bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased Activation of the Mammalian Target of Rapamycin Pathway in Liver and Skeletal Muscle of Obese Rats: Possible Involvement in Obesity-Linked Insulin Resistance
Authors: Khamzina Leila , Veilleux Alain , Bergeron Sébastien , Marette André
Published: December 2004

The mammalian target of rapamycin (mTOR) pathway integrates insulin and nutrient signaling in numerous cell types. Recent studies also suggest that this pathway negatively modulates insulin signaling to phosphatidylinositol 3-kinase/Akt in adipose and muscle cells. However, it is still unclear whether activation of the mTOR pathway is increased in obesity and if it could be involved in the promotion of insulin resistance. In this paper we show that basal (fasting state) activation of mTOR and its downstream target S6K1 is markedly elevated in liver and skeletal muscle of obese rats fed a high fat diet compared with chow-fed, lean controls. Time-course studies also revealed that mTOR and S6K1 activation by insulin was accelerated in tissues of obese rats, in association with increased inhibitory phosphorylation of insulin receptor substrate-1 (IRS-1) on Ser636/Ser639 and impaired Akt activation. The relationship between mTOR/S6K1 overactivation and impaired insulin signaling to Akt was also examined in hepatic cells in vitro. Insulin caused a time-dependent activation of mTOR and S6K1 in HepG2 cells. This was associated with increased IRS-1 phosphorylation on Ser636/Ser639. Inhibition of mTOR/S6K1 by rapamycin blunted insulininduced Ser636/Ser639 phosphorylation of IRS-1, leading to a rapid (∼5 min) and persistent increase in IRS-1-associated phosphatidylinositol 3-kinase activity and Akt phosphorylation. These results show that activation of the mTOR pathway is increased in liver and muscle of high fat-fed obese rats. In vitro studies with rapamycin suggest that mTOR/S6K1 overactivation contributes to elevated serine phosphorylation of IRS-1, leading to impaired insulin signaling to Akt in liver and muscle of this dietary model of obesity.
Characterization and Regulation of the Rat and Human Ghrelin Promoters
Authors: Wei Wei , Wang Guiyun , Qi Xiang , Englander Ella W. , Greeley George H.
Published: December 2004

Ghrelin is a recently discovered stomach hormone and endogenous ligand for the GH secretagogue receptor. The aim of these studies is to elucidate molecular mechanisms underlying regulation of the ghrelin gene. Distal and proximal transcription initiation sites are present. A short transcript, a product of the proximal site, showed a more widespread distribution. Two sets of 5′-upstream segments of the rat and human ghrelin genes were cloned and sequenced. Rat promoter segments upstream of the distal site showed highest activity in kidney (COS-7) and stomach (AGS) cells, whereas human promoter segments upstream of the proximal site showed highest activity in AGS and pituitary (GH3) cells in transient transfection assays. For the human, the core promoter spanned −667 to −468 bp, including the noncoding exon 1 and a short 5′ sequence of intron 1. For the rat, the core promoter spanned −581 to −469 bp, and inclusion of exon 1 and a short 5′-sequence of intron 1 reduced activity by 67%. Mutation of initiator-like elements in the rat lowered activity by 20–50%, whereas in the human, all activity was abolished. Overexpression of upstream stimulatory factors increased ghrelin core promoter activity. Fasting increases stomach ghrelin expression, glucagon-a fasting-induced hormone, increased ghrelin expression in vivo in rats, and promoter activity by approximately 25–50%. Together, these findings indicate that structural differences between the rat and human ghrelin core promoters may account in part for the differences in their transcriptional regulation. Nonetheless, upstream stimulatory factor and glucagon exert similar effects on regulation of rat and human ghrelin promoters.
Progesterone Stimulates Mammary Gland Ductal Morphogenesis by Synergizing with and Enhancing Insulin-Like Growth Factor-I Action
Authors: Ruan Weifeng , Monaco Marie E. , Kleinberg David L.
Published: December 2004

Progestins have been implicated in breast cancer development, yet a role for progesterone (Pg) in ductal morphogenesis (DM) has not been established. To determine whether Pg could cause DM, we compared relative effects of Pg, estradiol (E2) and IGF-I on anatomical and molecular biological parameters of IGF-I-related DM in oophorectomized female IGF-I(−/−) mice. Pg had little independent effect on mammary development, but together with IGF-I, in the absence of E2, Pg stimulated an extensive network of branching ducts, occupying 92% of the gland vs. 28.3% with IGF-I alone, resembling pubertal development (P < 0.002). Its major effect was on enhancing duct length and branching (P < 0.002). Additionally, Pg enhanced phosphorylation of IRS-1, increased cell division, and increased the antiapoptotic effect of IGF-I. Pg action was inhibited by RU486 (P < 0.01). E2 also stimulated DM by enhancing IGF-I action but had a greater effect on terminal end bud formation and side branching (P < 0.002). In contrast to previous findings, long-term exposure to E2 alone, without IGF-I, caused formation of ducts and side branches, a novel finding. Both IGF-I and E2 were found necessary for Pg-induced alveolar development. In conclusion, Pg, through Pg receptor can enhance IGF-I action in DM, and E2 acts through a similar mechanism; E2 alone caused formation of ducts and side branches; there were differences in the actions of Pg and E2, the former largely affecting duct formation and extension, and the latter side branching; and both IGF-I and E2 were necessary for Pg to form mature alveoli.
Leiomyoma and Myometrial Gene Expression Profiles and Their Responses to Gonadotropin-Releasing Hormone Analog Therapy
Authors: Luo Xiaoping , Ding Li , Xu Jingxia , Williams R. Stan , Chegini Nasser
Published: December 2004

