, zapfenartige Duplikaturen auf. Die Zapfen sind überwiegend ependymwärts gerichtet. Verbindungen zwischen den Basalmembranzapfen und den interependymalen Basalmembranlabyrinthen werden in den ersten 30 Lebenstagen nicht gefunden. 5. Sowohl an den die interependymalen Labyrinthe begrenzenden Plasmalemmata als auch am Plasmalemm der pericapillären Zellen fallen Stachelsaumbläschen auf, deren Membran in die Zellwand eingebaut wird. Ihr Inhalt scheint in die entstehenden Labyrinthe entleert zu werden. 6. Da sich an den tubulären Enden der Doppellamellen der Dictyosomen Strukturen befinden, die den Stachelsaumbläschen morphologisch gleichen, und da im Bereich des Golgifeldes und im Cytoplasma zwischen diesem und der Zellwand zahlreiche Stachelsaumbläschen liegen, wird angenommen, daß das Material der Basalmembranlabyrinthe dem Golgiapparat entstammt und vermittels der Stachelsaumbläschen zur Zellwand transportiert wird. Bogenförmige Ausbuchtungen lokal verbreiterter Zellmembranen im Bereich entstehender Labyrinthe werden als Reste von Stachelsaumbläschen aufgefaßt, deren Membran in die Zellwand eingebaut wurde. 7. Da die phylogenetische Zunahme des Hirnmantels mit einem Verlust der langen in das Gehirn reichenden basalen Ependymfortsätze an den größten Teilen der Ventrikelwand einhergeht und niedere Tiere noch nicht über Basalmenbranlabyrinthe verfügen, wird angenommen, daß diese die Transportfunktion für Stoffe aus dem Liquor übernommen haben, die vordem nach allgemeiner Auffassung über die langen Fortsätze in das Gehirn gelangten.
    Notes: Summary The brains of embryonic and new-born rats were investigated by means of light- and electron microscopy with regard to the early formation of basement membrane labyrinths. 1. Though basement membranes are already found around the brain capillaries of embryonic rats from the 2nd week of pregnancy, sub- and interependymal basement membrane labyrinths are still absent. 2. Basement membrane labyrinths, being demonstrable for light microscopy by a periodicacid-bisulfite-aldehydethionin-method, appear around the 20th day after birth at certain places of the ventricular system. By means of electron microscopy, basement membrane labyrinths have first been detected at the 12th postnatal day. 3. The earliest interependymal basement membrane labyrinths are found in enlargements of the interependymal spaces near a distended Golgi apparatus. The contents of the labyrinths, being composed of a loose flocculent material, are of a lamellar structure. In the intercellular space the material is situated opposite bow-shaped excavations of local broadenings of cell membranes. 4. From the 12th postnatal day, plug-like duplications of basement membranes occur at the ependymal side of the pericapillar cells, which contain glycoproteids. The plugs of basement membranes are directed towards the ependymal layer. No connections between the interependymal basement membrane labyrinths and the plugs of pericapillary basement membranes exist within the first 30 days of life. 5. At the plasmalemma of ependymal cells bordering the interependymal labyrinths, and at the cell membrane of pericapillary cells, coated vesicles are to be found, which are fused with the cell membrane. The contents of these vesicles seem to be released into the developing labyrinths. 6. At the tubular ends of dictyosomes, coated vesicle-like structures can be demonstrated. In the environment of the Golgi apparatus many coated vesicles are situated; they can even be found between the Golgi apparatus and the walls of labyrinthś. Therefore the coated vesicles are considered to be transport vesicles, transporting the material which is formed in the Golgi apparatus towards the cell membrane. 7. Since the phylogenetic increase of the brain mantle is accompanied by loss of the long processes of ependymal cells that reach far into the brain, and since lower animals have no basement membrane labyrinths, it is suggested that the basement membrane labyrinths have a transport functions for material from the cerebrospinal fluid which in lower animals is assumed to be transported by the long processes of ependymal cells.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 144 (1974), S. 195-203 
    ISSN: 1432-0568
    Keywords: Development ; Adrenal glands ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Untersuchung der vorgeburtlichen Entwicklung der Nebennieren erfolgte an H.-E.-Schnitten und wurde ergänzt durch den Nachweis alkalischer Phosphatase. 1. Markzellen beginnen mit 11–12 Tagen in das Rindenblastem einzuwandern. Mit 14 Tagen a.p. ist die Einwanderung bereits abgeschlossen, d.h. viel früher als bei menschlichen Embryonen entsprechenden Alters. 2. Der Cortex beginnt sich am 11. Tag zu entwickeln, wie bei menschlichen Embryonen vergleichbaren Alters. Vor der Geburt kann bei der Maus nicht zwischen einem “fetalen” und “permanenten” Cortex unterschieden werden. 3. Eine frühzeitige Einwanderung von versprengten Geschlechtszellen kann in der Cortexanlage durch die Reaktion auf alkalische Phosphatase nachgewiesen werden. Später verschwinden sie wieder. Eine Infiltration von Leuko-und Lymphocyten besteht nicht. Beim Herannahen des Geburtszeitpunktes treten aber Blutbildungsherde auf.
    Notes: Summary A detailed reinvestigation of the prenatal development of the adrenal gland has been carried out, using H.-E. sections supplemented by investigation of alcaline phosphatase activity. 1. Medullary cells start to invade the cortex blastema at 11–12 days. Immigration is completed at 14 days a.p., i.e. much earlier than in human embryos of corresponding age. 2. Cortex development starts at 11 days, like in human embryos of corresponding age. Before birth, there is no distinction between “fetal” and “permanent” cortex in mice. 3. Early invasion of gonocytes into the cortex blastema can be demonstrated by alcaline phosphatase reaction. Later on they disappear. There is no infiltration of leuco-and lymphocytes. Near term foci of blood-forming cells are appearing.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 144 (1974), S. 205-214 
    ISSN: 1432-0568
    Keywords: Adrenal gland ; Juxtamedullary X-zone ; Mouse ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die postnatale Entwicklung der Nebennieren wurde an hybriden Mäusen (Kreuzung der Inzuchtstämme C57BL/6 und CBA) und an nu/+ Mäusen (BALB/c) untersucht. Dabei standen uns von weiblichen und männlichen Tieren beider Stämme Schnittserien der folgenden Stadien zur Verfügung: 1, 7, 14, 21, 42, 63 und 84 Tage. Neben Zona glomerulosa und Zona fasciculata weist die Nebennierenrinde 2–3 Wochen alter Mäuse zwei innere Schichten auf. An die dem Mark anliegende, schon mehrfach beschriebene X-Zone schließt sich nach außen ein Gürtel kleiner Zellen an. Diese zwischen X-Zone und Fasciculata gelegene, bei Weibschen stärker ausgeprägte Rindenschicht bildet sich mit dem Verschwinden der X-Zone zurück. Wegen ihrer morphodynamischen und wahrscheinlich auch funktionellen Eigenständigkeit haben wir diese Schicht von der X-Zone abgetrennt und als kleinzellige Zone bezeichnet. Auf Grund unserer Beobachtungen neigen wir zur Ansicht, daß die definitive Zona reticularis aus der kleinzelligen Zone hervorgeht. Der Zeitpunkt beginnender Rückbildung der X-Zone zegt neben den bekannten geschlechtsabhängigen Unterschieden eine ganz erhebliche Variabilität (bis 10 Wochen) zwischen den verschiedenen Tierstämmen. Die X-Zone der Maus und die fetale Zone der menschlichen Nebenniere können—obwohl beides vorübergehende Strukturen—, wegen ihrer verschiedenartigen Entwicklung kaum als Analoga betrachtet werden.
    Notes: Summary The postnatal development of the adrenal glands was investigated in hybrid mice (from crossing the two inbred strains C57BL/6 and CBA) and in nu/+ mice (BALB/c). Serial sections of the following stages: day 1, 7, 14, 21, 42, 63, and 84 respectively from both strains and sexes were studied. The adrenal cortex of 2–3 week old mice is structurally differentiated into the zona glomerulosa, the zona fasciculata and two inner zones: 1: the well known x-zone surrounding the medulla; 2: a distinct zone (more pronounced in females, than in males) of small cells lying between the x-zone and the zona fasciculata. The latter disappears parallel to the removal of the x-zone. In view of the distinct morphological, developmental and probably even functional individuality of this zone, it was separated from the x-zone and given the name “zone of small cells”. It is assumed, that the definitive zona reticularis originates from the zone of small cells. The time at which the x-zone starts to degenerate depends on the sex, and varies considerably from one strain to another. The x-zone of the mouse and the fetal zone of the human adrenal gland—both transitory structures—differ too much in their development to be considered as analogous structures. New-born mice show a positive chromaffine reaction of the medullary cells. During the first 3 weeks the intensity of reaction increases considerably and then remains at the higher level for the time of further development.
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  • 9
    ISSN: 1432-0568
    Keywords: Reptiles ; CNS ; Development ; Cell proliferation ; H3-thymidine autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Early ontogenetic events in the brain of a lizard, Lacerta sicula, were investigated by means of H3-thymidine autoradiography. Varying dynamic properties—beginning, duration, and end of the proliferating activity, dynamics of the generation cycle—of the matrix zones of different regions and areas of the brain were observed. The main interest was focused on the rhombencephalon, where a distinct heterochronism of proliferation was described for different systems and nuclear groups. Eye muscle nuclei, the trigeminal system, and the hypoglossal nucleus arrive earliest (stage day 1/2–1 1/2). The vestibular and the cochlear system cease their proliferation at stage day 2 1/2 and stage day 3 1/2 respectively. Their proliferation is very rapid. In contrast, the sensory regions of the VIIth, IXth, and Xth nerves and the tegmental regions show a slow, long-lasting proliferation. The great difficulties for embryologic and experimental approach in reptiles are discussed.
