Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0004135 (ATM)
 13,001 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reports indicate that cancer of the prostate, soft tissue sarcomas, salivary gland tumors, and melanomas respond well to fast-neutron treatment. To better understand the action of fast neutrons on such tumor tissues, we have begun studies with the versatile Dunning rat prostate tumor system. In our initial studies with the R3327-AT1 subline we observed a relative biological effectiveness (RBE) of approximately 3 for single doses of 14-meV fast neutrons. As a continuation of those studies the present report discusses our findings following fractionated treatments with 10 equal fractions of 14-MeV fast neutrons or 60Co gamma rays at several dose levels per fraction. After either fractionated neutron or photon treatment the volume of the tumors continued to increase for 2 weeks and then reached a plateau, the level of which was dose dependent. Tumor growth resumed and no local control was observed. Analysis of the data using growth delay as biological end point yielded an RBE of approximately 4.2 +/- 1.3.
 ...
PMID:Response of the rat Dunning R3327-AT1 prostate tumor to treatment with fractionated fast neutrons. 172 53

We have examined a hexafluorinated 2-nitroimidazole, CCI-103F, as a probe for hypoxic tumor cells by in vivo 19F magnetic resonance spectroscopy (MRS). Following initial intraperitoneal injections of the drug in tumor-bearing (Dunning R3327-AT1-Matlylu) rats, 19F spectra were obtained on an Otsuka 2.0T Vivospec spectrometer using a 1.5-cm surface coil. Signal at 1- and 2-h time points indicated initial biodistribution of drug in the tumor. At 4 and 8 h, a progressive increase in signal intensity was observed, indicating retention of drug within the tumor. Tumor signal remained detectable in 4 of 10 rats at 24 h, indicating possible nitroreductive bioactivation by hypoxic cells. Immunohistochemistry of these tumors revealed a staining pattern consistent with labeling of hypoxic cells. No detectable 19F signal was found at 24 h for the other rats, indicating complete washout of unbound drug. Immunohistochemical assessment of these tumors revealed some staining for bound drug at the periphery of necrotic zones. 31P-MRS of the tumors showed good correlation with the presence or absence of hypoxia as evaluated by 19F-MRS, T1- and T2-weighted images, and immunohistochemistry. These results provide the groundwork for further studies using this misonidazole analog for noninvasive identification of hypoxic tumor cells in vivo by MRS.
 ...
PMID:Evaluation of a fluorinated 2-nitroimidazole binding to hypoxic cells in tumor-bearing rats by 19F magnetic resonance spectroscopy and immunohistochemistry. 172 59

Specific binding site for 125I-angiotensin II (Ang II), with unique pharmacological properties uncommon to the hitherto recognized receptor subtypes, was observed in mouse neuroblastoma cells (Neuro-2A). Differentiation of the cells with 100 nM PGE1 resulted in a 10-fold increase in the number of Ang II binding sites without changing the binding affinity (Kd value: 12.0 nM). 125I-Ang II binding to membranes of differentiated Neuro-2A was inhibited by unlabeled Ang II with a Ki value of 7.06 +/- 1.09 nM but not by Ang III (1 microM). Both AT1 antagonist, Dup753, and AT2 antagonist, PD123319, failed to inhibit 125I-Ang II binding at 1 microM. 125I-Ang II binding was not affected by GTP analogs such as GTP gamma S and Gpp(NH)p. These results suggest that Neuro-2A cells possess a binding site for Ang II which is different from the presently known subtypes of Ang II receptors, and that the number of the binding site is regulated by cell differentiation.
 ...
PMID:Identification and characterization of a new binding site for angiotensin II in mouse neuroblastoma neuro-2A cells. 173 96

