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Query: UMLS:C1658953 (tumor vasculature)
 2,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Of 190 sets selective celiac and/or hepatic angiograms obtained in patients with hepatocellular carcinoma (HCC), comparison with gross anatomy of the liver was subsequently made by autopsy in 77 and by surgery in 23. It was found that the gross anatomy of HCC can be assessed with certain accuracy by careful interpretation of the angiograms, because tumor vasculature and vascular alterations in the noncancerous parenchyma are closely related to the mode of tumor growth, size of tumor nodules and their distribution. Even a fibrous capsule of the tumor may be discerned as a radiolucent zone around the tumor contour. Diagnosis of the gross anatomical type of HCC is important to the selection of therapeutic measure and assessment of prognosis.
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PMID:Angiographic assessment of gross anatomy of hepatocellular cardinoma: comparison of celiac angiograms and liver pathology in 100 cases. 19 72

The concept of antiangiogenic therapy was first proposed in the early 1970s as a method of restricting tumor growth by inhibiting angiogenesis. In subsequent years sufficient knowledge about the process of angiogenesis itself was obtained so that it is now possible to begin to develop antiangiogenic therapy for clinical use. At least three strategies are feasible: (i) inhibition of release of angiogenic molecules from tumor cells; (ii) neutralization of angiogenic molecules that have already been released; and (iii) inhibition of vascular endothelial cells from responding to angiogenic stimulation. Most of the angiogenic inhibitors that have been discovered at the time of writing, directly interfere with the ability of endothelial cells to form new capillary blood vessels. Antiangiogenic activity is a newly found property of alpha-interferon. Although alpha-interferon is a relatively weak angiogenesis inhibitor in comparison to others, it has been very successful in the treatment of life-threatening hemangiomas in children. Early clinical experience with this first angiogenesis inhibitor to reach clinical trial, indicates that optimal antiangiogenic therapy in the future is likely to be based on the long-term use of inhibitors with low toxicity, and with little chance of inducing drug-resistance. It is apparent that different types of angiogenesis inhibitor may be administered together and that these compounds may also be administered to cancer patients as adjuncts to conventional chemotherapy. It is important to recognize that tumor vasculature has other properties besides angiogenesis, which make it a potential specific target for anti-cancer therapy.
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PMID:Inhibition of angiogenesis. 137 14

Liposomes as drug carriers in cancer chemotherapy have attracted considerable interest. To enhance the therapeutic effect of Adriamycin entrapped in liposomes (Lip-ADM) on human solid tumors, we investigated the therapeutic effects of Lip-ADM in combination with recombinant human tumor necrosis factor-alpha (rTNF-alpha), which is known to have specific effects on tumor vasculature. rTNF-alpha or saline solution was injected intravenously into nude mice bearing a human colon cancer strain, HC-1, at 1 hour before intravenous administration of Lip-ADM. The significant therapeutic effect of Lip-ADM in combination with rTNF-alpha was demonstrated by the evaluation with tumor growth curve and the actual tumor weights, in comparison with groups of mice treated with saline solution, rTNF-alpha alone, or with a Lip-ADM after saline. Levels of Adriamycin in tumor tissue in the Lip-ADM in combination with rTNF-alpha-treated group were higher than those in Lip-ADM with saline solution-treated group.
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PMID:Therapeutic effects of liposomal adriamycin in combination with tumor necrosis factor-alpha. 154 76

