bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic model testing and statistical power in population‐based association studies of quantitative traits
Authors: Lettre Guillaume , Lange Christoph , Hirschhorn Joel N.
Published: March 2007

The optimal method for considering different genetic models in association studies is not clear. We compared analytical strategies that use different genetic models to analyze genotype–phenotype information from association studies of quantitative traits in unrelated individuals. We created simulated datasets where the minor alleles are causal with an additive, dominant, or recessive mode of inheritance over a range of allele frequencies. We then computed power to detect these causal alleles using one or a combination of statistical models in a standard regression framework, including corrections for the multiple testing incurred by analyzing multiple models. Our results show that, as expected, maximal power is achieved when we test a single genetic model that matches the actual underlying mode of inheritance of the causal allele. When the inheritance pattern of the causal allele is unknown, the co‐dominant model, a single two degrees of freedom test, has good overall performance in any of the three simple modes of inheritance simulated. Alternatively, it is slightly more powerful to analyze all three genetic models together (additive, dominant, and recessive), but only if the significance thresholds used to correct for analyzing multiple models are appropriately determined (such as by permutation). Finally, a commonly employed approach, testing the additive model alone, performs poorly for recessive causal alleles when the minor allele frequency is not close to 50%. Our observations were confirmed by analyzing an existing genetic association dataset in which we detect the effect of a KCNJ11 variant on insulinogenic index in unrelated non‐diabetic individuals. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Inhibitory effect of 4‐methylesculetin on hyaluronan synthesis slows the development of human pancreatic cancer in vitro and in nude mice
Authors: Hajime Morohashi , Shuichi Yoshihara , Makoto Nakai , Masanori Yamaguchi , Ikuko Kakizaki , Atsushi Kon , Mutsuo Sasaki , Keiichi Takagaki
Published: March 2007

We report the inhibitory effect of 4‐methylesculetin (ME), a 4‐methylumbelliferone derivative, on hyaluronan (HA) synthesis by pancreatic cancer cells, and its resulting anticancer action. First, HA in cell culture was analyzed using competitive inhibition with hyaluronic acid‐binding protein (HABP) to study HA synthesis by the human pancreatic cancer cell line KP1‐NK, and cell‐surface HA was visualized using a particle‐exclusion assay to study the synthesis of extracellular matrix HA. We also analyzed the inhibitory effect of ME on cell adhesion and invasion, which play a role in the invasion, growth and metastasis of human pancreatic cancer. Furthermore, we examined HA in human pancreatic cancer cells transplanted into the hypodermis of nude mice to study the inhibitory effect of ME on HA synthesis. Moreover, pancreatic cancer cells were also transplanted into the abdomen of nude mice to study whether ME would have the potential to prolong the survival of patients with end‐stage pancreatic cancer. ME at 10 μM did not inhibit the growth of human pancreatic cancer cells, but inhibited HA synthesis in cell culture by 40%, adhesion by 44% and invasion by 40%. ME inhibited the proliferation of subcutaneous tumors and HA synthesis (by 50%) of pancreatic cancer transplanted into the hypodermis of nude mice. ME also prolonged the survival time of nude mice bearing abdominally transplanted pancreatic cancer cells. ME inhibited pancreatic cancer growth and metastasis by inhibition of HA synthesis. These results suggest that ME may prolong the survival time of patients with end‐stage pancreatic cancer. © 2007 Wiley‐Liss, Inc.
Potential for treatment of liposarcomas with the MDM2 antagonist Nutlin‐3A
Authors: Müller Christoph R. , Paulsen Erik B. , Noordhuis Paul , Pedeutour Florence , Sæter Gunnar , Ola Myklebost
Published: March 2007

The MDM2‐antagonist Nutlin 3A can efficiently induce apoptosis in osteosarcoma cell lines with amplified MDM2. However, Nutlin‐based therapy could be even more important in more common sarcoma types where this aberration is frequent. The well‐ and de‐differentiated liposarcomas have complex marker chromosomes, consistently including multiple copies of the MDM2 locus. Since amplification seems to be a primary aberration in these tumors, whereas amplification in osteosarcoma generally is a progression marker, the underlying biological mechanisms may be different. We have therefore investigated the molecular response to Nutlin treatment in several liposarcoma cell lines with such markers, as well as a panel of other sarcoma cell lines. We report that Nutlin efficiently stabilized p53 and induced downstream p53 dependent transcription and apoptosis in liposarcoma cells with amplified MDM2 in vitro. Some effect of Nutlin was also observed on cell lines without amplified MDM2 but with wt TP53, but no apoptosis was induced. The MDM4 protein, reported to interfere with the reactivation of p53, was undetectable in cells with amplified MDM2. Thus, Nutlin represents a promising new therapeutic principle for the treatment of an increasing group of sarcomas. © 2007 Wiley‐Liss, Inc.
Six‐month natural history of oral versus cervical human papillomavirus infection
Authors: D'Souza Gypsyamber , Fakhry Carole , Sugar Elizabeth A. , Seaberg Eric C. , Weber Kathleen , Minkoff Howard L. , Anastos Kathryn , Palefsky Joel M. , Gillison Maura L.
Published: March 2007

