BACKGROUNDIt is of value to identify the non-invasive means that can accurately reflect the blood supply of epiphysis and is more sensitive in detection of early ischemia of epiphysis than the conventional gadoteridol (Gd)-enhanced SE T1WI. The aim of this study was to evaluate the blood supply of various anatomic regions at the end of normal growing long bone using dynamic Gd-enhanced MR imaging and compare the sensitivities between dynamic Gd-enhanced MR imaging and conventional Gd-enhanced SE T1WI in the detection of decreased blood perfusion of early epiphyseal ischemia.

METHODSTwenty-seven two-week-old piglets were used in this study. For the study of the end of normal growing long bone, unilateral MR imaging of the distal femur and proximal tibia was performed on eleven piglets. The comparison was made among various anatomic regions (physeal and epiphyseal cartilage, metaphyseal spongiosa, the secondary ossification center and metaphysis) using MRI in terms of the enhancement ratio and speed. Their relationships with the histological findings, including RBC/mm(2) and vessel distribution, were evaluated. To examine ischemic femoral head, 16 piglets were divided into two groups, with the control group having 8 piglets (involving 16 normal hips) and an ischemic group having 8 piglets (involving 16 hips with hyperabduction). In the ischemic group, MR imaging was performed on the hips in the hyperabduction immobilized persistently for 30 minutes. After MRI, the piglets were allowed to ambulate freely for 1 day and the same MR scanning was then repeated in a neutral position. The difference in enhancement ratio and speed of the femoral head between the control and ischemic group were evaluated.

RESULTSWith regard to the end of normal growing long bone, the enhancement ratio of the metaphyseal spongiosa was greatest among all the anatomic regions (P < 0.001). The enhancement ratio of physeal cartilage was greater than that of epiphyseal cartilage (P < 0. 001), which was the lowest in all tissues (P < 0.001). The enhancement speed of the spongiosa was greater than that of physis but the difference was not significant (P > 0.05). The enhancement speed of physis was greater than that of epiphyseal cartilage (P < 0.05), which was the lowest among all the tissues (P < 0.05). The enhancement ratio and speed were found to be related to the histological findings, including RBC/mm(2) (R > 0.75) and distribution of vessels in the tissues. With ischemic femoral head, the enhancement ratios of physis, anterior part and posterior part of capital femoral epiphysis were significantly lower (P < 0.05) and enhanced more slowly (P < 0.05) than those of normal femoral head on dynamic Gd-enhanced MR imaging. On conventional Gd-enhanced SE T1WI, however, no apparent decrease in enhancement ratio and speed in ischemic hips was found (P < 0.05), when they were compared with those in the normal hips.

CONCLUSIONSDynamic gadoteridol-enhanced MR imaging can reveal the blood supply in various anatomic regions of the end of normal growing long bone. It is more sensitive than conventional Gd-enhanced SE T1WI in the detection of early epiphyseal ischemia.

Animals ; Contrast Media ; pharmacology ; Epiphyses ; blood supply ; Femur ; blood supply ; Gadolinium ; Heterocyclic Compounds ; pharmacology ; Image Enhancement ; Magnetic Resonance Imaging ; methods ; Organometallic Compounds ; pharmacology ; Swine

Objective To explore the ability of texture analysis of gadoxetic acid-enhanced magnetic resonance imaging (MRI) T1 mapping images, as well as T1-weighted (T1W), T2-weighted (T2W) and apparent diffusion coefficient (ADC) maps for distinguishing between varying degrees of hepatic fibrosis in an experimental rat model.Methods Liver fibrosis in rats was induced by carbon tetrachloride intraperitoneal injection for 4-12 weeks (n=30). In the control group (n=10) normal saline was applied. The MRI protocol contained T2W, diffusion weighted imaging, pre-and post-contrast image series of T1W and T1 mapping images. METAVIR score was used to grade liver fibrosis as normal (F0), mild fibrosis (F1-2), and advanced fibrosis (F3-4). Texture parameters including mean gray-level intensity (Mean), standard deviation (SD), Entropy, mean of positive pixels (MPP), Skewness, and Kurtosis were obtained. Nonparametric Mann-Whitney U test was used to compare the average value of each texture parameter in each sequence for assessing the difference between F0 and F≥1 as well as F0-2 and F3-4. Receiver operating characteristic (ROC) curves were obtained to assess the diagnosing accuracy of the parameters for differentiating no liver fibrosis from liver fibrosis and rats with liver fibrosis grading F0-2 from those with grading F3-4. The area under ROC curve (AUC) was calculated to evaluate the diagnostic efficiency of texture parameters.Results Finally, 20 rats completed MR T1 mapping image scan. The pathologic staging of these 20 rats was no fibrosis (F0, n=6), mild fibrosis (F1-2, n=5) and advanced fibrosis (F3-4, n=9). On pre-contrast T1 mapping image, Entropy was seen to be statistically significant higher in the F≥1 group than that in the F0 group at each spatial scaling factor (SSF) setting (P=0.015, 0.015, 0.015, 0.013, 0.015 and 0.018 respectively to SSF=0, 2, 3, 4, 5, 6), and Mean of the F≥1 rats was statistically significant higher than that of the F0 rats at SSF 4, 5, 6 (P=0.004, 0.006, and 0.013, respectively). Entropy and Mean showed a moderate diagnostic performance in most SSF settings of T1 mapping pre-contrast images for differentiation of normal liver from liver fibrosis.Conclusions Certain texture features of gadoxetic acid-enhanced MR images, especially the Entropy of non-contrast T1 mapping image, was found to be a useful biomarker for the diagnosis of liver fibrosis.
Animals ; Contrast Media ; pharmacology ; Diffusion Magnetic Resonance Imaging ; Disease Models, Animal ; Gadolinium DTPA ; pharmacology ; Liver Cirrhosis ; diagnostic imaging ; physiopathology ; Male ; Rats ; Rats, Sprague-Dawley

