bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of both cellular and humoral responses to genetic immunization by co‐administration of an antigen‐expressing plasmid and a plasmid encoding the pro‐apoptotic protein Bax
Authors: Kinsey Berma M. , Marcelli Marco , Song Ling , Bhogal Balbir S. , Ittmann Michael , Orson Frank M. 
Published: March 2004

AbstractBackgroundTransfecting cells with plasmid DNA encoding the protein Bax causes programmed cell death (apoptosis) and results in the formation of cell fragments (apoptotic bodies). It has been known for some time that when dendritic cells phagocytose apoptotic bodies derived from tumor cells, an immune response to tumor antigens can be generated.MethodsGene expression in the skin was evaluated after intradermal injection with plasmids encoding fluorescent proteins. Plasmids encoding foreign antigens were co‐injected intradermally with Bax‐encoding plasmids or control plasmids to elicit both humoral and cytotoxic immunity. Immune responses to the antigens were assessed by ELISA and cytotoxicity assays.ResultsWe demonstrate here that injection of a mixture of reporter gene plasmids into the skin results in the expression of both plasmids in the large majority of the transfected cells. It is known that immune responses to multiple antigens can be elicited by co‐injection of separate individual plasmids. When mice were injected with equal quantities of two antigenic plasmids and either the Bax plasmid or a noncoding control plasmid, antibody responses were increased 4–8‐fold in the Bax group. Similarly, cytotoxic T lymphocyte (CTL) responses in the Bax group showed an 80% increase in the number of lytic units per million cells.ConclusionsThis data shows that simply including the apoptosis‐inducing Bax plasmid along with antigen‐expressing plasmids may provide a significant enhancement of immune responses to DNA vaccines. Published in 2004 by John Wiley & Sons, Ltd.
Reduction in mortalin level by its antisense expression causes senescence‐like growth arrest in human immortalized cells
Authors: Wadhwa Renu , Takano Syuichi , Taira Kazunari , Kaul Sunil C. 
Published: March 2004

AbstractBackgroundHuman normal cells have active p53 and pRB tumor suppressor pathways and undergo telomere shortening at each cell division. When immortalized, these exhibit functional inactivation of one or both tumor suppressor pathways and activation of telomere‐maintaining mechanisms. Regulation of immortalization promoting molecular pathways by other genes is poorly understood and is an essential component of cancer therapeutics. In the present study, we have immortalized human normal cells by functional inactivation of p53 and pRB tumor suppressor proteins and simultaneous activation of telomerase function. We demonstrate that when the expression of mortalin (a member of hsp70 family proteins) was suppressed in such genetically defined immortal cells they underwent a permanent growth arrest.MethodsWI‐38 cells were transfected with expression plasmids encoding papilloma virus E6 and E7 proteins and a catalytic subunit of human telomerase enzyme. The derivative cells were compromised for p53 and pRB senescence pathways, showed telomerase activity and were immortalized. These cells were transfected with antisense expression plasmid for mortalin. The derivative clones were analyzed for mortalin expression, proliferation and telomerase activity.ResultsWI‐38 cells were immortalized with E6, E7 and the catalytic subunit of human telomerase. The derivative‐immortalized cells when suppressed for mortalin expression underwent senescence‐like growth arrest.ConclusionsThe data demonstrate that suppression of mortalin is sufficient to induce growth arrest in human immortalized cells that have compromised p53 and pRB functions and possess telomerase activity. Copyright © 2004 John Wiley & Sons, Ltd.
Hepatic delivery of particulates in the submicron range by a hydrodynamics‐based procedure: implications for particulate gene delivery systems
Authors: Kobayashi Naoki , Hirata Kazuhiro , Chen Shi , Kawase Atsushi , Nishikawa Makiya , Takakura Yoshinobu 
Published: March 2004

