Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Intussusceptive arborization contributes to vascular tree formation in the chick chorio-allantoic membrane (2000)
    Springer
    Anatomy and embryology 202 (2000), S. 347-357 
    Details
    ISSN: 1432-0568
    Keywords: Key words Intussusceptive angiogenesis ; Intussusceptive microvascular growth ; Intussusceptive arborization ; Chorio-allantoic membrane ; CAM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Various reports indicate that the process of intussusceptive microvascular growth (IMG) plays a crucial role in capillary network formation of the chorio-allantoic membrane (CAM). In the present study we demonstrate by methylmethacrylate (Mercox) casting and in vivo time-lapse observations that intussusception, i.e. insertion of transcapillary tissue pillars, is also strongly involved in vascular tree formation, a process we refer to as intussusceptive arborization (IAR). From day 7 to day 14 of incubation, several arterial and venous branching generations arise from the capillary plexus. The process is initiated by pillar formation in rows, which are demarcating future large vessels in the capillary meshwork. In a subsequent step the pillars undergo reshaping to form narrow tissue septa that successively merge, which results in the production of new generations of blood vessels. This is followed by growth and maturation of all vascular components. The process of IAR in the CAM is very active at days 10 and 11 of incubation and takes place in preferentially perfused capillary regions determining ”dynamic areas”. The process of intussusception may be preceded by endothelial division, but the transcapillary pillar formation itself occurs primarily by rearrangement and attenuation of the endothelial cells without local endothelial cell proliferation. We conclude that after the early sprouting phase, the process of intussusception is the basic mechanism of CAM vascularization. It leads to capillary network growth and expansion (IMG) and, at the same time to feed vessel formation with several branching generations (IAR).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290000126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Evidence for intussusceptive capillary growth in the chicken chorio-allantoic membrane (CAM) (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 121-130 
    Details
    ISSN: 1432-0568
    Keywords: Chorio-allantoic membrane ; Capillary growth ; Development ; Endothelial cell ; Microcirculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of our investigations was to test whether the chicken chorio-allantoic membrane (CAM) could be an adequate in vivo model for a new mode of capillary growth, originally described in the rat lung and termed intussusceptive microvascular growth. According to that concept the capillary system does not grow by sprouting of vessels, but expands by insertion of transcapillary tissue pillars or posts which form new intercapillary meshes. In the present study, we observed slender transcapillary tissue pillars with diameters around 1 μm in the CAM by in vivo microscopy, and analyzed their ultrastructure by transmission electron microscopic investigation of serial sections. The pillars corresponded in size to those previously described in rat lung microvasculature. On day 7, the pillar core contained endothelial-, endothelial-like cells and collagen fibers, and on day 12 additionally chorionic epithelial cells. As a hypothesis we propose that slender cytoplasmic extensions of endothelial cells, heavily interdigitated in the post area and often projecting into the vascular lumen, could initiate the first step of pillar formation, i.e., interconnect opposite capillary walls. During both stages of development endothelial-like cells were observed in close relationship with the pillars. These cells seem to be relevant for tissue post completion and growth, as they were found to invade the core of the pillars. From the localization of the interendothelial junctions in the post region, a certain similarity to the concept proposed for the lung can be found. The observations confirm that the CAM is a very suitable material for the in vivo investigation of intussusceptive capillary growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171743