Gene microarray was used to characterize the molecular environment of leiomyoma and matched myometrium during growth and in response to GnRH analog (GnRHa) therapy as well as GnRHa direct action on primary cultures of leiomyoma and myometrial smooth muscle cells (LSMC and MSMC). Unsupervised and supervised analysis of gene expression values and statistical analysis in R programming with a false discovery rate of P ≤ 0.02 resulted in identification of 153 and 122 differentially expressed genes in leiomyoma and myometrium in untreated and GnRHa-treated cohorts, respectively. The expression of 170 and 164 genes was affected by GnRHa therapy in these tissues compared with their respective untreated group. GnRHa (0.1 μm), in a time-dependent manner (2, 6, and 12 h), targeted the expression of 281 genes (P ≤ 0.005) in LSMC and MSMC, 48 of which genes were found in common with GnRHa-treated tissues. Functional annotations assigned these genes as key regulators of processes involving transcription, translational, signal transduction, structural activities, and apoptosis. We validated the expression of IL-11, early growth response 3, TGF-β-induced factor, TGF-β-inducible early gene response, CITED2 (cAMP response element binding protein-binding protein/p300-interacting transactivator with ED-rich tail), Nur77, growth arrest-specific 1, p27, p57, and G protein-coupled receptor kinase 5, representing cytokine, common transcription factors, cell cycle regulators, and signal transduction, at tissue levels and in LSMC and MSMC in response to GnRHa time-dependent action using real-time PCR, Western blotting, and immunohistochemistry. In conclusion, using different, complementary approaches, we characterized leiomyoma and myometrium molecular fingerprints and identified several previously unrecognized genes as targets of GnRHa action, implying that local expression and activation of these genes may represent features differentiating leiomyoma and myometrial environments during growth and GnRHa-induced regression.
Ascending Brainstem Pathways Are Not Involved in Lipopolysaccharide-Induced Suppression of Thyrotropin-Releasing Hormone Gene Expression in the Hypothalamic Paraventricular Nucleus
Authors: Fekete Csaba , Singru Praful S. , Sarkar Sumit , Rand William M. , Lechan Ronald M.
Published: December 2004

The nonthyroidal illness syndrome associated with fasting, infection, and chronic illness is characterized by low thyroid hormone levels and low or inappropriately normal TSH levels in circulating blood and reduced synthesis of TRH in hypophysiotropic neurons residing in the hypothalamic paraventricular nucleus (PVN). To test the hypothesis that ascending brainstem pathways are involved in mediation of bacterial lipopolysaccharide (LPS)-induced suppression of TRH mRNA in the PVN, we unilaterally transected brainstem pathways to the PVN and determined the effects of LPS on TRH gene expression and, as a control, on CRH gene expression in hypophysiotropic neurons using semiquantitative in situ hybridization histochemistry. The efficacy of the transection was determined by immunocytochemical detection of ascending adrenergic pathways in the PVN. In vehicle-treated animals, CRH mRNA in the PVN showed a significant reduction on the transected side compared with the intact side, whereas a significant increase in TRH mRNA was observed on the transected side compared with the intact side. After LPS administration (250 μg/100 g body weight), a dramatic increase in CRH mRNA was observed on the intact side, and a significantly lesser increase was found on the transected side. In contrast, LPS treatment resulted in reduction in TRH mRNA on the transected side compared with the intact side and a significant reduction in TRH mRNA on the transected side compared with vehicle-treated animals. These studies confirm an important role of ascending brainstem projections in LPS-induced activation of CRH gene expression, but indicate that they do not mediate the effect of LPS to inhibit hypophysiotropic TRH gene expression.
Minireview: Transcriptional Regulation of Gonadal Development and Differentiation
Authors: Park Susan Y. , Jameson J. Larry
Published: December 2004