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  • 10
    ISSN: 1432-0568
    Keywords: Development ; Genetics ; Mouse ; Vertebrae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The recessive mutation, rachiterata, reduces the number of cervical vertebrae to 6 by shifting the cervico-thoracic boundary in a cranial direction, and produces partial duplication of the neural arch of the axis. Rachiterata also produces malformations of thoraco-lumbar vertebrae, often associated with fusions of ribs. These malformations are caused by a disturbed arrangement of somites first detectable in 11-day embryos.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 146 (1974), S. 141-156 
    ISSN: 1432-0568
    Keywords: Tapetum lucidum cellulosum ; Cat ; Development ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die postnatale Entwicklung des Tapetum lucidum cellulosum der Katze wird mit licht- und elektronenmikroskopischen Methoden untersucht. Bereits am ersten postnatalen Tag sind im Bereich des prospektiven Tapetum zwei Zellarten voneinander zu unterscheiden: 1. mesenchymale Bindegewebszellen und 2. prospektive Tapetumzellen, die durch elektronendichte Tapetumstäbchen gekennzeichnet sind. Die Mesenchymzellen unterteilen als parallel zur Retinaoberfläche ausgebreitete Zellplatten in der Choriodea am hinteren Augenpol den weiten extracellulären Raum in 20–25 etwa 5 μm hohe Schichten. Die Tapetumzellen liegen zwischen den Mesenchymzellplatten und wachsen im Verlaufe der ersten vier postnatalen Wochen innerhalb der Schichten in die Breite, bis sie den extracellulären Raum vollständig ausfüllen und als polygonale Zellen direkt aneinander grenzen. Im weiteren Verlauf der Entwicklung werden die Mesenchymzellplatten rückgebildet, so daß bei der adulten Katze die Tapetumzellschichten direkt übereinander liegen und nur von Netzen elastischer und kollagener Fasern getrennt sind. Die von einer Elementarmembran umgebenen Tapetumstäbchen enthalten einen elektronendichten, in den ersten postnatalen Wochen mit einer Periode von 100 Å quergestreiften Kern. Zunächst nehmen sie an Zahl und Länge zu und füllen am Ende der vierten postnatalen Woche, zu Bündeln von parallel verlaufenden Stäbchen geordnet, das Cytoplasma der Tapetumzellen. Dann nehmen die Tapetumstäbchen an Dicke zu, und ihre Querstreifung wird von einem elektronendichten Material überlagert. Die Entwicklung der Tapetumstäbchen hat eine starke Ähnlichkeit mit der in der Literatur beschriebenen Entwicklung von Melanosomen in Melanocyten. Das Tapetum lucidum cellulosum wird als ein dichter Verband hochdifferenzierter extrakutaner Melanocyten angesehen.
    Notes: Summary The postnatal development of the tapetum lucidum cellulosum of the cat was studied by light and electron microscopy. Already by the first postnatal day two cell types can be distinguished in the prospective tapeta area: 1. mesenchymal cells and 2. prospective tapetal cells, characterized by electron dense, membrane bound, rod-like inclusions. The flattened mesenchymal elements form 20–25 separate layers of cells, which are arranged parallel to the surface of the retina, subdividing the extracellular space of the chorioidea at the posterior pole of the eye into 5 μm high compartments. These compartments contain the tapetal cells which enlarge (in their longitudinal axis) during the first four weeks post partum until they occupy the extracellular space almost completely. At this stage, the tapetal cells are polygonal in shape and closely attached to each other. During the subsequent period of development there is a gradual involution of the mesenchymal cell plates. Thus, in adult cats the individual layers of tapetal cells are only separated from each other by networks of collagen and elastic fibers. The tapetal rods are bound by unit membranes and contain an electron dense core which, during the early postnatal weeks, exhibits a periodic cross-striation (100 Å). The tapetal rods increase in number and length during the first four weeks post partum; by the end of the fourth week, they occupy the whole cytoplasm of the tapetal cells. Parallelly arranged rods are grouped into individual bundles coursing inside the cytoplasm in different directions. Thereafter, the tapetal rods increase in thickness and their cross-striation becomes obscured by an electron dense material. This development of the tapetal rods closely resembles that of melanosomes. Thus the tapetum lucidum cellulosum can be regarded as a compact tissue made up of modified extracutaneous melanocytes.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 27 (1974), S. 163-169 
    ISSN: 1432-0533
    Keywords: Cerebellum ; Development ; X-Irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The heads of seven day old rats were irradiated with 600 rads. The permanent long-term effects on the cerebellum were examined histologically seven months after irradiation. The effects of radiation were not homogenous, with selective loss or abnormal distribution of granular cells and disorientation of Purkinje cells. The possible reasons for these modifications in cerebellar structure are discussed.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 27 (1974), S. 317-328 
    ISSN: 1432-0533
    Keywords: Dentale Nucleus ; Inferior Olive ; Development ; Micropolygyria ; Pachygyria ; Dental Gyrification Gliosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of dentate nucleus and inferior olivary nucleus were studied in 78 fetal brains (between 2 and 8 fetal months) and in 41 early infantile brains (until 12 postnatal months), in which the characteristic gyrification mechanisms were followed up. It is remarkable that the peculiar gyrification gliosis (dentate nucleus), gyrification paling and marginal arrangement of nerve cells (olivary nucleus) temporarily appeared in the course of gyrification around both nuclei. The teratological terminal determination periods are different for the various dysgenesias, e.g. pachy- and micropolygyrias, meta- and dysplastic malformations of both nuclei which is in accordance with the temporal determination of normal developmental stage. In certain stages of fetal development peridental matrix-cell nests are not infrequently found. This type of spindle cell dysgenesia may be related to retarded gyrification and myelinization glia.
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  • 14
    ISSN: 1432-072X
    Keywords: cAMP ; Acanthamoeba ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Durch drei verschiedene Methoden wurde in Kulturen vonAcanthamoeba castellanii die stationäre Wachstumsphase, in deren Verlauf sich Trophozoiten zu Cysten entwickeln, induziert: Durch Nahrungsmangel, indem Amöben der logarithmischen Wachstumsphase in ein nährstofffreies Medium überführt wurden, durch Sauerstoffmangel, indem Kulturen zu großer Zelldichte heranwuchsen, und durch Hemmung der mitochondrialen DNS-Synthese, indem Kulturen der logarithmischen Phase mit Äthidiumbromid versetzt wurden. Unabhängig von den Encystierungsbedingungen nimmt die intracelluläre Konzentration von Adenosin-3′,5′-monophosphat (cAMP) bei Verminderung der Zellteilungsrate bis zu Beginn der stationären Wachstumsphase um das 2–3 fache zu. Die Ergebnisse deuten an, daß der Anstieg von intracellulärem cAMP auf eine Erhöhung der Adenylat-Cyclase- und nicht auf eine Verminderung der Phosphodiesterase-Aktivität zurückzuführen ist. Extracelluläres cAMP konnte weder in Kulturen der logarithmischen noch in Kulturen der stationären Phase nachgewiesen werden. Dies ist vermutlich auf die extracellulär vorhandene cAMP-Phosphodiesterase zurückzuführen. Die Tatsache, daß auch durch Theophyllin die stationäre Wachstumsphase und Encystierung induziert werden kann, läßt auf eine Beteiligung von cAMP an den Entwicklungsprozessen, speziell an dem Abbau von Glykogen, schließen.
    Notes: Abstract In cultures ofacanthamoeba castellanii the stationary growth phase in which trophozoites develop to cysts, was induced in three ways: by transferring cells from a logarithmic growing culture into a nutrient-free medium, by growth in nutrient medium to high cell density and by inhibition of the mitochondrial DNA synthesis with ethidium bromide. In all cases, the intracellular concentration of adenosine-3′,5′-monophosphate (cAMP) rises by a factor of two to three from the end of the logarithmic phase to the beginning of the stationary phase. The results show that this rise may be more a consequence of an increased adenylate cyclase activity than of a diminished cAMP phosphodiesterase activity. No extracellular cAMP could be measured in cultures of the logarithmic and stationary growth phase, perhaps because of the extracellular cAMP phosphodiesterase. Because theophylline also induces the stationary phase and encystation, cAMP seems to be of importance for the development ofAcanthamoeba castellanii, especially for the degradation of glycogen.
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  • 15
    ISSN: 1432-072X
    Keywords: Myxomycetes ; Ultrastructure ; Development ; Systematics ; Food Vacuoles ; Stalk Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Observations of sporophore development in fresh and glutaraldehydeosmium sequentially-fixed material ofProtophysarum phloiogenum show the following sequence. Small plasmodia cease streaming and round up. Food vacuoles collect in the lower center of the cytoplasmic mass. As the cytoplasm rises the food vacuolar contents are excluded from the plasmalemma and become the stalk core. A continuous, fibrous peridium and stalk tube enclose cytoplasm and stalk core respectively. Capillitial formation just precedes spore cleavage. Sporophore development is marked by autophagic activity and calcium deposition. Stalks of dried herbarium specimens of seven additional species have been examined. A mature stalk morphology very similar toProtophysarum with recognizable remnants of microorganismal food material is seen in all of them. It is thought that this marker is indicative of non-stemonitaceous stalk development.
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  • 16
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    Archives of microbiology 96 (1974), S. 353-364 
    ISSN: 1432-072X
    Keywords: Coprinus ; Agaricaceae ; Mushroom ; Development ; Growth Regulator ; Stipe Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some of the morphological and physiological parameters of stipe growth or elongation inCoprinus radiatus were investigated. During the development of the fruit body the number of cells in a row in the growing portion of the stipe doubled during the development of the button, and again during the phase of rapid stipe elongation. Also during the stage of rapid elongation the cells in the upper 2/3 of the stipe increased 6–8 fold in length. The existence of a growth regulator synthesized in the cap and exerting control over the stipe was demonstrated through decapitation experiments. The cap appears to be required for normal stipe development until the stipe reaches about 1/4 of its final length. Through decapitation and cap-stipe exchanges it was found that the cap produced growth regulator up to the time of autodigestion; however, the stipe responded to the regulator only during a brief period at the onset of elongation.
