bluuebunny/crossref_metadata_2025_split huggingface dataset:
Achieving standards in urban systemic reform: An example of a sixth grade project‐based science curriculum
Authors: Rivet Ann E. , Krajcik Joseph S. 
Published: July 2004

AbstractA challenge for urban systemic reform initiatives in science education has been to achieve local, state, and national standards for teaching and learning. We have collaborated with teachers in the Detroit Public School System to design project‐based curriculum materials that contextualize the learning of science in meaningful real‐world problems, engage students in science inquiry, and use learning technologies. We present a sixth grade project‐based science unit in which students explored the driving question “How Do Machines Help Me Build Big Things?” and address the science learning goals of balanced and unbalanced forces, simple and complex machines, and mechanical advantage. Twenty‐four teachers and over 2500 students in Detroit participated in enactments of this project over 4 years. Student learning outcomes were determined for the three learning goals and inquiry process skills using pre‐ and postachievement tests. Achievement outcomes as measured by the pre/posttest show significant and consistently high learning gains, even as participation in the project increased to include greater numbers of teachers and students in successive enactments, and leadership of the professional development support for this project transitioned from university researchers to district teacher leaders. These results illustrate that materials which contextualize learning and support student inquiry as part of an urban systemic reform effort can promote learning of important and meaningful science content aligned with standards. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 669–692, 2004
HXT5 expression is under control of STRE and HAP elements in the HXT5 promoter
Authors: Verwaal René , Arako Megumi , Kapur Rick , Verkleij Arie J. , Theo Verrips C. , Boonstra Johannes 
Published: July 2004

AbstractHexose transporter (Hxt) proteins transport glucose across the plasma membrane in the yeast Saccharomyces cerevisiae. Recently, we have shown that expression of HXT5 is regulated by the growth rate of the cells. Because gene expression is regulated by binding of specific transcription factors to regulatory elements in the promoters of genes, the presence of putative regulatory elements in the promoter of HXT5 was determined by computer‐assisted analysis. This revealed the presence of two putative stress‐responsive elements (STREs), one putative post‐diauxic shift (PDS) element and two putative Hap2/3/4/5p (HAP) complex binding elements. The involvement of these elements was studied by using mutations in a HXT5 promoter–LacZ fusion construct. Growth during various conditions that result in low growth rates of yeast cells revealed that the STRE most proximal to the translation initiation site seemed to be involved in particular in regulation of HXT5 expression during growth at decreased growth rates. In addition, the HAP elements seemed to be required during growth on non‐fermentable carbon sources. The PDS element and, to a lesser extent, the other STRE showed particular involvement in regulation of HXT5 expression during growth on ethanol. Finally, it was shown that the PKA pathway, which is known to be involved in expression of STRE‐regulated genes, was also involved in regulation of HXT5 expression. A possible mechanism by which expression of HXT5 could be regulated by the transcriptional regulatory elements in the promoter is discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Actin distribution is disrupted upon expression of Yersinia YopO/YpkA in yeast
Authors: Nejedlik L. , Pierfelice T. , Geiser J. R. 
Published: July 2004

AbstractPathogenic Yersinia spp. use a Type III secretion system to inject effector proteins directly into host cells. The effector proteins interfere with normal cellular signalling and disrupt cytoskeletal structures that are required for phagocytosis of the invader. Here we show that Saccharomyces cerevisiae responds to one of these effector proteins, YopO/YpkA, essentially as has been observed in mammalian model systems. Expression of YopO in yeast results in inhibition of growth on solid medium. YopO expression confers a cytotoxic effect upon yeast with only 6% of cells remaining viable after 3 h of expression. Moreover, there is no obvious cell cycle arrest associated with cytotoxicity. YopO expression disrupts the normal distribution of actin in yeast. Actin is no longer observed exclusively at sites of cell growth. Concurrent with disruption of actin, we find YopO localizes to the cell periphery, where it may disrupt actin localization. Inactivation of the YopO kinase has no apparent effect upon the deleterious effects of YopO. Collectively, our results show that the yeast model system that has been constructed meets all requirements to serve as an excellent genetic model to exploit examination of YopO and its intracellular targets. Copyright © 2004 John Wiley & Sons, Ltd.
Ischemic complications of transcatheter arterial chemoembolization in liver malignancies
Authors: Tarazov P.G. , Polysalov V.N. , Prozorovskij K.V. , Grishchenkova I.V. , Rozengauz E.V. 
Published: July 2004