Many grading systems for prostatic carcinoma exist; however, none allows pathologists to predict accurately the prognosis of individual patients. The Dunning R-3327 prostatic adenocarcinoma model consist of sublines of known metastatic potential which were indistinguishable until recently. A visual grading system of cancer cell motility distinguished the metastatic potentials of Dunning sublines maintained in vitro and was validated prospectively. We used this grading system to assess the metastatic potential of cells harvested directly from in vivo Dunning tumors. We graded the motility of cells from three Dunning sublines of low (less than 10%) (G, AT1, AT2) and three sublines of high (greater than 90%) AT3, (MAT-LyLu, PAT2) metastatic potential. Cells obtained from primary tumors were studied by time lapse videomicroscopy after passages 1, 3 and 5 in vivo and in vitro. Membrane ruffling, pseudopodal extension and cellular translation were graded 0-10. Serial analysis of mean and heterogeneity (coefficient of variation) of membrane ruffling, pseudopodal extension and cellular translation demonstrated that subline motility grades were assessed adequately by a sample of 10 cells. Motility did not depend upon whether cells were maintained in vitro or in vivo; however, motility increased with successive passages in four of six sublines. In 60 cells harvested directly from the fifth in vivo passage, three sublines of low metastatic potential were distinguished from three sublines of high metastatic potential (Student's t test, p less than 0.01). Individual cells from the sublines were identified correctly as high or low metastatic in 83, 78 and 70% of cases by membrane ruffling, pseudopodal extension and cellular translation respectively, and logistic regression analysis failed to improve classification accuracy. A visual grading system of cancer cell motility described the metastatic potential of in vivo neoplasms in the Dunning model and may warrant testing in human prostatic cancer.
 ...
PMID:Prediction of metastatic potential by cancer cell motility in the Dunning R-3327 prostatic adenocarcinoma in vivo model. 173 34

Angiotensin-converting enzyme inhibitors have been shown to inhibit intimal thickening following balloon catheterization of rat carotid arteries. To assess the role of the renin-angiotensin pathway and the angiotensin type-I (AT1) receptor in this effect, the nonpeptide Ang II antagonist losartan (DuP 753) or vehicle was infused continuously i.v. in rats from two days before to two weeks after balloon injury to the left common carotid artery; drug effects upon intimal thickening were examined histologically. Losartan produced a dose-dependent reduction in cross-sectional area of intimal lesions determined two weeks post balloon injury. At 5 mg/kg/day a nonsignificant 23% reduction of intimal area was observed. At the higher dose of 15 mg/kg/day, losartan produced a 48% reduction in intimal area (P less than 0.05) compared to the vehicle-infused group. The cellular density of the neointima was not affected by losartan, indicating a probable effect of the drug upon migration and/or proliferation of smooth muscle cells. In separate groups of non-ballooned rats, losartan infusions of 5 and 15 mg/kg/day produced significant rightward shifts (averaging 6.4- and 55-fold, respectively) in curves relating increases in blood pressure to intravenous Ang II in pithed rats determined between 2 and 16 days following initiation of losartan infusion. Mean arterial blood pressure (determined under alpha-chloralose anesthesia) was reduced following continuous losartan infusion for 6 days from 128 +/- 8 mm Hg (vehicle) to 105 +/- 8 mm Hg at 5 mg/kg/day (P less than 0.05), and 106 +/- 4 mm Hg at 15 mg/kg/day (P less than 0.05). Thus, losartan attenuated the vascular response to balloon catheter injury, and this effect was associated with functional block of vascular AT1 receptors. The results support a role for Ang II, acting via AT1 receptors, in myointimal thickening subsequent to balloon injury of rat carotid arteries.
 ...
PMID:Losartan, a nonpeptide angiotensin II (Ang II) receptor antagonist, inhibits neointima formation following balloon injury to rat carotid arteries. 174

DuP 753 (or EXP3174) and PD123177 are nonpeptide angiotensin (AII)-specific ligands, which show high affinities for two AII receptor subtypes, i.e. AT1 and AT2 sites, respectively. In furosemide-treated conscious dogs with high renin, DuP 753 and EXP3714, but not PD123177, were as effective as captopril in lowering blood pressure. Both DuP 753 and EXP3174 exhibited selective vascular antagonism of AII. In conscious dogs with normal renin, DuP 753, but not captopril or EXP3174, caused a dose-dependent but transient decrease in blood pressure. In anesthetized dogs, DuP 753 and captopril caused similar renal vasodilatation and natriuresis. The renal hemodynamic effects of DuP 753 and captopril were more pronounced in dogs with sodium depletion. These results suggest that the AT1 receptor mediates the pressor and renal effects of AII in dogs. The acute transient hypotensive effect of DuP 753 in normal-renin conscious dogs is probably unrelated to AII antagonism.
 ...
PMID:Nonpeptide angiotensin II receptor antagonists. Studies with DuP 753 and EXP3174 in dogs. 174 55