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  • 17
    ISSN: 1432-0878
    Keywords: Protonephridium ; Pomatoceros triqueter (Annelida, Polychaeta, Sedenta-ria) ; Terminal cell ; Channel cell ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During the development of the intermediate and late gastrula of Pomatoceros triqueter, the terminal and channel cells grow towards each other and form the protonephridium. They interdigitate through lateral microvilli. The junctions between the cells form filtration clefts, which are bridged by fibrils.
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  • 18
    ISSN: 1432-0827
    Keywords: Mucopolysaccharides ; Collagen ; Calvarium ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Mucopolysaccharides (MPS) and collagen have been analyzed in different types of cartilage and some other tissues at various stages of prenatal and postnatal human development. The concentration of the chondroitin sulfate-type MPS increased from the 38th embryonal day, the 6-sulfate exceeding in amount the 4-sulfate. The increase in collagen concentration was accompanied by a decrease in the proportion of neutral salt-soluble collagen. There was no accumulation of chondroitin sulfates in the calvaria. A maximal concentration of MPS of a low molecular weight occurred in the skin and in the ear pinna after the 10th prenatal week. Postnatally, the MPS-concentration in the iliac crest and in the tibial articular cartilages decreased gradually, the highest values being reached in the newborn; the collagen-concentration showed an approximately reciprocal course.
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  • 19
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    Journal of molecular evolution 3 (1974), S. 109-113 
    ISSN: 1432-1432
    Keywords: “Custom Fitting” ; Development ; Evolution ; Antibody response ; Genetic Redundancy ; Perturbation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When the complexity of a developmental system evolves to a certain point, appreciable variation must occur in the process. The problem the biologist faces is whether this point constitutes a limit to the evolution of complexity in developmental systems. If not, what mechanisms are employed to cope with the problem ? The problem—essentially one in “custom fitting” of parts, — and the possible solution(s) to it that have evolved are discussed. The antibody producing system appears to be one that “solves” the custom-fitting problem.
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  • 20
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    Pflügers Archiv 351 (1974), S. 259-270 
    ISSN: 1432-2013
    Keywords: Renin-Angiotensin System ; Development ; Kidney Renin ; Kidney Angiotensinases ; Sex Differences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In rats during perinatal, suckling, weaning, sexual maturation and adult periods (ages 1, 10, 20, 40 and 80 days) we determined the concentration of renin (PRC) and its substrate (RSC) in blood plasma, and renin (RRA) and “angiotensinase” (RAA) activity in the kidney. These measurements were complemented by determinations of glomerular counts per unit weight (CG) of kidneys of animals aged 20, 40 and 80 days. From age 40 days the sexes were separated. Between ages 1 and 20 days, PRC values were higher than in adults, whereas RSC was at the same level. The highest PRC values were found in 1-day-old animals, where we also showed the highest RRA values. Between ages 1 and 10 days both parameters decreased. Between ages 40 and 80 days there was no sex difference in PRC, whereas RRA decreased in males as in the case of CG. In adults, RRA in males was lower by 25 and CG by 30% than in females. RAA was lower at ages 1–20 days than in adult animals. At the time of sexual maturation these values increased, earlier and to a more marked degree in males than in females. It is argued that a) the origin of the sex differences of RRA is related to the decrease in concentration of structures containing this activity in the male kidney. This may result in part from a more rapid rate of growth of structures containing RAA; b) that in early postnatal ontogenesis inactivation of angiotensin in the kidneys can be lower, and its formation in the body fluids higher than in adult animals.
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  • 21
    ISSN: 1432-0878
    Keywords: Muscle spindles ; Intrafusal fibre types ; Development ; De-efferentation ; Utrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hind limb muscles were de-efferented in 19 new-born rats by removal of the lumbosacral spinal cord, with preservation of spinal ganglia and their peripheral branches. The juxtaequatorial and polar zones of muscle spindles were studied in different leg muscles 3 to 9 weeks after the operation in order to establish whether intrafusal fibre types would become differentiated after permanent motor denervation. De-efferented intrafusal fibres developed into distinct ultrastructural fibre types similar to those found in control muscles. The nuclear bag type had confluent myofibrils with ill-defined M lines and relatively few mitochondria. The nuclear chain type had discrete myofibrils with prominent M lines, numerous large mitochondria and a more developed sarcotubular system. The fibre type characteristics were sometimes blurred by disarranged cross striation, but they were clearly discernible in 59 out of 69 de-efferented fibres of 31 spindles investigated in the electron microscope. A sample of 220 de-efferented spindles from leg muscles of 6 rats was examined in the light microscope on transverse sections stained for ATPase activity. The difference in the ATPase activity among intrafusal fibre types was marked in about 70% spindles; in contrast to this, no distinct fibre types could be discerned in the population of extrafusal fibres which were stained rather uniformly. In de—efferented spindles-as in normal control spindlesnuclear chain fibres always exhibited high ATPase activity, whereas one of the nuclear bag fibres had low ATPase and the other either low or medium to high ATPase activity. However, the ATPase activity of de-efferented muscles was generally lower than that of normal muscles. It can be concluded that intrafusal fibres do acquire their fibre type characteristics after fusimotor denervation despite complete deprivation of nerve impulse activity during the postnatal period when intrafusal fibre types differentiate in normal spindles.
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  • 22
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    Cell & tissue research 151 (1974), S. 433-456 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus (Rat) ; Development ; Renin ; Pools ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die perinatale Entwicklung des juxtaglomerulären Apparates, insbesondere das Verhalten der epitheloiden Zellen wurde an 18 trächtigen Ratten and 65 Embryonen bzw. Jungtieren elektronenmikroskopisch untersucht. Parallel dazu wurde die Reninkonzentration bzw. der Reningehalt bestimmt. Spezifische Sekretgranula finden sich erstmals am 18. Tag der Fetalzeit, und zwar in den epitheloiden Zellen des juxtaglomerulären Apparates juxtamedullärer Nephrone. Die Granula machen einen Struktur- und wahrscheinlich auch Funktionswandel durch, der eine Einteilung in drei verschiedene Granulatypen nahelegt. Diesen drei Typen spezifischer (reninhaltiger) Sekretgranula werden die Lysosomen als unspezifische Einschlüsse der epitheloiden Zellen gegenübergestellt. Im einzelnen kommt es während der perinatalen Phase in den fetalen Epitheloidzellen zuerst, d.h. pränatal, zu einer Hypertrophie des rauhwandigen endoplasmatischen Retikulums und des Golgi-Apparates. Hierin sehen die Autoren einen Hinweis auf eine erhöhte Proteinsynthese mit entsprechender Zunahme der Transport- und Konzentrationsvorgänge. Nach der Geburt findet sich dann auch eine deutliche Zunahme der Sekretgranula vom Typ III, die als reife Reningranula (mature granules) angesehen werden. Die bisher noch nicht beschriebenen kleinen Sekretgranula vom Typ I dagegen kommen in weniger entwickelten Epitheloidzellen häufiger vor. Bestimmungen der Reninverteilung zwischen Zytoplasma und den durch Differential-zentrifugation gewonnenen Granula-Fraktionen ergeben auffallende Parallelen zu den morphologischen Befunden. Diese sprechen im allgemeinen dafür, daß “freies Renin” im Ergasto-plasma und “gebundenes Renin” in den Sekretgranula vorliegt. Mit zunehmendem Alter scheint es außerdem — parallel zur relativen Abnahme des Ergastoplasmas und Zunahme der reifen Reningranula — zu einer Verminderung des extragranulären zugunsten des granulär gebundenen Renins zu kommen.
    Notes: Summary The perinatal development of the Juxtaglomerular apparatus (JGA), with particular reference to the epithelioid cells, was studied. Electron microscopic studies were carried out on 18 gravid rats and 65 embryos with corresponding determinations of renin concentration and the renin contents by bio-assay. Specific secretory granules of the epithelioid cells of the JGA of juxtamedullary nephrons are first observed on the 18th day of gestation. The classification into three types of secretory granules suggests that they undergo a structural and probably also a functional transformation. All three types of secretory granule may be regarded as specific, renin-containing, cytoplasmic organelles. During the last days of gestation, the rough-surfaced endoplasmic reticulum and the Golgi apparatus become hypertrophied in epithelioid cells, indicating an increased protein synthesis as well as transport and concentration processes. After birth, there is a definite increase in the number of Type III secretory granules-which may be regarded as mature granules. The small Type I secretory granulesnot previously described-are found more frequently in the immature epithelioid cells. Determinations of the renin distribution in the plasma and in fractions of cytoplasmic constituents (total homogenate, secretory granules) prepared by differential centrifugation showed striking congruence with the morphological findings. It is generally assumed that “soluble renin” occurs in the endoplasmic reticulum and “bound renin” in secretory granules. A shift from extragranular to granular (bound) renin, occurs with increasing age, having its morphological equivalent in the relative decrease of the endoplasmic reticulum and increase in mature secretory granules.
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  • 23
    ISSN: 1432-0878
    Keywords: Glandula submandibularis (Mouse) ; Acinar ultrastructure ; Cell types ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the submandibular gland of the mouse was studied by means of electron microscopy, from the 14th day of gestation up to birth. In the first two days the acini are solid and their cells contain polyribosomes and a few lamellae of endoplasmic reticulum. Beginning with the 16th day secretory granules appear and rapidly fill an increasing number of cells. The different electron density of the granules makes it possible to distinguish 1. two types of granules, dense and pale, and sometimes intermediate ones, 2. “polymorphic” granules. The latter consists of electron dense and electron pale parts combined in different configurations. The possible significance of the various types of granules is discussed.