BACKGROUNDThe assessment of regional pulmonary ventilation and perfusion is essential for the evaluation of a variety of lung disorders. Pulmonary ventilation MRI using inhaled oxygen as a contrast medium can be obtained with a clinical MR scanner, without additional equipment, and has been demonstrated to be a feasible means of assessing ventilation in animal models and some clinical patients. However, few studies have reported on MR ventilation-perfusion imaging. In this study, we evaluated the usefulness of oxygen-enhanced ventilation in combination with first-pass Gd-DTPA-enhanced perfusion MRI in a canine model of pulmonary embolism and airway obstruction.

METHODSPeripheral pulmonary embolisms were produced in eight dogs by intravenous injection of gelfoam strips at the pulmonary segmental arterial level, and airway obstructions were created in five of the dogs by inserting a self-designed balloon catheter into a secondary bronchus. Oxygen-enhanced MR ventilation images were produced by subtracting images from before and after inhalation of pure oxygen. Pulmonary perfusion MR images were acquired with a dynamic three-dimensional fast gradient-echo sequence. MR ventilation and perfusion images were read and contrasted with results from general examinations of pathological anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography.

RESULTSRegions identified as having airway obstructions matched using both MR ventilation and perfusion imaging, but regions of pulmonary embolisms were mismatched. The area of airway obstruction defects was smaller using MR ventilation imagery than that using ventilation scintigraphy. Abnormal perfusion regions due to pulmonary embolisms were divided into defective regions and reduced regions based on the time course of signal intensity changes. In the diagnosis of pulmonary embolisms with the technique of ventilation and perfusion MRI, sensitivity and specificity were 75.0% and 98.1%, respectively, and the diagnostic results of this MRI technique were in agreement with the results of ventilation-perfusion scintigraphy and pulmonary angiography (K: 0.899, 0.743).

CONCLUSIONSOxygen-enhanced ventilation in combination with pulmonary perfusion MRI can be used to diagnose abnormalities of airways and blood vessels in the lungs, and can provide regional functional information with high spatial and temporal resolution. This method possesses great potential value for clinical applications.

Airway Obstruction ; diagnosis ; physiopathology ; Animals ; Disease Models, Animal ; Dogs ; Gadolinium DTPA ; Magnetic Resonance Imaging ; Oxygen ; pharmacology ; Pulmonary Circulation ; Pulmonary Embolism ; diagnosis ; physiopathology ; Respiration

Akt/protein kinase B is a well-known cell survival factor and activated by many stimuli including mechanical stretching. Therefore, we evaluated the cardioprotective effect of a brief mechanical stretching of rat hearts and determined whether activation of Akt through phosphatidylinositol 3-kinase (PI3K) is involved in stretch-induced cardioprotection (SIC). Stretch preconditioning reduced infarct size and improved post-ischemic cardiac function compared to the control group. Phosphorylation of Akt and its downstream substrate, GSK-3beta, was increased by mechanical stretching and completely blocked by wortmannin, a PI3K inhibitor. Treatment with lithium or SB216763 (GSK-3beta inhibitors) before ischemia induction mimicked the protective effects of SIC on rat heart. Gadolinium (Gd3+), a blocker of stretch-activated ion channels (SACs), inhibited the stretch-induced phosphorylation of Akt and GSK-3beta. Furthermore, SIC was abrogated by wortmannin and Gd3+. In vivo stretching induced by an aorto-caval shunt increased Akt phosphorylation and reduced myocardial infarction; these effects were diminished by wortmannin and Gd3+ pretreatment. Our results showed that mechanical stretching can provide cardioprotection against ischemia-reperfusion injury. Additionally, the activation of Akt, which might be regulated by SACs and the PI3K pathway, plays an important role in SIC.
Androstadienes/pharmacology ; Animals ; Gadolinium/pharmacology ; Glycogen Synthase Kinase 3/*metabolism ; Indoles/pharmacology ; *Ischemic Preconditioning, Myocardial ; Lithium/pharmacology ; Male ; Maleimides/pharmacology ; Myocardial Reperfusion Injury/enzymology/physiopathology/*prevention & control ; Phosphatidylinositol 3-Kinase/*antagonists & inhibitors/metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt/*metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Specific Pathogen-Free Organisms

