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At least 19 recordsLinked to original sources
PubMed1995

Endogenous basic fibroblast growth factor is implicated in the vascularization of the chick embryo chorioallantoic membrane.

Chorioallantoic membrane (CAM) and chorioallantoic fluid (CAF) of the chick embryo were studied for the presence of immunoreactive and biologically active basic fibroblast growth factor (bFGF) from Day 6 to Day 18 of incubation. An immunoreactive M(r) 16,000 bFGF-like molecule was detected both in CAM and in CAF. This molecule was identified as bFGF on the basis of its molecular weight, its affinity for heparin, and its capacity to induce plasminogen activator production in cultured endothelial GM 7373 cells. The levels of biologically active and immunoreactive bFGF vary in CAM and CAF during embryonic development, maximal concentrations being observed between Days 10 and 14 of incubation. At all time points investigated, absolute concentrations of bFGF were significantly higher in CAM (ranging from 25 to 183 ng/g of wet tissue) than in CAF (ranging from 0.2 to 4 ng/ml). In a parallel series of experiments performed at Day 8 and evaluated at Day 12 of chick embryo development, human recombinant bFGF and neutralizing anti-bFGF antibody were investigated for their capacity to affect the vasoproliferative processes of the CAM. The two molecules either were applied onto the surface of the CAM or were injected into the allantoic sac. When bFGF or anti-bFGF antibodies were absorbed on methylcellulose discs and applied on the top of the CAM, they exerted a strong angiogenic or anti-angiogenic effect, respectively. On the contrary, when bFGF or the corresponding neutralizing antibody was injected into the allantoic sac, no modifications of the vasoproliferative processes of the CAM were observed at either the macroscopic or the microscopic level. These results provide evidence indicating that endogenous bFGF has a rate-limiting role in the vascularization of the CAM during chick embryogenesis. bFGF located within the CAM, rather than that present in the CAF, appears to be involved in this developmental process.

Allantois↗
PubMed1980

Initial SEM observations of Herpes simplex virus infected chicken chorioallantoic membranes.

Chorioallantoic membranes (CAMs) of 10 day old embryonated chicken eggs were experimentally infected with types 1 and 2 Herpes simplex virus (HSV) and observed by scanning electron microscopy. This preliminary report examined CAMs at time periods ranging from 30 minutes to 24 hours post-infection. Samples also were taken for transmission electron microscopy to correlate topographic alterations with ultrastructural changes. Uninfected control CAMs, throughout the study, consisted of a homogeneous population of flattened chorionic ectodermal cells whose surface were covered with uniformly distributed microvilli of varying lengths and fairly constant diameter. At thirty minutes post infection, irrespective of infecting herpes type, microvilli were markedly decreased in numbers with those remaining showing noted blunting. Later stages of infection with type 1 HSV strains showed a cytopathic process consisting of a generalized rounding of individual cells and the presence of cells apparently containing multilobulated nuclei. CAMs infected with type 2 strains demonstrated a more focal spread of infection and the presence of intranuclear filamentous structures by transmission electron microscopy.

Allantois↗
PubMed2004

Irritative effects of some pesticides and a technical component on tissue structure of the chorioallantoic membrane.

The chorioallantoic membrane (CAM) is a complete tissue that responds to injury with a complete inflammatory reaction, this process similar to that induced by chemicals in the conjunctival tissue of the rabbit eye. During the study chemicals are placed directly onto the chorioallantoic membrane and the occurrence of vascular injury or coagulation in response to a compound is as an indication of the potential of a chemical to damage mucous membranes. In our study irritant pesticides (Fusilade S, Karathane LC) and a technical pesticide component (Trend) were tested and their effects on the tissue structures of CAM were examined. After treatment with the test materials, first lysis and then haemorrhage were observed macroscopically on CAM. In histological pictures stained with H-E the rupture of the blood vessel wall was seen and blood was observed around the blood vessels in the middle layer. The histological findings correlated well with the macroscopic appearance in this study. In general a good correlation was found between the HET-CAM results and reported data from Draize test. The subjective nature of the evaluation is reduced through the histological examination of treated CAM. The HET-CAM test can be a useful component of a battery of tests needed for replacing the Draize rabbit eye irritation test.

Allantois↗
PubMed1987

Mechanism and regulation of calcium transport by the chick embryonic chorioallantoic membrane.