Human papillomavirus (HPV) infection is etiologically associated with a subset of oral cancers, and yet, the natural history of oral HPV infection remains unexplored. The feasibility of studying oral HPV natural history was evaluated by collecting oral rinse samples on 2 occasions at a 6‐month interval from 136 HIV‐positive and 63 HIV‐negative participants. Cervical vaginal lavage samples were concurrently collected for comparison. HPV genomic DNA was detected in oral and cervical samples by consensus primer PCR and type‐specified for 37 HPV types. The six‐month cumulative prevalence of oral HPV infection was significantly less than for cervical infection (p < 0.0001). HIV‐positive women were more likely than HIV‐negative women to have an oral (33 vs. 15%, p = 0.016) or cervical (78 vs. 51%, p < 0.001) infection detected. Oral HPV infections detected at baseline were as likely as cervical infections to persist to 6 months among HIV‐negative (60% vs. 51%, p = 0.70) and HIV‐positive (55% vs. 63%, p = 0.27) women. Factors that independently elevated odds for oral HPV persistence differed from cervical infection and included current smoking (OR = 8, 95% CI = 1.3–53), age above 44 years (OR = 20, 95% CI = 4.1–83), CD4 < 500 (OR = 6, 95% CI = 1.1–26), use of HAART therapy (OR = 12, 95% CI = 1.0–156), and time on HAART therapy (trend p = 0.04). The rate of oral HPV infections newly detected at follow‐up was significantly lower than cervical infection among HIV‐positive (p < 0.001) and HIV‐negative women (p < 0.001). Our study not only demonstrates that it is feasible to study the natural history of oral HPV infection with oral rinse sampling, but also indicates that oral and cervical HPV natural history may differ. © 2007 Wiley‐Liss, Inc.
Physical activity and risk of endometrial cancer: The European prospective investigation into cancer and nutrition
Authors: Friedenreich Christine , Cust Anne , Lahmann Petra H. , Steindorf Karen , Boutron‐Ruault Marie‐Christine , Clavel‐Chapelon Françoise , Mesrine Sylvie , Linseisen Jakob , Rohrmann Sabine , Pischon Tobias , Schulz Mandy , Tjønneland Anne , Johnsen Nina Fons , Overvad Kim , Mendez Michelle , Arguelles M.V. , Garcia Carmen Martinez , Larrañaga Nerea , Chirlaque María‐Dolores , Ardanaz Eva , Bingham Sheila , Khaw Kay‐Tee , Allen Naomi , Key Tim , Trichopoulou Antonia , Dilis Vardis , Trichopoulos Dimitrios , Pala Valeria , Palli Domenico , Tumino Rosario , Panico Salvatore , Vineis Paolo , Bueno‐de‐Mesquita H. Bas , Peeters Petra H.M. , Monninkhof Evelyn , Berglund Göran , Manjer Jonas , Slimani Nadia , Ferrari Pietro , Kaaks Rudolf , Riboli Elio
Published: March 2007

The etiologic role of physical activity in endometrial cancer risk remains unclear given the few epidemiologic studies that have been conducted. To investigate this relation more fully, an analysis was undertaken in the European prospective investigation into cancer and nutrition (EPIC). During an average 6.6 years of follow‐up, 689 incident endometrial cancer cases were identified from an analytic cohort within EPIC of 253,023 women. Cox proportional hazards models were used to estimate the associations between type of activity (total, occupational, household, recreational) and endometrial cancer risk. For total activity, women in the highest compared with the lowest quartile of activity had a risk of 0.88 (95% confidence interval (95% CI = 0.61–1.27). No clear associations between each type of activity and endometrial cancer risk were found for the total study population combined. Associations were more evident in the stratified results, with premenopausal women who were active versus inactive experiencing a risk of 0.66 (95% CI = 0.38–1.14) overall. Among premenopausal women, for household and recreational activities the risk estimates in the highest as compared with the lowest quartiles were, respectively, 0.48 (95% CI = 0.23–0.99) and 0.78 (95% CI = 0.44–1.39). No effect modification by body mass index, hormone replacement therapy, oral contraceptive use or energy intake was found. This study provides no evidence of a protective effect of increased physical activity in endometrial cancer risk in all women but some support for a benefit among premenopausal women. The relative risk reductions are most apparent for household activities. © 2007 Wiley‐Liss, Inc.
Prognosis of adenocarcinoma of the uterine cervix: p53 expression correlates with higher incidence of mortality
Authors: Baalbergen Astrid , Ewing‐Graham Patricia C. , Eijkemans Marinus J. , Helmerhorst Theo J.M.
Published: March 2007

We investigated the significance of prognostic markers‐estrogen receptor, progesterone receptor, p53, MIB‐1 and bcl‐2 ‐ in adenocarcinoma of the uterine cervix. In 101 patients with primary cervical adenocarcinoma, treated from 1989 to 2000, we evaluated clinical parameters in relation to these prognostic markers. Mean age of patients was 45 years. Seventy eight percent of the patients were in FIGO stage I, 16% stage II, 7% stage III and IV. estrogen receptor, progesterone receptor, p53 and bcl‐2 immunoreactivity was scored as 0 (up to 5% positive cells), 1+ (5–25% of cells positive), 2+ (26–50% of cells positive), 3+ (51–75% of cells positive) or 4+ (>76% of cells positive). MIB‐1 was scored in 10 categories: 0–10, 11–20, 21–30, 31–40, 41–50, 51–60, 61–70, 71–80, 81–90, 91–100. The overall survival rate was 67%. Survival was not influenced by estrogen receptor, progesterone receptor, MIB‐1, or bcl‐2 strongly positive staining. Only p53 showed significant influence on survival, even when adjusted for stage or tumor grade. In conclusion, it does not seems useful to determine estrogen receptor, progesterone receptor, MIB‐1 or bcl‐2 in cervical adenocarcinomas as an indication of prognosis: survival is not influenced by presence or absence. However, if p53 staining is strongly positive survival is significantly worse than in tumors scored as negative or weak positive. © 2007 Wiley‐Liss, Inc.
Breast cancer risk and erythrocyte compositions of n‐3 highly unsaturated fatty acids in Japanese
Authors: Kuriki Kiyonori , Hirose Kaoru , Wakai Kenji , Matsuo Keitaro , Ito Hidemi , Suzuki Takeshi , Hiraki Akio , Saito Toshiko , Iwata Hiroji , Tatematsu Masae , Tajima Kazuo
Published: March 2007