AbstractBackgroundA large‐volume intravenous (i.v.) injection of DNA, i.e. a hydrodynamics‐based transfection procedure, is known to be an efficient and liver‐specific method of in vivo gene delivery. However, little is available on an applicable particle size in the procedure.MethodsWe examined the effect of particle size on the hepatic delivery by the hydrodynamics‐based procedure, using fluorescein isothiocyanate labeled polystyrene microspheres (MS) of 50, 200 or 500 nm in diameter. MS were injected intravenously to mice by a conventional (normal) or the hydrodynamics‐based procedure and their degree of hepatic uptake was determined fluorometrically.ResultsFor all sizes tested, the two procedures were similar in terms of the apparent degree of hepatic uptake, whereas the intrahepatic localization of MS was apparently different between the procedures as shown by an examination of frozen tissue sections. In mice with gadolinium chloride induced Kupffer cell blockade, the hepatic uptake of MS following the normal procedure was decreased while that of the hydrodynamics‐based procedure was less affected. This phenomenon of enhanced hepatic delivery seemed to be more effective for larger particles. Confocal microscopic observation of hepatocyte suspensions indicated that part of the injected MS‐50 was delivered intracellularly following the hydrodynamics‐based procedure, whereas almost all the observed MS‐200 and MS‐500 were detected in the extracellular compartment or on the surface of the cells. This was supported by the fact that most of the injected MS existed pericellularly around the transgene‐expressing cells.ConclusionsThe hydrodynamics‐based procedure facilitated extravasation and hepatic delivery of MS. Larger MS were more efficiently extravasated and trapped by the liver, whereas intracellular delivery hardly occurred with them. Copyright © 2004 John Wiley & Sons, Ltd.
Dependence of the cellular internalization and transfection efficiency on the structure and physicochemical properties of cationic detergent/DNA/liposomes
Authors: Llères David , Weibel Jean‐Marc , Heissler Denis , Zuber Guy , Duportail Guy , Mély Yves 
Published: March 2004

AbstractBackgroundControl of the structure and physicochemical properties of DNA complexed with nonviral vectors is essential for efficient biodistribution and gene delivery to cells. Cationic liposomes interact with DNA giving transfection competent but large and heterogeneous aggregates. On the other hand, cationic detergents condense DNA into small homogeneous but reversible complexes inefficient for transfection.MethodsIn order to combine the favorable features of both vectors, ternary complexes were prepared by adding cationic liposomes to plasmid DNA condensed by cationic detergents. The structure and physicochemical properties of these complexes were investigated by electron microscopy, quasi‐elastic light scattering, gel electrophoresis and fluorescence techniques. These data were then correlated with the transfection efficiency and intracellular trafficking of the ternary complexes determined by luciferase gene expression and confocal microscopy, respectively.ResultsThe ternary complexes were found to form small, homogeneous, globular, stable and positively charged particles with a highly dense and packed lamellar internal structure differing from the multilamellar structure $(L_{\alpha}^{C})$ of the corresponding lipoplexes. In the presence of serum, the ternary complexes were more efficiently internalized into cells, less toxic and showed 20‐fold higher transfection efficiency than lipoplexes.ConclusionsThis study showed that small, monodisperse and highly stable complexes could be obtained by precompaction of DNA with cetyltrimethylammonium bromide, followed by addition of cationic lipids. The higher efficiency of the ternary complexes with respect to their corresponding lipoplexes was related to their internal structure which prevents their dissociation by serum proteins and allows efficient internalization in the target cells. Copyright © 2004 John Wiley & Sons, Ltd.
In vivo measurement of T1ρ dispersion in the human brain at 1.5 tesla
Authors: Borthakur Arijitt , Wheaton Andrew J. , Gougoutas Alexander J. , Akella Sarma V.S. , Regatte Ravinder R. , Charagundla Sridhar R. , Reddy Ravinder 
Published: March 2004

AbstractPurposeTo measure T1ρ relaxation times and T1ρ dispersion in the human brain in vivo.Materials and MethodsMagnetic resonance imaging (MRI) was performed on a 1.5‐T GE Signa clinical scanner using the standard GE head coil. A fast spin‐echo (FSE)‐based T1ρ‐weighted MR pulse sequence was employed to obtain images from five healthy male volunteers. Optimal imaging parameters were determined while considering both the objective of the study and the guarantee that radio‐frequency (RF) power deposition during MR did not exceed Food and Drug Administration (FDA)‐mandated safety levels.ResultsT1ρ‐weighted MR images showed excellent contrast between different brain tissues. These images were less blurred than corresponding T2‐weighted images obtained with similar contrast, especially in regions between brain parenchyma and cerebrospinal fluid (CSF). Average T1ρ values for white matter (WM), gray matter (GM), and CSF were 85 ± 3, 99 ± 1, and 637 ± 78 msec, respectively, at a spin‐locking field of 500 Hz. T1ρ is 30% higher in the parenchyma and 78% higher in CSF compared to the corresponding T2 values. T1ρ dispersion was observed between spin‐locking frequencies 0 and 500 Hz.ConclusionT1ρ‐weighted MRI provides images of the brain with superb contrast and detail. T1ρ values measured in the different brain tissues will serve as useful baseline values for analysis of T1ρ changes associated with pathology. J. Magn. Reson. Imaging 2004;19:403–409. © 2004 Wiley‐Liss, Inc.
Four‐dimensional magnetic resonance velocity mapping of blood flow patterns in the aorta in patients with atherosclerotic coronary artery disease compared to age‐matched normal subjects
Authors: Bogren Hugo G. , Buonocore Michael H. , Valente Richard J. 
Published: March 2004