Objective: To determine the frequency, character, methods of treatment, and outcome of ischemic complications after transcatheter hepatic artery chemoembolization (TACE). Material and Methods: Between 1985 and 1998, 827 sessions of TACE with Doxorubicin mixed with iodized oil, and gelatin sponge particles were performed in 282 patients with primary and metastatic liver cancer. Post-TACE monitoring included clinical observation, US and CT. Results: Ischemic complications appeared in 13 (4.6%) and included the following: hepatic (n=6) and splenic abscess (n=1), cholecystitis (n=3), and bile duct necrosis (n=3). The treatment was US-guided drainage in 12 cases and systemic antibacterial therapy in 1. No negative influence of these complications on survival of patients was detected. Conclusion: Serious ischemic complications of TACE occur in about 5% of patients and can be successfully managed without open surgery. These complications do not worsen the survival of patients.
Factors influencing patient radiation doses from barium enema examinations
Authors: Vehmas T. , Lampinen J.S. , Mertjärvi A. , Rannikko S. 
Published: July 2004

Purpose: To analyse factors behind the variation of patient doses from barium enema (BE) examinations. Material and Methods: The patients' (n=89) organ and effective doses (E) due to BE examinations were computed with the ODS-60 program. An average risk factor for BE examinations was derived using the BEIR V schema. The correlation of E with several independent variables was analysed. Results: Median Es at five hospitals were 4.4, 6.1, 7.1, 13 and 16 mSv. The E of the female patients (median 9.2 mSv) was higher than that of the males (median 5.4 mSv) ( p&lt;0.001) due to the higher female doses to the gonads, bladder and uterus, resulting from different body structure. An average fatal risk factor of 0.02% per one BE examination was derived. Factors controlled by the radiologist (screening time, number of exposures) explained 40% and patient-related factors explained 16% of the total variation of E. The equipment-related factors are included in the residual 44%. Conclusion: Due to the large contribution of the radiologists' examination technique in the value of E, an optimal examination technique is essential in reducing doses and the stochastic risk to patients.
Localization of insulinomas: Comparison of conventional arterial stimulation with venous sampling (ASVS) and superselective ASVS
Authors: Baba Y. , Miyazono N. , Nakajo M. , Kanetsuki I. , Nishi H. , Inoue H. 
Published: July 2004

Purpose: To examine the value of superselective arterial stimulation venous sampling (ASVS) to localize insulinomas. Material and Methods: Superselective ASVS (SS-ASVS) was performed in 9 patients with insulinoma. Injection of secretagogue (calcium gluconate: 0.01 mEq Ca++/kg) was performed into the gastroduodenal, splenic (proximal and distal), and superior mesenteric arteries in 9 patients and additionally into the dorsal pancreatic artery in 6 patients. Sampling from the hepatic vein was performed to measure serum insulin concentrations at 30, 60 and 120 s after each injection of secretagogue into these arteries. SS-ASVS results were correlated with surgical findings, compared to those of conventional ASVS. Results: Insulinomas were correctly localized to the head, body or tail of the pancreas by SS-ASVS in 8 patients (89%). Conventional ASVS detected insulinomas in 7 patients (78%), although it could not distinguish whether the insulinoma was located in the pancreatic body or tail in 4 of the 7 patients. There were eight-fold or more increases in serum insulin levels in hepatic venous samples related to the artery supplying the tumor in 8 patients. Localization of the insulinomas was verified at surgery in all patients. Conclusion: SS-ASVS is a useful method for detailed evaluation of overproduction of insulin from pancreatic insulinomas and their localization. When the pancreatic insulinoma is situated in the pancreatic body or tail, the localization is more accurately made by SS-ASVS than by conventional ASVS.
Quantitative bone scintigraphy: A methodological evaluation in prostate cancer
Authors: Rydh A. , Åhlström K. Riklund , Larsson A. , Johansson L. , Damber J.-E. , Tomiç R. , Hietala S.-O. 
Published: July 2004