OBJECTIVETo observe the role of Kupffer cells in the postburn production of TNFalpha, IL-1beta and IL-6 in severely scalded rats.

METHODS(1) The production of TNFalpha, IL-1beta and IL-6 from rat Kupffer cells stimulated by burn serum was observed. (2) The postburn change in the expression of cytokine mRNA from rat Kupffer cells was monitored. (3) The change in the plasma cytokine contents in scalded rats was determined after the application of gadolinium chloride, a specific inhibitor of Kupffer cells.

RESULTSKupffer cells could be stimulated by burn serum to release cytokines TNFalpha, IL-1beta and IL-6. The mRNA expression of TNFalpha, IL-1beta and IL-6 from rat Kupffer cells increased significantly after injury. But the postburn plasma levels of TNFalpha, IL-1beta and IL-6 decreased obviously to 34.71%, 36.99% and 33.7% of those in scalding group, respectively, after the Kupffer cell activity was inhibited.

CONCLUSIONThe plasma cytokines, i.e. TNFalpha, IL-1beta and IL-6, were primarily produced from Kupffer cells after injury in scalded rats, initiated by TNFalpha, IL-1beta and IL-6 mRNA transcription.

Animals ; Burns ; immunology ; metabolism ; Gadolinium ; pharmacology ; Interleukin-1 ; biosynthesis ; genetics ; Interleukin-6 ; biosynthesis ; genetics ; Kupffer Cells ; physiology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; biosynthesis ; genetics

The effects of estriol on oxygen uptake, glucose release, lactate and pyruvate production, beta-hydroxybutyrate and acetoacetate production in perfused rat liver as well as, carbon uptake in rat liver and intracellular calcium in isolated Kupffer cells were investigated. Basal oxygen consumption of perfused liver increased significantly in estriol or ethanol-treated rats. But these increased effects were blocked by gadolinium chloride pretreatment. In a metabolic study, pretreatment with estriol resulted in a decrease in glucose production and in glycolysis while an increase in ketogenesis. A more oxidized redox state of the mitochondria was indicated by increased ratios of perfusate [lactate]/[pyruvate] and decreased ratios of perfusate [beta-hydroxybutyrate]/[acetoacetate]. Carbon uptake of Kupffer-cell increased significantly in estriol-treated rats. But these increased uptake were not shown in rats pre-treated by gadolinium chloride blocking phagocytosis. In isolated Kupffer cells from estriol-treated rats, intracellular calcium was more significantly increased after addition of lipopolysaccharide (LPS) than in controls. These findings suggest that the metabolic effects of estriol (two mg per 100 mg body wt) can be summarized to be highly toxic in rat liver, and these findings suggest that oral administration of estrogens may induce hepatic dysfunctions and play a role in the development of liver disease.
3-Hydroxybutyric Acid/metabolism ; Acetoacetates/metabolism ; Animal ; Calcium/metabolism ; Carbohydrates/metabolism ; Carbon/metabolism ; Cells, Cultured ; Colloids/metabolism ; Estriol/pharmacology* ; Estriol/metabolism ; Ethanol/pharmacology ; Female ; Gadolinium/pharmacology ; Glucose/biosynthesis ; Intracellular Fluid/metabolism ; Kupffer Cells/metabolism ; Kupffer Cells/cytology ; Lactates/metabolism ; Lipids/metabolism ; Liver/metabolism ; Liver/drug effects* ; Oxygen Consumption ; Phagocytosis ; Pyruvic Acid/metabolism ; Rats ; Rats, Sprague-Dawley

