bluuebunny/crossref_metadata_2025 huggingface dataset:
Pre‐Lamin A processing is linked to heterochromatin organization
Authors: Lattanzi Giovanna , Columbaro Marta , Mattioli Elisabetta , Cenni Vittoria , Camozzi Daria , Wehnert Manfred , Santi Spartaco , Riccio Massimo , Del Coco Rosalba , Maraldi Nadir M. , Squarzoni Stefano , Foisner Roland , Capanni Cristina
Published: July 2007

Pre‐lamin A undergoes subsequent steps of post‐translational modification at its C‐terminus, including farnesylation, methylation, and cleavage by ZMPSTE24 metalloprotease. Here, we show that accumulation of different intermediates of pre‐lamin A processing in nuclei, induced by expression of mutated pre‐lamin A, differentially affected chromatin organization in human fibroblasts. Unprocessed (non‐farnesylated) pre‐lamin A accumulated in intranuclear foci, caused the redistribution of LAP2alpha and of the heterochromatin markers HP1alpha and trimethyl‐K9‐histone 3, and triggered heterochromatin localization in the nuclear interior. In contrast, the farnesylated and carboxymethylated lamin A precursor accumulated at the nuclear periphery and caused loss of heterochromatin markers and Lap2alpha in enlarged nuclei. Interestingly, pre‐lamin A bound both HP1alpha and LAP2alpha in vivo, but the farnesylated form showed reduced affinity for HP1alpha. Our data show a link between pre‐lamin A processing and heterochromatin remodeling and have major implications for understanding molecular mechanisms of human diseases linked to mutations in lamins. J. Cell. Biochem. 102: 1149–1159, 2007. © 2007 Wiley‐Liss, Inc.
Sphingosine kinase activity is required for myogenic differentiation of C2C12 myoblasts
Authors: Meacci Elisabetta , Nuti Francesca , Donati Chiara , Cencetti Francesca , Farnararo Marta , Bruni Paola
Published: July 2007

Sphingosine kinase (SphK) is a conserved lipid kinase that catalyzes the formation of sphingosine 1‐phosphate (S1P), an important lipid mediator, which regulates fundamental biological processes. Here, we provide evidence that SphK is required for the achievement of cell growth arrest as well as myogenic differentiation of C2C12 myoblasts. Indeed, SphK activity, SphK1 protein content and S1P formation were found to be enhanced in myoblasts that became confluent as well as in differentiating cells. Enforced expression of SphK1 reduced the myoblast proliferation rate, enhanced the expression of myogenic differentiation markers and anticipated the onset of differentiated muscle phenotype. Conversely, down‐regulation of SphK1 by specific silencing by RNA interference or overexpression of the catalytically inactive SphK1, significantly increased cell growth and delayed the beginning of myogenesis; noticeably, exogenous addition of S1P rescued the biological processes. Importantly, stimulation of myogenesis in SphK1‐overexpressing myoblasts was abrogated by treatment with short interfering RNA specific for S1P2 receptor. This is the first report of the role of endogenous SphK1 in myoblast growth arrest and stimulation of myogenesis through the formation of S1P that acts as morphogenic factor via the engagement of S1P2. J. Cell. Physiol. 214:210–220, 2008. © 2007 Wiley‐Liss, Inc.
Gap junctional intercellular communication is required to maintain embryonic stem cells in a non‐differentiated and proliferative state
Authors: Todorova Mariana G. , Soria Bernat , Quesada Ivan
Published: July 2007

Pluripotent embryonic stem (ES) cells are capable of maintaining a self‐renewal state and have the potential to differentiate into derivatives of all three embryonic germ layers. Despite their importance in cell therapy and developmental biology, the mechanisms whereby ES cells remain in a proliferative and pluripotent state are still not fully understood. Here we establish a critical role of gap junctional intercellular communication (GJIC) and connexin43 (Cx43) in both processes. Pharmacological blockers of GJIC and Cx43 down‐regulation by small interfering RNA (siRNA) caused a profound inhibitory effect on GJIC, as evidenced by experiments of fluorescence recovery after photobleaching. This deficient intercellular communication in ES cells induced a loss of their pluripotent state, which was manifested in morphological changes, a decrease in alkaline phosphatase activity, Oct‐3/4 and Nanog expression, as well as an up‐regulation of several differentiation markers. A decrease in the proliferation rate was also detected. Under these conditions, the formation of embryoid bodies from mouse ES cells was impaired, although this inhibition was reversible upon restoration of GJIC. Our findings define a major function of GJIC in the regulation of self‐renewal and maintenance of pluripotency in ES cells. J. Cell. Physiol. 214: 354–362, 2008. © 2007 Wiley‐Liss, Inc.
Prostaglandin E2 upregulates EGF‐stimulated signaling in mitogenic pathways involving Akt and ERK in hepatocytes
Authors: Dajani Olav F. , Meisdalen Kristin , Guren Tormod K. , Aasrum Monica , Tveteraas Ingun Heiene , Lilleby Peggy , Thoresen G. Hege , Sandnes Dagny , Christoffersen Thoralf
Published: July 2007