AbstractPurposeTo test the hypothesis that age and atherosclerotic coronary artery disease (CAD) may influence aortic blood flow patterns.Materials and MethodsA total of 21 patients with CAD, 37–86 years old, were studied, together with 20 age‐matched normal subjects. Time‐resolved, three‐direction velocity data over an entire volume were obtained with sequential single‐slice two‐dimensional cardiac‐gated magnetic resonance (MR) velocity‐encoded phase‐contrast sequences.ResultsIn both normal subjects and CAD patients, the time it took for particles to travel from aortic valve to descending aorta was significantly longer in the elderly age group than in the younger (37–46 years old). This time was significantly longer in patients than in normal subjects. Systolic velocities were significantly higher in young normal subjects than in elderly normal subjects, and significantly lower in CAD patients than in age‐matched normal subjects. Retrograde velocity was higher in CAD patients than in normal subjects, and higher in elderly CAD patients than in young.ConclusionCAD patients have abnormal blood flow patterns in the aorta compared with age‐matched normal subjects, especially young patients ages 37–46. The aging process has a similar effect on blood flow patterns as atherosclerosis. Ascending aorta flow is chaotic in some very elderly normal subjects and in CAD patients of all ages. Chaotic aortic flow may result in reduced blood flow into the coronary arteries. J. Magn. Reson. Imaging 2004;19:417–427. © 2004 Wiley‐Liss, Inc.
Stability of real‐time MR temperature mapping in healthy and diseased human liver
Authors: Weidensteiner Claudia , Kerioui Noureddine , Quesson Bruno , de Senneville Baudoin Denis , Trillaud Hervé , Moonen Chrit T.W. 
Published: March 2004

AbstractPurposeTo determine the stability and quality of MR temperature mapping using the proton resonance frequency (PRF) method in the liver of hepatic tumor patients.Materials and MethodsThe standard deviation (SD) of a series of temperature maps was determined in 30 patients (21 patients with cirrhotic livers with carcinoma, and nine patients with noncirrhotic livers with metastasis or angioma) and in five volunteers at normal body temperature under free breathing. A respiratory‐gated segmented echo‐planar imaging (EPI) sequence (three slices in one expiration phase) was performed with sensitivity encoding (SENSE) acceleration on a 1.5 T scanner. Motion‐corrupted images were identified by calculation of the cross‐correlation coefficient, and discarded.ResultsA T2* range of 10–33 msec was found, with especially low values in advanced cirrhotic livers. The mean temperature SD in patients was 2.3°C (range = 1.5–5.0°C). The stability in healthy livers was slightly better than that in cirrhotic livers, and it was higher in the right liver than in the left liver. The gating failed in 4% of the images when the respiratory cycle was irregular, leading to motion artifacts and errors in the temperature maps.ConclusionThe achieved temperature stability and image quality makes real‐time quantitative monitoring of thermal ablation of liver tumors feasible on a clinical scanner. J. Magn. Reson. Imaging 2004;19:438–446. © 2004 Wiley‐Liss, Inc.
Analytical error propagation in diffusion anisotropy calculations
Authors: Poonawalla Aziz Hatim , Zhou Xiaohong Joe 
Published: March 2004

