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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The application of a monoclonal antibody to bromodeoxyuridine (BUdR) provides a rapid, reproducible, nontoxic, immunohistochemical method to measure cellular kinetics of intracerebral tumor angiogenesis. The rabbit brain tumor model of angiogenesis consists of tumor and endothelial cell populations with high proliferative rates that demonstrate the close interdependence between microvascular and neoplastic growths as well as topographic gradients, heterogeneity, and regional microdomains of cell proliferation. The labeling index (LI) of endothelial cells was 25.8% at the tumor periphery, compared to 1.7% in the tumor center (P less than 0.001). Concomitant with an increased turnover of neoplastic cells at the tumor periphery. LI was 26.6% with a LI of 7.7% in the center (P less than 0.01). Furthermore, labeled tumor cells tended to be organized around proliferating capillaries, with less DNA synthesis farther from the nearest blood vessel. The established normal microvessels of the brain, e.g., in the opposite tumor-free hemisphere, were mitotically inactive with a LI of less than 0.001%. Quantitation of vascular cytokinetics should be useful in further studies of the pathophysiology of brain tumor angiogenesis and the development of pharmacological approaches directed toward the microvasculature.
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PMID:Rapid in situ cellular kinetics of intracerebral tumor angiogenesis using a monoclonal antibody to bromodeoxyuridine. 247 79

In recent years, tumor-related angiogenesis has become an important field of research in oncology. It could be stated that growth of solid tumors is completely dependent on neovascularization to provide the tumor with all required nutrients. Special compounds (tumor angiogenesis factor[s]) are released by tumor cells into the environment to stimulate different types of normal cells to become active for the tumor. In particular, endothelial cells of neighboring capillaries are induced to react. They disintegrate their own basal lamina, detach from their neighbors, enter the extracellular matrix, and migrate toward the tumor mass. Cell divisions occur within such sprouts, thereby increasing the number of migrating endothelial cells. Strands of such cells are formed, and inter- and intracellular lumina develop. Loops of these hollow strands anastomose to form a network of new vessels which become connected with the blood circulation. The tumor mass thus becomes vascularized and can continue to grow. The prevention of neoangiogenesis has an enormous impact on cancer treatment by inhibiting the growth of the tumor. In this review, all important aspects of tumor-related angiogenesis are presented.
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PMID:Tumor-related angiogenesis. 248 Jan 45

Relation of tumor-associated macrophages to tumor neovascularization in murine transplanted tumor, sarcoma 180(S180), was quantitatively analysed in situ on days 3, 6 and 9 after tumor implantation. Infiltrating macrophages in tumor were identified in paraffin section by alpha-naphthyl butyrate esterase stain and subdivided by electron microscopy according to the peroxidase activity. Simultaneously, the structure of newly formed microvessels was quantitated under light microscope by stereological morphometry. The results showed that, as the tumor grew and blood vessels proliferated, the number of infiltrating macrophages in tumor increased obviously but the ratio of peroxidase (PO) positive mononuclear phagocytes tended to decrease in contrast to the increase of PO-negative phagocytes. Microvasculature volume was found to be positively correlated to the proportion of PO-negative macrophages but negatively correlated to the proportion of PO-positive mononuclear phagocytes. It was indicated that tumor angiogenesis was related to the mature macrophages in the tumor.
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PMID:[Tumor-associated macrophages in tumor neovascularization--in situ ultrastructural cytochemical and quantitative study]. 248 37

We examined the effect of medroxyprogesterone acetate (MPA) on secondary spreading of endometrial cancer. There was no significant difference in the adhering capacity of dispersed Ishikawa cells (derived from well-differentiated endometrial cancer) to a cell basement membrane matrix, fibronectin or laminin between cells treated with MPA, with cortisol, and without treatment. The adhering capacity of cells treated with cortisol to collagen type IV was higher than that without treatment. However, the adhering capacity was little affected by treatment with MPA. These results indicate that although cortisol may induce the initial process of metastasis by inducing the attachment of tumor cells to the basement membrane of vascular endothelium, MPA has no influence on the attachment, although it has a glucocorticoid action similar to that of cortisol. There was no significant difference in tumor angiogenesis factor (TAF) or fibroblast growth factor (FGF) activity of the tumor extract from Ishikawa cell colonies between cortisol-treated and control group. TAF or FGF activity of the MPA-treated group was lower than that of the control group. MPA may reduce the neovascularization in the terminal process of metastasis via the reduction of TAF and FGF produced by tumor cells, in spite of its glucocorticoid action.
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PMID:Effect of medroxyprogesterone acetate on secondary spreading of endometrial cancer. 252 39

In order to investigate the production of PGE2 and its' function in human hepatocellular carcinoma, the effects of indomethacin and PGE2 on tumor growth were examined using in vivo and in vitro techniques. HH2-6 cells produced PGE2 in the culture media, and the inverse relationship was observed in between the cell proliferation and the culture supernatant PGE2 levels. While in vivo, plasma and tumor tissue PGE2 levels of tumor bearing nude mice were significantly increased for 1 or 2 weeks after tumor inoculation. In the case of which indomethacin was injected daily into the abdominal cavity (4 mg/kg body weight), the elevation of plasma and tissue PGE2 levels was remarkably suppressed, and the latent time of tumor growth was also prolonged. On the other hand, another case of which PGE2 was injected (10 micrograms or 0.1 microgram i.p.) at first 10 days revealed shortened latent time. These results indicate the intimate relation between PGE2 and latent time on tumor growth. Furthermore, histological findings suggest that tumor derived PGE2 might play an important role in tumor angiogenesis.
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PMID:[In vivo and in vitro studies on PGE2 production and function in human hepatocellular carcinoma]. 254 95