Elevated interstitial fluid pressure (IFP) of tumors may be a physiological barrier to the delivery of certain therapeutic agents. The objective of this study was to find out if IFP could be lowered using localized hyperthermia and if the reduction in IFP could predict the tumor response to treatment. Amelanotic melanoma (A-Mel-3) implanted into the dorsal skin of Syrian golden hamsters was exposed to hyperthermic treatment after 7 days of tumor growth at tumor volumes of about 100-150 mm3. Hyperthermia was induced by immersing the tumor in a water bath at 43 degrees C for 30 or 60 min. Forty-eight h later the IFP of control and treated tumors was determined by using the wick-in-needle technique. The mean IFP in control tumors was 12.6 mmHg. Hyperthermic treatment for 30 min induced a significant decrease to 2.8 mmHg (P less than 0.001 versus controls), whereas a 60-min immersion of the tumors induced a further decrease to 0.8 mmHg (P less than 0.05 versus 43 degrees C for 30 min). Separate experiments on tumor growth in corresponding groups of animals revealed a significant growth delay of 2.7 days after hyperthermia for 30 min. Enhanced growth delay and partial tumor response in 66% of the tumors were found following 60 min of hyperthermia at 43 degrees C. The thermal dose-dependent decrease in IFP presumably results from the dose-dependent damage to the tumor vasculature. In addition, the association of an enhanced biological effect with a more pronounced reduction of interstitial fluid pressure suggests that the IFP might serve as a quantitative parameter to predict the response of tumors to hyperthermic therapy.
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PMID:Interstitial fluid pressure in solid tumors following hyperthermia: possible correlation with therapeutic response. 172 21

A model for the study of tumor angiogenesis within the rabbit brain is presented. Implantation of the VX2 carcinoma provides a reproducible tumor accompanied by angiogenesis. The authors report the sequential growth, histology, tumor neovascularization, and vascular permeability of this tumor following its intracerebral implantation. Tumor angiogenesis correlates with the rapid and logarithmic intracerebral tumor growth. The proliferation of blood vessels in the tumor and the organization of tumor cells around tumor vessels are described. Breakdown of the blood-brain barrier (detected by Evans blue leakage) starts in the early stages of tumor development and becomes prominent as the tumor vasculature and size increase. This model is useful for experimental studies of angiogenesis.
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PMID:Neovascularization and tumor growth in the rabbit brain. A model for experimental studies of angiogenesis and the blood-brain barrier. 245 89

Complementary antitumor treatments are required to increase the cure rate achieved by surgery and/or radiotherapy by avoiding future recurrences and metastases. The growth of most solid tumors, particularly carcinomas, depends upon the simultaneous development of internal tumor vasculature to allow the proliferation of tumor cells. Inhibition of tumor vascularization is an indirect means of limiting tumor expansion. Daily administration of cortisone and maltose tetrapalmitate (MTP) abolished growth of implanted syngeneic C3HBA mammary tumor. Gross and macroscopic examination of these tumors revealed that tumor growth was prevented. Histological examination demonstrated lack of vascularization within the neoplastic tissue. We believe that this combination in an appropriate form could provide a prophylactic treatment regimen after conventional antitumor treatments in humans.
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PMID:Prophylactic antiangiogenic tumor treatment. 247 30

Twelve patients with malignant brain tumors who had failed to respond to conventional therapies were treated with thermotherapy. Hyperthermic temperatures (approximately 43 degrees C) were induced in the tumors using microwaves at a frequency of 2450 MHz that were guided into the tumors by one or more semirigid coaxial applicators. These applicators fit into 16 gauge tubes or needles and can be inserted into the brain with minimal damage to healthy tissues. During each treatment, the tumors were maintained at hyperthermic temperatures for 1 hour. Several treatments spaced a few days apart were usually administered. The procedure used for producing hyperthermia in brain tumors with microwaves proved to be safe and could be repeated several times without producing toxic effects. Objective tumor responses were obtained in 75% of the patients (decrease in tumor size, 3 patients; slowing of tumor growth, 2 patients; necrosis of tumor tissues verified by pathological examination, 4 patients). Favorable clinical responses were observed in 75% of the patients (rapid decrease in intractable headaches, 5 patients; improvements in clinical deficits, 4 patients). Also, in all patients, the microwave power required to heat for a given time or a given volume decreased during most of the thermotherapy sessions, possibly because of heat damage to the tumor vasculature. Our results, taken together with the results of other investigators, indicate that thermotherapy is a promising modality for treating malignant brain tumors, either as the sole therapy or in combination with radiotherapy and chemotherapy. The next logical steps would be Phase I/II type trials of subjects whose disease is less advanced than the disease of patients treated in the current series of investigations.
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PMID:Microwave hyperthermia for brain tumors. 299 66