AbstractPurposeTo develop an analytical formalism describing how noise and selection of diffusion‐weighting scheme propagate through the diffusion tensor imaging (DTI) computational chain into variances of the diffusion tensor elements, and errors in the relative anisotropy (RA) and fractional anisotropy (FA) indices.Materials and MethodsSingular‐value decomposition (SVD) was used to determine the tensor variances, with diffusion‐weighting scheme and measurement noise incorporated into the design matrix. Anisotropy errors were then derived using propagation of error. To illustrate the applications of the model, 12 data sets were acquired from each human subject, over a range of b‐values (500–2500 seconds/mm2) and diffusion‐weighting gradient directions (N = 6–55). The mean RA and FA values and their respective errors were calculated within a region of interest (ROI) in the splenium. The RA and FA errors as a function of b‐value and N were evaluated, and a number of diffusion‐weighting schemes were assessed based on a new metric, sum of diffusion tensor variances.ResultsWhen the acquisition time was held constant, the sum of the diffusion tensor variances decreased as N increased. The same trend was also observed for several diffusion‐weighting schemes with constant condition number when noise in the diffusion‐weighted (DW) images was assumed unity. Errors in both FA and RA increased with b‐value and decreased with N. The FA error in the splenium was approximately threefold smaller than RA error, irrespective of b‐value or N.ConclusionThe condition number may not adequately characterize the noise sensitivity for a given diffusion‐weighting scheme. Signal averaging may not be as effective as increasing N, especially when N is small (e.g., N < 13). Due to its smaller error, FA is preferred over RA for quantitative DTI applications. J. Magn. Reson. Imaging 2004;19:489–498. © 2004 Wiley‐Liss, Inc.
Volumetric interpolated contrast‐enhanced MRA for the diagnosis of pulmonary embolism in an ex vivo system
Authors: Biederer Jürgen , Liess Carsten , Charalambous Nikolas , Heller Martin 
Published: March 2004

AbstractPurposeTo implement a three‐dimensional gradient‐recalled echo (GRE) volumetric interpolated breath‐hold examination (VIBE) sequence for pulmonary contrast‐enhanced MRA (CE‐MRA) in an experimental setup.Materials and MethodsEight porcine lungs were intubated, inflated inside a chest phantom, and examined at 1.5 T during slow perfusion (2–300 mL/minute). Three‐dimensional‐MRA was performed with and without contrast agent using three‐dimensional‐GRE (VIBE) with TR/TE = 4.5/1.9 msec, TA = 23 seconds, FOV = 390 mm, FA = 12°/30°, as well as a standard three‐dimensional‐GRE sequence and T2 fast spin‐echo (FSE) sequences. Four of the eight lungs were embolized with autologous blood clots. By consensus readings, two observers evaluated the detectability of peripheral vessels, signal intensity over vessels and lung, and visualization of emboli. Digital subtraction angiograms served as a control to document vessel patency.ResultsPrior to contrast administration, three‐dimensional‐VIBE/12° yielded the best results for lung parenchyma signal and visualization of small vessels (third‐order, P < 0.01); however, no emboli were detected (due to lack of contrast). After administration of contrast agent, three‐dimensional‐GRE (VIBE) at FA = 30° provided significantly better results (fifth‐order branches, documentation of subsegmental occlusions [fourth order], P < 0.01). T2‐FSE images documented water uptake into the lungs. Digitally subtracted angiography (DSA) confirmed the patency of seventh‐order branches.ConclusionThis ex vivo study confirms the potential advantages of using a dual MR investigation for pulmonary embolism, combining three‐dimensional‐GRE (VIBE) at FA = 12° to image lung parenchyma and at FA = 30° for CE‐MRA. J. Magn. Reson. Imaging 2004;19:428–437. © 2004 Wiley‐Liss, Inc.
Parallel and nonparallel simultaneous multislice black‐blood double inversion recovery techniques for vessel wall imaging
Authors: Itskovich Vitalii V. , Mani Venkatesh , Mizsei Gabor , Aguinaldo Juan Gilberto S. , Samber Daniel D. , Macaluso Frank , Wisdom Paul , Fayad Zahi A. 
Published: March 2004