Purpose: To evaluate a simple method for quantification of focal activity in bone scintigraphy (BS). Material and Methods: The gamma camera was calibrated using a phantom. Quantitative bone scintigraphy (QBS) was performed on 11 men recently diagnosed with prostate cancer (PCa), for whom routine BS showed involvement of the skeleton. Following endocrine therapy for 4 to 8 months, a second QBS was performed. Changes in QBS values were then compared to changes in serum levels of prostate-specific antigen (PSA). Results: PSA response indicating regression of PCa was accompanied by a decrease in the QBS value in 8 of the 11 patients. The overall mean error of the QBS values was 15%. Conclusion: QBS according to this method is a relatively simple procedure that might contribute to objective evaluation of therapeutic effects in skeletal metastases, although its validity must be tested in a larger clinical material.
Activity-based costing in radiology: Application in a pediatric radiological unit
Authors: Laurila J. , Suramo I. , Brommels M. , Tolppanen E.-M. , Koivukangas P. , Lanning P. , Standertskjöld-Nordenstam C.-G. 
Published: July 2004

Purpose: To get an informative and detailed picture of the resource utilization in a radiology department in order to support its pricing and management. Material and Methods: A system based mainly on the theoretical foundations of activity-based costing (ABC) was designed, tested and compared with conventional costing. The study was performed at the Pediatric Unit of the Department of Radiology, Oulu University Hospital. The material consisted of all the 7,452 radiological procedures done in the unit during the first half of 1994, when both methods of costing where in use. Detailed cost data were obtained from the hospital financial and personnel systems and then related to activity data captured in the radiology information system. Results: The allocation of overhead costs was greatly reduced by the introduction of ABC compared to conventional costing. The overhead cost as a percentage of total costs dropped to one-fourth of total costs, from 57% to 16%. The change of unit costs of radiological procedures varied from −42% to +82%. Conclusion: Costing is much more detailed and precise, and the percentage of unspecified allocated overhead costs diminishes drastically when ABC is used. The new information enhances effective departmental management, as the whole process of radiological procedures is identifiable by single activities, amenable to corrective actions and process improvement.
CT scores of emphysema and oxygen desaturation during low-grade exercise in patients with emphysema
Authors: Taguchi O. , Gabazza E.C. , Yoshida M. , Yasui H. , Kobayashi T. , Yuda H. , Hataji O. , Adachi Y. 
Published: July 2004

Purpose: We evaluated the usefulness of CT for assessing oxygen desaturation during walking in patients with emphysema. Material and Methods: The study comprised 32 patients with emphysema (mean age 67±6 years). Serial CT images of 5 mm were obtained from the apex to the basal regions of the lung during deep inspiration. The severity of emphysema was scored by four physicians according to a visual method. A six-minute walking test and oxygen desaturation (pSO2) measurements were performed. Results and Conclusion: The mean CT score of the four observers was signfiicantly correlated with the nadir pSO2 and ΔpSO2, but did not correlate with the total distance walked. These results suggest that CT may be used for the assessment of oxygen desaturation during low-grade exercise in patients with emphysema.
Effect of CT digital image compression on detection of coronary artery calcification
Authors: Zheng L.-M. , Sone S. , Itani Y. , Wang Q. , Hanamura K. , Asakura K. , Li F. , Yang Z.-G. , Wang J.-C. , Funasaka T. 
Published: July 2004

Purpose: To test the effect of digital compression of CT images on the detection of small linear or spotted high attenuation lesions such as coronary artery calcification (CAC). Material and Methods: Fifty cases with and 50 without CAC were randomly selected from a population that had undergone spiral CT of the thorax for screening lung cancer. CT image data were compressed using JPEG (Joint Photographic Experts Group) or wavelet algorithms at ratios of 10:1, 20:1 or 40:1. Five radiologists reviewed the uncompressed and compressed images on a cathode-ray-tube. Observer performance was evaluated with receiver operating characteristic analysis. Results: CT images compressed at a ratio as high as 20:1 were acceptable for primary diagnosis of CAC. There was no significant difference in the detection accuracy for CAC between JPEG and wavelet algorithms at the compression ratios up to 20:1. CT images were more vulnerable to image blurring on the wavelet compression at relatively lower ratios, and "blocking" artifacts occurred on the JPEG compression at relatively higher ratios. Conclusion: JPEG and wavelet algorithms allow compression of CT images without compromising their diagnostic value at ratios up to 20:1 in detecting small linear or spotted high attenuation lesions such as CAC, and there was no difference between the two algorithms in diagnostic accuracy.
Intravascular ultrasound angioplasty in peripheral arterial occlusion: Preliminary experience
Authors: Goyen M. , Kröger K. , Buss C. , Rudofsky G. 
Published: July 2004