To delineate the complex relationships between overall tumor oxygenation and vascular configuration, intravascular oxyhemoglobin (HbO2) saturation distributions were measured with cryospectrophotometric techniques. Four factors related to vascular morphometry and tumor growth were evaluated: a) vessel diameter, b) distance of vessel from the tumor surface, c) tumor volume, and d) vascular density. To measure intertumor heterogeneity, two murine sarcomas (RIF-1 and KHT) and two human ovarian carcinoma xenografts (OWI and MLS) were utilized. In contrast to skeletal muscle, a preponderance of very low HbO2 saturations was observed for both large and small tumors of all lines. Saturations up to about 90% were also generally present, however, even in very large tumors. Variations in vascular configuration were predominantly tumor-line dependent rather than due to inherent characteristics of the host vasculature, and widely disparate HbO2 distributions were found for alternate lines implanted in identical host mice. Although peripheral saturations remained fairly constant with tumor growth, HbO2 values were markedly lower for vessels nearer the tumor center and further decreased with increasing tumor volume. HbO2 saturations did not change substantially with increasing vascular density (except for KHT tumors), although density did decrease with increasing distance from tumor surface. Combined effects of vessel diameter, tumor volume, and vessel location on HbO2 saturations were complex and varied markedly with both tumor line and vessel class. For specific classes, HbO2 distributions correlated closely with radiobiological hypoxic fractions, i.e., for tumor lines in which hypoxic fraction increased substantially with tumor volume, corresponding HbO2 values decreased, while for lines in which hypoxic fraction remained constant, HbO2 values also were unchanged. Although these trends may also be a function of differing oxygen consumption rates between tumor lines, functional alterations in the rapidly expanding tumor vasculature undoubtedly play a primary role in explaining spatial oxygenation heterogeneities.
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PMID:Cryospectrophotometric determination of tumor intravascular oxyhemoglobin saturations: dependence on vascular geometry and tumor growth. 319 79

Stereoscopic observation via an implanted sight glass in mice bearing transplanted methylcholanthrene-induced A-cells showed tumorivascular hemorrhage at 1-2 h after tumor necrosis factor (TNF) administration, congestion at 4-6 h, and hemorrhage, congestion, and blood circulation blockage at 24 h. Histological examination after TNF administration to mice bearing similar methylcholanthrene-induced A-cell transplants showed thrombus formation in the tumor vasculature at 4 h and thereafter. Suppression of this thrombus formation with heparin had no apparent influence on the necrotic response, tumor growth inhibition or complete cure rate following TNF administration to mice bearing the methylcholanthrene-induced A-cell tumors. The results suggest that direct toxicity of TNF on tumor vasculature is a factor in the overall antitumor mechanism of TNF.
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PMID:Toxic effect of tumor necrosis factor on tumor vasculature in mice. 334 88

The effects of hyperthermia on murine tumor vasculature were studied by microangiography and histological examination. The tumors used were SCC VII carcinoma and mammary adenocarcinoma of syngeneic C3H/He mice. For the quantitative analysis of microangiographic changes, the percent (%) vascular area, which was defined as the percentage of opacified tumor vessel area to the entire tumor area, was determined in each microangiogram. The % vascular area after heating in a water bath at 44 degrees C for 30 min was minimized 24 hr after heating in both types of tumors. The histologic study revealed that the initial decrease of the % vascular area was due to congestion, thrombosis, and rupture of tumor vessels, and its subsequent increase was due to angiogenesis. SCC VII was more heat sensitive than mammary adenocarcinoma in terms of tumor growth delay, and tumor vessels of SCC VII were more vulnerable to heat than those of mammary adenocarcinoma. Histological examinations showed a marked difference in the architecture of vessels between the two types of tumors. Tumor vessels of mammary adenocarcinoma were supported by a connective tissue band, whereas those of SCC VII consisted of a single endothelial cell layer. Our findings suggest that the tumor vessels supported by a connective tissue band are less sensitive to heat than those without such support. The vascular damage of SCC VII was temperature dependent, and the critical temperature at which dramatic vascular damage appeared was between 42.7 degrees C and 43.7 degrees C.
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PMID:Microangiographic and histologic analysis of the effects of hyperthermia on murine tumor vasculature. 340 22


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