The embryonic gonad is undifferentiated in males and females until a critical stage when the sex chromosomes dictate its development as a testis or ovary. This binary developmental process provides a unique opportunity to delineate the molecular pathways that lead to distinctly different tissues. The testis comprises three main cell types: Sertoli cells, Leydig cells, and germ cells. The Sertoli cells and germ cells reside in seminiferous tubules where spermatogenesis occurs. The Leydig cells populate the interstitial compartment and produce testosterone. The ovary also comprises three main cell types: granulosa cells, theca cells, and oocytes. The oocytes are surrounded by granulosa and theca cells in follicles that grow and differentiate during characteristic reproductive cycles. In this review, we summarize the molecular pathways that regulate the distinct differentiation of these cell types in the developing testis and ovary. In particular, we focus on the transcription factors that initiate these cascades. Although most of the early insights into the sex determination pathway were based on human mutations, targeted mutagenesis in mouse models has revealed key roles for genes not anticipated to regulate gonadal development. Defining these molecular pathways provides the foundation for understanding this critical developmental event and provides new insight into the causes of gonadal dysgenesis.
Feedback Inhibition of Leptin Receptor/Jak2 Signaling via Tyr1138 of the Leptin Receptor and Suppressor of Cytokine Signaling 3
Authors: Dunn Sarah L. , Björnholm Marie , Bates Sarah H. , Chen Zhibin , Seifert Matthew , Myers Martin G.
Published: December 2004

Leptin is an adipocyte-derived hormone that communicates the status of body energy stores to the brain to regulate feeding and energy balance. The inability of elevated leptin levels to adequately suppress feeding in obesity suggests attenuation of leptin action under these conditions; the activation of feedback circuits due to high leptin levels could contribute to this leptin resistance. Using cultured cells exogenously expressing the long form of the leptin receptor (LRb) or an erythropoietin receptor/LRb chimera, we show that chronic stimulation results in the attenuation of LRb signaling and the establishment of a state in which the receptor is refractory to reactivation. Mutation of LRb Tyr1138 (the site that recruits signal transducer and activator of transcription 3) alleviated this feedback inhibition, suggesting that signal transducer and activator of transcription 3 mediates the induction of a feedback inhibitor, such as suppressor of cytokine signaling 3 (SOCS3), during chronic LRb stimulation. Indeed, manipulation of the expression or activity of the LRb-binding tyrosine phosphatase, SH2-domain containing phosphatase-2, by overexpression of wild-type and dominant negative isoforms or RNA interference-mediated knockdown did not alter the attenuation of LRb signals. In contrast, SOCS3 overexpression repressed LRb signaling, whereas RNA interference-mediated knockdown of SOCS3 resulted in increased LRb signaling that was not attenuated during chronic ligand stimulation. These data suggest that Tyr1138 of LRb and SOCS3 represent major effector pathways for the feedback inhibition of LRb signaling. Furthermore, we show that mice expressing an LRb isoform mutant for Tyr1138 display increased activity of the leptin-dependent growth and immune axes, suggesting that Tyr1138-mediated feedback inhibition may regulate leptin sensitivity in vivo.
Gli2 and Gli3 have redundant and context-dependent function in skeletal muscle formation
Authors: McDermott Aileen , Gustafsson Marcus , Elsam Thomas , Hui Chi-Chung , Emerson Charles P. , Borycki Anne-Gaëlle
Published: December 2004

The Gli family of zinc finger transcription factors are mediators of Shh signalling in vertebrates. In previous studies, we showed that Shh signalling,via an essential Gli -binding site in the Myf5 epaxial somite (ES)enhancer, is required for the specification of epaxial muscle progenitor cells. Shh signalling is also required for the normal mediolateral patterning of myogenic cells within the somite. In this study, we investigate the role and the transcriptional activities of Gli proteins during somite myogenesis in the mouse embryo. We report that Gli genes are differentially expressed in the mouse somite. Gli2 and Gli3 are essential for Gli1 expression in somites, establishing Gli2 and Gli3 as primary mediators and Gli1 as a secondary mediator of Shh signalling. Combining genetic studies with the use of a transgenic mouse line expressing a reporter gene under the control of the Myf5 epaxial somite enhancer, we show that Gli2 or Gli3 is required for Myf5 activation in the epaxial muscle progenitor cells. Furthermore, Gli3, but not Gli2 represses Myf5 transcription in a dose-dependent manner in the absence of Shh. Finally, we provide evidence that hypaxial and myotomal gene expression is mispatterned in Gli2–/–Gli3–/–and Gli3–/–Shh–/–somites. Together, our data demonstrate both positive and negative regulatory functions for Gli2 and Gli3 in the control of Myf5 activation in the epaxial muscle progenitor cells and in dorsoventral and mediolateral patterning of the somite.
Dlx1andDlx2function is necessary for terminal differentiation and survival of late-born retinal ganglion cells in the developing mouse retina
Authors: de Melo Jimmy , Du Guoyan , Fonseca Mario , Gillespie Leigh-Anne , Turk William J. , Rubenstein John L. R. , Eisenstat David D.
Published: December 2004