Dietary intake of fish rich in n‐3 highly unsaturated fatty acids (HUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been proposed to decrease cancer risk. In contrast to results from laboratory studies, however, protective effects for breast cancer have proved equivocal in epidemiological studies. In the present case‐control study, we examined associations between breast cancer risk and fatty acid compositions in erythrocyte membranes as biomarkers for those intakes. Dietary information and blood samples were collected from 103 incident breast cancer cases and 309 non‐cancer controls (matched by age and season) and erythrocyte fatty acids were measured using accelerated solvent extraction and gas‐liquid chromatography. Dietary intake of n‐3 HUFAs demonstrated a negative association with risk (the highest to the lowest tertile, odds ratio (OR), 0.51; 95% confidence interval (CI), 0.27–0.98; ptrend < 0.05), but there was no association with those of saturated fatty acids (SFAs) and meat. Moreover, risk was inversely associated with erythrocyte compositions of EPA (OR, 0.27; 95% CI, 0.14–0.53; ptrend < 0.0001), DHA (OR, 0.06; 95% CI, 0.02–0.16; ptrend < 0.0001) and n‐3 HUFAs (OR, 0.11; 95% CI, 0.05–0.24; ptrend < 0.0001), and positively with that of SFAs (OR, 12.29; 95% CI, 4.94–30.57; ptrend < 0.0001) and the ratio of SFAs/n‐3 HUFAs (OR, 14.65; 95% CI, 5.67–37.82; ptrend < 0.0001). In conclusion, we showed that erythrocyte compositions of specific fatty acids derived from fish intake, as biomarkers, are associated with lower risk of breast cancer, but further studies are needed to investigate mechanisms linked to the etiology. © 2007 Wiley‐Liss, Inc.
Nonparametric estimation of concave production technologies by entropic methods
Authors: Allon Gad , Beenstock Michael , Hackman Steven , Passy Ury , Shapiro Alexander
Published: March 2007

An econometric methodology is developed for nonparametric estimation of concave production technologies. The methodology, based on the principle of maximum likelihood, uses entropic distance and convex programming techniques to estimate production functions. Empirical applications are presented to demonstrate the feasibility of the methodology in small and large datasets. Copyright © 2007 John Wiley & Sons, Ltd.
The transmission mechanism in a changing world
Authors: Artis Michael , Galvão Ana Beatriz , Marcellino Massimiliano
Published: March 2007

The paper aims to identify those factors that cause changes in the speed and strength of the international transmission of output shocks from the USA to specified European economies. These factors are identified through the use of generalized impulse response functions conditioned on histories defined by an abrupt transition VAR. The chosen transition variables comprise changes in exchange rates, financial prices, international capital flows, trade links and monetary policy instruments. Besides the identification of asymmetric responses, the proposed model is useful in analyzing the strong effect of the recent US recession on the European economies and changes in business cycle synchronization over time. Copyright © 2007 John Wiley & Sons, Ltd.
Expectation horizon and the Phillips Curve: the solution to an empirical puzzle
Authors: Lee Jaejoon , Nelson Charles R.
Published: March 2007

Estimates of the slope of the Phillips curve reported in the literature cover a range from roughly − 0.6 to zero depending on specification. Forward‐looking specifications, favored by theory, produce the smallest slope estimates. This paper addresses this puzzle by studying the bivariate process of inflation and unemployment in a fairly general unobserved components framework allowing for stochastic trends and related cycles. Analysis reveals that the slope of the implied Phillips curve will depend critically on the horizon of the forward‐looking inflation expectation provided the cyclical component of unemployment is highly persistent. Empirical analysis results show that is the case, suggesting that the choice of expectation horizon, generally set at one quarter in the New Keynesian literature, may play an important role in this debate. Copyright © 2007 John Wiley & Sons, Ltd.
An evaluation of the forecasts of the federal reserve: a pooled approach
Authors: Clements Michael P. , Joutz Fred , Stekler Herman O.
Published: March 2007

The Federal Reserve Greenbook forecasts of real GDP, inflation and unemployment are analysed for the period 1974–1997. We consider whether these forecasts exhibit systematic bias, and whether efficient use is made of information, that is, whether revisions to these forecasts over time are predictable. Rather than analyse the forecasts separately for each horizon of interest, we discuss and implement methods that pool information over horizons. We conclude that there is evidence of systematic bias and of forecast smoothing of the inflation forecasts. Copyright © 2007 John Wiley & Sons, Ltd.
High affinity interaction of integrin α4β1 (VLA‐4) and vascular cell adhesion molecule 1 (VCAM‐1) enhances migration of human melanoma cells across activated endothelial cell layers
Authors: Klemke Martin , Weschenfelder Tatjana , Konstandin Mathias H. , Samstag Yvonne
Published: March 2007

