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At least 217 records · Page 12Linked to original sources

PubMed1998

Normal bladder wall morphology in Gd-DTPA-enhanced clinical MR imaging using an endorectal surface coil and histological assessment of submucosal linear enhancement using [14C]Gd-DOTA autoradiography in an animal model.

OBJECTIVE: The purpose of this study was to investigate normal bladder wall morphology in gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance (MR) imaging using an endorectal surface coil and to perform histological assessment of submucosal linear enhancement with experimental [14C]-gadolinium-tetraazacyclododecane-tetraacetic acid (Gd-DOTA) autoradiography. METHODS AND MATERIAL: MR imaging of the bladder was performed using an endorectal coil in 13 consecutive patients with bladder carcinoma and T1-, T2-, and Gd-DTPA-enhanced spin-echo images of the bladder wall were compared. After injection of [14C]Gd-DOTA into a hamster, autoradiograms of the bladder wall were obtained and compared with serial histological sections. RESULTS: The normal bladder wall appeared as a homogeneous layer of intermediate intensity on T1-weighted images. After administration of Gd-DTPA, the bladder wall was visualized as three layers: an inner thin layer of low intensity, a middle layer of marked enhancement, and a thick outer layer of intermediate intensity. The autoradiograms demonstrated dense accumulation of [14C]Gd-DOTA in the submucosal layer. Thus, the inner, middle, and outer layers corresponded to the mucosa, submucosa, and muscularis propria, respectively. The thickness of the bladder wall demonstrated on T2-weighted images was almost equal to that of the outer layer on enhanced T1-weighted images. Thus, T2-weighted images revealed only the muscle layer as an intermediate-intensity band. In the preliminary clinical study, MR imaging invariably showed accurate stages of the bladder carcinoma in 13 patients. CONCLUSION: In MR imaging of the normal bladder wall, the submucosa was strikingly enhanced after Gd-DTPA administration, separating the bladder wall into three layers. This may have a potential role in the staging of bladder tumors.

Animals↗

PubMed2005

Enhanced vascular reactivity of small mesenteric arteries from diabetic mice is associated with enhanced oxidative stress and cyclooxygenase products.

Vascular reactivity to the alpha-adrenoceptor agonist phenylephrine (PE) was enhanced in small mesenteric arteries (SMA) from diabetic (db/db) mice under both high and low in vitro oxygen conditions. Mechanical removal of the endothelium significantly attenuated the enhanced vascular reactivity of SMA from db/db mice. Acute incubation of the SMA with sepiapterin, a precursor of tetrahydrobiopterin, and N(omega)-nitro L-arginine (L-NA), an inhibitor of nitric oxide (NO) synthase (NOS), resulted in no significant change in the enhanced vascular reactivity to PE in db/db mice. Endothelial nitric oxide synthase (eNOS) mRNA and protein levels in SMA were not different between db/+ and db/db mice. Acute incubation of SMA with a combination of polyethylene glycol superoxide dismutase and catalase significantly reduced the enhanced contraction to PE in db/db mice. There were higher levels of malondialdehyde, a marker of lipid peroxidation and basal superoxide as measured by dihydroethidium staining, in SMA from db/db mice compared to db/+ mice. Acute incubation with indomethacin, a nonselective inhibitor of cyclooxygenase, SQ 29548, a selective thromboxane receptor antagonist and furegrelate, a thromboxane synthesis inhibitor, significantly attenuated the enhanced contraction to PE in SMA from db/db mice. This study demonstrates that the enhanced contractility of SMA from db/db mice to PE was endothelium dependent and involves elevated reactive oxygen species, cyclooxygenase activity and thromboxane synthesis, but not changes in the eNOS/NO pathway.

Animals↗

PubMed2000

A simple phenolic antioxidant protocatechuic acid enhances tumor promotion and oxidative stress in female ICR mouse skin: dose-and timing-dependent enhancement and involvement of bioactivation by tyrosinase.