Prostaglandins (PGs) such as PGE2 enhance proliferation in many cells, apparently through several distinct mechanisms, including transactivation of the epidermal growth factor (EGF) receptor (EGFR) as well as EGFR‐independent pathways. In this study we found that in primary cultures of rat hepatocytes PGE2 did not induce phosphorylation of the EGFR, and the EGFR tyrosine kinase blockers gefitinib and AG1478 did not affect PGE2‐stimulated phosphorylation of ERK1/2. In contrast, PGE2 elicited EGFR phosphorylation and EGFR tyrosine kinase inhibitor‐sensitive ERK phosphorylation in MH1C1 hepatoma cells. These findings suggest that PGE2 elicits EGFR transactivation in MH1C1 cells but not in hepatocytes. Treatment of the hepatocytes with PGE2 at 3 h after plating amplified the stimulatory effect on DNA synthesis of EGF administered at 24 h and advanced and augmented the cyclin D1 expression in response to EGF in hepatocytes. The pretreatment of the hepatocytes with PGE2 resulted in an increase in the magnitude of EGF‐stimulated Akt phosphorylation and ERK1/2 phosphorylation and kinase activity, including an extended duration of the responses, particularly of ERK, to EGF in PGE2‐treated cells. Pertussis toxin abolished the ability of PGE2 to enhance the Akt and ERK responses to EGF. The results suggest that in hepatocytes, unlike MH1C1 hepatoma cells, PGE2 does not transactivate the EGFR, but instead acts in synergism with EGF by modulating mitogenic mechanisms downstream of the EGFR. These effects seem to be at least in part Gi protein‐mediated and include upregulation of signaling in the PI3K/Akt and the Ras/ERK pathways. J. Cell. Physiol. 214: 371–380, 2008. © 2007 Wiley‐Liss, Inc.
Exposure of normal human melanocytes to a tumor promoting phorbol ester reverses growth suppression by transforming growth factor beta
Authors: Stavroulaki Melanthia , Kardassis Dimitris , Chatzaki Ekaterini , Sakellaris George , Lindschau Carsten , Haller Hermann , Tosca Androniki , Krasagakis Konstantin
Published: July 2007

Transforming growth factor‐beta (TGF‐β), a potent inhibitor of normal melanocyte growth, does not significantly suppress growth of melanoma cells. The mechanism of melanocyte desensitization to TGF‐β in the transformation process remains largerly unknown. We investigated whether the tumor promoting phorbol ester 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) may induce melanocyte resistance to TGF‐β. Cell proliferation and DNA synthesis of normal human melanocytes were strongly inhibited by TGF‐β, whereas in the presence of TPA remained largerly unaffected. The inactive phorbol ester 4α‐phorbol 12,13 didecanoate did not modify the TGF‐β antiproliferative effect, whereas the diacylglycerol analog 1‐oleoyl‐2‐acetyl‐sn‐glycerol counteracted TGF‐β effects. Protein kinase C (PKC) is the major cellular receptor of tumor promoting phorbol esters. PKC‐α expression and phosphorylation were almost completely downregulated under combined treatment with TGF‐β + TPA at 24 and 72 h, as shown by immunoblots. Confocal microscopy demonstrated that TGF‐β‐induced nuclear accumulation of PKC‐α was abolished in the presence of TPA at the same time points. The selective PKC inhibitor Ro‐31‐8220 weakened the TGF‐β antiproliferative effect. Smads are central mediators for TGF‐β signal transduction. Smad‐dependent transcriptional activity was suppressed in TGF‐β‐treated melanocytes in the presence of TPA, as well as in ALK5 (constitutively active type I TGF‐β receptor)‐ or Smad3 + Smad4‐transfected melanocytes in the presence of Ro‐31‐8220. In addition, an antisense oligodeoxynucleotide against PKC‐α abolished TGF‐β‐driven Smad‐mediated transcription. These findings show that tumor promoting phorbol esters induce melanocyte resistance to TGF‐β, associated with downregulation of PKC‐α and suppression of Smad‐dependent transcription. This may represent an important mechanism for expansion of melanocytes exposed to PKC‐targeting tumor promoters. J. Cell. Physiol. 214: 363–370, 2008. © 2007 Wiley‐Liss, Inc.
Seeing the light: New insights into the molecular pathogenesis of retinal diseases
Authors: Campochiaro Peter A.
Published: July 2007

In the past, most treatments for retinal diseases have been empirical. Steroids and/or laser photocoagulation and/or surgery have been tried for almost every condition with little or no understanding of the underlying disease. Over the past several years vision researchers have uncovered molecular components of processes, such as visual transduction and the visual cycle, that are critical for visual function, and identified other molecules that lead to dysfunction and disease processes such as neovascularization and macular edema. It is becoming clear that dysregulation of certain molecules can have major effects on retinal structure and function. Studies in animal models have suggested that inhibiting or augmenting levels of a single molecule can have major effects in complex disease processes. Although several molecules probably contribute to neovascularization and excessive vascular permeability in the eye, blockade of vascular endothelial growth factor (VEGF) has remarkable beneficial effects in animal models that have now been proven to apply to human diseases in clinical trials. Intraocular injection of VEGF antagonists has revolutionized the treatment of choroidal neovascularization (CNV) and macular edema and serves as a model of targeted ocular pharmacotherapy. Significant progress elucidating the molecular pathogenesis of several disease processes in the eye may soon lead to new treatments following the lead of VEGF antagonists. Initial treatments that provide benefit from frequent intraocular injections are likely to be followed by sustained delivery of drugs and/or prolonged protein delivery by gene transfer. The eye has entered the era of molecular therapy. J. Cell. Physiol. 213: 348–354, 2007. © 2007 Wiley‐Liss, Inc.
Lipolysis is stimulated by PEGylated conjugated linoleic acid through the cyclic adenosine monophosphate‐independent signaling pathway in 3T3‐L1 cells: Activation of MEK/ERK MAPK signaling pathway and hyper‐secretion of adipo‐cytokines
Authors: Moon Hyun‐Seuk , Lee Hong‐Gu , Seo Ji‐Hye , Guo Ding‐Ding , Kim In‐Yong , Chung Chung‐Soo , Kim Tae‐Gyu , Choi Yun‐Jaie , Cho Chong‐Su
Published: July 2007