The capacity of tumor cells to form metastatic foci correlates with their ability to interact with and migrate through endothelial cell layers. This process involves multiple adhesive interactions between tumor cells and the endothelium. Only little is known about the molecular nature of these interactions during extravasation of tumor cells. In human melanoma cells, the integrin αvβ3 is involved in transendothelial migration and its expression correlates with metastasis. However, many human melanoma cells do not express β3 integrins. Therefore, it remained unclear how these cells undergo transendothelial migration. In this study we show that human melanoma cells with different metastatic potency, which do not express β2 or β3 integrins, express the VCAM‐1 receptor α4β1. VCAM‐1 is up‐regulated on activated endothelial cells and is known to promote transendothelial migration of leukocytes. Interestingly, despite comparable cell surface levels of α4β1, only the highly metastatic melanoma cell lines MV3 and BLM, but not the low metastatic cell lines IF6 and 530, bind VCAM‐1 with high affinity without further stimulation, and are therefore able to adhere to and migrate on isolated VCAM‐1. Moreover, we demonstrate that function‐blocking antibodies against the integrin α4β1, as well as siRNA‐mediated knock‐down of the α4 subunit in these highly metastatic human melanoma cells reduce their transendothelial migration. These data imply that only high affinity interactions between the integrin α4β1 on melanoma cells and VCAM‐1 on activated endothelial cells may enhance the metastatic capacity of human β2/β3‐negative melanoma cells. J. Cell. Physiol. 212: 368–374, 2007. © 2007 Wiley‐Liss, Inc.
Echocardiographic aspects of hiatal hernia: A review
Authors: Khouzam Rami N. , Akhtar Asif , Minderman Daniel , Kaiser Jacqueline , D'Cruz Ivan A.
Published: March 2007

It was realized 20 years ago that the sonographic appearance of a diaphragmatic hernia could simulate a left atrial mass. Many papers have appeared on this topic since then, but they mainly consist of single case reports. Clinical symptoms due to cardiac compression by the hernia are uncommon but may occur if the hernia is very large; such patients have presented with episodes of syncope or dyspnea, typically after a large meal. Sonographers, cardiologists, gastroenterologists, and internists are generally not yet aware that sonographic presentations can be varied and are often perplexing. These include the combination of hiatal hernia with gastroesophageal reflux demonstrable in the subcostal view, and hiatal hernia in patients with ascites. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Abdominal cocoon
Authors: Rokade Muktachand L. , Ruparel Mitosh , Agrawal Jugal B.
Published: March 2007

Abdominal cocoon is a rare cause of small intestinal obstruction observed in young females in tropical regions. It manifests by forming a membrane that typically encases the small bowel loops, leading to mechanical obstruction. Preoperative diagnosis is difficult and is usually established during laparotomy. We report a case of abdominal cocoon in a young woman diagnosed on abdominal sonography. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Pentalogy of Cantrell: Sonographic assessment
Authors: Desselle Claire , Herve Philippe , Toutain Annick , Lardy Hubert , Sembely Catherine , Perrotin Franck
Published: March 2007

Pentalogy of Cantrell is a rare thoraco‐abdominal disruption with a variable association of abdominal wall, diaphragm, pericardium, sternum, and heart defects. Diagnosis is feasible on antenatal sonography. However, because prognosis depends on the extent of the defect, anatomic assessment is crucial for optimal parental counseling and decision‐making regarding the outcome of pregnancy. We report the use of 2‐dimensional and 3‐dimensional sonography in the diagnosis of pentalogy of Cantrell. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Splenic focal lesions as manifestation of sarcoidosis: Characterization with contrast‐enhanced sonography
Authors: Pérez‐Grueso María José , Repiso Alejandro , Gómez Rafael , Gonzalez Concepción , de Artaza Tomás , Valle Julio , García Almudena , Carrobles Jose María
Published: March 2007

We report the case of a 74‐year‐old woman with elevated liver enzyme levels in whom abdominal sonographic examination revealed a diffusely heterogeneous liver parenchyma and multiple hypoechoic subcentimetric splenic nodules. Contrast‐enhanced sonography (CEUS) revealed that the splenic focal lesions did not enhance. CT examination revealed a low‐density, multinodular pattern both in the liver and in the spleen. Core biopsy of 1 hepatic nodule revealed noncaseating epithelioid cell granuloma, and the patient was diagnosed with systemic sarcoidosis. CEUS has shown to be useful in the diagnosis of focal hepatic lesions, but studies referring to splenic lesions are lacking. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Biological evaluation and comparison of three different procedures for labelling of amino acids tyrosine and lysine with technetium‐99m
Authors: Djokić D. , Janković D.
Published: March 2007

The 99mTc‐labelling of the amino acids tyrosine (Tyr) and lysine (Lys), fundamental building blocks of proteins and peptides, as well as biological properties of the labelled compounds are investigated. Three different approaches for the labelling with 99mTc have been investigated: direct reduction with stannous tin in the presence of the amino acids, the preformed chelate approach through polydentate chelates DTPA and GH, and the ‘organometallic approach’ using [99m Tc(CO)3(H2O)3]+ precursor. The direct labelling approach was not successful and the yield was poor. In the presence of DTPA and GH, the labelling efficiency was between 43.6 and 97.8%, depending on the amino acid and the polydentate chelate. The use of [99mTc(CO)3(H2O)3]+ precursor point at the formation of 99m Tc(I) co‐ordinated complexes with high yield. In this approach, pH and heating influenced the yields. The results of organ distribution study for [99mTc(Tyr)(H2O)(CO)3] and [99mTc(Lys)(H2O)(CO)3] show accumulation in liver, kidneys and intestine. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and 124I‐labeling of m‐iodophenylpyrrolomorphinan as a potential PET imaging agent for delta opioid (DOP) receptors
Authors: Akgün Eyup , Portoghese Philip S. , Sajjad Munawwar , Nabi Hani A.
Published: March 2007

Condensation of phenylazo‐β‐ketoamide 4 with oxymorphone 5 afforded an m‐iodophenylpyrrolomorphinan (m‐IPPM) 6 mediated by elemental zinc in acetic acid/sodium acetate buffer. m‐IPPM 6 is a novel opioid receptor agonist (Ki = 4.53 nM for DOP) with high selectivity for DOP receptors. m‐IPPM 6 was converted into the positron emitter m‐[124I]PPM 8 via the stannylated intermediate 7. The final yield was 24.5 ± 1.9 % (n = 6) with a specific activity of 2.5 ± 1.2 Ci/µmol. Copyright © 2007 John Wiley & Sons, Ltd.
A tin precursor for the synthesis of no‐carrier‐added [*I]MIBG and [211At]MABG
Authors: Vaidyanathan Ganesan , Affleck Donna J. , Alston Kevin L. , Zalutsky Michael R.
Published: March 2007