The modifying effects of topical application of the phenolic antioxidant protocatechuic acid (PA) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse skin tumor promotion were investigated. Dimethylbenz[a]anthracene-initiated female ICR mice were treated with TPA (1.6 nmol) twice weekly for 20 weeks to promote papilloma formation. Pre-treatment with 16nmol PA 30 min prior to each TPA treatment significantly inhibited the number of papillomas per mouse by 52% (P < 0.05). On the other hand, PA pre-treatment at a high dose (1600 nmol) significantly enhanced tumor numbers by 38% (P < 0.05). Interestingly, in the group treated with a quite high dose (20000 nmol) of PA 5 min prior to each TPA application, the average number of tumors per mouse was reduced by 38%, whereas the same PA dose 3 h before TPA treatment significantly enhanced tumor numbers by 84% (P < 0.01). These results suggested that topically applied PA was converted to compound(s) lacking antioxidative properties and/or rather possessing the potential to enhance tumor development. A similar tendency was also observed in the short-term experiment of TPA-induced inflammation and oxidative stress; i.e. two groups pre-treated with PA at 20000 nmol, 30min and 3h before TPA treatment, did not show suppression or even significantly enhanced TPA-induced leukocyte infiltration, H(2)O(2) generation, thiobarbituric acid-reacting substances level and proliferating cell nuclear antigen index, while PA treatment together with TPA significantly suppressed these parameters. Treatment with a high dose (20000 nmol) of PA alone for 3h enhanced oxidative stress by reducing glutathione levels in mouse skin, which was counteracted by the tyrosinase inhibitor arbutin. Oxidative stress responses such as leukocyte infiltration and H(2)O(2) generation were also counteracted by arbutin. These results suggested that tyrosinase-dependent oxidative metabolism of PA was at least partially involved in the enhanced effects of PA on TPA-induced inflammatory responses and thus tumor promotion.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1991

Histologic basis for increased extraocular muscle enhancement in gadolinium-enhanced MR imaging.

Minimal to mild enhancement of skeletal muscles is normally seen on gadolinium-enhanced magnetic resonance images. The enhancement of the extraocular muscles is much more intense than that of other skeletal muscles. The authors investigated the structural features of extraocular muscles that contribute to this increased enhancement. After comparing samples of extraocular muscle and quadriceps muscle, the authors concluded that the rich vascularity and the prominence of extravascular space most probably cause extraocular muscles to demonstrate intense enhancement on gadolinium-enhanced images.

Gadolinium DTPA↗

PubMed1996

Solitary pulmonary nodules: MR evaluation of enhancement patterns with contrast-enhanced dynamic snapshot gradient-echo imaging.

PURPOSE: To evaluate the enhancement patterns of solitary pulmonary nodules (SPNs) with dynamic contrast-material-enhanced magnetic resonance (MR) imaging to differentiate between benign and malignant SPNs. MATERIALS AND METHODS: Twenty-eight patients with SPNs 30 mm or smaller in diameter were examined with pre- and postcontrast, electrocardiographically gated, T1-weighted spin-echo (SE) sequences and a snapshot gradient-echo (GRE) sequence after bolus injection of a paramagnetic contrast agent. For all SPNs (20 malignant, eight benign), the percentage increase in signal intensity (%SI) on the postcontrast T1-weighted SE images and the enhancement curves (%SI/sec) for the snapshot GRE measurements were established from regions of interest. RESULTS: Malignant nodules showed a higher increase of signal intensity during the first transit of the bolus of contrast material on the dynamic snapshot GRE images (malignant: median, 18.1 %SI/sec; range, 6.7-95.2 %SI/sec; benign: median, 2.3 %SI/sec; range, 0.1-8.1 %SI/sec) (P < .0001). Static T1-weighted SE measurements did not allow differentiation between malignant (median, 53.4 %SI; range 12.5-110.0 %SI) and benign (median, 33 %SI; range, 0.8-85.5 %SI) (P > .2) nodules on the basis of the degree of contrast enhancement. CONCLUSION: Dynamic contrast-enhanced MR measurements of tumor enhancement can provide additional information about the nature of SPNs.

Adult↗

PubMed2002

Aminated gelatin as a nasal absorption enhancer for peptide drugs: evaluation of absorption enhancing effect and nasal mucosa perturbation in rats.