We previously reported that PEGylated conjugated linoleic acid (PCLA) as a pro‐drug treatment of cultures of 3T3‐L1 cells containing differentiated adipocytes caused de‐differentiation by downregulation of PPARγ2‐induced adipogenesis, and cell apoptosis induced by PCLA was lower than that induced by conjugated linoleic acid (CLA) owing to the biocompatible and hydrophilic properties of poly(ethylene glycol) (PEG). To further investigate our previous observations, the present study is designed to evaluate the lipolytic action of PCLA and its role in biochemical signaling pathways of 3T3‐L1 cells when compared to the CLA itself. Although both CLA and PCLA stimulated lipolysis, our results indicated a sensitivity difference between CLA and PCLA treatment: a time‐dependent effect on lipolysis and p‐extracellular signal‐related kinases (ERK) expression was observed for PCLA‐treated, but not for CLA‐treated cultures. Also, the induction by PCLA of mitogen‐activated protein kinase kinase (MEK)/ERK mitogen‐activated protein kinase (MAPK) activation was linked to secretion of adipo‐cytokines, interleukin‐6 (IL‐6), and interleukin‐8 (IL‐8), in time‐dependent manners. Interestingly, adenylyl cyclase inhibitor, 2′, 5′‐dideoxyadenosine (DDA), pre‐treatment did not prevent PCLA‐stimulated lipolysis. In fact, isoproterenol, but not PCLA, caused a significant increase in cyclic adenosine monophosphate (cAMP) levels, suggesting that the PCLA‐induced lipolysis was not mediated in the conventional cAMP‐dependent pathway and the cAMP was the intracellular mediator for isoproterenol‐induced lipolysis. Overall, our findings provide support for a role for PCLA as a pro‐drug in the regulation of metabolism in adipose tissue. J. Cell. Physiol. 214: 283–294, 2008. © 2007 Wiley‐Liss, Inc.
CFTR gene transfer to human cystic fibrosis pancreatic duct cells using a Sendai virus vector
Authors: Rakonczay Zoltán , Hegyi Péter , Hasegawa Mamoru , Inoue Makoto , You Jun , Iida Akihiro , Ignáth Imre , Alton Eric W.F.W. , Griesenbach Uta , Óvári Gabriella , Vág János , Da Paula Ana C. , Crawford Russell M. , Varga Gábor , Amaral Margarida D. , Mehta Anil , Lonovics János , Argent Barry E. , Gray Michael A.
Published: July 2007

Cystic fibrosis (CF) is a fatal inherited disease caused by the absence or dysfunction of the CF transmembrane conductance regulator (CFTR) Cl− channel. About 70% of CF patients are exocrine pancreatic insufficient due to failure of the pancreatic ducts to secrete a HCO‐rich fluid. Our aim in this study was to investigate the potential of a recombinant Sendai virus (SeV) vector to introduce normal CFTR into human CF pancreatic duct (CFPAC‐1) cells, and to assess the effect of CFTR gene transfer on the key transporters involved in HCO transport. Using polarized cultures of homozygous F508del CFPAC‐1 cells as a model for the human CF pancreatic ductal epithelium we showed that SeV was an efficient gene transfer agent when applied to the apical membrane. The presence of functional CFTR was confirmed using iodide efflux assay. CFTR expression had no effect on cell growth, monolayer integrity, and mRNA levels for key transporters in the duct cell (pNBC, AE2, NHE2, NHE3, DRA, and PAT‐1), but did upregulate the activity of apical Cl−/HCO and Na+/H+ exchangers (NHEs). In CFTR‐corrected cells, apical Cl−/HCO exchange activity was further enhanced by cAMP, a key feature exhibited by normal pancreatic duct cells. The cAMP stimulated Cl−/HCO exchange was inhibited by dihydro‐4,4′‐diisothiocyanostilbene‐2,2′‐disulfonic acid (H2‐DIDS), but not by a specific CFTR inhibitor, CFTRinh‐172. Our data show that SeV vector is a potential CFTR gene transfer agent for human pancreatic duct cells and that expression of CFTR in CF cells is associated with a restoration of Cl− and HCO transport at the apical membrane. J. Cell. Physiol. 214: 442–455, 2008. © 2007 Wiley‐Liss, Inc.
Induction of regulatory T cells by physiological level estrogen
Authors: Tai Ping , Wang Junpeng , Jin Huali , Song Xiaoming , Yan Jun , Kang Youmin , Zhao Lin , An Xiaojin , Du Xiaogang , Chen Xiufen , Wang Songbo , Xia Guoliang , Wang Bin
Published: July 2007

Naturally occurring CD4+CD25+regulatory T cells (Treg) exert an important role in mediating maternal tolerance to the fetus during pregnancy, and this effect might be regulated via maternal estrogen secretion. Although estrogen concentration in the pharmaceutical range has been shown to drive expansion of CD4+CD25+Treg cells, little is known about how and through what mechanisms E2 within the physiological concentration range of pregnancy affects this expansion. Using in vivo and in vitro mouse models in these experiments, we observed that E2 at physiological doses not only expanded Treg cell in different tissues but also increased expression of the Foxp3 gene, a hallmark for CD4+CD25+Treg cell function, and the IL‐10 gene as well. Importantly, our results demonstrate that E2, at physiological doses, stimulated the conversion of CD4+CD25−T cells into CD4+CD25+T cells which exhibited enhanced Foxp3 and IL‐10 expression in vitro. Such converted CD4+CD25+T cells had similar regulatory function as naturally occurring Treg cells, as demonstrated by their ability to suppress naïve T cell proliferation in a mixed lymphocyte reaction. We also found that the estrogen receptor (ER) exist in the CD4+CD25−T cells and the conversion of CD4+CD25−T cells into CD4+CD25+T cells stimulated by E2 could be inhibited by ICI182,780, a specific inhibitor of ER(s). This supports that E2 may directly act on CD4+CD25−T cells via ER(s). We conclude that E2 is a potential physiological regulatory factor for the peripheral development of CD4+CD25+Treg cells during the implantation period in mice. J. Cell. Physiol. 214: 456–464, 2008. © 2007 Wiley‐Liss, Inc.
Cross‐intersecting couples of graphs
Authors: Fachini Emanuela , Körner János
Published: July 2007