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  • 24
    ISSN: 1432-0878
    Keywords: Seminiferous tubule, ovine ; Lamina propria ; Development ; Endocrine factors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the lamina propria in the ovine seminiferous tubule was studied from 54 days (postcoitum) fetuses up to sexual maturity. In young animals (aged about two months) the effect of hypophysectomy and/or hormones was also analyzed. Initially, large areas of the lamina propria already show signs of morphological differentiation. The non cellular component is a single or sometimes double lamella. Outwardly, the cellular component is represented by rounded connective tissue cells or by elongated cells, exhibiting 80 Å filaments in the cytoplasm and arranged in 3 to 4 layers. By the first week after birth, the non cellular component is formed by 8 to 10 lamellae and the cellular component shows typical contractile cells, the fibroblasts being now located only in the periphery. Basically, the same aspect is found in the adult ram, thus differing from the more extensively studied prototypes of lamina propria architecture of rodents or primates. In as much as the sheep lamina propria differentiates precociously, probably induced by fetal testicular hormones, it is relatively insensitive to hypophysectomy or hormonal substitution. Hypophysectomy and cyproterone acetate administration cause intracytoplasmic lipid deposition in the contractile cells, the other components being not changed. Some questions are raised concerning the role of this peculiar lamina propria in the function of the blood-testis barrier.
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  • 25
    ISSN: 1432-0878
    Keywords: Gill ; Trout ; Secondary lamellae ; Development ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A light and electron microscope study of secondary lamellae of trout developing at 10° C is described. Collagen is secreted by mesenchyme cells in the connective tissue of the developing gill filament. This becomes enclosed in infoldings around the peripheries of mesenchyme cells. These cells become aligned in a single plane within folds of basement membrane and epithelium. The basement membrane of opposite sides of the fold becomes connected by a thick layer of collagen. Blood spaces form around the margin of the fold, connecting afferent and efferent filament blood vessels. Endothelial granules form in cells lining the outer border of the marginal channel when blood flow begins. Rows of pillar cells separate from the proximal layer of mesenchyme cells as the secondary lamellae develops further. New secondary lamellae are added at the filament tips. At 28 days, the basement membrane consists of 2 layers, a fine fibrous layer and 5–15 orthogonally arranged layers of collagen fibres. By 31 days, the collagen is arranged at random and the layer is thinner. A clear layer is also present by 67 days. A multilayered epithelium containing mucous and chloride cells is present at 28 days. By 102 days, the secondary lamellae are covered by 2 layers of epithelial cells only. Chloride cells are present in much greater numbers in developing gills than in the adult.
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  • 26
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    Cell & tissue research 152 (1974), S. 13-30 
    ISSN: 1432-0878
    Keywords: Human fetal pineal gland ; Development ; Secretion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the pineal gland of 18 human fetuses (crown-rump lengths 30–178 mm) was investigated. The pineal gland exhibits a pyramidal shape and consists of an anterior and posterior lobe. Only one parenchymal cell type, the pinealocyte, was observed. Few neuroblasts were seen between the pinealocytes and in the extended perivascular space. The pinealocytes possess all the organelles necessary for hormone synthesis. No specific secretory granule could be observed. The organ is abundantly vascularized and richly innervated. The morphology of the capillaries indicates the existence of a blood-brain barrier. The ultrastructure of the human fetal pineal gland suggests that the gland has a secretory function in early intrauterine life.
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  • 27
    ISSN: 1432-0878
    Keywords: Chordotonal (Tracheal) organ ; Teleogryllus commodus (Orthoptera) ; Hearing ; Development ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tracheal organ of the mesothoracic tibia of Teleogryllus is located in a corresponding position to the tympanal organ of the prothoracic tibia. The mesothoracic organ contains an average of only 12 scolopidia, the location of which corresponds to that of the proximal group A and proximal main group in the prothoracid tympanal organ. There are no scolopidia corresponding to the distal group of the tympanal organ. The variability in number of scolopidia is much greater in the mesothoracic organ than in the prothoracic organ. The adult tracheal system of the mesothoracic leg resembles the early nymphal tracheal system in both pro- and meso-thoracic legs. The development of the tracheal organ is usually complete by the sixth instar. The mesothoracic tracheal organ of the adult is broadly equivalent to the prothoracic tympanal organ of a fifth instar animal.
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  • 28
    ISSN: 1432-0878
    Keywords: Chordotonal organ ; Teleogryllus commodus ; Hearing ; Structure ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomical development of the tympanal organ, the tracheal system and the tympana of Teleogryllus commodus is described. The tympanal organ is undifferentiated until instar 3 when the first scolopales appear. The organ develops in a proximo-distal direction but the more distal groups begin to form before the proximal groups are complete. All groups of scolopidia are represented in instar 7 but numbers of scolopidia continue to increase until the adult stage. Scolopales and scolopale cells are first formed at less than adult size and increase in size during subsequent instars. The subgenual organ is present in instar 1 and is complete in instar 4. The posterior and anterior tympanal trachease develop respectively from the tracheal trunk and tracheal branch, which are present from instar 2. These remain as simple, unconnected tubes until instar 7 and begin to show the adult form during instars 8 and 9, finally enlarging in conjunction with the tympana at the last two moults. The tympana first appear as hairless areas of cuticle in the larval stages: the posterior tympanum in instar 8 and anterior tympanum in instar 10, but the translucent appearance of the adult tympana is not present before the final moult.
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  • 29
    ISSN: 1432-0878
    Keywords: Synaptosomes ; Rat brain stem ; Synaptogenesis ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure and protein content of the five subfractions of the crude mitochondrial fraction from the brain stem of the 1-day old and adult rat was examined. The morphological composition of the subfractions after fixation in glutaraldehyde and osmiumtetroxide in the adult rat brain stem resembled that previously reported for the whole brain; synaptosomes sedimented in a sucrose gradient in subfractions C and D. In the 1-day old rat, mature synaptosomes were found in subfractions A, B, C and D; E contained mainly free mitochondria. 80–95% of the processes in the adult and 10–30% in the 1-day old rat contained synaptic vesicles which were of four types: (1) small agranular vesicles (2) large dense core vesicles (3) large agranular vesicles (4) coated vesicles. Pre- and postsynaptic membrane thickenings were demonstrated in many nerve-ending particles. In the subfractions of the 1-day old rat the protein content was one half and the distribution resembled that in the adult. Evidently nerve endings develop faster in the brain stem than in cortical areas; a serotoninor adrenergic origin of the early synaptosomes is suggested.
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  • 30
    ISSN: 1432-1912
    Keywords: Development ; Biochemical Teratology ; Penfluridol ; Monoamines ; Tyrosine and Tryptophan Hydroxylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nursing rat mothers were given penfluridol 1.0 mg/kg on days 1, 3, and 5 after delivery. The male litter-mates were killed 4 weeks after birth 30 min after treatment with an inhibitor of aromatic l-aminoacid-decarboxylase, NSD-1015, and the concentrations of noradrenaline, dopamine, and 5-hydroxytryptamine were analyzed in regional brain areas. Additionally, the accumulation of Dopa and 5-hydroxytryptophan after administration of NSD-1015 was analyzed. In the offspring of mothers treated with penfluridol a marked decrease in the rate of tyrosine hydroxylation in specific brain regions was observed. The possibility that penfluridol interacts with the development of monoaminergic mechanisms in the brain at a sensitive developmental period, and thereby induces a decreased functional activity in central monoamine neurones, especially in the limbic system, is discussed.
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  • 31
    ISSN: 1435-2451
    Keywords: Indication ; Emergency Surgery ; Change ; Development ; Indikation ; Unfallchirurgie ; Wandlung ; Entwicklung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Unfallchirurgie hat neben der Chirurgie der Organtransplantation im vergangenen Jahrzehnt die größten und eindruckvollsten Wandlungen und Fortschritte zu verzeichnen. Die Indikation zu chirurgischem Vorgehen ist nicht nur erweitert, sondern auch exakt abgegrenzt worden. Drei Faktoren haben die Entwicklung direkt beeinflußt: 1. Die Anforderungen des modernen Lebens hinsichtlich der Einsatz- und Leistungsfähigkeit der Menschen sind größer geworden. 2. Die modernen technischen Weiterentwicklungen haben die Unfallchirurgie gefördert. 3. Die Ergebnisse der modernen Grundlagenforschung haben die Weiterentwicklung der chirurgischen Indikation beeinflußt.
    Notes: Summary Organ transplantation and accident surgery are the two areas of surgery that have seen the greatest and most impressive changes and progress during the past decade. Not only have the indications for surgical intervention been expanded, but their limits have also been exactly defined. Three factors have directly influenced this development: 1. The demands of modern life on the individualt's capacity for involvement and achievement have increased. 2. Emergency surgery has greatly benefited from modern technical developments. 3. The results of modern basic research have influenced the further development of surgical indications.
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  • 32
    ISSN: 1432-0568
    Keywords: Cardinal veins ; Sinus venosus ; Heart ; Chick ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 3-, 31/2, 4- und 5tägigen Hühnerembryonen (insgesamt 220) wurde der Ductus Cuvieri dexter mittels feinem Silberclip unterbrochen. Die dadurch bedingte massive Stauung in den Vv. cardinales dextrae übertrug sich auf die Kardinalvenen der linken Seite. Diese bildeten sich bei den älteren Stadien nur verzögert zurück. Im Laufe von einem bis anderthalb Tagen entstanden den Clip in der Regel caudal umgehende Kollateralvenen, worauf sich Kreislaufverhältnisse und Entwicklung normalisierten. Bei einem Teil der am 5. Tag operierten Embryonen kam es nicht mehr zur Kollateralenbildung. Die Vv. cardinalis anterior et cerebri media obliterierten kurz nach dem Eingriff. Das Blut aus der rechten Kopf- und Halshälfte floß über ein dichtes Capillarnetz im Bereiche von Myel- und Metencephalon nach links ab. Infolge der nicht mehr korrigierbaren veränderten Zirkulation gingen diese Keime innert 24 Std zugrunde. Vom 5. Tag an besitzt das Kardinalvenensystem noch in allen Fällen die Fähigkeit einer kurzfristigen Anpassung an neue Kreislaufverhältnisse, hingegen nur noch bedingt die Möglichkeit einer Reparation des veränderten Blutgefäßsystems.