This study was carried out to evaluate the potential of aminated gelatin as a nasal absorption enhancer for peptide drugs. The absorption-enhancing effect was investigated in rats using insulin and fluorescein isothiocyanate-dextran with a molecular weight of 4.4 kDa (FD-4) as model drugs. The absorption of insulin was estimated by measuring the changes in plasma glucose levels following intranasal administration, and that of FD-4 was determined by measuring its plasma concentration after dosing. The hypoglycaemic effect after intranasal administration of insulin with aminated gelatin significantly increased compared with that after intranasal administration of insulin in phosphate buffered saline, indicating that aminated gelatin effectively enhanced the nasal absorption of insulin. In contrast, neither kind of native gelatin (isoelectric point = 5.0 and 9.0) showed any absorption-enhancing effect. The pH of the formulations and the concentration of aminated gelatin were found to affect the hypoglycaemic effect. In addition, aminated gelatin at a concentration of 0.2% significantly enhanced the absorption and the efflux of FD-4 through the rat nasal mucosa. The possible perturbation of aminated gelatin to nasal mucosa was evaluated by measuring the leaching of lactate dehydrogenase (LDH) using an in-situ perfusion rat model. Aminated gelatin presented a concentration-dependent (0.1-0.4%) but relatively small effect on the LDH leaching from the rat nasal epithelial membrane. These results suggest that positively charged aminated gelatin could be a new absorption enhancer for nasal delivery of peptide drugs.

Absorption↗

PubMed2005

Dual layer and multilayer enhancements from silver film over nanostructured surface-enhanced Raman substrates.

Novel dual layer and multilayer silver film over nanostructure (SFON) substrates have been developed that provide surface-enhanced Raman scattering (SERS) signal enhancements of greater than 1000% compared to conventional single layer SFON substrates. These substrates provide signal enhancement factors of 3.8 x 10(5) and greater for a variety of SERS active analytes. Substrate preparation is accomplished by vapor depositing a thick (approximately 100 nm) layer of silver on top of an underlying layer of alumina nanoparticles, followed by deposition of additional layers of silver with silver oxide layers between them. Unlike previous dual layer silver island based substrates that have been developed, these substrates do not rely on achieving an optimal morphology via deposition of silver. Instead, these substrates rely on the roughness being provided by the original under-layer, providing enhanced substrate homogeneity and more reproducible signals than either silver island substrates or colloidal substrates. In addition, the signal enhancement gives these substrates extended lifetimes compared to conventional single layer SFON substrates. Finally, this study also shows that geometric surface structure and surface roughness factors play little or no role in this enhancement process, allowing for this multilayer fabrication process to be applied to many different types of substrates achieving similar or even greater results.

Benzoic Acid↗

PubMed2006

Multilayer enhanced gold film over nanostructure surface-enhanced Raman substrates.

We have developed a novel class of gold multilayer, surface-enhanced Raman scattering (SERS) substrates that are capable of enhancing SERS signals by 15.3-fold over conventional gold film over nanostructure (GFON) SERS substrates, making them comparable in sensitivity to optimized silver film over nanostructure (SFON) substrates, while providing the long-term stability obtained from gold. They are fabricated by depositing 10 A thick silver oxide islands on conventional GFON substrates, followed by deposition of a second continuous gold layer. The silver oxide layer acts as a dielectric spacer between the two continuous gold films and produces significantly enhanced SERS signals, as compared to optimized single layer substrates of the same geometry or comparable substrates prepared by deposition of silver islands that are not oxidized. In addition to the enhanced sensitivity of these multilayer substrates, they also exhibit long SERS active shelf-lives (i.e., months), with no measurable degradation in SERS enhancement, and relative standard deviations in SERS enhancement of less than 5.2% across the substrate's surface.

Coated Materials, Biocompatible↗

PubMed1989

Gadolinium-DTPA-enhanced MR imaging of the postoperative lumbar spine: time course and mechanism of enhancement.