Purpose: To determine if ultrasound angioplasty in a percutaneous approach was capable of recanalizing occluded arteries in acute and subacute peripheral arterial occlusions. Material and Methods: We applied an ultrasound angioplasty device in a percutaneous approach in 9 patients with peripheral arterial occlusions. All patients suffered from severe leg ischemia due to subacute thrombotic occlusions. Results: The ultrasound transmitter easily created a channel within the occlusive material. To further reduce the mass of the occlusive material, an aspiration thrombectomy was performed in all cases, leading to a complete recanalization in 7 cases. In 2 cases, a remaining stenosis was successfully dilated. Conclusion: Intravascular ultrasonic devices can be useful for recanalization of occluded peripheral arteries. In particular, if thrombolytic therapy of longer peripheral arterial occlusions fails or is contraindicated, ultrasound angioplasty may be a new approach for recanalization.
Symptomatic peripheral vascular tree stenosis: Comparison of subtracted and nonsubtracted 3D contrast-enhanced MR angiography with fat suppression
Authors: Sueyoshi E. , Sakamoto I. , Matsuoka Y. , Hayashi H. , Hayashi K. 
Published: July 2004

Objective: To determine the clinical feasibility of contrast-enhanced three-dimensional (3D) MR angiography (MRA) with fat suppression spectral inversion at lipids and to compare subtracted and nonsubtracted images. Material and Methods: In 13 patients suspected of having lower extremity ischemia, 3D dynamic contrast-enhanced MRA of the iliac and femoral arteries was performed using the fat suppression technique. The validity of the MRA interpretations of the degree of stenoses was evaluated by comparing with conventional angiography as the gold standard. The contrast-to-noise (C/N) ratios of both subtracted and nonsubtracted maximum-intensity-projection (MIP) images were calculated. Results: In the arteries with stenosis of 50% or greater, the sensitivity and specificity of the subtracted MR angiograms were 100% and 96.5%, respectively, not significantly different from the correponding values in nonsubtracted MRAs (100% and 94.1%, respectively). The C/N ratios of the subtracted images were significantly higher than those of the nonsubtracted images ( p<0.001). Conclusion: With this technique, fat suppression can be performed with only a slight increase in the examination time. A lower dose of contrast material can be used in MRA with fat suppression than without it. Subtracted MRA improves the ease of interpretation compared to nonsubtracted MRA.
Patient radiation exposure during coronary angiography and intervention
Authors: Fransson S.-G. , Persliden J. 
Published: July 2004

Purpose: To prospectively register fluoroscopic and cine times in a random fashion, and to measure patient radiation exposure from routine coronary angiography and coronary balloon angioplasty. We also evaluated an optional dose reduction system used during interventions. Material and Methods: The incident radiation to the patient was measured as kerma area product (KAP) in Gycm2, obtained from an ionisation chamber mounted on the undercouch tube during 65 coronary angiography procedures and another 53 percutaneous transluminal coronary angioplasties (including 29 stent procedures), mostly directly following complete coronary angiography. Results and Conclusion: The values from coronary angiography were comparable to other reports with a mean fluoroscopic time of 4.4 min and a mean KAP value of 62.6 Gycm2. The corresponding figures from coronary balloon angioplasty without stenting were lower than otherwise reported, with 8.2 min and 47.9 Gycm2, respectively. The use of coronary stents did prolong the mean fluoroscopic time (10.5 min) but did not significantly enhance the patient mean radiation dose (51.4 Gycm2). The dose reduction technique resulted in a significant KAP value reduction of 57%. In conclusion, with regard to radiation exposure, coronary angiography and balloon angioplasty are considered safe procedures.
CT and MR imaging of the liver: Clinical importance of nutritional status
Authors: Leander P. , Sjöberg S. , Höglund P. 
Published: July 2004