Radioiodinated MIBG has shown considerable promise as an imaging agent for cardiac and oncologic applications, and also as a targeted radiotherapeutic for treating patients with neuroendocrine tumors. This radiolabeled agent, synthesized at a no‐carrier‐added level, has demonstrated advantages over the carrier‐added preparation in preliminary clinical studies. Earlier we developed a silicon precursor from which both radioiodinated MIBG and the α‐particle‐emitting 211At analog [211At]MABG could be synthesized at a no‐carrier‐added level. In order to increase the practicality of this approach, we have developed a synthesis of a tin precursor in two steps from a readily available starting material. This tin precursor, N, N′‐bis(tert‐butyloxycarbonyl)‐3‐(trimethylstannyl)benzylguanidine (Bis‐Boc MTMSBG) was evaluated for the synthesis of n.c.a. [*I]MIBG and [211At]MABG via halodestannylation. The radiochemical yields were 83 ± 9% (n=7), 30 ± 21% (n=2), 77 ± 2% (n=2), and 66 ± 7% (n=4) for labeling with 131I, 124I, 125I, and 211At, respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of deuterium‐labelled meloxicam and piroxicam
Authors: Balssa Frédéric , Bonnaire Yves
Published: March 2007

Four step syntheses of deuterium‐labelled meloxicam and piroxicam from saccharin via selective CD3I alkylation are described. Labelled oxicams are of great interest for qualitative and/or quantitative isotope dilution‐mass spectrometry, coupled with liquid chromatography, currently performed in anti‐doping and forensic laboratories. Copyright © 2007 John Wiley & Sons, Ltd.
Hepatobiliary MRI: Current concepts and controversies
Authors: Glockner James F.
Published: March 2007

Evaluation of the liver and biliary system is a frequent indication for abdominal MRI. Hepatobiliary MRI comprises a set of noninvasive techniques that are usually very effective in answering most clinical questions. There are significant limitations, however, as well as considerable variation and disagreement regarding the optimal protocols for standard hepatic MRI and magnetic resonance cholangiopancreaticography (MRCP). This review discusses pulse sequences most often used in hepatic MRI and MRCP, examines a few sources of controversy in the current literature, and summarizes some recent and future developments in the field. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Effect of different condensed tannin‐containing forages, forage maturity and nitrogen fertiliser application on the formation of indole and skatole in in vitro rumen fermentations
Authors: Schreurs Nicola M , Tavendale Michael H , Lane Geoffrey A , Barry Tom N , López‐Villalobos Nicolas , McNabb Warren C
Published: March 2007

The objectives of this work were to establish the effect of seven different forages with a varied condensed tannin (CT) content, plant maturity and nitrogen fertiliser application on the ruminal formation of skatole and indole using an in vitro method designed to mimic rumen fermentation conditions. After 10 h of incubation, the concentration of indole and skatole was highest when incubating white clover (P < 0.05). Polyethylene glycol addition, to inhibit CT, showed that CT significantly reduced the formation of indole and skatole when incubating Lotus corniculatus, sulla, Dorynium rectum and Lotus pedunculatus (P < 0.01). Mature forage growth resulted in a significantly lower concentration of indole and skatole being formed in vitro compared to the incubation of new spring growth (P < 0.001). A higher application of nitrogen fertiliser to perennial ryegrass‐based pasture resulted in a higher crude protein concentration in the plant and a significantly higher concentration of skatole formed in vitro (P < 0.001). Forages containing CT reduced the conversion of endogenous protein to indole and skatole and plants containing a higher CT concentration tended to be more effective, but compositional differences of CT between forages may also have had an influence. New forage growth or swards that had a high application of nitrogen fertiliser promoted the formation of indole and skatole. Copyright © 2007 Society of Chemical Industry
Repurchase loyalty: The role of involvement and satisfaction
Authors: Olsen Svein Ottar
Published: March 2007

Most studies of satisfaction and loyalty focus on the brand level of decision making. Involvement, on the other hand, is mainly defined and measured on the product category level. This study explores this gap by investigating the role of product category involvement and satisfaction in the formation of repurchase loyalty toward a product category. The study proposes alternative models that suggest that involvement may be an antecedent, a motivational mediator as well as a moderator, between satisfaction and repurchase loyalty. Secondly, it discusses the relative importance of satisfaction in forming involvement and loyalty by introducing social norms and perceived control (opportunity) as alternative antecedents. Involvement proved to be a complete mediator between satisfaction and repurchase loyalty, and a partial mediator between social norm/perceived control and loyalty. Involvement as a moderator was not supported. Social norms showed nearly the same ability as individual satisfaction in explaining variance in product category involvement. However, perceived control had a significant direct influence on repurchase loyalty, but the relationship between perceived control and involvement was not significant. Implications of these findings for satisfaction–loyalty development and research are explored. © 2007 Wiley Periodicals, Inc.
Scope for Accessing the Chain Length Dependence of the Termination Rate Coefficient for Disparate Length Radicals in Acrylate Free Radical Polymerization
Authors: Lovestead Tara M. , Davis Thomas P. , Stenzel Martina H. , Barner‐Kowollik Christopher
Published: March 2007