AbstractPurposeTo reduce long examination times of black‐blood vessel wall imaging by acquiring multiple slices simultaneously and by using parallel acquisition techniques.Materials and MethodsDIR‐rapid acquisition with relaxation enhancement (;RARE) techniques imaging up to 10 simultaneous slices per acquisition with single and multiple 180°‐reinversion pulses were developed. A slab‐selective reinversion multislice DIR‐RARE sequence incorporating generalized autocalibrating partially parallel acquisitions (GRAPPA) imaging was implemented. Four‐channel and eight‐channel carotid coils were built to test these sequences. A total of 11 subjects were studied. Contrast‐to‐noise ratio (CNR) and signal‐to‐noise ratio (SNR) efficiency factor (SEF, SNR/unit time/slice) were measured from aortic images of three healthy subjects to determine optimal MR parameters. The DIR–RARE‐GRAPPA sequence was run on aortas and carotid arteries of the five remaining healthy subjects and three atherosclerotic patients with optimal parameters (acquisition times 12–21 seconds).ResultsSEFs of slab‐selective protocols were significantly higher than those of slice‐selective protocols, and SEFs of DIR‐RARE‐GRAPPA protocols were significantly higher than corresponding non‐GRAPPA protocols (P < 0.05). CNR was not significantly different for all imaging protocols. The DIR‐RARE‐GRAPPA multislice sequence showed 8.35‐fold time improvement vs. single–slice DIR‐2RARE sequence.ConclusionFuture MRI atherosclerotic plaque studies can be performed in substantially shorter times using these methods. J. Magn. Reson. Imaging 2004;19:459–467. © 2004 Wiley‐Liss, Inc.
Water diffusion in a rat glioma during ganciclovir‐thymidine kinase gene therapy‐induced programmed cell death in vivo: Correlation with cell density
Authors: Valonen Piia K. , Lehtimäki Kimmo K. , Väisänen Tuula H. , Kettunen Mikko I. , Gröhn Olli H.J. , Ylä‐Herttuala Seppo , Kauppinen Risto A. 
Published: March 2004

AbstractPurposeTo study the characteristics of diffusion magnetic resonance imaging (MRI) contrast in a rat brain BT4C glioma during progression of ganciclovir (GCV)‐thymidine kinase gene therapy‐induced programmed cell death (PCD) in vivo.Materials and MethodsThe trace of the diffusion tensor (Dav = 1/3Trace
equation image
), T2, and spin density were determined by MRI and the apparent diffusion coefficient (ADC) of water by diffusion nuclear MR (NMR) spectroscopy using largely varying b values and diffusion times (tD) at 4.7 T. Cell count and apoptotic cells were quantified by histological means.ResultsDecline in cell count was strongly associated with increase in both Dav and T2. Spin density ratio between tumor and contralateral parietal cortex increased with a very similar time course as Dav and T2, indicating net water gain into the eradicating tumor. Diffusion spectroscopy showed a nonmonoexponential signal decay at all tD values ranging from 14–192 msec. During PCD, the ADC of the component yielding fast diffusion coefficient (D1), as acquired with tD ≥ 47 msec, increased with kinetics similar to those of Dav (tD = 4.8 msec). The fractional size of D1 increased by 10% to 15% throughout the entire tD range. Apparent water residence time of the slow diffusion component, D2, shortened from a value of 38.3 ± 1.7 msec on day 0 to 33.4 ± 0.5 msec by day 8.ConclusionThe present results show that reduced cell density and increased water content, leading to altered water microenvironment, are associated with increased water diffusion coefficient in eradicating gliomas as a result of PCD. J. Magn. Reson. Imaging 2004;19:389–396. © 2004 Wiley‐Liss, Inc.
A novel method for analysis of TOMROP data
Authors: Pickup Stephen , Wood Andrew K.W. , Kundel Harold L. 
Published: March 2004

AbstractPurposeTo develop an efficient method for extracting maps of the corrected T1 from images generated using the T One by Multiple Read Out Pulses (TOMROP) sequence.Materials and MethodsAn expression is developed for the true T1 in terms of the parameters from a three‐parameter fit of the TOMROP data. Solutions of gadodiamide in normal saline with concentrations of 0.0, 0.06, 0.11, 0.23, 0.46, and 0.91 mM were prepared and T1 measurements were performed using both the inversion recovery (IR) and the TOMROP methods. The TOMROP data were analyzed using the proposed technique and the results compared to those from the IR measurements.ResultsThe T1 estimates generated from the TOMROP data using the proposed method were consistent with the IR results. However, systematic errors were observed in the T1 estimates when the repetition time was not sufficient for full recovery of axial magnetization. Relaxation times determined using the proposed method were within 1% of the spectroscopiclly determined values for T1 values in the range of 0.28–2.8 seconds when a suitable delay was employed.ConclusionThe proposed method of analysis was found to yield accurate T1 estimates when the assumptions used in the analysis were not violated. J. Magn. Reson. Imaging 2004;19:508–512. © 2004 Wiley‐Liss, Inc.