This report provides fine structural evidence that, dependent upon the malignancy, tumor as well as mesenchymal cells may participate actively in the neovascularization of experimental tumors grown in transparent tissue chambers implanted into skinfolds of syrian hamsters. Such non-endothelial cells may help to promote angiogenesis in two different ways: (1) They are incorporated into capillary sprouts thereby accelerating the growth rate of the latter independent of endothelial cell proliferation. (2) Extravascular cells (tumor and mesenchymal elements) become integrated in varying numbers into the linings of comparatively large blood-perfused vessels. This facilitates the rapid establishment and functional remodelling of the microvascular bed to adapt the microcirculation to the varying local demands of the growing tumor. If these results can be confirmed for other tumors, and if they are independent of the tumor's environment and the experimental protocol, then we will have to reconsider the significance of tumor angiogenesis as a realistic biological model from which general conclusions with regard to neovascularization in non-tumorous tissues may be drawn.
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PMID:The fine structure of tumor blood vessels. I. Participation of non-endothelial cells in tumor angiogenesis. 258 Aug 10

Cancer cells are able to produce tumor angiogenesis factors (TAF), by which the tumor growth could be maintained. Angiogenetic activity of 12 kinds of cells and tissues with distinct character from different sources were detected by chick embryo chorioallantoic membrane. The results indicated that all the cells and tissues tested showed angiogenetic activity but they differed from one another, some were strong and other weak. Of them, the breast cancer was the strongest. The ascitic tumor didn't show any angiogenetic activity, but it reappeared when the ascitic cells were transformed to solid tumors. The level of angiogenetic activity of tumors was closely related to their biological properties and form of existence.
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PMID:[Angiogenesis activity of tissues and cells of different malignancies]. 261 26

The amino acid sequence and disulfide bond pairing of human tumor derived angiogenin, the first tumor angiogenesis factor to be isolated in pure form from human sources, have been determined by conventional sequencing techniques adapted and applied to nanomole and subnanomole levels of material. Angiogenin, obtained from conditioned media of a human colonic adenocarcinoma cell line, is a single-chain protein consisting of 123 amino acids with the following sequences: less than Glu1-Asp-Asn-Ser-Arg-Tyr-Thr-His- Phe-Leu-Thr-Gln-His-Tyr-Asp15-Ala-Lys-Pro-Gln-Gly-Arg-Asp-Asp- Arg-Tyr-Cys-Glu-Ser-Ile-Met30- Arg-Arg-Arg-Gly-Leu-Thr-Ser-Pro-Cys-Lys-Asp-Ile-Asn-Thr- Phe45-Ile-His-Gly-Asn-Lys-Arg-Ser -Ile-Lys-Ala-Ile-Cys-Glu-Asn-Lys60-Asn-Gly-Asn-Pro-His-Arg-Glu-Asn -Leu-Arg-Ile -Ser-Lys-Ser-Ser75 -Phe-Gln-Val-Thr-Thr-Cys-Lys-Leu-His-Gly-Gly-Ser-Pro-Trp-Pro90-Pro -Cys-Gln-Tyr -Arg-Ala-Thr-Ala -Gly-Phe-Arg-Asn-Val-Val-Val105-Ala-Cys-Glu-Asn-Gly-Leu-Pro-Val- His-Leu-Asp-Gln-Ser-Ile-Phe120-Arg-Arg-Pro123-OH. Three disulfide bonds link the half-cystinyl residues 26-81, 39-92, and 57-107. The sequence is homologous to that of the pancreatic ribonucleases with 35% identity and many of the remaining residues conservatively replaced. Similarities are especially apparent around the major active-site residues His-12, Lys-41, and His-119 of ribonuclease which are conserved as are three of the four disulfide bonds.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Amino acid sequence of human tumor derived angiogenin. 286 94

The immunohistochemistry of the epidermal growth factor receptor (EGFR) was studied with monoclonal antibodies in 12 meningiomas of various histologic subtypes, nine benign and three malignant. Strong immunoreactivity of EGFR epitopes was found in the endothelia of the tumor vasculature in six cases. A much weaker reaction was detected within tumor cells in six cases, in one of which it was diffuse and five focal. No correlation was established between the presence of EGFR epitopes and the histologic type or biologic behavior of the meningiomas. The results suggest that the EGFR may participate in tumor angiogenesis, but its role in the growth of neoplastic meningioma cells remains elusive.
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PMID:Epidermal growth factor receptor in meningiomas is expressed predominantly on endothelial cells. 305 82

We have studied biologically active substances, tumor angiogenesis factors (TAF), which are supposed to be associated with the proliferation and metastases of choriocarcinoma cells. Eight human choriocarcinoma cell lines were used in the present study. TAF activity was assayed by bioassays using BALB/c mice subcutaneous tissue, chicken chorioallantoic membrane (CAM) and rabbit cornea in vivo and by proliferation of endothelial cells in vitro. 1. We found a positive correlation between the size of tumors developed in xenotransplantation and the number of blood vessels in the tumor tissues. A correlation between the number of blood vessels and TAF activity was also found. 2. With a gel-filtration method, TAF activity was observed in the common fractions in every cell line. The molecular weight of TAF was more than 10,000 daltons. 3. There was a heterogeneity of TAF activity among the cell lines. From these results, it appears that TAF initiates the choriocarcinoma cell-proliferation.
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PMID:[Fundamental studies on tumor angiogenesis factors with a choriocarcinoma model]. 342 90


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