A method that utilizes reversible addition fragmentation chain transfer (RAFT) chemistry is evaluated on a theoretical basis to deduce the termination rate coefficient for disparate length radicals k in acrylate free radical polymerization, where s and l represent the arbitrary yet disparate chain lengths from either a “short” or “long” RAFT distribution. The method is based on a previously developed method for elucidation of k for the model monomer system styrene. The method was expanded to account for intramolecular chain transfer (i.e., the formation of mid‐chain radicals via backbiting) and the free radical polymerization kinetic parameters of methyl acrylate. Simulations show that the method's predictive capability is sensitive to the polymerization rate's dependence on monomer concentration, i.e., the virtual monomer reaction order, which varies with the termination rate coefficient's value and chain length dependence. However, attaining the virtual monomer reaction order is a facile process and once known the method developed here that accounts for mid‐chain radicals and virtual monomer reaction orders other than one seems robust enough to elucidate the chain length dependence of k for the more complex acrylate free radical polymerization.
RAFT Polymerization: Adding to the Picture
Authors: Rizzardo Ezio , Chen Ming , Chong Bill , Moad Graeme , Skidmore Melissa , Thang San H.
Published: March 2007

SUMMARY: Factors affecting the choice of RAFT agent [RSC(Z) = S] for a given polymerization are discussed. For polymerization of methyl methacrylate (MMA), tertiary cyanoalkyl trithiocarbonates provide very good control over molecular weight and distribution and polymerizations show little retardation. The secondary trithiocarbonate RAFT agents with R = CHPh(CN) also gives good control but an inhibition period attributed to slow reinitiation is manifest. Radical induced reduction with hypophosphite salts provides a clean and convenient process for removal of thiocarbonylthio end groups of RAFT‐synthesized polymers. Two methods providing simultaneous control over stereochemistry and molecular weight distribution of chains formed by radical polymerization are reported. Polymerization of MMA in the presence of scandium triflate provides a more isotactic PMMA. A similar RAFT polymerization with trithiocarbonate RAFT agents also provides control and avoids issues of RAFT agent instability seen with dithiobenzoate RAFT agents in the presence of Lewis acids. RAFT polymerization of tetramethylammonium methacrylate at 45 °C provides a more syndiotactic PMMA of controlled molecular weight and distribution (after methylation; mm:mr:rr 2:21:77 compared to 3:35:62 when formed by bulk polymerization of MMA).
Mechanism and Kinetics of the Induction Period in Nitroxide Mediated Thermal Autopolymerizations. Application to the Spontaneous Copolymerization of Styrene and Maleic Anhydride
Authors: Bonilla‐Cruz José , Caballero Laura , Albores‐Velasco Martha , Saldívar‐Guerra Enrique , Percino Judith , Chapela Víctor
Published: March 2007

Recently we reported an experimental and theoretical (simulation) investigation on the mechanism of the induction period and the initial polymerization stages in the nitroxide mediated autopolymerization of styrene. In this paper we extend some of the results presented there and perform preliminary induction period experiments for the study of the mechanism and kinetics of the spontaneous copolymerization of styrene (S) and maleic anhydride (MA) in the presence of TEMPO and 4‐OH‐TEMPO. With even small amounts of MA (2% wt) the induction period is dramatically reduced by a factor of about 20 in comparison with the nitroxide‐mediated styrene autopolymerization at 120 °C. Our results suggest that the initiation mechanism involves a first step of reaction between S and MA. We speculate that this reaction is a Diels‐Alder cycloaddition followed by hydrogen abstraction through a monomer or TEMPO assisted homolysis to form a radical pair (monomer case) or a single radical (TEMPO case), which either initiates polymerization or is trapped by TEMPO depending on the conditions. Hall and Padias have studied similar electron donor‐acceptor co‐monomer pairs and favor the formation of a tetramethylene diradical as the initiating species for spontaneous copolymerization. In any case, the rate‐limiting step would be the initial reaction of S and MA. These induction experiments allow us to obtain an initial estimate of the order of magnitude for the kinetic constant of the rate‐limiting step, as 10−6 Lmol−1s−1.
NMR Spectroscopy in the Optimization and Evaluation of RAFT Agents
Authors: Klumperman Bert , McLeary James B. , van den Dungen Eric T.A. , Pound Gwenaelle
Published: March 2007

The selection of a suitable mediating agent in Reversible Addition‐Fragmentation Chain Transfer (RAFT) mediated polymerization is crucial to the degree of control that can be achieved. An overview of work from the Stellenbosch group is presented in which the use of NMR spectroscopy as a tool for evaluating RAFT‐agents is highlighted. The occurrence of selective initialization, i.e. the selective conversion of a RAFT‐agent into its single monomer adduct is discussed for various classes of monomers, as well as for copolymerization. One of the general rules for living polymerization is that chains should start growing early in the polymerization reaction. Selective initialization is claimed to be the extreme case where all chains have begun growing after the conversion of only one monomer equivalent per RAFT‐agent.
A Missing Reaction Step in Dithiobenzoate‐Mediated RAFT Polymerization
Authors: Buback Michael , Janssen Olaf , Oswald Rainer , Schmatz Stefan , Vana Philipp
Published: March 2007

The debate on the mechanism of dithiobenzoate‐mediated RAFT polymerization may be overcome by taking the so‐called “missing step” reaction between a highly reactive propagating radical and the three‐arm star‐shaped product of the combination reaction of an intermediate RAFT radical and a propagating radical into account. The “missing step” reaction transforms a propagating radical and a not overly stable three‐arm star species into a resonance‐stabilized RAFT intermediate radical and a stable polymer molecule. The enormous driving force behind the “missing step” reaction is estimated via DFT calculations of reaction enthalpies and reaction free enthalpies.
Reaction Calorimetry for the Development of Ultrasound‐Induced Polymerization Processes in CO2‐Expanded Fluids
Authors: Kemmere Maartje F. , Kuijpers Martijn W.A. , Keurentjes Jos T.F.
Published: March 2007