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Immunostaining of a heterodimeric dermatan sulphate proteoglycan is correlated with smooth muscles and some basement membranes (1995)
    Springer
    Histochemistry and cell biology 103 (1995), S. 271-279 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A heterodimeric 760-kDa dermatan sulphate proteoglycan tentatively named PG-760 was characterized as a product of keratinocytes, endothelial cells, and fibroblasts. The two core proteins of 460 kDa and 300 kDa are linked by disulphide bridges, and both carry one or only very few dermatan sulphate chains. Different antisera against PG-760 were used in the present study to investigate the distribution in selected murine tissues by light and electron microscopy. PG-760 immunostaining was observed in cornea (epithelium including basement membrane, stroma, and Descemet's membrane), skin, mucosa of the small intestine, Engelbreth-Holm-swarm (EHS)-tumour (matrix and cells), and the smooth muscle layers of uterus, small intestine, and blood vessels. No staining was observed in capillaries, striated muscles, and liver parenchyma including the central vein. The expression of PG-760 in EHS-tumour was also demonstrated after extraction with 4M guanidine and partial purification by diethylaminoethyl (DEAE)-chromatography. We conclude that this novel proteoglycan exhibits a unique tissue distribution being a constituent of some but not all basement membranes, of some other extracellular matrices, and additionally, of all investigated smooth muscle layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01457411
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Absence of acid phosphatase activity in specific endothelial organelles (1969)
    Springer
    Histochemistry and cell biology 20 (1969), S. 143-149 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Endothelial specific organelles in the aorta and in the small pulmonary blood vessels were investigated by electron microscopy with respect to their acid phosphatase activity. As controls, acid phosphatase reactions performed on liver and lung tissue showed, as expected, positive results. Since the endothelial specific organelles were in each case free of reaction product, it was concluded that they do not have a lysosomal function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00268708
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Beeinflussung einer spezifischen cytoplasmatischen Organelle von Endothelzellen durch Adrenalin (1968)
    Springer
    Cell & tissue research 88 (1968), S. 426-440 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Blutgefäßendothelien der Wirbeltiere enthalten eine spezifische cytoplasmatische Organelle, der nach einer schon früher geäußerten Hypothese eine Funktion im Rahmen der Blutgerinnung zukommen könnte. Da Adrenalin fähig sein soll, aus der Aortenwand eine gerinnungsaktive Substanz freizusetzen, wurde in vitro an 5 Rattenaorten die Wirkung einer „physiologischen“ Adrenalinlösung auf die endothelspezifische Organelle geprüft. Als Kontrolle dienten direkt fixierte, sowie in Ringerlösung inkubierte Aortenringe des gleichen Tieres. Die durch die Inkubation hervorgerufenen morphologischen Veränderungen der Gefäßintima werden beschrieben und besprochen. Mit stereologischen Methoden wurde die Volumendichte der Endothelkörperchen in den Kontroll- und Testgruppen ermittelt und miteinander verglichen. Adrenalin vermag binnen 20 sec die Volumendichte der Organellen in Endothelcytoplasma auf ca. 60% des Kontrollwertes zu verringern. Diese Abnahme ist statistisch signifikant (P 〈 0,001). Die oft beobachteten engen topographischen Beziehungen der Organellen mit der Zellmembran lassen an eine Stoffabgabe ins Gefäßlumen denken. Die Resultate stützen die Hypothese, daß diese Organellen eine von verschiedenen Seiten postulierte, gerinnungsaktive Substanz enthalten könnten.