Purpose: In an experimental study in rats a correlation between nutritional status and hepatic attenuation in CT and signal intensities in MR imaging was shown. Is physiological nutritional status of importance in clinical CT and MR imaging? Material and Methods: In a cross-over study including 12 healthy volunteers (6 women and 6 men, mean age 34 years), CT and MR imaging of the liver were performed with nutritional status at three different levels, i.e., normal, fasting and after glycogen-rich meals. CT and MR were performed on clinical imaging systems and hepatic attenuation and signal intensity, respectively, were assessed. In MR, T1-weighted, proton density-weighted and T2-weighted pulse-sequences were used. Results: In CT there were significantly ( p<0.01) higher liver attenuations in normal nutritional status and after glycogen rich-meals compared to the fasting condition. The difference between fasting and glycogen-rich meals were 10.5 HU for men, 7.4 for women and mean 8.8 HU for all 12 volunteers. In MR imaging the differences were small and non-significant. The results of this study are in accordance with an earlier experimental study in rats. Conclusion: In CT it may be of importance not to have patients in a fasting condition as it lowers the attenuation in normal liver tissue. The findings are important for planning of clinical studies where hepatic attenuation will be assessed and may be of some importance in clinical CT. In MR imaging the results indicate that the nutritional status is of less importance.
Multishot Echo-Planar Imaging with Gadopentetate Dimeglumine: Preliminary study of efficacy for detection of hypovascular metastatic liver tumors
Authors: Murakami T. , Kim T. , Hori M. , Takamura M. , Tsuda K. , Takahashi S. , Narumi Y. , Nakamura H. 
Published: July 2004

Objective: To evaluate the usefulness of sequential T2-weighted spin-echo type multishot echo-planar (T2-EP) imaging with gadopentetate dimeglumine for the detection of hypovascular metastatic liver tumors. Material and Methods: Fifteen consecutive patients with 56 proven hypovascular metastatic liver tumors were included in the study. Three observers blindly and independently read the whole-liver images obtained with T2-weighted spin-echo, T2-weighted single-shot fast spin-echo, T1-weighted fast multiplanar spoiled GRASS and T2-EP images obtained before and 25, 60, 90 and 120 s after injection of 0.2 mmol/kg b.w. of gadopentetate dimeglumine. The diagnostic accuracy was estimated by calculating the area under the observer-specific binomial receiver operating characteristics curves (Az). Results: T2-EP images obtained 60 s after contrast injection showed significantly higher contrast-to-noise (C/N) ratios than the other imaging techniques. A combination of all phases of the T2-EP images produced the highest sensitivity and specificity. In terms of the Az value, the diagnostic accuracy for tumor detection achieved with a combination of all phases of the T2-EP images was significantly higher than that with T1-SPGR and T2-SSFSE images ( p < 0.01). The Az values of the T2-EP images (Az = 0.975) were higher than those of T2-CSE images (Az = 0.948), but the difference was not significant. Conclusion: Our preliminary study revealed that sequential imaging with enhanced T2-EP images was useful for the detection of hypovascular metastatic liver tumors because of its superior C/N ratio and sensitivity.
MR Cholangiopancreaticography and Endoscopic Retrograde Cholangiopancreaticography in Patients with Suspected Common Bile Duct Stones: A prospective blinded study
Authors: Stiris M.G. , Tennøe B. , Aadland E. , Lunde O.C. 
Published: July 2004

Purpose: To prospectively compare MR cholangiopancreaticography (MRCP) vs. endoscopic retrograde pancreaticography (ERCP) in patients with suspected common bile duct (CBD) stone disease. Material and Methods: Fifty consecutive patients with suspected CBD disease underwent MRCP and then ERCP within 12 h of each other. The result of the MRCP was blinded to the reader of the ERCP. The MRCP was done using a superconducting 1.0 T unit with a heavily T2-weighted breath-hold technique. The ERCP was done in the fluoroscopy suite by one of the clinicians and was evaluated by one of the radiologists who had not read the MRCP examinations. Results: There were 28 true-positives, 17 true-negatives, 1 false-positive, and 4 false-negatives. The sensitivity was 87.5% and the specificity 94.4%, respectively. The positive predictive value was 96.6% and the negative predictive value was 81.1%. Conclusion: MRCP was shown to be good enough to replace ERCP as a diagnostic method in patients with suspected CBD disease. MRCP is now our modality of choice after ultrasound in the diagnostic evaluation of these patients.