Two graphs on the same vertex set form a cross‐intersecting couple if they have a pair of clique coverings with the property that every pair of cliques from the respective coverings intersect. In particular, a graph is called normal if it forms a cross‐intersecting couple with its complement. We determine the largest size of families of graphs every pair of which forms a cross‐intersecting couple under various additional restrictions. © 2007 Wiley Periodicals, Inc. J Graph Theory 56: 105–112, 2007
Evolution of the cephalopod head complex by assembly of multiple molluscan body parts: Evidence from Nautilus embryonic development
Authors: Shigeno Shuichi , Sasaki Takenori , Moritaki Takeya , Kasugai Takashi , Vecchione Michael , Agata Kiyokazu
Published: July 2007

Cephalopod head parts are among the most complex occurring in all invertebrates. Hypotheses for the evolutionary process require a drastic body‐plan transition in relation to the life‐style changes from benthos to active nekton. Determining these transitions, however, has been elusive because of scarcity of fossil records of soft tissues and lack of some of the early developmental stages of the basal species. Here we report the first embryological evidence in the nautiloid cephalopod Nautilus pompilius for the morphological development of the head complex by a unique assembly of multiple archetypical molluscan body parts. Using a specialized aquarium system, we successfully obtained a series of developmental stages that enabled us to test previous controversial scenarios. Our results demonstrate that the embryonic organs exhibit body plans that are primarily bilateral and antero‐posteriorly elongated at stereotyped positions. The distinct cephalic compartment, foot, brain cords, mantle, and shell resemble the body plans of monoplacophorans and basal gastropods. The numerous digital tentacles of Nautilus develop from simple serial and spatially‐patterned bud‐like anlagen along the anterior–posterior axis, indicating that origins of digital tentacles or arms of all other cephalopods develop not from the head but from the foot. In middle and late embryos, the primary body plans largely change to those of juveniles or adults, and finally form a “head” complex assembled by anlagen of the foot, cephalic hood, collar, hyponome (funnel), and the foot‐derived epidermal covers. We suggest that extensions of the collar‐funnel compartment and free epidermal folds derived from multiple topological foot regions may play an important role in forming the head complex, which is thought to be an important feature during the body plan transition. J. Morphol., 2008. © 2007 Wiley‐Liss, Inc.
Can principal component analysis provide atmospheric circulation or teleconnection patterns?
Authors: Compagnucci Rosa H. , Richman Michael B.
Published: July 2007

This investigation examines principal component (PC) methodology and the interpretation of the displays, such as eigenvalue magnitude, loadings and scores, which the methodology provides. The key question posed is, to what extent can S‐ and T‐mode decompositions of a dispersion matrix yield the kinds of interpretations placed on them typically? In particular, a series of experiments are designed based on various amalgamations of three distinct synoptic flow patterns. Since these flow patterns are known, a priori, this allows testing via subtle alterations of the methodology to determine whether there is equivalence between the S‐ and T‐mode decompositions, the degree to which the flow patterns or teleconnections can be recovered by each mode, and the interpretation of each mode.

The findings are examined in two contexts: how well they classify the flow patterns, and how well they provide meaningful teleconnections. Both correlation and covariance dispersion matrices are used to determine differences that arise from the standardization. Additionally, unrotated and rotated results are included. By examining a variety of commonly applied methodologies, the results hold for a wider range of studies. Key findings are that eigenvalue degeneracy can influence one mode (but not the other) or both modes for any set of flow patterns resulting in pattern intermixing at times. Similarly, such degeneracy is found in one or both dispersion matrices. Congruence coefficients are used to provide a measure of validity by matching the PC loadings to the parent correlations and covariances. This matching is vital as the loadings exhibit dipoles that have been interpreted historically as physically meaningful, but the present work indicates they may arise purely through the methodology. Overall, we observe that S‐mode results can be interpreted as teleconnection patterns and T‐mode as flow patterns for well‐designed analyses that are meticulously scrutinized for methodological problems. Copyright © 2007 Royal Meteorological Society
Strategy to improve the reproducibility of colloidal SERS
Authors: Tantra Ratna , Brown Richard J. C. , Milton Martin J. T.
Published: July 2007

There is a pressing need to improve the reproducibility of surface enhanced Raman spectroscopy (SERS) measurements, if the technique is to be used routinely for trace analysis. This is particularly true for colloidal SERS, in which data reproducibility is dominated by the final shape and size of metal clusters produced during colloid aggregation. This study presents general guidelines for designing appropriate measurement strategies that can be used to identify and optimise crucial steps in a protocol that leads to better reproducibility of the results. We show that the data reproducibility can be improved by optimising vortexing time during colloid aggregation, which we attribute to the formation of more reproducible metal clusters under conditions of ‘forced convection’. The study also investigated the effects of different storage conditions on the data reproducibility of SERS during a 6‐month study period. Storage conditions did not significantly influence the SERS reproducibility. However, at the end of 6 months, colloids that were stored (in plastic containers) at room temperature showed a difference in their quality, as mirrored by their different opto‐physical properties. This was made apparent through the analysis of UV‐vis spectroscopy measurements by principal component analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Procyanidins: extraction and micro‐ encapsulation
Authors: Zhang Lianfu , Mou Dehua , Du Yanshan
Published: July 2007