    Notes: Summary Endothelial cells of vertebrate blood vessels contain specific cytoplasmic organelles, distinguishable from other dense bodies by their rod shape and internal tubular substructure. The following observations led to the hypothesis that these organelles could correspond to a procoagulative substance previously observed in arterial walls. a) These organelles have some resemblance to α-granules of thrombocytes which proved to be procoagulative elements. b) Intima and endothelium of human aorta contain thromboplastic substances. c) Large blood vessels contain more organelles, a fact which could be explained as an indication of their blood-directed function. d) The epinephrine perfused rabbit aorta delivers a coagulation activating substance into the perfusate. To check this hypothesis strips of aortic wall of five rats were incubated in 0.5 μg-% epinephrine solution for 20 sec and as controls in Ringer solution. By comparison some material was directly fixed by immersion in 1% OsO4. The volume-density of organelles in endothelial cytoplasm was determined by means of stereologic methods. On the average the volume-density decreased from 0.93% in immediatly fixed, to 0.83% in Ringer incubated, and to 0.53% in epinephrine incubated tissue samples. The diminution after Ringer incubation can be explained by swelling of cytoplasm. The loss of some 40% of organelles between Ringer and epinephrine incubated material is statistically highly significant. Evidence is presented that the organelles are expulsed towards the vessel lumen. These results give support to the hypothesis that these organelles could contain a procoagulative substance of aortic endothelium postulated by several authors. Further experiments are needed to prove this relationship.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00540670
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The postnatal growth of the rat lung.This study was supported by grants 3.5.68 and 3.682.71 from the Swiss National Science Foundation. I. Morphometry (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 178 (1974), S. 711-730 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The postnatal growth of the lung was quantitatively investigated in rats aged 1, 4, 7, 10, 13, 21, 44 and 131 days by light and electron microscopic morphometry.Lung volume (VL) increased first directly with body weight (W). After day 10 VL followed the function W0.70. Based on the quantitative findings the postnatal lung growth could be divided into three phases.1Lung expansion (up to day 4): Lung volume increase resulted almost exclusively from an 87% enlargement of the existing air spaces.2Tissue proliferation (day 4 to 13): All tissue compartments showed a pronounced mass increase, followed by a high gain in capillary volume. Alveolar and capillary surface areas (Sa, Sc) developed rapidly due to subdivision of the primitive air sacs.3Equilibrated growth (third week to adult age): An initial period of redistribution of tissue mass with septal lengthening and further rapid increase in Sa and Sc was followed by proportionate alveolar growth. In the adult further lengthening of the interalveolar septa or continued alveolar formation could not be excluded.During the period of fundamental internal remodelling of the lung, its function, as determined by the morphometric pulmonary diffusing capacity, was not impaired.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091780405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A novel mechanism of capillary growth in the rat pulmonary microcirculation (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 228 (1990), S. 35-45 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Postnatally, the rat lung parenchyma undergoes impressive growth. Within four months of birth, lung volume and alveolar and capillary surface areas increase over 20-fold and capillary volume 35-fold. Investigation of methacrylate casts of the pulmonary microvasculature revealed that, with age, lung capillaries were not only growing in surface and volume but also increasing their network density. We proposed that the capillary bed grows by formation of slender intravascular tissue pillars and termed this type of growth intussusceptive microvascular growth (Caduff et al., Anat. Rec., 216:154-164, 1986). The aim of this investigation was to detect the presence and to analyze the ultrastructure of slender tissue posts (diameter 1-2.5 μm) extending across the capillary lumina in serial electron microscopic sections of rat lung parenchyma (age 44 days). Computer-assisted three-dimensional reconstruction of the capillary lumen confirmed that tissue posts were matching the holes previously observed in casts. Post ultrastructure varied with size from a simple area of interendothelial contact to tissue pillars with a core of interstitial tissue. Based on the changing morphology of the pillars, a hypothesis for their development can be proposed: phase I, creation of a zone of contact between opposite capillary walls (formation of an interendothelial bridge); phase II, reorganization of the intercellular junctions of the endothelium, with central perforation of the capillary layer; phase III, formation of an interstitial post core, with successive invasion by cytoplasmic extensions of myofibro-blasts, pericytes, and finally interstitial fibers; and phase IV, growth of the slender pillar to a normal full size capillary mesh. These findings support the new concept of intussusceptive growth of the lung capillary system.