To define the time course and mechanism of enhancement of epidural fibrosis after gadolinium-DTPA (Gd-DTPA) injection, we undertook a three-part study in humans and dogs with epidural scar after spine surgery. First, the dynamic in vivo contrast-enhancing properties of epidural scar were assessed by using sequential fast (18-sec) spin-echo sequences after contrast injection. Epidural scar in dogs rapidly enhanced; peak enhancement (101%) was 6 min after injection, with a slower decline toward baseline to 45% after 44 min. Epidural fibrosis in patients followed a similar pattern, with a maximum enhancement of 73% after 5 min. Paraspinal muscle had a lower peak enhancement in both patients (36%) and dogs (22%). Second, vascular injection in two dogs with India ink demonstrated multiple small vessels throughout the epidural scar. Third, light and electron microscopy was performed on epidural scar obtained at reoperation in both patients and dogs. Light microscopy showed multiple small capillaries scattered throughout a background of collagen. Electron microscopy demonstrated a wide variation in the junctions between endothelial cells ranging from "tight" to "loose." Regions of endothelial discontinuity were also visualized. This study suggests that Gd-DTPA diffuses rapidly into the extravascular space in epidural scar, with a slower, net movement toward the intravascular compartment as the agent is renally filtered. The contrast agent transgresses the endothelium through "leaky" intercellular junctions and areas of endothelial discontinuity.

Animals↗

PubMed2002

Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT.

OBJECTIVE: The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis. SUBJECTS AND METHODS: Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up. RESULTS: Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant). CONCLUSION: Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.

Adenocarcinoma↗

PubMed2003

Comparing Levovist-enhanced pulse inversion harmonic imaging and ferumoxides-enhanced MR imaging of hepatic metastases.

OBJECTIVE: The aim of this study was to compare the sensitivity of pulse inversion harmonic digital sonography, unenhanced transabdominal sonography, and ferumoxides-enhanced MR imaging in the depiction of liver metastases. In addition, pulse inversion harmonic digital sonography was performed at different scanning times after Levovist injection to define the best phase for depiction. SUBJECTS AND METHODS: Twenty-six consecutive patients with findings of extrahepatic primary malignancies and liver metastases suspected on transabdominal sonography were examined with both pulse inversion harmonic imaging and ferumoxides-enhanced MR imaging within a 7-day period. Pulse inversion harmonic imaging was performed before and at 20, 100, and 180 sec after a bolus injection of Levovist. MR imaging was performed before and after ferumoxides administration, using breath-hold gradient-recalled echo T1-weighted and turbo spin-echo short tau inversion recovery T2-weighted sequences. Two radiologists independently evaluated image quality, and the number, location, and diameter of lesions scanned using both techniques. Intraoperative sonography or at least 8-month follow-up confirmed the lesions depicted. Analyses included Wilcoxon's signed rank test and Interclass correlation test. RESULTS: Levovist-enhanced pulse inversion harmonic imaging revealed 104 metastases on the first scan after contrast injection, 126 on the second scan, and 118 on the third, compared with 66 on the unenhanced scan. Pulse inversion harmonic digital sonography depicted 90% of lesions shown on ferumoxides-enhanced MR imaging (140 metastases) (p = 0.001). CONCLUSION: Levovist-enhanced pulse inversion harmonic digital sonography is a sensitive technique for depiction of liver metastases. Pulse inversion harmonic digital sonography may have a potential role in imaging patients with possible metastatic involvement of the liver. Further studies are needed to define its place in the workup of these patients. At present, ferumoxides-enhanced MR imaging, being more sensitive, must be performed in all patients in whom pulse inversion harmonic digital sonography is not conclusive or when after pulse inversion harmonic digital sonography, patients remain eligible for surgery.

Adult↗

PubMed1999

Comparison of ultrasmall particles of iron oxide (USPIO)-enhanced T2-weighted, conventional T2-weighted, and gadolinium-enhanced T1-weighted MR images in rats with experimental autoimmune encephalomyelitis.