As by‐products of grape juice and wine production, grape seeds are a rich source of procyanidins but are usually discarded as waste. We have treated grape seeds with supercritical fluid extraction to remove the oils and have extracted the procyanidins from the residues. In order to extend the shelf life, micro‐encapsulating methods for procyanidins were studied: the use of gum arabic and maltodextrin as wall materials (the contents of arabic gum and maltodextrin were 40% and 60%, respectively). The raw materials were then mixed (the ratio of core substance to wall material was 30:70 w/w and the content of the slurry was 20% w/v). After homogenisation, spray drying was used to prepare microcapsules. The micro‐encapsulation efficiency was up to 88.84%. Analysis of the product showed that the procyanidin was not changed during the processing and the procyanidin microcapsule membrane was uninterrupted and with fairly good integrity. The stability of the products was also obviously improved. Copyright © 2007 Society of Chemical Industry
Opioid activity of Humana formula for newborns
Authors: Jarmołowska Beata , Szłapka‐Sienkiewicz Edyta , Kostyra Elżbieta , Kostyra Henryk , Mierzejewska Dagmara , Marcinkiewicz‐Darmochwał Katarzyna
Published: July 2007

Recent investigations have suggested that novel food should be evaluated not only from the nutritional but also from the physiological point of view. Opioid peptides derived from milk belong to compounds whose physiological importance has not yet been fully recognized. The commercial Humana formula for newborns sold on the Polish market was assayed in the study. Four opioid peptides with agonistic and antagonistic activity were found in a peptide extract from the Humana formula and its pepsin–trypsin hydrolysate: β‐casomorphin‐5, casoxin C and 6 and lactoferroxin A. The opioid activity of the peptide extracts was determined by examining their influence on the motor activity of isolated rabbit intestine. In conclusion, it was suggested that the opioid activity of the formulas could be an additional indicator of their diversity. Copyright © 2007 Society of Chemical Industry
Ability of physico‐chemical measure‐ments to discriminate rabbit meat from three different productive processes
Authors: Combes Sylvie , Larzul Catherine , Jehl Nathalie , Cauquil Laurent , Gabinaud Béatrice , Lebas François
Published: July 2007

BACKGROUND: To fulfil consumers' requirements for food traceability, it is necessary to have effective tools to differentiate food products according to their origin. The aim of the study was to identify a limited number of physico‐chemical measurements that could differentiate rabbit meat from three different rearing systems: standard production system or a high quality norm system or a very low growth breeding system.

RESULTS: The stepwise linear discriminant analysis (LDA) provided 14 physico‐chemical variables, then combined into two discriminant factors. Most of them (n = 8) were related to bone traits, and especially (n = 5) to mechanical femur assessments. Mechanical characteristics of meat were also relevant in this analysis. Decision tree analysis (DTA) selected two variables only (femur stiffness, and ratio of femur weight to chilled carcass weight) to discriminate the three groups. A total of 96% and 90% of rabbits were correctly assigned to their original group according to LDA and DTA, respectively.

CONCLUSION: This work demonstrated that simple physico‐chemical traits recorded in carcasses and meat were efficient to discriminate rabbits from three different rearing systems using LDA or DTA procedures. These systems could have further implications for future traceability of breeding origin. Copyright © 2007 Society of Chemical Industry
Microwave hepatic ablation: Initial experience of safety and efficacy
Authors: Martin Robert C.G. , Scoggins Charles R. , McMasters Kelly M.
Published: July 2007

Background

Microwave (MW) ablation is a new treatment modality for hepatic tumors in the United States. Past concerns had been related to small ablation size and efficacy. The aim of this study was to evaluate the safety, operative time, rate of complete ablation, and local recurrence.

Methods

A prospective Phase II study of MW of hepatic tumors from 1/2004 to 10/2004.

Results

MW ablation was utilized to treat 67 hepatic tumors in 20 patients, with 13 men, 7 women, with a median age of 65 years (range 46–83 years). Tumor types, metastatic colorectal cancer (n = 9), hepatocellular (n = 5), metastatic carcinoid (n = 2), and one patient each with metastatic ovarian, breast, and gastric. MW treated a median of two tumors (range 1–13) per patient, median size of 3 cm (range 1.5–4.5 cm). Total median ablation time was 10 min (range 5–40 min). The overall ablation success at the discharge CT of the abdomen was 100%. Nine patients underwent additional procedures, including partial hepatectomy, colectomy, and gastrectomy. There were no perioperative deaths, while perioperative complications occurred in five patients—none of them related to hepatic ablation. After median follow‐up of 19 months there has been one ablation recurrence.

Conclusions

MW ablation represents a reliable, efficient, and safe technique to perform hepatic tumor ablation. The ability to perform multiple ablations simultaneously allows for a more efficient surgical procedure. J. Surg. Oncol. 2007;96:481–486. © 2007 Wiley‐Liss, Inc.
Multiresidue analytical method of pesticides in peanut oil using low‐temperature cleanup and dispersive solid phase extraction by GC‐MS
Authors: Li Li , Zhang Hongyan , Pan Canping , Zhou Zhiqiang , Jiang Shuren , Liu Fengmao
Published: July 2007