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092280107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The postnatal growth of the rat lung III. MorphologyThis study was supported by grants 3.5.68 and 3.682.71 from the Swiss National Science Foundation. (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 77-98 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In order to investigate the postnatal growth of the gas exchange apparatus, the lungs of rats aged 1, 4, 7, 10, 13, and 21 days were fixed by intra-tracheal instillation of glutaraldehyde. The analysis and interpretation of the morphological changes observed by light and electron microscopy were based on the results of previous morphometric and autoradiographic studies performed on the same material.The newborn rat has no alveoli, but breathes with smooth walled air channels and saccules, which correspond to the prospective alveolar ducts and alveolar sacs, respectively. The bulk of alveoli are formed between days 4 and 13 by a rapid outgrowth of secondary septa from the primary septa present at birth. The arrangement of elastic fibers during this period suggests that these may play a role in septal outgrowth. Based on ultrastructural observations a model is described for the capillarisation of the secondary septa. Some evidence is given that alveoli may also be formed by outpouchings in the walls of terminal bronchioles.Primary and secondary septa have initially an immature appearance. They both show an apparently double capillary network, whereas the mature interalveolar septum is just wide enough to accommodate a single capillary. Possible mechanisms for this structural transformation which occurs within three weeks after birth are discussed.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091800109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The postnatal growth of the rat lung II. AutoradiographyThis study was supported by grants from the Council for Tobacco Research U.S.A. and from the Swiss National Science Foundation 3.5.68 and 3.682.71. (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 63-76 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Combined morphometric and autoradiographic methods were used to analyze the postnatal growth of rat lung from 1-21 days after birth. Each cell population had distinct growth patterns with an increase in the number of fibroblasts and capillary endothelial cells largely determining the increase in interstitial volume and capillary surface, respectively. The height of proliferation activity in mesodermally-derived cells was concurrent with the outgrowth of secondary alveolar septa (between days 4 and 13). Analysis of the location of labeled cells on day 7 showed that the higher labeling index on septal crests could be ascribed to the proliferative activity of fibroblasts and endothelial cells.Within the alveolar epithelium only the type II alveolar cells had a detectable labeling index. Over the first week, the number of type I epithelial cells steadily increased while the number of type II cells remained constant. Subsequently the number of type II cells increased rapidly, reached a peak on day 13 and then decreased, whereas type I cells continued to increase in number. These facts led us to consider that type II epithelial cells may represent the stem cell population of alveolar epithelium. The height of proliferative activity of type II cells on day 7 coincided with the outgrowth of septal crests and was followed by the steepest increase in number of type I and II cells.Between the 10th and 21st day labeling indices rapidly declined, cell production became undetectable after day 13. Increase in alveolar and capillary surface area however continued, resulting in a thinning of the interstitial layer and of the epithelial and endothelial sheets.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091800108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Structural analysis of fetal rat lung development (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 234 (1992), S. 399-418 
    Details
    ISSN: 0003-276X
    Keywords: Lung development ; Lung compartments ; Lung parenchyma ; Airways ; Pulmonary vasculature ; Cellular differentiation ; Morphometry ; Reference space ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The primary aim of this morphological investigation was to elaborate a concept allowing us to coherently define reference spaces for morphometric analysis of fetal lung development. Beyond this quantitative goal, morphological analysis of cell types, definition of compartments, and reflection about the prospective fate of their constitutents provided per se new insights into the developmental processes.Lungs of rat fetuses aged 17-23 days and newborns aged 20 hours were fixed with an osmium tetroxide and glutaraldehyde mixture and their volume determined. Left lungs were embedded in Epon and investigated by light and electron microscopy. The right lung of one animal per group was embedded in methacrylate and step sections obtained to precisely locate the airways within the mesenchyme.The various cell types, their topographical relationships, and their morphological alterations with ongoing development were analyzed with regard to their prospective potentials of differentiation.The developing lung could be partitioned into four zones further subdivided into defined compartments. Zone I forms a superficial mantle around the lobes and the future acini. Consisting of primitive mesenchymal cells, it represents a zone of growth which disappears with the onset of the saccular stage. Zone II is mainly a zone of differentiation. Its interstitium stains intensely due to a dense population of dark cells. Up to gestational day 19, zone II contains future conductive airways with their vessels. After day 21, it comprises the whole prospective gas exchange region. Zones III and IV contain the elements of the airway tree and vascular system, zone IV corresponding to the most proximal generations with an adventitial layer. For all differentiation processes, a centrifugal directionality is manifested.© Willey-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092340310
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...