    Notes: Summary The right common cardinal vein (Duct of Cuvier) was occluded by a silver clip in 220 chick embryos of three, three and a half, four and five days respectively. The swelling of the right cardinal veins caused by this operation gave rise to a swelling of the cardinal veins of the left side. Consequently the disappearance of the postcardinal veins was retarded. One to one and a half days after the operation collateral veins going round the clip were established. Thereby the circulatory situation as the development of the cardinal veins became normal. In some of the embryos operated the fifth day the collateral vein was not found. The anterior cardinal and middle cerebral vein disappeared soon after the operation. The blood from the right half of the head and neck passed through a capillary network situated over the met- and myelencephalon and emptied into the left anterior cardinal vein. Since these embryos were no longer able to correct the circulation by establishing collateral veins they died within 24 hours. After the fourth day the system of cardinal veins can accomodate itself to changed circulatory conditions for a short time but it has only in part the possibility of establishing the original situation.
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  • 33
    ISSN: 1432-0568
    Keywords: Synapses ; Development ; Migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Projections and trabeculae consisting of neurons, neuroglial cells, and their processes extend from the rostral aspect of the nucleus lateralis of the rat. The dendrites of these neurons interweave with large packets of incoming myelinated fibers. Electron microscopy shows that synapses occur between these neurons and the afferent axons. Two possible developmental explanations for this arrangement are considered. (1) The cells may have been induced to migrate away from the main mass of the nucleus as a result of the delayed arrival of an important contingent of afferents. Alternatively, (2) these rostral cells may have migrated a longer distance for intrinsic reasons and consequently met their afferents at a location more peripheral to the main nuclear mass. In either case, the projections and trabeculae may reflect the segregation from the main nuclear mass of a certain group of neurons and their afferents having specific topographic or functional attributes.
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  • 34
    ISSN: 1432-0568
    Keywords: Neuromuscular junction ; Development ; Cholinesterases ; Muscle ; Immobilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immobilization of the tibialis anterior muscle of the newborn rat was caused by amputation of the hind limb at the talocrural joint. Subsequent muscular atrophy was measured by weighing the muscle and the myoneural morphogenesis in the disused muscle was studied in light and electron microscope. The acetylcholinesterase (AChE; E.C.3.1.1.7) and nonspecific cholinesterase (Ns. ChE; E.C.3.1.1.8) activity at the myoneural junction was followed histochemically. It was observed that the myoneural morphogenesis proceeded normally in the immobilized and atrophied muscle. Cholinesterase activities at the developing myoneural junction were identical on both the immobilized and the contralateral control side. The myoneural morphogenesis may be solely controlled by the nerve since, at the light of the present observations, the abnormally diminished function of the muscle seems to have no effect on the myoneural development.
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  • 35
    ISSN: 1432-0568
    Keywords: Placenta ; Carnivores ; Development ; Chorionic leaves ; Chorionic lamellae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der Katzenplacenta sind Zotten bzw. zottenähnliche Gebilde nur vom 15. bis etwa zum 20. Tag, in der Hundeplacenta etwa vom 17. bis zum 24. Tag vorhanden. Während dieser Zeit bilden sich die zunächst zapfenförmigen Chorionsprossen um und werden zungenförmig. Dabei dringen sie tief zwischen die Schleimhautfalten, in die Drüsenmündungen und zum Teil penetrierend in die Propria mucosa ein. Nach dem 20. bzw. 24. Tag verbreitern sie sich rasch zu blattförmigen Gebilden. Aus den so entstandenen Hauptblättern des Chroions entwickeln sich Nebenblätter, die nach Art eines Quirls angeordnet sind. Bis zur Mitte der Trächtigkeit erfolgt ein rascher Abbau des Endometriums. Zu Beginn der zweiten Hälfte der Gravidität hat die Placenta im wesentlichen den Zustand wie in einer reifen Placenta erreicht. Mikroskopisch erscheint dann die Placenta als ein endloses, enggestelltes Lamellensystem. Diese Lamellen stellen aber keine morphologische Einheit dar, sondern bestehen jeweils aus den sich gegenüberliegenden Epithelien der untereinander nicht zusammenhängenden Chorionblätter mit ihren Nebenblättern und den dazwischen auf schmalem Spalt zusammengedrängten, durchgehenden Anteilen des Endometriums (vorwiegend Capillaren, Innen- und Riesenzellen sowie Bindegewebe), die gewissermaßen unendlich erscheinen.
    Notes: Summary In the placenta of the cat, a villus-like state of the chorionic membrane exists only between the 15th and 20th day, in the dog between approximately the 17th and the 24th day. During this period, the originally conical chorionic sprouts become tongue-like. They grow either into the infoldings and glandular excretory ducts of the endometrium or penetrate directly into the propria of the mucosa. After the 20th day, respectively the 24th day, these villi increase in width and assume a leaf-like shape. Their cross-sectional aspect exhibits a scalloped surface. Later, secondary leaves develop, so that a twirl-like picture results. During this transformation the chorionic leaves increase also in length, retaining their straight form. Up to the middle of pregnancy, there is a rapid degeneration of the maternal placenta, whereas the chorionic leaves proliferate to their definitive shape. In the second half of pregnancy, there is no further principal change in the architecture of the chorionic leaves. Microscopically the placenta appears then like an endless labyrinthine system of lamellae. But these lamellae do not represent a morphological unit. Each consists of two opposing foetal, chorionic-leaf epithelia separated by highly compressed and continuous uterine material (capillaries, giant cells, connective tissue).
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  • 36
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    Acta neuropathologica 23 (1973), S. 48-58 
    ISSN: 1432-0533
    Keywords: Human Cerebellum ; Development ; Lamina Dissecans ; Granular Layers ; Matrix Cell Nests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histological study of normal cerebella in 72 human autopsies allowed defining several readily identifiable landmarks by which cerebellar development was dated for vermis and for hemispheres respectively: Disappearance of the lamina dissecans at 28 and 32 weeks gestation; Purkinje cells first discernible at the same age for both; onset of growth of inner granular layer at 30 and 32 weeks; sharp boundary between inner granular layer and white matter at approximately 36 weeks and about term; onset of marked growth of molecular layer at 30 and 38 weeks; adult thickness of molecular layer at approximately the 8th postnatal month for both; and accelerated involution of outer granular layer between the 2nd and 4th postnatal months, remnants persisting up to 9 and 13 months. Nests of matrix cells in the cerebellar nuclei were found in 28% of the cases less than 4 months old. These cell nests appear to undergo involution by the 4th month—that is, at the same time as the outer granular layer. The significance of these developmental events for the interpretation of pathological alterations in the developing cerebellum is discussed.
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  • 37
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    Calcified tissue international 12 (1973), S. 259-279 
    ISSN: 1432-0827
    Keywords: Osteocyte ; Calvarium ; Histology ; Development ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cartes tissulaires ainsi que les caractéristiques et propriétés cellularires ont été relevées au cours d'une étude de microscopie optique du développement de la calotte cranienne de souris, avant la naissance, jusqu'au 26ème jour. Les population d'ostéocytes de moitiés droite et gauche de ces calottes sont semblables, mais décroissent avec le temps dans un volume donné. De petites plages limitées de matrice osseuse se colorent pour le phosphate (ou carbonate) de façon plus nette que la matrice environnante, qui se colore légèrement après coupe. Les divers types ostéocytaires se distinguent par les réactions histochimiques du calcium et du phosphate, qui sont associés dans les cellules osseuses de façon complexe, variant dans le temps et la localisation. Ces deux constituants ne sont pas toujours présent dans les cellules des diverses régions, ou dans la même localisation dans un type cellulaire donné. En tenant compte des changements visible dans les divers types cellulaires avec le temps, dans des régions données, une hypothèse de “charge” et “décharge” cellulaire est émise.
    Abstract: Zusammenfassung Anläßlich einer mikroskopischen Studie über die Entwicklung des Mäuse-Calvariums von der Pränatalperiode bis zu 26 Tagen nach der Geburt wurden auch die Gewebetopographie sowie die Charakteristica und Eigenschaften der Zellen aufgezeichnet. Die Osteocyten-populationen in der linken und rechten Hälfte des Calvariums waren sich gleich, nahmen jedoch bei einem gegebenen Volumen mit der Zeit ab. Kleine isolierte Stellen von Knochen-matrix konnten leichter auf Ph sphat (oder Carbonat) angefärbt werden, als die umgebende Matrix, welche sich wohl am Schnitt, nicht aber am ganzen Stück färben ließ. Die verschiedenen Typen von Osteocyten wurden aufgrund histochemischer Calcium- und Phosphat-reaktionen bestimmt. Calcium und Phosphat waren innerhalb der Knochenzellen auf komplexe Art miteinander verbunden, die je nach Zeit und Lagerung unterschiedlich war. Zellen in abgetrennten Bereichen enthielten nicht immer Calcium und Phosphat und beide waren bei einer bestimmten Zellenart auch nicht immer am gleichen Ort abgelagert. Aufgrund der an ausgewählten Stellen beobachteten, zeitlich bedingten Veränderungen innerhalb der verschiedenen Zelltypen wird vorgeschlagen, daß es sich dabei um eine Sequenz von “Ladung” und “Entladung” der Zellen handelt.