A method for the determination of 33 pesticides in peanut oil by GC‐MS was described. Two extraction procedures based on (i) low‐temperature extraction and (ii) liquid–liquid extraction were tested for the optimization of the method. The mixture of anhydrous MgSO4 with primary secondary amine (PSA) or with PSA and C18 was performed as sorbents in dispersive SPE. Low temperature along with PSA and C18 cleanup gave the best results. Pesticides were identified and quantified by GC‐MS in SIM mode. The correlation coefficients, R2, in the linear range tests were better than 0.990. The average recoveries for most pesticides (spiked at 0.02, 0.05, 0.2, and 1 mg/kg) ranged from 70 to 110%, the RSD was below 20% in most instances, and LODs varied from 0.5 to 8 μg/kg.
Determination of flavonoid aglycones in several food samples by mixed micellar electrokinetic chromatography
Authors: Herrero‐Martínez José Manuel , Oumada Fadoua Z. , Rosés Martí , Bosch Elisabeth , Ràfols Clara
Published: July 2007

The application of mixed micellar electrokinetic chromatography to the separation of ten flavonoid aglycones (catechin, epicatechin, naringenin, morin, fisetin, quercetin, kaempferol, galangin, apigenin, and chrysin) belonging to four different classes (flavanols, flavanones, flavonols, and flavones), and expected to be prominent in commonly consumed foods, has been developed. A micellar system composed of 25 mM SDS and 25 mM sodium cholate buffered at pH 7.0 provided a simultaneous separation of all compounds in less than 20 min. The procedure could be easily adapted to the determination of some flavonoids from each of these classes in real complex samples (propolis, Ginkgo biloba, etc.). The LODs of these compounds were in the range of 1.2–4 μg/mL, and the peak area and migration time repeatabilities were below 6.0 and 3.1%, respectively.
Modeling oxygen effects in tissue‐preparation neuronal‐current MRI
Authors: Luo Qingfei , Liu Ho‐Ling , Parris Brent , Lu Huo , Senseman David M. , Gao Jia‐Hong
Published: July 2007

Tissue‐preparation neuronal‐current MRI (ncMRI) was recently developed to directly detect neuronal activity without hemodynamic contamination. However, as a paramagnetic substance, the oxygen molecules present in the tissue may also alter the ncMRI signal through relaxivity and susceptibility effects. To study the effects of oxygen on the ncMRI signal and estimate their impact on tissue‐preparation experiments, oxygen‐induced MRI signal changes were formulated as a function of oxygen concentration (OC) of gas, oxygen consumption rate, and imaging parameters. Under favorable conditions of these parameters, the maximum oxygen‐induced signal magnitude and phase change were estimated to be 0.32% and 3.85°, respectively. Considering that the ncMRI signal changes obtained in previous tissue‐preparation experiments (3–5% in magnitude, 0.8–1.7° in phase) were tens or hundreds of times larger than the corresponding oxygen‐induced signal changes (0.03% in magnitude, 0.03–0.07° in phase), it is concluded that the oxygen had negligible effects in the previous experiments. Magn Reson Med 58:407–412, 2007. © 2007 Wiley‐Liss, Inc.
Applications and limitations of whole‐brain MAGIC VASO functional imaging
Authors: Scouten A. , Constable R. T.
Published: July 2007

This work extends the multiple acquisitions with global inversion cycling vascular space occupancy (MAGIC VASO) method to human whole‐brain functional magnetic resonance imaging (fMRI) at 3.0 Tesla and demonstrates the need to consider the dynamic contribution of cerebrospinal fluid (CSF) to the relative VASO signal change (ΔVASO/VASO). Simulations were performed to determine the optimal slice number between global inversions, and correction factors were obtained to account for incomplete blood nulling in particular slices. The necessity of an accurate estimate of resting cerebral blood volume (CBVrest) is discussed in the context of ΔCBV/CBV calculations. A three‐compartment model is proposed to include both the resting and changing fractional CSF contribution (xc,rest and Δxc, respectively) to ΔVASO/VASO. A MAGIC VASO sequence that provides whole‐brain coverage is demonstrated using a paradigm comprised of visual, motor, and auditory stimulation. Activated regions are quantitatively compared in the corresponding blood oxygenation level‐dependent (BOLD) images. Estimates of the minimum ΔCBV/CBV resulting from motor and visual stimulation were comparable to previous findings at 17 ± 8% (N = 8) and 19 ± 9% (N = 6), respectively. The absence of VASO activation for auditory stimulation and evidence of activation‐induced decreases in CSF volume fraction around the insula and superior temporal gyrus support the possibility of a Δxc contribution to the VASO signal. Without specific knowledge of the CSF components (xc,rest and Δxc), inference of ΔCBV/CBV from ΔVASO/VASO is severely limited. Magn Reson Med 58:306–315, 2007. © 2007 Wiley‐Liss, Inc.
Quantitative assessment of hepatic fibrosis in an animal model with magnetic resonance elastography
Authors: Yin Meng , Woollard John , Wang Xiaofang , Torres Vicente E. , Harris Peter C. , Ward Christopher J. , Glaser Kevin J. , Manduca Armando , Ehman Richard L.
Published: July 2007

Chronic liver disease is a world‐wide problem that causes progressive hepatic fibrosis as a hallmark of progressive injury. At present, the gold standard for diagnosing hepatic fibrosis is liver biopsy, which is an invasive method with many limitations, including questionable accuracy and risks of complications. MR elastography (MRE), a phase‐contrast MRI technique for quantitatively assessing the mechanical properties of soft tissues, is a potential noninvasive diagnostic method to assess hepatic fibrosis. In this work, MRE was evaluated as a quantitative method to assess the in vivo mechanical properties of the liver tissues in a knockout animal model of liver fibrosis. This work demonstrates that the shear stiffness of liver tissue increases systematically with the extent of hepatic fibrosis, as measured by histology. A linear correlation between liver stiffness and fibrosis extent was well‐defined in this animal model. An additional finding of the study was that fat infiltration, commonly present in chronic liver disease, does not significantly correlate with liver stiffness at each fibrosis stage and thus does not appear to interfere with the ability of MRE to assess fibrosis extent. In conclusion, MRE has the potential not only for assessing liver stiffness, but also for monitoring potential therapies for hepatic fibrosis. Magn Reson Med 58:346–353, 2007. © 2007 Wiley‐Liss, Inc.
MR grid‐tagging using hyperpolarized helium‐3 for regional quantitative assessment of pulmonary biomechanics and ventilation
Authors: Cai J. , Altes T.A. , Miller G.W. , Sheng K. , Read P.W. , Mata J.F. , Zhong X. , Cates G.D. , de Lange E.E. , Mugler J.P. , Brookeman J.R.
Published: July 2007