BACKGROUND AND PURPOSE: Ultrasmall particles of iron oxide (USPIO) constitute a contrast agent that accumulates in cells from the mononuclear phagocytic system. In the CNS they may accumulate in phagocytic cells such as macrophages. The goal of this study was to compare USPIO-enhanced MR images with conventional T2-weighted images and gadolinium-enhanced T1-weighted images in a model of experimental autoimmune encephalomyelitis (EAE). METHODS: Nine rats with EAE and four control rats were imaged at 4.7 T and 1.5 T with conventional T1- and T2-weighted sequences, gadolinium-enhanced T1-weighted sequences, and T2-weighted sequences obtained 24 hours after intravenous injection of a USPIO contrast agent, AMI-227. Histologic examination was performed with hematoxylin-eosin stain, Perls' stain for iron, and ED1 immunohistochemistry for macrophages. RESULTS: USPIO-enhanced images showed a high sensitivity (8/9) for detecting EAE lesions, whereas poor sensitivity was obtained with T2-weighted images (1/9) and gadolinium-enhanced T1-weighted images (0/9). All the MR findings in the control rats were negative. Histologic examination revealed the presence of macrophages at the site where abnormalities were seen on USPIO-enhanced images. CONCLUSION: The high sensitivity of USPIO for macrophage activity relative to other imaging techniques is explained by the histologic findings of numerous perivascular cell infiltrates, including macrophages, in EAE. This work supports the possibility of intracellular USPIO transport to the CNS by monocytes/macrophages, which may have future implications for imaging of human inflammatory diseases.

Animals↗

PubMed1996

Lumbosacral nerve root enhancement with disk herniation on contrast-enhanced MR.

PURPOSE: To evaluate the clinical importance of nerve root enhancement associated with lumbar disk herniation. METHODS: Thirty-two patients with lumbar disk herniation were examined with unenhanced and contrast-enhanced MR imaging. We investigated the relationship between nerve root enhancement and location of herniated disk in the epidural space, onset pattern of symptoms, subsequent treatment, and surgical findings. RESULTS: Ten of the 32 patients had nerve root enhancement, and all belonged to the group with abrupt and severe nerve root compression with no residual space for the root between the herniated disk and the pedicle in the lateral recess. Tight compression of the root without mobility was seen in the four patients with nerve root enhancement who were treated surgically. CONCLUSION: Nerve root enhancement may indicate the existence of abrupt and severe compression of the nerve root as well as the presence of severe adhesion of the herniated disk and the nerve root. This finding does not necessarily determine the type of subsequent treatment.

Adolescent↗

PubMed1998

Chemical chaperones enhance superantigen and conventional antigen presentation by HLA-DM-deficient as well as HLA-DM-sufficient antigen-presenting cells and enhance IgG2a production in vivo.

Chemical chaperones, first defined in studies of mutant cystic fibrosis transmembrane conductance regulator proteins, are small molecules that act as stabilizers of proteins in their native state and have the ability in some cases to rescue protein-folding mutants within cells. HLA-DM is an MHC II-specific molecular chaperone that facilitates peptide loading onto MHC II proteins and also stabilizes empty MHC II molecules prior to their acquisition of antigenic peptides. APC that lack HLA-DM exhibit quantitative defects in protein Ag as well as superantigen presentation. Here we show that both the superantigen and protein presentation defect in MHC II-transfected, HLA-DM-deficient T2 cells can be partially overcome by treating the APC with the chemical chaperones glycerol, DMSO, or trimethylamine oxide. These chemical chaperones also enhance superantigen and conventional Ag presentation by wild-type APC. In vivo, glycerol was found to act as an adjuvant and resulted in enhanced IgG2a production to trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH). In vitro, the enhancement of Ag presentation by chemical chaperones was found to take place at the level of the APC and took several hours to develop. Subcellular fractionation experiments show that HLA-DM enhances presentation of peptides by dense endosome fractions whereas chemical chaperones enhance presentation by light membrane fractions (early endosome or plasma membrane). The mechanism by which these chemical chaperones augment Ag presentation is not defined, but flow cytometric analysis suggests that the enhancement may be due to a subtle effect on the stability of several different proteins at the cell surface.

Adjuvants, Immunologic↗

PubMed1993

Characterization of a nuclear factor, papilloma enhancer binding factor-1, that binds the long control region of human papillomavirus type 16 and contributes to enhancer activity.

Human papillomavirus type-16 (HPV-16) is an epitheliotropic DNA tumor virus associated with the development of cervical carcinoma. The expression of HPV-16 early genes is driven by a cell-type-specific enhancer located in the long control region of the viral genome. We identified an element within the HPV-16 minimal enhancer that has enhancer activity and binds a nuclear factor, designated papillomavirus enhancer binding factor-1 (PEF-1). The element (called-FP-F by us and fp5e by Gloss et al. (EMBO J 6:3735-3743, 1987)) was originally identified as a footprint by DNase I protection experiments. The PEF-1 binding site is centered around a CCAAT box-like CCAAC element. Introduction of A-->T transversions into the CCAAC element of fp5e abolished binding of PEF-1 and concomitantly abolished enhancer function. fp5e resembles binding sites for the transcriptional activators CTF/NF-1 and AP-2; however, we showed that neither of these factors interacted with this element. PEF-1 has an apparent molecular weight of about 110 kDa, and we propose that it is a novel factor involved in the transcriptional activation of HPV-16 gene expression.