    Notes: Abstract Tissue maps, and cell characteristics and properties were recorded in a study under the optical microscope of the development of the mouse calvarium from pre-natal to 26 days. Osteocyte populations in left and right halves of the calvarium were similar, but decreased with time for a given volume. Small isolated areas of bone matrix stained for phosphate (or carbonate) in a more readily available form from that in the surrounding matrix, which could be stained after sectioning but failed to stain in bulk. Osteocyte types were defined on the basis of histochemical methods for calcium and phosphate, which were associated inside bone cells in a complex manner, varying with time and position. The calcium and phosphate were not always present within the cell in discrete regions and were not always present in the same place in a given cell type. On the basis of a study of changes in cell types with time in selected sites a sequence of “loading” and “unloading” is proposed.
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  • 38
    ISSN: 1432-2072
    Keywords: Ethanol ; Pregnancy ; Tyrosine Hydroxylase ; Development ; Caudate nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pregnant rats were fed a regimen of ethanol and metrecal from the tenth day of pregnancy until delivery. Control females received metrecal and an isocaloric replacement of ethanol with sucrose. Tyrosine hydroxylase activity was measured in the caudate nuclei of the offspring at 1, 2 and 3 weeks of age. The activity of the enzyme was found to be significantly increased in pups whose mothers were exposed to ethanol.
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  • 39
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    Cell & tissue research 136 (1973), S. 511-520 
    ISSN: 1432-0878
    Keywords: Muscle spindle ; Sensory ending ; Rat ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fine structural study of sternothyroid muscle spindles of young adult rat demonstrates the rare occurrence of unique nerve endings. These endings are situated in the juxta-equatorial region of nuclear-bag fibers, adjacent to the annulo-spiral sensory endings. They consist of a bundle of terminal axons less than 0.3 μ in diameter and appear to be disposed nearly longitudinally to the axis of the intrafusal fibers. Whereas, the annulo-spiral endings consist of a single axon, coiling around the intrafusal fibers. Transverse sections of these muscle spindles reveal these unique endings scattered around the muscle fibers, fitting into depressions on their surface. The innermost axons directly face the muscle surface and are separated by a narrow gap less than 200 Å in width. No Schwann cell process appears to be associated with these endings. From their unique multi-axonal composition, these endings are termed “bundled endings”. Investigations of developing muscle spindles show the occasional presence of a similar multi-axonal composition of sensory endings in perinatal rats. It is suggested that “bundled endings” are sensory in nature, carrying an immature feature over to adult life.
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  • 40
    ISSN: 1432-0878
    Keywords: Macroglia ; Microglia ; Spinal Cord ; Monkey ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron-microscopic study has been made of the glial cells in the developing lateral funiculus of the cervical spinal cord in fetal rhesus monkeys. The various macroglial cell types, their precursor cells, and microglia are discussed in detail. An astrocytic lineage is proposed in which glioblasts present in the lateral funiculus give rise to astroblasts that then develop into mature astrocytes. Oligoblasts apparently migrate into the lateral funiculus as such and develop into active oligocytes. The active oligocytes become most predominant during the initial stages of myelinogenesis and are in direct continuity with developing myelin. The active oligocytes develop into mature oligocytes after myelination is completed. Microglia cells are present throughout development as three forms; resting microglia, globose microglia, and active microglia. The globose and active microglia predominates at specific times early in development when degeneration of apparent neuronal processes is taking place. The microglia cells are characterized by dense nuclear chromatin clumps, lipid inclusion bodies, dense vesicles, and, often, intracellular debris.
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  • 41
    ISSN: 1432-0878
    Keywords: Synapses ; Development ; Chick embryo ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The formation and development of synaptic contacts between dissociated chick spinal cord neurons has been investigated. By the 6th day in vitro “immature” profiles with few vesicles were observed. By 14–18 days “mature” types with numerous vesicles were found, indistinguishable from those of newly hatched chick spinal cord. After this period degeneration occurred, and was especially marked in the post-synaptic element. Such degeneration could be postponed by the addition of small numbers of somatic muscle cells. The Kanaseki and Kadota (1969) technique was applied to the study of coated vesicles at various stages of synaptic development.
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  • 42
    ISSN: 1432-0878
    Keywords: Hypophysis ; Rana temporaria ; Development ; Corticotropin cells, melanotropin cells ; Immunofluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During the embryonic and larval developmental stages of the frog, Rana temporaria L, anti-β 1–24, α 17–39 corticotropine, α and β MSH antibodies were used to define, with immunofluorescence technique, the appearence of corticotropic and melanotropic cells. A very small number of fluorescent corticotropic cells appears for the first time during the embryonic stage (10 mm), just before the differentiation of the pars intermedia. The cells are small, their large nucleus is surrounded by a fine rim of fluorescent cytoplasm. During premetamorphic stage, the anti-ACTH antibodies (anti-β 1–24 and anti-α 17–39 corticotropine) reveal more fluorescent cells in the whole pars distalis. The pars intermedia cells can also be visualized by both antisera. At the end of prometamorphosis and during climax the corticotropic cells show a more precise localization. As in adult frog pars distalis, they are concentrated in the rostral half of the lobe. With the same technique anti-α and β MSH antibodies reveal only the cells of the pars intermedia. No other cell type of the pars distalis reacts with these antibodies. This technique has the advantage to show that the ACTH and the MSH cells appear very early during the embryonic life.
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  • 43
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    Cell & tissue research 144 (1973), S. 435-452 
    ISSN: 1432-0878
    Keywords: Muscle spindles ; Intrafusal fibre types ; Development ; Deefferentation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Muscle spindles of limb muscles were deefferented in neonatal rats by sectioning ventral roots or by removal of the lumbosacral spinal cord. Ten to 56 days after the operation, muscle spindles were examined in the medial gastrocnemius, extensor digitorum longus and soleus muscles. The differentiation of muscle spindles was not affected by deefferentation. The number of spindles in the investigated muscles was not reduced. Intrafusal fibres increased in number from two at birth to four per spindle on the average, as in normal muscles. The characteristic ultrastructural distinctions of nuclear bag and nuclear chain fibres developed as under normal conditions. However, intrafusal fibres atrophied slowly after fusimotor denervation, their polar zones becoming reduced in diameter by about 25% in comparison with control fibre diameters. Spindle capsules, on the other hand, increased in size and attained diameters comparable with normal spindles, appearing even somewhat distended. As intrafusal fibres degenerate after complete denervation at birth (Zelená, 1957), but differentiate in the absence of fusimotor innervation, it can be concluded that sensory nerve terminals induce and support their development. It is assumed that the morphogenetic influence of sensory terminals is mediated by release and uptake of a trophic substance at the synaptic junction. The occurrence of light and dense core vesicles in the sensory terminals and of coated invaginations and vesicles at both the axonal and plasma membrane speak in favour of such a possibility.
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  • 44
    ISSN: 1432-0878
    Keywords: Pars tuberalis ; Rat ; Development ; Secretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the pars tuberalis was studied in the rat fetus from 13 days of gestation to 6 weeks after birth. After the closure of Rathke's pouch, the pars tuberalis anlage is clearly distinguishable from the anlagen of the partes intermedia and distalis. It comprises the entire basal portion of the adenohypophysial anlage; the limit between the anlagen of the pars tuberalis and the pars distalis is defined by Atwell's recess, i.e. the pathway taken by the hypophysial vessels coming from the vascular plexus of the median eminence. At 14 days the pars tuberalis cells are characterized by the presence of glycogen which persists in the adult. Their secretory differentiation (elaboration of granules with a diameter of 100–120 nm) is obvious at 15 days of gestation. It therefore, clearly precedes that of the other hypophysial cell types. Its functional differentiation takes place well before its adhesion to the primary vascular plexus of the portal system. Cystic formations appear just before birth in the pars tuberalis, much later than those of the pars distalis. These observations on the development of the pars tuberalis, together with previous observations on the adult PT in various species, showing that the specific glandular cells of the pars tuberalis are cytologically different from all known adenohypophysial cell types, seem to indicate a specific endocrine function of this lobe.
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  • 45
    ISSN: 1432-0878
    Keywords: Sympathetic neurons ; Chromaffin cells ; SIP cells (Newborn rat) ; Development ; Administration of hydrocortisone ; Stretch preparations ; Fluorescence microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Air-dried stretch preparations were used to study adrenergic nerve fibres and catecholamine-containing cells with the formaldehyde-induced fluorescence method in the abdominal tissue block containing the para-aortic paraganglia, in the neurovascular structures of the cervical region including the carotid body, in the bladder, in the ileum, in the mesentery, in the vagus nerve and in the sympathetic ganglia of 5- or 15-day-old rats. The adrenergic nerves and the catecholamine-containing cells were well preserved and showed little or no diffusion of amines. While most intensely fluorescent cells of the main para-aortic body disappeared during the first two postnatal weeks, some such cells survived and they showed long, slender fluorescent processes. Administration of 20 mg/kg of hydrocortisone acetate daily for 5 days after birth caused a striking increase in the number and size of the clusters of the intensely fluorescent cells in the organ of Zuckerkandl, in the sympathetic ganglia and in the bladder, as well as an increase in the fluorescence intensity of the carotid body. In rats treated with hydrocortisone for 5 days and left to recover for 10 days an increased fluorescence was still observed. However, in the organ of Zuckerkandl the intensely fluorescent cells of hydrocortisone-treated 15-day-old rats showed less processes than those of the control rats of the same age.