PURPOSE: To investigate the correlations between parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and prognostic factors in rectal cancer. MATERIALS AND METHODS: We studied 29 patients with rectal cancer who underwent gadolinium contrast-enhanced, T1-weighted DCE-MRI with a three Tesla scanner prior to surgery. Signal intensity on DCE-MRI was independently measured by two observers to examine reproducibility. A time-signal intensity curve was generated, from which four semiquantitative parameters were calculated: steepest slope (SLP), time to peak (Tp), relative enhancement during a rapid rise (Erise), and maximal enhancement (Emax). Morphologic prognostic factors including T stage, N stage, and histologic grade were identified. Tumor angiogenesis was evaluated in terms of microvessel count (MVC) and microvessel area (MVA) by morphometric study. As molecular factors, the mutation status of the K-ras oncogene and microsatellite instability were assessed. DCE-MRI parameters were correlated with each prognostic factor using bivariate correlation analysis. A p-value of <0.05 was considered significant. RESULTS: Erise was significantly correlated with N stage (r=-0.387 and -0.393, respectively, for two independent data), and Tp was significantly correlated with histologic grade (r=0.466 and 0.489, respectively). MVA was significantly correlated with SLP (r=-0.532 and -0.535, respectively) and Erise (r=-0.511 and -0.446, respectively). MVC was significantly correlated with Emax (r=-0.435 and -0.386, respectively). No significant correlations were found between DCE-MRI parameters and T stage, K-ras mutation, or microsatellite instability. CONCLUSION: DCE-MRI may provide useful prognostic information in terms of histologic differentiation and angiogenesis in rectal cancer.
Adult ; Aged ; Aged, 80 and over ; Cell Differentiation ; Contrast Media/*pharmacology ; DNA Mutational Analysis ; Female ; Gadolinium/pharmacology ; Genes, ras ; Humans ; Magnetic Resonance Imaging/*methods ; Male ; Microcirculation ; Microsatellite Instability ; Middle Aged ; Neoplasm Staging ; Neovascularization, Pathologic ; Prognosis ; Rectal Neoplasms/*diagnosis/genetics/*pathology ; Retrospective Studies ; Time Factors

AIMTo study the biochemistry of lanthanides, the cooperative action of inorganic and organic anti-tumor drugs.

METHODSA series of rare earth complexes were synthesized with Ln(NO3) 6H2O, Phen and 5-Fu. Their anti-tumor activity was measured by the improved MTT, SRB methods.

RESULTSThe formula of complex Ln[(Phen)2(5-Fu)3(NO3)](NO3)2(Ln = Y, La, Ce, Sm, Gd, Dy, Er; Phen = 1, 10-phenanthroline; 5-Fu = fluorouracil) was characterized by elemental analyses, molar conductivity, IR, TGA, and 13C NMR spectra. The preliminary biological activity studies indicated that Lanthanide complex has strong anti-tumor activity in vitro.

CONCLUSIONThe complex might have anti-tumor cooperation action.

Antineoplastic Agents ; chemical synthesis ; chemistry ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cerium ; chemistry ; Drug Synergism ; Dysprosium ; chemistry ; Erbium ; chemistry ; Fluorouracil ; chemistry ; Gadolinium ; chemistry ; Humans ; Lanthanoid Series Elements ; chemistry ; Lanthanum ; chemistry ; Phenanthrolines ; chemistry ; Samarium ; chemistry ; Structure-Activity Relationship ; Yttrium ; chemistry

Hair cells at the base of the cochlea appear to be more susceptible to damage by the aminoglycoside gentamicin than those at the apex. However, the mechanism of base-to-apex gradient ototoxicity by gentamicin remains to be elucidated. We report here that gentamicin caused rodent cochlear hair cell damages in a time- and dose-dependent manner. Hair cells at the basal turn were more vulnerable to gentamicin than those at the apical turn. Gentamicin-conjugated Texas Red (GTTR) uptake was predominant in basal turn hair cells in neonatal rats. Transient receptor potential vanilloid 1 (TRPV1) and 4 (TRPV4) expression was confirmed in the cuticular plate, stereocilia and hair cell body of inner hair cells and outer hair cells. The involvement of TRPV1 and TRPV4 in gentamicin trafficking of hair cells was confirmed by exogenous calcium treatment and TRPV inhibitors, including gadolinium and ruthenium red, which resulted in markedly inhibited GTTR uptake and gentamicin-induced hair cell damage in rodent and zebrafish ototoxic model systems. These results indicate that the cytotoxic vulnerability of cochlear hair cells in the basal turn to gentamicin may depend on effective uptake of the drug, which was, in part, mediated by the TRPV1 and TRPV4 proteins.
Animals ; Cell Death/drug effects ; Cell Polarity/drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Gadolinium/metabolism ; Gentamicins/*metabolism/pharmacology ; Hair Cells, Auditory/drug effects/*metabolism ; Hair Cells, Auditory, Inner/drug effects/metabolism ; Rats ; Rats, Sprague-Dawley ; Ruthenium Red/metabolism ; TRPV Cation Channels/*metabolism ; Time Factors ; Xanthenes/metabolism ; Zebrafish