Dlx homeobox genes, the vertebrate homologs of Distal-less, play important roles in the development of the vertebrate forebrain, craniofacial structures and limbs. Members of the Dlx gene family are also expressed in retinal ganglion cells (RGC), amacrine and horizontal cells of the developing and postnatal retina. Expression begins at embryonic day 12.5 and is maintained until late embryogenesis for Dlx1, while Dlx2expression extends to adulthood. We have assessed the retinal phenotype of the Dlx1/Dlx2 double knockout mouse, which dies at birth. The Dlx1/2 null retina displays a reduced ganglion cell layer (GCL), with loss of differentiated RGCs due to increased apoptosis, and corresponding thinning of the optic nerve. Ectopic expression of Crx, the cone and rod photoreceptor homeobox gene, in the GCL and neuroblastic layers of the mutants may signify altered cell fate of uncommitted RGC progenitors. However,amacrine and horizontal cell differentiation is relatively unaffected in the Dlx1/2 null retina. Herein, we propose a model whereby early-born RGCs are Dlx1 and Dlx2 independent, but Dlx function is necessary for terminal differentiation of late-born RGC progenitors.
Insights into developmental mechanisms and cancers in the mammalian intestine derived from serial analysis of gene expression and study of the hepatoma-derived growth factor (HDGF)
Authors: Lepourcelet Maina , Tou Liqiang , Cai Li , Sawada Jun-ichi , Lazar Alexander J. F. , Glickman Jonathan N. , Williamson Jessica A. , Everett Allen D. , Redston Mark , Fox Edward A. , Nakatani Yoshihiro , Shivdasani Ramesh A.
Published: December 2004

The vertebrate intestine is a model for investigating inductive cellular interactions and the roles of epithelial stem cells in tissue regeneration,and for understanding parallels between development and cancer. We have used serial analysis of gene expression to measure transcript levels across stages in mouse intestine development. The data(http://genome.dfci.harvard.edu/GutSAGE)identify novel differentiation products, potential effectors of epithelial-mesenchymal interactions, and candidate markers and regulators of intestinal epithelium. Transcripts that decline significantly during intestine development frequently are absent from the adult gut. We show that a significant proportion of such genes may be reactivated in human colon cancers. As an example, hepatoma-derived growth factor (HDGF) mRNA is expressed prominently in early gut tissue, with substantially reduced levels after villous epithelial differentiation. HDGF expression is dramatically increased in human colorectal cancers, especially in tumors proficient in DNA mismatch repair, and thus represents a novel marker for a distinctive tumor subtype. HDGF overexpression in fetal intestine explants inhibits maturation,suggesting a role in epithelial differentiation. To investigate the molecular basis for HDGF functions, we isolated components of a nuclear HDGF complex,including heterogeneous nuclear ribonucleoproteins implicated in processing RNA. These genes are regulated in tandem with HDGF during intestine development and one factor, TLS/Fus, is commonly overexpressed in colon cancers. Tumor expression of fetal genes may underlie similarities between developing and malignant tissues, such as self-renewal, invasion and angiogenesis. Our findings also advance understanding of HDGF functions and implicate this developmentally regulated gene in RNA metabolic pathways that may influence malignant behaviors in colorectal cancer.
Associating a time‐based prospective memory task with an expected context can improve or impair intention completion
Authors: Cook Gabriel I. , Marsh Richard L. , Hicks Jason L.
Published: December 2004

Three experiments investigated time‐based prospective memory defined here as remembering to fulfil an intention during a later window of time. When people associated the response window with a future context, time‐based responding was better if that context expectation was correct as compared with having no context expectation at all. By contrast, if the response window occurred in a context that preceded the expected context, time‐based performance was worse than having no context expectation at all. An explicit reminder about the intention was sufficient to ameliorate the decrement found with an incorrect context association. However, successfully completing a different, event‐based prospective memory intention was not sufficient to overcome the incorrect context association. The authors assert that possessing such associations alters normal monitoring of the passage of time which in turn leads to the pattern of results obtained. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of overlearning on long‐term retention
Authors: Rohrer Doug , Taylor Kelli , Pashler Harold , Wixted John T. , Cepeda Nicholas J.
Published: December 2004

Once material has been learned to a criterion of one perfect trial, further study within the same session constitutes overlearning. Although overlearning is a popular learning strategy, its effect on long‐term retention is unclear. In two experiments presented here, 218 college students learned geography facts (Experiment 1) or word definitions (Experiment 2). The degree of learning was manipulated and measured via multiple test‐with‐feedback trials, and participants returned for a final cued recall test between 1 and 9 weeks later. The overlearners recalled far more than the low learners at the 1‐week test, but this difference decreased dramatically thereafter. These data suggest that overlearning (and its concomitant demand for additional study time) is an inefficient strategy for learning material for meaningfully long periods of time. Copyright © 2004 John Wiley & Sons, Ltd.
Gain scheduling control of functional electrical stimulation for assisted standing up and sitting down in paraplegia: a simulation study
Authors: Previdi Fabio , Ferrarin Maurizio , Savaresi Sergio M. , Bittanti Sergio
Published: December 2004