The chorioallantoic membrane (CAM) is the tissue responsible for translocating eggshell calcium into the circulation of the developing chick embryo. Calcium transport by the CAM is highly specific and is expressed as a function of development. We review here first our recent studies on three previously identified, putative components of the CAM calcium transport pathway: a calcium-binding protein (CaBP), a Ca2+-ATPase, and carbonic anhydrase. Using in vivo and in vitro procedures to measure CAM calcium uptake, we have shown that all three components are indeed functionally involved. Based on these results, an "endocytosis mechanism" is postulated for CAM calcium transport. In this mechanistic model, the CaBP serves as the cell surface "calcium-binding receptor" and the Ca2+-ATPase pumps calcium into endosomes. In addition, we summarize here results showing that the expression of calcium transport activity and of functional CaBP in the CAM both require the proximity of the eggshell, the transport substrate, and depend on proper embryonic vitamin K metabolism. We have also initiated a study of the molecular aspects of CaBP expression by cloning a cDNA to CaBP mRNA. Finally, our recent data show that vitamin D may be involved in chick embryonic calcium metabolism by regulating the mobilization of yolk calcium.

Allantois↗
PubMed1992

The human carotid atherosclerotic plaque stimulates angiogenesis on the chick chorioallantoic membrane.

The chick chorioallantoic membrane was used to determine whether the carotid atherosclerotic plaque stimulates angiogenesis. Carotid endarterectomy specimens (1 mm3) with fibromuscular plaque (n = 8) and complicated plaque (n = 11) were implanted on the membrane on day nine of incubation and the response evaluated on day 11. Following fixation in situ with 10% formalin the angiogenic response was evaluated by: (1) examining whole membrane mounts, (2) quantitatively from a vascular density index and (3) from a histological study. Unmanipulated chorioallantoic membrane (n = 11) and plaque boiled prior to implantation (n = 6) served as controls. The vascularity of whole mounts of both fibromuscular and complicated plaque was greater than the controls. Vessel density of the membrane was estimated by counting the number of vessels intersecting four concentric circles (144.5 mm total circumference) placed on the formalin fixed membrane. The vascular density index due to the fibromuscular plaque (390.6 +/- 8.3) and complicated plaque (391.0 +/- 14.9) were similar (P greater than 0.9) but were significantly greater (P less than 0.001) than the unmanipulated membrane (327.9 +/- 5.6) or after treatment with the boiled plaque (283.8 +/- 15.6). Transforming growth factor beta 1 confirmed the validity of the experimental model to study angiogenesis. The histology of the chorioallantoic membrane due to either type of plaque was similar. Numerous vessels surrounded the plaque, and intraplaque vessels containing nucleated chick erythrocytes were observed. Although scattered vessels surrounded the boiled plaque, intraplaque vessels were not observed. This study demonstrates that the atherosclerotic plaque has angiogenic properties that may account for the increase in vasa vasorum that is associated with the plaque.

Allantois↗
PubMed1976

Energy-dependent Mn2+ and Ca2+ uptake by the embryonic chick chorioallantoic membrane.

The chick chorioallantoic membrane is an epithelial tissue which actively transports large amounts of Ca2+ during embryonic development. In this paper Mn2+ uptake by the tissue was studied and compared to Ca2+ uptake in parallel experiments. The purpose of these experiments was to determine if Mn2+ could be used to gain more information about the Ca2+ transport system. It was found that Mn2+ uptake was reduced significantly under conditions that reduced Ca2+ uptake and that Mn2+, like Ca2+, was taken up preferentially by the ectodermal side of the tissue. Mn2+ uptake showed saturation kinetics with a Km of 0.33 MM. Mn2+ uptake was also competitively inhibited by Ca2+, and Ca2+ uptake inhibited by Mn2+. Electron microprobe studies showed that Mn2+ was localized in the ectoderm of the tissue in the same way as Ca2+. It was concluded from these studies that significant amounts of Mn2+ were accumulated by the active Ca2+ transport mechanism and that Mn2+ could be useful paramagnetic probe of divalent cation transport in this tissue.

Animals↗
PubMed1987

Induction of angiogenesis by mixtures of two angiogenic proteins, angiogenin and acidic fibroblast growth factor, in the chick chorioallantoic membrane.

The chick chorioallantoic membrane assay was employed to assess the angiogenic response induced by mixtures of human angiogenin with bovine heparin-binding acidic fibroblast growth factor. Statistical evaluation of data accumulated at several molar ratios of the two proteins indicate that the angiogenic activity observed is neither an additive nor a synergistic resultant of the activities of the proteins separately. The possibility exists, however, that at an approximately 1:1 mole ratio an apparent inhibitory effect can be observed. Mechanisms which could underlie such observed effects are discussed.

Allantois↗
PubMed1969

Morphogenesis of Newcastle disease virus in chorioallantoic membrane.