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  • 46
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    Cell & tissue research 147 (1973), S. 75-85 
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Denervation ; Development ; Fiber types, myofibrils ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural diversification of muscle fibers, with regard particularly to myofibrillar changes, has been investigated in the fast-twitch extensor digitorum longus (EDL) and the slow-twitch soleus muscles of the rat during fetal and postnatal development in the presence and in the absence of motor innervation. The band pattern and the shape of the myofibrils were uniform in fetal and neonatal muscle fibers and underwent differential changes during the first weeks after birth, concomitantly with fiber type specialization. The most evident variations in myofibrillar structure arising in this period concern the thickness of the Z band and the arrangement of the myofibrils. Myofibril formation was at first not impaired by denervation of rat muscles performed in utero and, although focal disintegration of myofibrils and detachment and loss of orientation of filaments became apparent by one week, atrophic muscle fibers with well-organized myofibrils could be seen as late as 2 months after birth. However, denervated muscle fibers of EDL and soleus did not display any significant and consistent difference in myofibrillar band pattern and shape. No variation in mitochondrial content and sarcoplasmic reticulum development was likewise seen in muscle fibers of EDL and soleus after fetal denervation. The findings emphasize the importance of neuromuscular interactions in muscle differentiation.
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  • 47
    ISSN: 1432-0878
    Keywords: Nervous system ; Stick insect ; Blood-brain barrier ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fat body sheath which surrounds the ventral nerve cord of the adult stick insect, Carausius morosus, is absent in the hatchling. Since the haemolymph sodium ion compositions of the two stages are similar, it is suggested that the fat body sheath is not a site of a blood-brain barrier dealing with extra-axonal regulation of sodium. Similarities of ultrastructure in connectives of adults and hatchlings are demonstrated, and tight junctions are shown to occur in perineural cells of both stages. The possible significance of this to the blood-brain barrier of this insect is discussed.
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  • 48
    ISSN: 1432-0878
    Keywords: Synapse ; Development ; Spinal cord ; Amphibian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopical study has been made of the cervical spinal cord of Xenopus laevis embryos, from the time that the neural tube closes until the larvae were hatched and could swim. Sections of the whole cord were searched for intercellular junctions during this period. Two nonsynaptic types were found, the first were widely distributed puncta adherentia, the second were rare and similar to “gap” junctions. Membrane specializations with synaptic vesicles were first found when the neural folds had fused; “membrane-vesicle clusters” which looked like the presynaptic half of a synaptic junction were present, together with synaptic junctions lacking any postsynaptic membrane thickening or cytoplasm density. About four hours later, mature synaptic junctions with full thickening of the postsynaptic membrane, dense cytoplasm and striated or dense material in the synaptic cleft were present. Presynaptic mitochondria, dense-cored and flattened vesicles, fibre to fibre and fibre to cell body synapses were present from the first, as were synapses onto very fine dendrites which might be filopodia from dendritic growth cones. Synaptogenesis may start with the accumulation of vesicles in dense cytoplasm near a thickened cell membrane; the postsynaptic element becomes associated with this “membrane-vesicle cluster” and matures by increasing cleft and cytoplasmic density, and by membrane thickening.
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  • 49
    ISSN: 1432-0878
    Keywords: Hypothalamo-hypophysial system ; Development ; Monoamines ; Colour change ; Fluorescence microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In Xenopus laevis the development of hypothalamic monoaminergic cells was studied in relation to adaptation to background colour. The first melanophores appear at stage 33/34 (normal table of Nieuwkoop and Faber, 1956), gradually increasing in number. The melanine granules are dispersed throughout the cell, irrespective of the background colour. The dispersion apparently is caused by MSH released by the developing pars intermedia cells. Between stage 39 and stage 41, larvae placed on a white background changed colour from black to white due to aggregation of the melanine granules within the melanophores. With Falck's method for demonstrating monoamines, a small number of fluorescent cells was observed in the hypothalamus simultaneously with the first background-dependent colour change. These cells were arranged in a paired nucleus, bordering the third ventricle. Initially, the nucleus extends from 50 microns behind the optic chiasma to the lateral dilatations of the third ventricle; 8–10 hours later, similar cells were also found at the lateral dilatations and in the dorso-lateral part of the infundibular lobe. The cells have apical processes protruding in the ventricular lumen. Fluorescent axons, originating from the cells, were occasionally observed. Considering the above-mentioned results in combination with the electron microscopical data of Nyholm (1972), it is concluded that the MSH producing cells are under monoaminergic nervous control from the beginning of background colour adaptation.
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  • 50
    ISSN: 1432-0878
    Keywords: Neuromuscular junction ; Development ; Cholinesterases ; Axonal transport, Neurotubules, Colchicine, Vinblastine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Colchicine (0.1 M) or vinblastine (0.01 M) was locally applied on the sciatic nerves of newborn rats. Both colchicine and vinblastine caused reversible disappearance of axonal neurotubules and appearance of increased amounts of neurofilaments at the site of application. Subsequent morphogenesis of myoneural junctions in the tibialis anterior muscle was studied after histochemical demonstration of acetylcholinesterase (AChE; E.C. 3.1.1.7) and non-specific cholinesterase (Ns. ChE; E.C. 3.1.1.8) activity in the myoneural area. Development of the postsynaptic muscle plasma membrane of the myoneural junction was arrested in the ipsilateral, but not in the contralateral control side, for a period of about three weeks following treatment with the test substances. After this delay the myoneural morphogenesis continued normally and neurotubules were seen in the axoplasm. Since disruption of neurotubules is likely to cause blockage of the intratubular axoplasmic transport system, it seems possible that the neurotrophic influence responsible for the development of the postsynaptic muscle membrane is mediated through a secretory product transported along axons intratubularly to the nerve endings.
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  • 51
    ISSN: 1432-1750
    Keywords: Hyperoxia ; Normoxia ; Hyperoxia ; Chick Embryo ; Development ; Area Vasculosa ; Growth ; Malformation ; Lactic and Pyruvic Acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Hühnerembryonen, 48 bis 72 h bei unterschiedlichen O2-Drucken (11 bis 100% O2) bebrütet, wird mit zunehmender O2-Konzentration eine Beschleunigung der Entwicklung und eine Verkleinerung der Area vasculosa festgestellt. Die Hämoglobinkonzentration in Embryo und Area vasculosa ändert sich jedoch nicht. 53 h bebrütete Embryonen zeigen mit zunehmender O2-Konzentration bei der Bebrütung eine Lactat- und Pyruvat-Konzentrationsabnahme, wobei sich der L/P-Quotient nicht signifikant ändert. Die meisten Mißbildungen wurden bei Bebrütung mit 50% O2 gefunden, und bei 100% O2-Bebrütung fand sich über der Area vasculosa eine fast 1 mm dicke, gallertartige Schicht, die evtl. infolge erhöhter Flüssigkeitsresorption durch die Gefäße der Area vasculosa entsteht.
    Notes: Abstract Exposure of chick embryos to different O2 pressures (11 to 100%) for 48 to 72 hours results in developmental acceleration of the embryo itself and decreasing size of the area vasculosa with increasing O2 pressures, while the concentration of hemoglobin in the embryo as well as in the area vasculosa does not change. Chick embryos, preincubated for 53 hours and exposed to different O2 pressures (13 to 100%) show decreasing concentrations of lactic and pyruvic acid, whereas the L/P ratio does not change significantly. We found the highest rate of malformation after exposure to 50% of oxygen. There was a gelatinous layer about 1 mm thick all over the membrana vasculosa, presumably caused by increased fluid resorption by the vessels of the area vasculosa.
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  • 52
    ISSN: 1432-1912
    Keywords: Conditioned Avoidance Response ; Learning ; Development ; Penfluridol ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acquisition of a conditioned avoidance response (CAR) was investigated in rats of nursing mothers given penfluridol 1.0 mg/kg on days 1, 3 and 5 after delivery. The male litter-mates were tested for CAR acquisition 4 weeks after birth. The animals whose mothers had received penfluridol were markedly inferior in the CAR acquisition than rats of mothers given glucose. Furthermore, rats of penfluridol-treated mothers were found to be heavier than those of glucose-treated mothers when weighed at 8 weeks of age. However, there was no difference between the groups at 4 weeks of age. The possibility that penfluridol interacts with the development of catecholamine mechanisms in the brain at a sensitive developmental period, and thereby influences later performance, is discussed.
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  • 53
    ISSN: 1432-1076
    Keywords: Alpha1 Fetoprotein ; Immune Double Diffusion ; Radial Diffusion ; Preterm, Gestational Age ; Newborn ; Development ; Hepatitis ; Hepatoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Vorkommen von Alpha1-Fetoprotein (AFP) wurde mit einer Mikromodifikation der Immundoppeldiffusion im Agargel bei Neugeborenen, Säuglingen und Kindern qualitativ untersucht und AFP-Spiegel mit der Technik der radialen Immundiffusion im antikörperhaltigen Gel quantitativ bestimmt. Im Nabelvenenserum von 59 reifen Neugeborenen fanden sich AFP-Werte zwischen 0 und 20 mg/100 ml mit einem mittleren Spiegel von 5,5±5 mg/100 ml. Die AFP-Konzentration im Nabelvenenserum unreifer Neugeborener lag zwischen 10 und 150 mg/100 ml mit einem Mittelwert von 33±18 mg/100 ml. Zwischen den Werten reifer Neugeborener und solchen von small-for-date-infants bestand kein signifikanter Unterschied. Der Korrelationskoeffizient des AFP zum Gestationsalter war höher als der zum Geburtsgewicht. Die AFP-Konzentration könnte also zur Beurteilung der Reife herangezogen werden. In den ersten Lebenstagen fällt der AFP-Spiegel kontinuierlich ab und ist nach der 3. Lebenswoche unter normalen Bedingungen nicht mehr nachweisbar. Bei einem Säugling mit Neugeborenen-Hepatitis und einem 15jährigen Jungen mit einem malignen Hepatom konnte das AFP quantitativ bestimmt werden.