A new technique is demonstrated in six healthy human subjects that combines grid‐tagging and hyperpolarized helium‐3 MRI to assess regional lung biomechanical function and quantitative ventilation. 2D grid‐tagging, achieved by applying sinc‐modulated RF‐pulse trains along the frequency‐ and phase‐encoding directions, was followed by a multislice fast low‐angle shot (FLASH)‐based acquisition at inspiration and expiration. The displacement vectors, first and second principal strains, and quantitative ventilation were computed, and mean values were calculated for the upper, middle, and lower lung regions. Displacements in the lower region were significantly greater than those in either the middle or upper region (P < 0.005), while there were no significant differences between the three regions for the two principal strains and quantitative ventilation (P = 0.11–0.92). Variations in principal strains and ventilation were greater between subjects than between lung zones within individual subjects. This technique has the potential to provide insight into regional biomechanical alterations of lung function in a variety of lung diseases. Magn Reson Med 58:373–380, 2007. © 2007 Wiley‐Liss, Inc.
Magnetic resonance imaging of blood–spinal cord barrier disruption in mice with experimental autoimmune encephalomyelitis
Authors: Schellenberg Angela E. , Buist Richard , Yong V. Wee , Del Bigio Marc R. , Peeling James
Published: July 2007

Inflammation, demyelination, and blood‐spinal cord barrier (BSB) breakdown occur in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. The purpose of this study was to evaluate the utility of MRI for detecting lesions and BSB disruption in vivo during EAE in the mouse lumbar spinal cord, to determine how MR features of BSB disruption change during the course of disease, and to relate such changes to clinical signs and histological features of disease. Following induction of EAE in C57BL/6 mice, contrast‐enhanced (CE) T1‐weighted MR images were acquired to detect BSB disruption in the lumbar spinal cord at the early stage of disease, at peak disease, and at remission, and T2‐weighted images were obtained to monitor spinal cord morphology. Following imaging the spinal cords were assessed in situ for general features of inflammation, BSB leakage, activated macrophages/microglia, and demyelination. No focal lesions were evident on T2‐weighted MR images. BSB disruption was greatest at the onset of signs of disease, and decreased progressively thereafter. Inflammation and demyelination were pronounced at the initial stage of disease and at peak disease, and were decreased at remission. Nonuniform contrast enhancement indicated that breakdown of the BSB occurred predominantly within the white matter (WM) of the spinal cord. Magn Reson Med 58:298–305, 2007. © 2007 Wiley‐Liss, Inc.
Quantitative imaging of cartilage morphology at 3.0 Tesla in the presence of gadopentate dimeglumine (Gd‐DTPA)
Authors: Eckstein Felix , Buck Robert J. , Wyman Bradley T. , Kotyk John J. , Le Graverand Marie‐Pierre Hellio , Remmers Ann E. , Evelhoch Jeffrey L. , Hudelmaier Martin , Charles H. Cecil
Published: July 2007

MRI‐based cartilage morphometry was previously validated in the absence of gadopentate dimeglumine (Gd‐DTPA). However, Gd‐DTPA is required for compositional (proteoglycan) imaging using delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC). Therefore, the effect of Gd‐DTPA on cartilage morphometry was studied. A total of 165 female participants (67 with and 98 without osteoarthritis [OA]) were imaged at 3.0 Tesla before and 2 hr after intravenous Gd‐DTPA injection. Flip angles in post‐Gd‐DTPA scans varied between 12° and 35°. Cartilage volume and thickness of post‐ vs. pre‐Gd‐DTPA scans showed intraclass correlation coefficients (ICCs) of 0.85 ≥ r ≥ 0.95, mean differences between –2.1% and +1.1%, and standard deviations (SDs) of differences between 4.7% and 9.2%. Mixed‐effect models found no consistent impact of flip angle and OA status on post‐ vs. pre‐Gd‐DTPA differences. Accurate morphological measurements of cartilage can be obtained after Gd‐DTPA injection, allowing compositional and morphological imaging to be combined into one session. Magn Reson Med 58:402–406, 2007. © 2007 Wiley‐Liss, Inc.
Inversion‐recovery‐prepared SSFP for cardiac‐phase‐resolved delayed‐enhancement MRI
Authors: Detsky J.S. , Stainsby J.A. , Vijayaraghavan R. , Graham J.J. , Dick A.J. , Wright G.A.
Published: July 2007