This paper reports on a simulation study that concerns the design of a non‐linear controller for the standing up and the sitting down of a paraplegic patient by means of functional electrical stimulation. The simulations refer to a specific experimental device developed at the Fondazione Don Gnocchi (Italy). This is a seesaw, with the patient on one side and a weight on the other side. The patient is seated so that its posture can be fully known in real‐time by continuously monitoring the knee joint angle. By delivering a suitable electrical stimulation to the quadriceps muscles groups, the patient can be raised and made to sit via smooth movements. Hitherto, the only feedback control law, which has been implemented in this area, is based on a PID controller and usually provides poor tracking performances. Hence, in this work, a non‐linear gain scheduling controller has been designed and tested in a series of simulation experiments. The controller is tuned following a gain scheduling strategy: a set of local linear quadratic controllers is designed using a set of linear tangent models. A global non‐linear gain scheduled controller is then obtained via interpolation. The gain‐ scheduled controller is implemented following an advanced strategy that guarantees that the so‐called linearization property holds. Copyright © 2004 John Wiley & Sons, Ltd.
Liquid residence time distribution in the film flow monolith reactor
Authors: Heibel Achim K. , Lebens Paul J. M. , Middelhoff Jack W. , Kapteijn Freek , Moulijn Jacob
Published: December 2004

An experimental method and data analysis procedure are introduced to determine the liquid residence time distribution (RTD) of monoliths based on the imperfect pulse injection of a dye tracer. Repeatable experiments for two different lengths allowed for the deconvolution of the RTD function of a 375‐mm‐long monolith section with 3.64‐mm2 channels out of dense ceramic material. The experimentally determined liquid saturations are in fair agreement with the predictions of computational fluid dynamics (CFD) calculations, assuming uniform corner flow in the square channels. The laminar film flow results in strong tailing of the RTD curves and large reduced standard deviation values. Despite the reasonable agreement for the mean residence time the CFD model based on uniform liquid distribution over the monolith channels and the individual channel corners failed to describe the experimentally determined reduced RTD curves. Applying a measured corner‐scale liquid distribution pattern in combination with the CFD model resulted in good agreement with the experiments. Furthermore, this approach also improved the agreement between measurement and model for the mean residence time. © 2004 American Institute of Chemical Engineers AIChE J, 51: 122–133, 2005
Neonatal phenotype in Kabuki syndrome
Authors: Vaux Keith K. , Hudgins Louanne , Bird Lynne M. , Roeder Elizabeth , Curry Cynthia J.R. , Jones Marilyn , Jones Kenneth L.
Published: December 2004

The Kabuki syndrome is a well‐established pattern of human malformation with readily recognizable features, however the diagnosis is rarely made in the newborn period. The purpose of this study was to determine if there exists a neonatal phenotype for this disorder. We ascertained 16 infants evaluated in the first 28 days of life by a dysmorphologist who subsequently received the diagnosis of Kabuki syndrome. The average age of initial evaluation was 8 days and the average age of diagnosis was 2 years 6 months. Based on these findings, it is suggested that the distinctive clinical phenotype seen in older patients is also evident in the newborn period. Published 2004 Wiley‐Liss, Inc.
Improvement of the production of GFPuv‐β1,3‐N‐acetylglucosaminyltransferase 2 fusion protein using a molecular chaperone‐assisted insect‐cell‐based expression system
Authors: Kato Tatsuya , Murata Takeomi , Usui Taichi , Park Enoch Y.
Published: December 2004