The angiotensin-converting enzyme (ACE) inhibitor, benazeprilat and the angiotensin II (Ang II), AT1-specific receptor antagonist, DuP753, were compared for their effects on intimal lesion formation as well as smooth muscle cell (SMC) proliferation and migration in Sprague Dawley rats after carotid balloon injury. Both the ACE inhibitor (benazeprilat, 3 mg/kg/day) and the AT1 antagonist (DuP 753, 10 mg/kg/day) significantly reduced intimal lesion formation after balloon injury (by 35% and 49%, respectively). Medial SMC proliferation after injury was reduced 53% by the AT1 antagonist; however, the ACE inhibitor had no effect on SMC proliferation. SMC migration was reduced 94% by the AT1 antagonist and 68% by the ACE inhibitor. These data demonstrate the importance of Ang II in SMC proliferation and migration after balloon injury. They also demonstrate that in the balloon injury model, the ACE inhibitor reduced intimal lesion size by inhibiting SMC migration alone without affecting SMC proliferation. A more pronounced reduction in lesion size was obtained after AT1 antagonism, however, when both SMC migration and proliferation were inhibited.
 ...
PMID:Angiotensin-converting enzyme inhibitor versus angiotensin II, AT1 receptor antagonist. Effects on smooth muscle cell migration and proliferation after balloon catheter injury. 175 May 4

The angiotensin II receptor subtype-specific antagonists Dup 753 (AT1) and PD 123177 (AT2) were used to characterize the angiotensin II receptor subtypes present in 18 day gestation fetal Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rat brain using in vitro receptor autoradiography. The AT2 subtype was predominant in the brain of both rat strains, even in areas that display predominantly the AT1 subtype in the adult rat brain.
 ...
PMID:The AT2 angiotensin receptor subtype predominates in the 18 day gestation fetal rat brain. 176 Jul 41

Angiotensin II (AII) receptor subtypes were analyzed in the brains of adult and 2-week-old rats by in vitro autoradiography with 125I-labeled [Sar1,Ile8]AII and competition studies with three AII antagonists: the nonpeptide antagonist, DuP 753, which is specific for AT1 receptors that mediate the calcium-inositol phospholipid signaling actions of AII; and nonpeptide (PD 123177) and peptide (CGP 42112A) antagonists that are selective for AT2 receptors of yet unknown function. In the adult rat brain, DuP 753 inhibited radioligand binding to the circumventricular organs and paraventricular nucleus but not to the lateral septum, subthalamic nucleus, and inferior olive. However, binding of 125I-labeled [Sar1,Ile8]AII in the latter regions was inhibited by the AT2 receptor antagonists PD 123177 and CGP 42112A. These areas showed similar displacement by the AT2 receptor subtype-specific antagonists in 2-week-old rats. In addition, radioligand binding at multiple sites of transient expression of AII receptors in 2-week-old rats, including several thalamic nuclei, the nuclei of the 3rd and 12th cranial nerves, geniculate bodies, cerebellum, and cingulate cortex, was displaced by the AT2 antagonists but not by DuP 753. These studies have demonstrated the presence of two AII receptor subtypes in the brain, one (AT1) in areas related to regulation of blood pressure, water intake, and pituitary hormone secretion, and one (AT2) whose function is not yet defined. The abundance and location of brain AT2 receptors in young animals, and the age-related changes in relative expression of the receptor subtypes, suggest that AII exerts specific actions according to the developmental stage of the central nervous system.
 ...
PMID:Differential distribution of AT1 and AT2 angiotensin II receptor subtypes in the rat brain during development. 176 58

CGP 42112A, a potent angiotensin AT2 receptor selective ligand, was radio-iodinated and its binding characteristics compared with those of [125I]angiotensin II. In human myometrium (only AT2 expressed), binding was saturable (Kd 1.03 x 10(-10) M; Bmax 807 fmol/mg) and reversible (K+1 1.89 x 10(8) M-1.min-1; K-1 3.77 x 10(-3) min-1). The order of potency of a number of peptides and non-peptides was the same as when [125I] angiotensin II was used as tracer. No specific binding could be detected on membranes from vascular smooth muscle cells (only AT1 expressed). In rat adrenal glomerulosa membranes (mixed AT1/AT2), [125I]CGP 42112A bound only to AT2. [125I]CGP 42112A can therefore be used as a specific probe for AT2 receptors and will be especially useful in tissues where other subtypes are also present.
 ...
PMID:Radioiodinated CGP 42112A: a novel high affinity and highly selective ligand for the characterization of angiotensin AT2 receptors. 176 88


<< Previous 1 2 3 4 5 6 7 8 9 10