Delayed‐enhancement magnetic resonance imaging (DE‐MRI) can be used to visualize myocardial infarction (MI). DE‐MRI is conventionally acquired with an inversion‐recovery gradient‐echo (IR‐GRE) pulse sequence that yields a single bright‐blood image. IR‐GRE imaging requires an accurate estimate of the inversion time (TI) to null the signal from the myocardium, and a separate cine acquisition is required to visualize myocardial wall motion. Simulations were performed to examine the effects of a steady‐state free precession (SSFP) readout after an inversion pulse in the setting of DE‐MRI. Using these simulations, a segmented IR‐SSFP sequence was optimized for infarct visualization. This sequence yields both viability and wall motion images over the cardiac cycle in a single breath‐hold. Viability images at multiple effective TIs are produced, providing a range of image contrasts. In a study of 11 patients, IR‐SSFP yielded infarct sizes and left ventricular ejection fractions (LVEFs) similar to those obtained by IR‐GRE and standard SSFP, respectively. IR‐SSFP images yielded improved visualization of the infarct‐blood border because of the simultaneous nulling of healthy myocardium and blood. T recovery curves were extracted from IR‐SSFP images and showed excellent qualitative agreement with theoretical simulations. Magn Reson Med 58:365–372, 2007. © 2007 Wiley‐Liss, Inc.
Eight‐channel transmit/receive body MRI coil at 3T
Authors: Vernickel P. , Röschmann P. , Findeklee C. , Lüdeke K.‐M. , Leussler Ch. , Overweg J. , Katscher U. , Grässlin I. , Schünemann K.
Published: July 2007

Multichannel transmit magnetic resonance imaging (MR) systems have the potential to compensate for signal‐intensity variations occurring at higher field strengths due to wave propagation effects in tissue. Methods such as RF shimming and local excitation in combination with parallel transmission can be applied to compensate for these effects. Moreover, parallel transmission can be applied to ease the excitation of arbitrarily shaped magnetization patterns. The implementation of these methods adds new requirements in terms of MRI hardware. This article describes the design of a decoupled eight‐element transmit/receive body coil for 3T. The setup of the coil is explained, starting with standard single‐channel resonators. Special focus is placed on the decoupling of the elements to obtain independent RF resonators. After a brief discussion of the underlying theory, the properties and limitations of the coil are outlined. Finally, the functionality and capabilities of the coil are demonstrated using RF measurements as well as MRI sequences. Magn Reson Med 58:381–389, 2007. © 2007 Wiley‐Liss, Inc.
Phase contrast using multiecho steady‐state free precession
Authors: Pai Vinay M.
Published: July 2007

Conventional phase‐contrast (PC) MRI is limited in the temporal resolution (typically 50 ms) that can be achieved, due to the need to implement bipolar velocity encoding gradients. PC using steady‐state free precession (SSFP) has recently been developed to acquire PC data at higher rates without sacrificing contrast‐to‐noise ratio (CNR). This work presents two multiecho SSFP PC implementations that can be used to increase the time efficiency of PCSSFP. Both approaches (extrinsic and intrinsic) enable reference image lines to be acquired within the same TR as the flow‐encoded lines, thus minimizing the scan time and permitting TR‐equivalent temporal resolutions. Both approaches have been implemented and tested successfully on human volunteers at 1.5T and 3T. While the intrinsic approach is useful for encoding higher velocity flows in‐plane, the extrinsic implementation can be used for studying a wider range of encoding velocities for flow in the imaging plane and through the imaging plane. Magn Reson Med 58:419–424, 2007. © 2007 Wiley‐Liss, Inc.
Fat quantification with IDEAL gradient echo imaging: Correction of bias from T1 and noise
Authors: Liu Chia‐Ying , McKenzie Charles A. , Yu Huanzhou , Brittain Jean H. , Reeder Scott B.
Published: July 2007

Quantification of hepatic steatosis is a significant unmet need for the diagnosis and treatment of patients with nonalcoholic fatty liver disease (NAFLD). MRI is capable of separating water and fat signals in order to quantify fatty infiltration of the liver (hepatic steatosis). Unfortunately, fat signal has confounding T1 effects and the nonzero mean noise in low signal‐to‐noise ratio (SNR) magnitude images can lead to incorrect estimation of the true lipid percentage. In this study, the effects of bias from T1 effects and image noise were investigated. An oil/water phantom with volume fat‐fractions ranging linearly from 0% to 100% was designed and validated using a spoiled gradient echo (SPGR) sequence in combination with a chemical‐shift based fat‐water separation method known as iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL). We demonstrated two approaches to reduce the effects of T1: small flip angle (flip angle) and dual flip angle methods. Both methods were shown to effectively minimize deviation of the measured fat‐fraction from its true value. We also demonstrated two methods to reduce noise bias: magnitude discrimination and phase‐constrained reconstruction. Both methods were shown to reduce this noise bias effectively from 15% to less than 1%. Magn Reson Med 58:354–364, 2007. © 2007 Wiley‐Liss, Inc.
Simultaneous separation of intracellular and extracellular lactate NMR signals of human erythrocytes
Authors: Kohler Götz , Rost Florian , Seelig Joachim
Published: July 2007

Intracellular/extracellular lactate (Lac) distribution has been determined before in human and animal erythrocytes (red blood cells [RBCs]) with various methods. However, all previous methods determine intra‐ and extracellular Lac separately or indirectly. Now, 13C‐NMR spectroscopy has been used to monitor intra‐ and extracellular Lac simultaneously in intact RBCs. Isolated human RBCs were incubated with [3‐13C]‐Lac, [3‐13C]‐pyruvate (Pyr), and [1‐13C]‐glucose (Gluc). A distortionless enhancement by polarization transfer (DEPT) sequence was used (TR = 3.3 s, N = 128) to monitor the 13C‐NMR resonances in both compartments. The intra‐ and extracellular methyl group resonances of Lac and Pyr were clearly separated by 9.6 Hz and 7.0 Hz, respectively, under normoxic conditions due to the RBC chemical‐shift effect. The results show that the chemical‐shift effect of RBCs is convenient to monitor intra‐ and extracellular Lac simultaneously in intact RBCs under normoxic conditions. Magn Reson Med 58:213–217, 2007. © 2007 Wiley‐Liss, Inc.