A stable Tn‐5B1‐4 insect cell line co‐expressing the recombinant GFPuv‐β1,3‐N‐acetylglucosaminyltransferase 2 (GFPuv‐β3GnT2) protein fused to a melittin signal sequence with a lectin‐like molecular chaperone, human calnexin (hCNX) or human calreticulin (hCRT), was constructed. The expression of either of these molecular chaperones is under the control of a weak promoter, OpMNPV IE2, while that of GFPuv‐β3GnT2 is under the control of Bombyx mori actin promoter. This co‐expression system was compared between two different insect cell–baculovirus expression systems: (1) co‐infection of the recombinant baculovirus containing a molecular chaperone (AcNPV‐hCNX or ‐hCRT) with a recombinant baculovirus containing GFPuv‐β3GnT2 fused with the melittin signal sequence (AcNPV‐me‐GGT); (2) infection of AcNPV‐me‐GGT to a stably expressing cell line for either hCNX or hCRT. In the co‐infection system, the intracellular GFPuv‐β3GnT2 expression level was low because of the improved secretion level ratio of the fusion protein, due to the chaperone expression. In the case of infection to the stably expressing cell line for a chaperone, the extracellular GFPuv‐β3GnT2 expression level was similar to the intracellular expression level. This suggests that the amount of expressed chaperone is not sufficient to process β3GnT2. On the other hand, the co‐expression system produced an extracellular β3GnT activity of 22–23 mU/mL, which was approximately 3.5‐ and 11‐fold higher than those of the stable expression of the fusion gene without the chaperone and the conventional BES with the addition of protease, respectively. The secretion level ratio of the fusion protein of this system increased to 82%, which was approximately 1.5‐fold that of any other expression system investigated thus far. These results indicate that the ratio of the expression level of the target gene to that of the chaperone gene may be an important factor in maximizing the production of a target protein. The molecular‐chaperone‐assisted expression system using a stably transformed insect cell line offers promising prospects for the efficient production of recombinant secretory proteins in insect cells. © 2004 Wiley Periodicals, Inc.
Baculovirus as a highly efficient gene delivery vector for the expression of hepatitis delta virus antigens in mammalian cells
Authors: Wang Kuei‐Chun , Wu Jaw‐Chin , Chung Yao‐Chi , Ho Yi‐Chen , Dah‐Tsyr Chang Margaret , Hu Yu‐Chen
Published: December 2004

Baculovirus has been employed for a wide variety of applications. In this study, we further expanded the application to the high‐level expression of hepatitis delta virus (HDV) antigens and the formation of virus‐like particles (VLP) in transduced mammalian cells. To this end, two recombinant baculoviruses were constructed to express large hepatitis delta antigen (L‐HDAg) and hepatitis B surface antigen (HBsAg) under mammalian promoters. With a simplified transduction protocol using unconcentrated virus, high transduction efficiencies were achieved in hepatoma cells, in which L‐HDAg and HBsAg were expressed abundantly, allowing for easy colorimetric detection in Western blots. L‐HDAg alone was nucleus‐bound and HBsAg alone was secreted; formation and secretion of HDV‐like particles were readily detected upon coexpression, indicating that the baculovirus‐expressed proteins were processed correctly as the authentic proteins. Quantitative real‐time PCR (Q‐PCR) analyses quantitatively revealed that baculovirus transduction was more efficient than plasmid transfection with respect to DNA uptake and DNA transport to the nucleus. Furthermore, superinfection introduced more baculovirus DNA into cells in the long‐term culture as revealed by Q‐PCR, thereby enhancing and prolonging the expression. In summary, baculovirus transduction can be an attractive method as an alternative to the plasmid transfection commonly employed for HDV research thanks to the significantly higher gene delivery efficiencies as well as the abundant expression and proper processing. Baculovirus can also be envisaged as a useful tool for investigating protein–cell interactions and virus assembly. © 2004 Wiley Periodicals, Inc.
Effective follow-up for recurrence or a second primary cancer in patients with early gastric cancer
Authors: Ikeda Y , Saku M , Kishihara F , Maehara Y
Published: December 2004

Background

Patients with early gastric cancer have an excellent prognosis with low rates of recurrence, but may have an increased risk of developing a second primary cancer. Because the number of early gastric cancers has increased, clarification of both recurrences and second primary cancers is important for the development of effective postoperative follow-up programmes.

Methods

Data on 1070 patients with early gastric cancer were analysed retrospectively with respect to the clinicopathological features of both recurrence and second primary cancers after surgical treatment.

Results

Multivariate analysis showed that lymph node metastasis and older age were independent risk factors for recurrence of early gastric cancer. The incidence of second primary cancers was 5·0 per cent; lung and colorectal cancers were detected most frequently, followed by cancers in the oesophagus, breast and remnant stomach.

Conclusion

Clinicopathological features of patients with early gastric cancer can be used to identify those most at risk of developing either recurrence or a second primary cancer.
Major urinary dysfunction after mesorectal excision for rectal carcinoma
Authors: Kneist W , Heintz A , Junginger T
Published: December 2004

Background

Urinary dysfunction may occur after mesorectal excision and pelvic autonomic nerve preservation (PANP) in patients with rectal carcinoma. The aim of this prospective study was to identify factors predictive of long-term urinary catheterization.

Methods

Two hundred and ten patients without significant urological problems underwent resection of rectal cancer with mesorectal excision. The number of patients with complete, partial or no identification of the nerves was documented and correlated with possible predictive factors for postoperative major urinary dysfunction.

Results

Eight patients (3·8 per cent) required long-term urinary catheterization: two after complete PANP (two of 168) and six in whom PANP was incomplete (six of 42) (P = 0·001). Multiple regression analysis identified incomplete PANP (odds ratio 13·8 (95 per cent confidence interval 2·7 to 71·3); P = 0·002) as a predictive factor for major urinary dysfunction.