Chick embryo chorioallantoic membrane, infected with the Blacksburg strain of Newcastle disease virus, was examined with an electron microscope to investigate the sequence of viral-induced host cell alterations. These were evident mostly in the endodermal epithelial cells lining the allantoic sac and were divided arbitrarily into three stages. Stage 1 was characterized by commencement of cell hypertrophy and hyperplasia and presence of fewer cytoplasmic inclusion bodies normally found in the cells; in stage 2, juxtanuclear nucleocapsid-glycogen aggregates appeared, and there were increased numbers of microvilli; stage 3 was characterized by increased cytoplasmic density and evidence of viral assembly and release. The morphological features of viral assembly and the virion are also described.

Animals↗
PubMed1988

The two- and three-dimensional structure of the microcirculation of the chick chorioallantoic membrane.

The chick chorioallantoic membrane (CAM) is a common model for studying biological processes, but descriptions of the CAM circulatory system and especially experimental preparations of the CAM in shell-less eggs are both scant and controversial. We studied the CAM structure and the three-dimensional spatial configuration of the CAM vessels using five methods: in vivo stereoscopic observations, whole-mount preparations, histological sections, corrosion cast microinjection techniques, and the reconstruction of a three-dimensional wax model. Our findings show that the CAM consists of a superficial two-dimensional layer composed of a network of a very dense capillary mesh, floating over and enclosing a deeper three-dimensional space in which medium and larger free-floating vessels are seen to supply and drain the superficial layer. It is interesting to note that no tips or sprouts of blood vessels were observed during the development of the CAM vessels. In a shell-less egg preparation, the capillaries were found in the mesoderm layer of the CAM and not in or superficial to the ectoderm as is the case in the CAM of the intact egg which adheres to the shell membrane.

Allantois↗
PubMed2003

Use of adenovirus vectors for functional gene analysis in the chicken chorioallantoic membrane.

The chicken chorioallantoic membrane (CAM) assay represents one of the most widely used in vivo screening assay for genes with angiogenic (blood vessel-inducing) or angiostatic (inhibition of vessel formation or their destruction) activities. Here we show that adenovirus gene transfer vectors infect cells in the CAM and lead to expression of the viral transgene. Furthermore, infection with an adenovirus vector containing the human vascular endothelial growth factor gene induced the formation of new blood vessels. This improved method saves a considerable amount of time in the identification of genes that can influence blood vessel formation because the expensive and time-consuming production and purification of recombinant protein can be omitted.

Adenoviruses, Human↗
PubMed1978

Functional involvement of carbonic anhydrase in calcium transport of the chick chorioallantoic membrane.

Carbonic anhydrase activity was demonstrated in the chick-embryonic chorioallantoic membrane and was correlated with the Ca2+-transport activity of the membrane. It is inhibited by sulphonamides and is expressed in the chorioallantoic membrane in an age-dependent fashion during embryonic development. Ca2+ uptake by the chorioallantoic membrane in vivo also increases in a similar age-dependent manner. The temporal increase in these activities is coincident with calcium deposition in the embryonic skeleton. Incubation of the chorioallantoic membrane in ovo with sulphonamides specifically inhibits both the carbonic anhydrase and the Ca2+ uptake activities of the membrane in vivo. Enzyme histochemistry revealed the carbonic anhydrase activity is localized in the Ca2+-transporting ectodermal cells of the chorioallantoic membrane. These results, taken together, indicate that carbonic anhydrase may be functionally important in the Ca2+-transport activity of the chorioallantoic membrane.

Age Factors↗
PubMed1983

Selection of metastatic variants from heterogeneous tumor cell lines using the chicken chorioallantoic membrane and nude mouse.

The chicken chorioallantoic membrane was used to select variant tumor cell subpopulations from the murine melanoma B16-BL6 and the rat glioma C6 cell lines. Tumor cells were deposited on the chicken chorioallantoic membrane of eggs 10 days postfertilization. Upon hatching, chickens were autopsied, and organs were removed, minced, and implanted s.c. in C57BL/6J mice (for melanoma) or nude mice (for glioma). A glioma growing s.c. from a chicken lung implant metastasized to the liver of the recipient nude mouse, and a melanoma growing s.c. from a chicken liver implant metastasized to the lung of its murine host. The s.c. melanoma contained distinct black and gray areas. Cell lines were established from the s.c. glioma (C6-V-1), from a metastasis of the C6-V-1 tumor (C6-V-2), and from the black and gray regions of the melanoma. Marked differences in lung colonization were seen 14 days after 1 X 10(5) parent BL6, Black, or Gray cultured cells were injected by tail vein into C57BL mice. In four separate experiments, fewer than 15 lung foci per mouse were found when BL6 cells were injected, whereas 100 to several hundred lung melanoma colonies per mouse were observed when Black or Gray cells were inoculated. Four of 18 nude mice bearing the s.c. C6-V-1 glioma developed liver metastases; no metastases have been observed in 15 nude mice bearing the s.c. parent C6 glioma. Significant differences in sensitivities to antineoplastic drugs were demonstrated between parent and variant glioma cell lines. The 33-fold increase in sensitivity to vincristine determined for C6-V-1 cells compared to parent C6 cells was particularly striking. Results suggest that the use of the chicken chorioallantoic membrane in situ, together with the nude mouse, might provide a method suitable for the selection and isolation of aggressive variants in heterogeneous human tumors.