A strong viscosity increase upon polymerization hinders radical formation during an ultrasound‐induced bulk polymerization. Since CO2 acts as a strong anti‐solvent for most polymers, it can be used to reduce the viscosity of the reaction mixture. In this work, a process for the ultrasound‐induced polymerization in CO2‐expanded fluids has been developed. Temperature oscillation calorimetry has been applied to study the influence of CO2 on the viscosity during the ultrasound‐induced polymerization. In contrast to polymerizations in bulk, the results show that a low viscosity is maintained during polymerization reactions in CO2‐expanded methyl methacrylate (MMA). As a consequence, a constant or even increasing polymerization rate is observed when pressurized CO2 is applied. Moreover, the ultrasound‐induced polymer scission in CO2‐expanded MMA is demonstrated, which appears to be a highly controlled process. Finally, a preliminary sustainable process design is presented for the production of 10 kg/hour pure PMMA (specialty product) in CO2‐expanded MMA by ultrasound‐induced initiation.
Production of Polyacrylic Acid Homo‐ and Copolymer Films by Electrochemically Induced Free‐Radical Polymerization: Preparation and Swelling Behavior
Authors: Bünsow Johanna , Johannsmann Diethelm
Published: March 2007

Films of polyacrylic acid hydrogels were produced on a conducting substrate by means of electrochemically initiated polymerization (EIP). An electro‐chemical quartz crystal microbalance was used to monitor film growth in situ. Homopolymer and copolymer films of polyacrylic acid and poly‐N‐isopropylacrylamide were characterized by FTIR spectroscopy. The degree of swelling of these films could be tuned via the pH.
Reversible Addition Fragmentation Chain Transfer Mediated Dispersion Polymerization of Styrene
Authors: Saikia Prakash J. , Lee Jung Min , Lee Byung H. , Choe Soonja
Published: March 2007

Polystyrene microspheres have been synthesized by the reversible addition‐fragmentation chain transfer (RAFT) mediated dispersion polymerization in an alcoholic media in the presence of poly(N‐vinylpyrrolidone) as stabilizer and 2,2′‐azobisisobutyronitrile as a conventional radical initiator. In order to obtain monodisperse polystyrene particles with controlled architecture, the post–addition of RAFT agent was employed to replace the weak point from the pre‐addition of RAFT. The feature of preaddition and postaddition of RAFT agent was studied on the polymerization kinetics, particle size and its distribution and on the particle stability. The living polymerization behavior as well as the particle stability was observed only in the postaddition of RAFT. The effects of different concentration on the postaddition of RAFT agent were investigated in terms of molecular weight, molecular weight distribution, particle size and its distribution. The final polydispersity index (PDI) value, particle size and the stability of the dispersion system were found to be greatly influenced by the RAFT agent. This result showed that the postaddition of RAFT agent in the dispersion polymerization not only controls the molecular weight and PDI but also produces stable monodisperse polymer particles.
Acid Cleaning of Steel Using Arghel Echo Friendly Corrosion Inhibitor
Authors: Khamis E. , Hefnawy A. , El‐Demerdash A.M.
Published: March 2007

Acid cleaning of mild steel dissolution by 1M sulfuric acid/10 % methanol (test solution) in presence of Arghel herb extract as green inhibitor were monitored by potentiodynamic and electrochemical impedance techniques in the temperature range 30–60oC. At all temperature, the corrosion rate decreased with increasing inhibitor concentration. Potentiodynamic polarization measurements indicated that the inhibitor has strong effect on the corrosion behavior of the steel and behave as mixed type inhibitor. Impedance results indicate that the charge transfer controls the dissolution mechanism of steel across the phase boundary in the absence and the presence of the inhibitor. The inhibition efficiency obtained from various employed methods is in good agreement.

Thermodynamic and activation parameters obtained from this study indicated that the presence of the Arghel increases the activation energy, and the adsorption process of the inhibitor on the metal surface is spontaneous.
Oxidationsverhalten von HVOF–gespritzten MCrAlY–Schichten
Authors: Mărginean G. , Frunzăverde D. , Brandl W.
Published: March 2007

Der Einfluss zweier Spritzparameter (Kerosindurchfluss und Brennkammerdruck) auf das Hochtemperaturoxidationsverhalten von HVOF ‐ gespritzten MCrAlY ‐ Schichten wurde anhand von CoNiCrAlY ‐ Schichten mit 15 Gew.‐% Aluminium untersucht. Verschiedene Testproben wurden nach dem thermischen Spritzen zur Verbesserung des Aufbaus (Homogenisierung, Verminderung der Porosität und der inneren Spannungen, Ausscheidung neuer Phasen) wärmebehandelt und anschließend bei 950 °C für 3000 Minuten in synthetischer Luft oxidiert. Um den Einfluss der unterschiedlichen Spritzparameter auf das Oxidationsverhalten der Schichten zu erfassen wurde die thermogravimetrische Analyse (TG) eingesetzt. Zusätzlich wurde vor und nach der Oxidation der Aufbau der Schichten mit Hilfe der Rasterelektronenmikroskopie (REM) und Röntgendiffraktometrie (XRD) untersucht. Die Ergebnisse zeigten eindeutig, dass das Oxidationsverhalten der HVOF‐gespritzten Schichten abhängig von den Spritzparametern ist. Eine Erhöhung des Kerosindurchflusses bzw. des Brennkammerdruckes führen zu einer Verbesserung des Oxidationsverhaltens dieser Beschichtungen.
Self‐reported adherence versus pill count in Parkinson's disease: The NET‐PD experience
Authors: Elm Jordan J. , Kamp Cornelia , Tilley Barbara C. , Guimaraes Paulo , Fraser Debbie , Deppen Patricia , Brocht Alicia , Weaver Chris , Bennett Susan ,   NINDS NET‐PD Investigators and Coordinators
Published: March 2007

Purpose

To compare the Morisky medication adherence questionnaire to pill counts as measures of adherence in the NET‐PD futility clinical trials. Background: Like in other chronic diseases, non‐adherence with medications occurs in Parkinson's disease (PD), although nonadherence has not been of significant concern in most PD clinical trials. The most common approach to assessment is to do a pill count at each visit. The simple, 4‐question Morisky medication adherence questionnaire may provide an alternative approach to monitoring treatment adherence in PD.