Conclusion

Major urinary dysfunction after mesorectal excision for rectal cancer is associated with an incomplete nerve-sparing technique.
Multipoint Recognition of Catecholamines by Hydrindacene‐Based Receptors Accompanied by the Complexation‐Induced Conformational Switching
Authors: Kawai Hidetoshi , Katoono Ryo , Fujiwara Kenshu , Tsuji Takashi , Suzuki Takanori
Published: December 2004

The molecular recognition of catecholamines by hydrindacene‐based receptors 1 and 2, as well as the durene‐based receptor 3, and the guest‐induced conformational changes are reported. These receptors selectively bind adrenaline and dopamine salts through the guests' ammonium group and 3‐hydroxyl group on the aromatic ring. In the case of adrenaline, an additional hydrogen bond with a benzylic hydroxyl group is formed. In 2 % CD3CN/CDCl3, the association constants are of the order of 104 M−1, which is much larger than with guests without the 3‐hydroxyl groups (103 M−1). The two amide groups of receptor 1 can rotate freely around the CaromaticCamide bond, whereas the tert‐amide in 2 changes between two stable conformations at a slow enough rate to allow detection by 1H NMR spectroscopy. In the absence of a guest molecule, the syn‐conformer is less stable than the anti‐conformer. On complex formation with adrenaline, the syn‐conformer becomes dominant due to an intramolecular dipole‐reversal effect in addition to multipoint hydrogen bonding.
Outer‐Sphere Hydration and Liquid−Liquid Partition of Metal(III) Chelates − Density Functional Calculations
Authors: Czerwiński Marian , Narbutt Jerzy
Published: December 2004

Hydration of two coordinatively saturated metal chelates, tris(propane‐1,3‐dionato)scandium(III) and tris(propane‐1,3‐dionato)cobalt(III), was studied theoretically using the density functional method with a three‐parameter B3LYP implementation at different variants for calculating the hydration energy, including corrections for ZPVE, BSSE, polarisation functions, temperature and the number of hydrating water molecules in the system. Formation of hydrates was demonstrated, with water hydrogen‐bonded to ligands (outer‐sphere hydration). After corrections for side effects, good correlations were found between the energy and the length of these hydrogen bonds in the hydrates of both chelates. Also, the calculated changes in charge distribution on the atoms of hydrogen‐bonded water in these model chelates qualitatively agree with the experimental 1H NMR spectroscopic data for the analogous tris(pentane‐2,4‐dionato)cobalt(III) species. An implicit solvation model (SCI‐PCM) was used to take into account solvent effects of water and heptane on the energies of the model chelates studied and to calculate their enthalpies of transfer from heptane to water. In spite of simplifications in the model, satisfactory agreement was found between the calculated values and the experimental standard enthalpies of transfer of the analogous chelates, namely the tris(pentane‐2,4‐dionates) of scandium and cobalt(III). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Tetracyanoquinodimethanido Derivatives of (Terpyridine)‐ and (Phenanthroline)metal Complexes − Structural and Magnetic Studies of Radical‐Ion Salts
Authors: Alonso Cristina , Ballester Loreto , Gutiérrez Angel , Perpiñán M. Felisa , Sánchez Ana E. , Azcondo M. Teresa
Published: December 2004

Several derivatives of formulae [M(terpy)2](TCNQ)2 or [M(terpy)2](TCNQ)3 (M = Ni, Cu, Zn; terpy = 2,2′:6′,2"‐terpyridine; TCNQ= 7,7,8,8‐tetracyanoquinodimethane) and [M(phen)3](TCNQ)2 or [M(phen)3](TCNQ)4 (M = Fe, Ni; phen = 1,10‐phenanthroline) have been obtained. The crystal structures of [M(terpy)2](TCNQ)2 (M = Ni, Cu) show that the metal is surrounded by the terpyridine nitrogen atoms in a closed octahedral environment and the TCNQ anions are dimerised by π overlap. The cationic [M(terpy)2]2+ and the anionic [TCNQ]22− groups alternate in the crystal. For the derivatives with three TCNQ groups, the existence of a stack of trimeric [TCNQ]32− ions having electronic delocalisation is proposed. The compound [Fe(phen)3](TCNQ)2, which shows a strong interaction between TCNQ anions, led to the formation of a σ bond in the diamagnetic species [TCNQ−TCNQ], while the nickel analogue is expected to have a localised structure formed by alternation of cationic metal complexes and dimeric [TCNQ]22− anions similar to those observed in the analogous terpy derivatives. The derivatives having four TCNQ groups also show electronic delocalisation and a 1D stack based on the magnetic data is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Gold(0) and Gold(III) Reactivity towards the Tetraphenyldithioimidodiphosphinic Acid, [Ph2P(S)NHP(S)Ph2]
Authors: Abbati G. Luca , Aragoni M. Carla , Arca Massimiliano , Carrea M. Bonaria , Devillanova Francesco A. , Garau Alessandra , Isaia Francesco , Lippolis Vito , Marcelli Marco , Silvestru Cristian , Verani Gaetano
Published: December 2004