    Notes: Abstract The serum concentrations of alpha1 fetoprotein (afp) were determined in mature and premature newborns, infants, and children, using a micro modification of immune double diffusion and a radial diffusion method. In 59 cord serum specimens taken from mature newborns afp levels ranged between 0 and 20 mg/100 ml with a mean concentration of 5.5±5 mg/100 ml while the values in specimens from 42 premature newborns ranged between 10 and 150 mg/100 ml with a mean afp concentration of 33±18 mg/100 ml. No significant difference was noted between the values for mature newborns and small-for-dates infants. Correlation with gestational age was more significant than with birth weight, so that afp concentration could be used as an indicator of maturity. In the first postnatal days afp levels decreased continuously and after the 3rd week of life it could not be measured under normal conditions. It was possible to quantify afp in an infant with neonatal hepatitis and a 15-year-old boy suffering from malignant hepatoma.
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  • 54
    ISSN: 1432-0568
    Keywords: Chick Mesencephalic Nuclei ; Development ; Gallus domesticus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The mesencephalic borders in the chick have been analysed and reconstructed. It is stated that the di-mesencephalic border corresponds to the border between postneuromeres 5 and 6, and the mes-rhombencephalic border with the border between postneuromeres 7 and 8. 2. The migration areas have been carefully analysed and reconstructed. 3. The ontogenesis of the mesencephalic brain nuclei has been traced from migration areas by means of reconstructions of successive series of stages. Some facts may be taken into consideration: a) The pretectal nuclear complex originates from the diencephalic region, close to the di-mesencephalic border, and during its expansion this nuclear complex passes the di-mesencephalic border, so the nuclei come to lie in both the diencephalic and mesencephalic regions. b) Some mesencephalic nuclei originate from a mixed cell material of different migration areas. Brain nuclei from a mixed cell material seem to be: the nucleus mesencephalicus lateralis, the nucleus isthmii, pars principalis complex, the nucleus of the basal optic root, the nuclei of the lateral genicular complex. 4. The mesencephalic anatomical topography is seen to change as follows: The optic tectum starts a rotation caudorostrally; it divides into two separate lobes, which are pushed away laterally along the tegmental sides. The tegmentum expands very greatly and there is tegmental axial straightening. The agueduct comes to lie horizontally.
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  • 55
    ISSN: 1432-0568
    Keywords: Sympathetic System ; Mouse ; Development ; Monoamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The early development of the sympathetic chain with adjacent ganglia and chromaffin tissue and the appearance of monoamines in these organs was mapped with the Falck-Hillarp fluorescence technique. In the 11 days embryo a few fluorescent cells are found lateral to the aorta in the thoracal region. During the following days the sympathetic chain with segmentally arranged ganglia develops. The cells have a weak to medium fluorescence intensity. A migration of fluorrescent cells ventral to the sympathetic chain can be seen in embryos 12 days old. These migrating cells will later form the prevertebral ganglia and the chromaffin tissue. At the 14 days old stage the adrenal medulla and the paraganglia can be distinguished, while the prevertebral plexa are differentiated in the 15 days old embryo. The chromaffin tissue has a brilliant fluorescence but in the neonatal stages parts of the paraganglia show a weaker fluorescence and though they have their largest extension around the 10th day of postnatal life a brilliant fluorescence can be seen only in a smaller part of the ganglia at that time. The paraganglia are reduced in adult stages.
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  • 56
    ISSN: 1432-0568
    Keywords: SIF-cells ; Development ; Biogenicamines ; Autonomic ganglia ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the rat paracervical (frankenhäuser) ganglion was studied during postnatal development after immersion or perfusion fixation with the glutaraldehyde, followed by postosmification. Three different neuronal cell types were found in the ganglion: (1) Primitive sympathetic nerve cells. They had a “primitive” structure and contained, in one section, one to two dense cored vesicles (DCV) of 700–1100 Å in diameter. They were not found after the fourth day of postnatal development. (2) Principal neurons grew in size during the whole period of postnatal development. Part of them were already well developed in the ganglia of the newborn rat, and no particular changes in the content of their cytoplasmic organelles occurred thereafter. (3) Small granule-containing (SGC) cells. They usually occurred in small groups, often close to blood capillaries of the fenestrated type and were sometimes devoid of their satellite cell sheath in this region. They became slightly smaller in size as the animal aged. The size of their granulated vesicles (GV) varied mainly between 800–1400 Å in all age groups in most of the cells. In addition, another type of SGC-cell containing larger GV up to 3000 Å in diameter were observed in the ganglia of 32-day old and older rats. Degenerating principal neurons and SGC-cells were encountered, especially in the young animals. Mitotic figures were seen in the SGC-cells up to the 8-day stage. The synapses to the principal neurons were mainly axo-somatic. There were only a few synapses present in the newborn, but their number greatly increased during development. It appeared as if the accumulation of synaptic vesicles preceded or appeared simultaneously with the formation of the pre-and post-synaptic membrane thickenings. Synapses to the SGC-cells were few in all the age groups studied.
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  • 57
    ISSN: 1432-0568
    Keywords: Placenta ; Villous surface ; Development ; Morphometry ; Bos taurus ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Wachstum der Zottenoberfläche wurde an Placenten des Rindes und des Menschen morphometrisch untersucht. Während der zweiten Hälfte der Gravidität wächst nach unseren Befunden die Zottenoberfläche in der Weise, daß die Quadratwurzel aus der Zottenoberfläche annähernd proportional bleibt zur Kubikwurzel aus dem Volumen von Fetus und Placenta. Aus dem Vergleich mit physiologischen Untersuchungen anderer Autoren ergibt sich, daß das Wachstum der Zottenoberfläche der Placenta wahrscheinlich parallel geht mit der Zunahme des Stoffwechselbedarfs von Fetus und Placenta. Daraus kann der Schluß gezogen werden, daß, zumindest während der zweiten Hälfte der Gravidität, einem gegebenen Volumen von Fetus und Placenta jeweils eine Zottenoberfläche von optimaler Größe für den Stoffaustausch zur Verfügung steht.
    Notes: Summary The growth of the placental villous surface was investigated morphometrically in placentas of bos taurus and man. The results show, that during the second half of pregnancy the placental villous surface grows in such a way that the square-root of the villous surface remains proportional to the cube-root of the volume of fetus and placenta. Comparison with physiological investigations of other authors shows that the placental villous surface grows probably in parallel with the increase of energy consumption of fetus and placenta. From this we can conclude that at least during the second half of pregnancy a given volume of fetus and placenta has always an optimal size of villous surface for metabolic exchange at its disposal.
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  • 58
    ISSN: 1432-0568
    Keywords: Development ; Nervous system ; Mauthner cell ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Mauthner cell can first be recognized in Xenopus embryos at stage 31+–32 by its position and by the size of its nucleus and nucleolus. At early stages the perikaryon is dominated by a large ellipsoidal nucleus containing a single relatively compact nucleolus. The cytoplasm is characterized by numerous free ribosomes, poorly developed membrane systems, yolk platelets and globules, and by the presence of dense bodies containing what appear to be remnants of yolk breakdown. During subsequent development, membranes of both the endoplasmic reticulum and the Golgi apparatus become increasingly numerous. Long sinuous tubules of the endoplasmic reticulum are replaced by shorter repeatedly branching cisterns, and incidents of fusion between these elements and the nuclear envelope are less frequent. Large intramitochondrial granules and yolk elements are seldom encountered. The number of multivesicular bodies, alveolate vesicles and small secondary lysosomes increases. The originally nearly homogeneous cytoplasm is rearranged into areas rich in ribosomes and membranous organelles separated by channels containing predominantly neurofilaments and microtubules. At intermediate stages of development a cytoplasmic inclusion consisting of short arcs of parallel beaded strands, each 130–150 Å in diameter, is often present. The relationship of these morphological changes to the overall synthetic pattern of the cell is discussed. It is suggested that they signal the end of “seeking” growth by the cell.
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  • 59
    ISSN: 1432-0568
    Keywords: Development ; Chick ; Notochord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The author examines by means of ultrastructural, histochemical and autoradiographic techniques the development of the notochord of the chick embryo in the period between Hamburger-Hamilton's Stages 9 and 26. The interest in this research is that, during this period, the notochord is transformed from an apparently undifferentiated organ into an organ with secretory activity, and at the same time becomes an inductive organ in the development of the axial skeleton. The study shows that, starting from Stage 10, the notochord cells become hypertrophic and acquire the characteristics of secretory elements, with the production of chondroitin sulphate (A and/or C) and probably of collagen microfibrils. Such substances not only cluster densely around the notochord, thus contributing to the formation of the perichordal sheath, but they also diffuse outwards, becoming distributed among the sclerotomic cells; the latter, on the other hand, start to differentiate into cartilaginous cells only after the halo deriving from the notochord has enlarged and diffused among them. It is also pointed out that there is a close temporal connection between the high degree of secretory activity of the notochord and the start of its inductive activity on the sclerotomes.
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  • 60
    ISSN: 1432-0568
    Keywords: Synapse formation ; Development ; Migration ; Maturation ; Stellate cells ; Basket cells ; Neuroglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Foci of undescended and arrested granule cells occur beneath the pial surface in the normal cerebellar cortex. The dendrites of the cells participate in synaptic glomeruli with mossy fibers and axons of stellate or basket cells that have been isolated in the foci. Thus, ectopic masses of granular layer are present at these sites in the molecular layer. These granule cells are probably among the last cells to proliferate in the external granular layer. It is proposed that because they may have been late in this phase of their development they were arrested prior to or during migration. Maturation and synapse formation, however, occur because of the arrival of mossy fibers from the internal granular layer. These observations exemplify the specificity of neuronal interaction during development. In addition, the data suggest that neurons may mature and form synapses with their proper partners despite having missed the migratory phase imposed on similar neurons in the normal state.
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  • 61
    ISSN: 1432-0568
    Keywords: Cortex ; Development ; Columns
    Source: Springer Online Journal Archives 1860-2000