Amino Acid Sequence↗

PubMed1987

A cellular transcription factor E4F1 interacts with an E1a-inducible enhancer and mediates constitutive enhancer function in vitro.

Efficient transcription of the adenovirus E1a-inducible E4 gene is mediated by an E1a-dependent enhancer in vivo. In vitro, the enhancer functions constitutively in the absence of E1a, conferring high levels of transcription on the E4 and heterologous promoters. Binding of a cellular transcription factor, E4F1, to two sites within the E4 enhancer and to one other functionally important site located directly upstream of the E4 TATA box is required for transcriptional activity. The relationship between the enhancer and the TATA box proximal site is further demonstrated by the fact that the E4 enhancer can be functionally substituted by two copies of the TATA box proximal site. These and other results suggest that the E4 promoter may be comprised solely of multiple E4F1 binding sites and a TATA box. In addition to the E4 promoter, E4F1 interacts with other adenovirus early promoters and thus may be involved in the co-ordinate expression of E1a-inducible early viral genes.

Adenovirus Early Proteins↗

PubMed1995

IgM receptor-mediated transactivation of the IgH 3' enhancer couples a novel Elf-1-AP-1 protein complex to the developmental control of enhancer function.

The function of the temporally regulated B lymphocyte-specific immunoglobulin heavy chain (IgH) 3' enhancer has been linked to the IgH class switch machinery, but the physiological mechanism(s) of activation has not been discerned. Following crosslinking of the IgM receptor, we demonstrate that the enhancer is transactivated in the B lymphoma cell line BAL-17. In both induced primary B lymphocytes and BAL-17 cells, the enhancer activation is concomitant with the recruitment of a novel DNA binding complex, nuclear factor of activated B cells (NFAB). NFAB contains the tissue-restricted Ets protein Elf-1 and the AP-1 factors Jun-B and c-Fos, which bind to a novel 3' enhancer ETS-AP-1 motif. IgM receptor-mediated activation or stimulation by phorbol-ester in BAL-17 cells demonstrates that the ETS-AP-1 motif, when linked to a heterologous gene, can confer a ligand/receptor-dependent response. In NIH 3T3 cells, Elf-1 expression is required for efficient ETS-AP-1 promoter activity in response to stimulation by 12-O-tetradecanylphorbol 13-acetate. Our results suggest a biological role for Elf-1 in the regulation of IgH gene expression, attribute a functional role for receptor-induced AP-1 proteins in B lymphocytes and provide evidence for a direct link between IgM receptor-mediated signalling and 3' enhancer activation.

Animals↗

PubMed2007

Diagnosis of breast tumors by contrast-enhanced MR imaging: comparison between the diagnostic performance of dynamic enhancement patterns and morphologic features.

PURPOSE: To compare the diagnostic performance of breast lesions by the enhancement patterns and morphologic criteria on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Both T1-weighted 3D gradient-echo sequences with high temporal resolution and high-spatial-resolution MRI were performed on 190 patients with a total of 204 enhancing lesions (144 malignant and 60 benign). The enhancement patterns and morphologic features of each mass and nonmass lesion were analyzed, and the diagnostic performance was compared. RESULTS: The sensitivity and specificity of the morphologic criteria were statistically significantly higher than those of the enhancement patterns (sensitivity: P = 0.0012, specificity: P = 0.0003), and the A(z) values for the three observers were 0.900, 0.919, and 0.900. The diagnostic accuracy of the morphologic criteria for both types of lesions was superior, and the differences were statistically significant (mass: P = 0.0001, nonmass: P = 0.0389). CONCLUSION: The analysis of the morphologic features of enhancing breast lesions alone showed higher diagnostic performance; therefore, signal intensity (SI) time-course data may not be needed to diagnose malignant breast lesions.

Adult↗