Methods

Adherence data from two NET‐PD Phase II clinical trials enrolling a total of 413 participants were analyzed. The association between demographic and clinical characteristics and adherence was explored.

Results

Ninety‐percent of participants took 80% or more of the study drug. However, the Morisky medication adherence questionnaires showed 56% report high and 44% report medium adherence. Agreement between the two measures is fair (ICC = 0.40).

Conclusions

Overall adherence as assessed by pill count appears high. The Morisky medication adherence questionnaire may be useful in PD clinical trials, since it is moderately correlated to pill count and may be more sensitive to nonadherence. © 2007 Movement Disorder Society
Clinical and genetic characterizations of 16q‐linked autosomal dominant spinocerebellar ataxia (AD‐SCA) and frequency analysis of AD‐SCA in the Japanese population
Authors: Nozaki Hiroaki , Ikeuchi Takeshi , Kawakami Akio , Kimura Akio , Koide Reiji , Tsuchiya Miyuki , Nakmura Yuusaku , Mutoh Tatsuro , Yamamoto Hiroko , Nakao Naoki , Sahashi Ko , Nishizawa Masatoyo , Onodera Osamu
Published: March 2007

Autosomal dominant spinocerebellar ataxias (AD‐SCAs) form a clinically and genetically heterogeneous group of neurodegenerative disorders. Recently, a single nucleotide substitution in the 5′‐untranslated region of the puratrophin‐1 gene was found to be associated with one type of AD‐SCA linked to chromosome 16q (16q‐SCA). To obtain further insight into the contribution of the C‐to‐T substitution in the puratrophin‐1 gene to the clinical and genetic characteristics of patients with 16q‐SCA, we analyzed 686 families with 719 individuals diagnosed with progressive ataxia. We found C‐to‐T substitution in the puratrophin‐1 gene in 57 unrelated families with 65 affected individuals. The mean age at onset in the patients with 16q‐SCA was 59.1 (range, 46–77). Ataxia is the most common initial symptom. The elderly patients over 65 occasionally showed other accompanying clinical features including abnormalities in tendon reflexes, involuntary movements, and reduced vibration sense. We also examined the frequency of the AD‐SCA subtype, considering the effects of age at onset. In the 686 AD‐SCA families, SCA6 and Machado‐Joseph disease/SCA3 are frequent subtypes, followed by dentatorubral‐pallidoluysian atrophy and 16q‐SCA. 16q‐SCA is not a rare subtype of Japanese AD‐SCA, particularly in patients with ages at onset over 60. © 2007 Movement Disorder Society
Video documented follow‐up of liver transplantation in Wilson's disease with predominant neurological manifestation
Authors: Suess Thorsten , Bokemeyer Martin , Schomerus Georg , Donnerstag Frank , Manns Michael Peter , Klempnauer Juergen , Kolbe Hans , Weissenborn Karin
Published: March 2007

Wilson's disease (WD) is a rare autosomal‐recessive disorder of copper metabolism with predominantly hepatic and extrapyramidal motor symptoms. Copper chelating therapy has proven to be an effective treatment for WD. Yet, if conservative treatment fails, liver transplantation (LT) often is the only remaining therapeutic option. The indication for LT especially in patients with stable liver function but severe neurological manifestation is debated controversially. In this case report, we document the follow up of neurological symptoms in WD after LT for the first time on video. © 2007 Movement Disorder Society
Imaging of shifted stimulated echoes and multiple spin echoes
Authors: Mori Susumu , Hurd Ralph E. , Van Zijl Peter C. M.
Published: March 2007

It is shown that a repetitive pulse sequence consisting of two 90° pulses and gradients in a 1:2 ratio around the second 90° pulse generates interscan shifted stimulated echoes (SSTEs) and intrascan multiple spin echoes (MSEs). Separation of these two types of signals is accomplished using specific gradient crusher schemes. The intensity of the SSTEs is an order of magnitude larger than that of the MSEs and determines the signal contrast if both effects are selected simultaneously. The SSTE sequence generates improved contrast between gray and white matter, even at high field, which is explained in terms of increased inverse T1‐weighting for the interscan echo. The MSE image has low signal to noise and no detectable contrast. The effect of interscan diffusion weighting is also discussed.
Three‐dimensional spectral‐spatial excitation
Authors: Morrell Glen , Macovski Albert
Published: March 2007

A method of three‐dimensional spectral‐spatial excitation is presented which is selective simultaneously in two spatial dimensions and in the spectral or chemical shift dimension. This method can be used to create spectral passbands whose center frequency varies as a function of spatial location within an imaging plane. This variation of passband center frequency may be specified by an acquired main field (B0) map; the resulting excitations compensate for inhomogeneity of the B0 field. In vivo images are presented in which three‐dimensional spectral‐spatial excitation allows selective water‐only imaging in the presence of large B0 inhomogeneity where conventional spectrally selective imaging fails. Phantom studies give a detailed profile of the performance of three‐dimensional spectral‐spatial pulses suitable for water‐only or fat‐saturation imaging. These pulses may also be useful for fat and water suppression in spectroscopic imaging. Performance constraints imposed by limited gradient slew rates are analyzed and quantified.