Allantoin↗
PubMed2004

Expression of calbindin-D28K by yolk sac and chorioallantoic membranes of the corn snake, Elaphe guttata.

The yolk splanchnopleure and chorioallantoic membrane of oviparous reptiles transport calcium from the yolk and eggshell to the developing embryo. Among oviparous amniotes, the mechanism of calcium mobilization to embryos has been studied only in domestic fowl, in which the mechanism of calcium transport of the yolk splanchnopleure differs from the chorioallantoic membrane. Transport of calcium is facilitated by calbindin-D(28K) in endodermal cells of the yolk splanchnopleure of chickens but the chorioallantoic membrane does not express calbindin-D(28K). We used immunoblotting to assay for calbindin-D(28K) expression in yolk splanchnopleure and chorioallantoic membrane of the corn snake, Elaphe guttata, to test the hypothesis that the mechanism of calcium transport by extraembryonic membranes of snakes is similar to birds. High calbindin-D(28K) expression was detected in samples of yolk splanchnopleure and chorioallantoic membrane during late embryonic stages. We conclude that calbindin-D(28K) is expressed in these extraembryonic membranes to facilitate transport of calcium and that the mechanism of calcium transport of the chorioallantoic membrane of the corn snake differs from that of the chicken. Further, we conclude that calbindin-D(28K) expression is developmentally regulated and increases during later embryonic stages in the corn snake.

Animals↗
PubMed1989

Antiangiogenic action of heparin plus cortisone is associated with decreased collagenous protein synthesis in the chick chorioallantoic membrane system.

In the chick chorioallantoic membrane system heparin plus cortisone caused a marked depression in the rate of collagenous protein biosynthesis in vivo during inhibition of angiogenesis. This suggests that monitoring the rate of collagenous protein biosynthesis in the chick chorioallantoic membrane system can be used as a quantitative method for evaluating angiogenesis inhibitors.

Allantois↗
PubMed1987

Response to antitumor agents of murine transplantable tumors implanted onto chorioallantoic membrane of chick embryo.

The chorioallantoic membrane of chick embryo was used to examine the chemosensitivity of the murine tumors, B16-F1 melanoma, B16-F10 melanoma, Meth-A fibrosarcoma, and Ehrlich carcinoma. The tumors were grown on the membrane, and the effects of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride, cyclophosphamide, dacarbazine, 5-fluorouracil, methotrexate, adriamycin, mitomycin C, vincristine, and cisplatin on the growth of the tumors were tested by iv injection into a vein of the chorioallantoic membrane or injection into the yolk sac. The use of chick embryo limits the time for drug exposure to 3 or 4 days, but Ehrlich carcinoma and Meth-A fibrosarcoma needed longer for the test; the use of irradiation from a cobalt source overcame the problem by increasing the growth rate of the grafts of these two tumors. There appeared to be a good correlation between the effects of the drugs on B16 melanomas grown in the eggs and in the original animals. Many compounds, including pro-drugs such as cyclophosphamide and dacarbazine, could be assayed in this way.

Allantois↗
PubMedDate not supplied

Metastatic potential of MDA435 and Hep2 cell lines in chorioallantoic membrane (CAM) model.

Chick embryo chorioallantoic membrane model is a very sensitive assay for studying metastasis in vivo. In this organism, tissue barriers provide a real support to demonstrate the infiltration pathway of two human tumoral cell stains: a line of breast adenocarcinoma (MDA435), and a line of larynx epidermoid carcinoma (Hep2). We studied the metastatic potential of these cells to migrate from the upper chorioallantoic membrane (CAM) to the lower CAM, using as marker a human p53 primer, known for flanking exclusively a human region of exon 8. Our results show that both cell lines possess the ability to migrate from the inoculation site (on the upper CAM) to distant sites of the CAM (lower CAM). A difference in the pattern of migration among the two cell lines was also observed. While Hep2 cells showed a uniform migration from the inoculation site, MDA435 cell line showed a different migration pattern consistent with the idea of two different populations within the same cell line.

Allantois↗