The reaction of gold powder with the iodine adduct of Ph2P(S)NHP(S)Ph2 (HL) in Et2O gave the complex [Au(L)I2] under mild reaction conditions. Its crystal structure is comprised of discrete, monomeric molecules with a central AuIII ion bonded to two sulfur atoms by an anionic ligand L and two iodide anions in a slightly distorted square‐planar coordination geometry. From the reaction of [AuCl3(tht)] with HL in CH2Cl2 it is possible, besides the main complex [Au(L)]2, to separate the neutral AuI complex [Au(L′2H)], L′ = [Ph2P(S)NP(O)Ph2]−, the crystal structure of which features a AuI ion linearly coordinated to two sulfur atoms and a proton bridging two oxygen atoms of the PO groups. 31P NMR CP MAS spectroscopy is in accordance with the nature of the ligands in the complex. The reaction chemistry of [Au(L′2H)] in CH2Cl2 towards the acid CF3COOH and the organic base 1,8‐bis(dimethylamino)naphthalene is reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Sonochemical Reaction of [Fe(CO)5] with 1‐Methylimidazole in An Ionic Liquid: Formation of [(1‐Methylimidazole)6FeII](PF6)2
Authors: Jacob David S. , Kahlenberg Volker , Wurst Klaus , Solovyov Leonid A. , Felner Israel , Shimon Linda , Gottlieb Hugo E. , Gedanken Aharon
Published: December 2004

The ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate, (BMI+)(PF6−), has been used as a solvent in the sonochemical reaction of 1‐methylimidazole and [Fe(CO)5] at 40−50 °C under air. The reaction afforded [(1‐methylimidazole)6FeII](PF6)2, the structure of which was determined at 293 K by single‐crystal X‐ray diffraction methods. The salt crystallizes in the trigonal space group P$\bar 3$
with unit‐cell parameters of a = 11.4603(16) Å, c = 8.0172(11) Å, and Z = 1. The crystals showed twinning by merohedry, which was accounted for in the structure determination and refinement calculations. All the 1‐methylimidazole ligands are equivalent, with a Fe−N bond length of 2.204(3) Å. Mössbauer spectroscopy confirmed the presence of Fe2+. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Controls on the transition from meandering to straight channels in the wetlands of the Okavango Delta, Botswana
Authors: Tooth S. , McCarthy T. S.
Published: December 2004

Previous studies of alluvial rivers have shown that channel patterns form a continuum controlled by interactions among factors such as gradient, discharge, sediment size, and bank strength. Data from channels in the permanent wetlands of the Okavango Delta add to these ﬁndings by focusing on pattern transitions in channels with banks formed by sedges and grasses that are rooted in peat and underlain by unconsolidated sediment. Channels are well deﬁned, and transport ﬁne–medium sand as bedload between the vertical, vegetation‐lined banks. Water depths, velocities, grain sizes, and bankline vegetation do not vary signiﬁcantly or systematically downstream, but the permeable banks allow water to leak from the channels, contributing to an overall downstream decrease in discharge and width. In addition, as the Okavango River ﬂows from the <12 km wide ‘Panhandle’ and splits into distributaries in the broader ‘Fan’, valley gradient steepens by c. 60 per cent.

These downstream changes result in channel pattern adjustments. In the Panhandle, the Okavango River is a relatively wide (c. 30–100 m), actively meandering, sinuous channel (P > 2·0), but further downstream in the Fan, the narrower (<40 m) distributaries follow laterally stable, less sinuous (‘straight’) courses (P < 1·75). Some channel pattern discrimination diagrams based on simple indices of gradient, discharge, sediment size or stream power are inadequate for analysing the meandering–straight transition in the Okavango but Parker's (1976) approach, based on ratios of depth–width and slope–Froude number, accurately characterizes the transition. Our ﬁeld observations, combined with the results from previous experimental studies, suggest that in relatively wide channels (w/d > 10), thalweg meandering results in scour of the unconsolidated sediment at the bank base, leading to undermining and collapse of the vegetation, and to slow meander migration. However, as channels narrow downstream (w/d < 10) with discharge losses, proportionally increasing sidewall drag exerted by bankline vegetation suppresses thalweg meandering and bank scour, and channels follow stable, less sinuous courses. Copyright © 2004 John Wiley & Sons, Ltd.
Pattern robustness of diagnostic gene expression signatures in leukemia
Authors: Kohlmann Alexander , Schoch Claudia , Dugas Martin , Rauhut Sonja , Weninger Felix , Schnittger Susanne , Kern Wolfgang , Haferlach Torsten
Published: December 2004

Microarray technology has been proposed as an addition to the methods in current use for diagnosing leukemia. Before a new technology can be used in a diagnostic setting, the method has to be shown to produce robust results. It is known that, given the technical aspects of specimen sampling and target preparation, global gene expression patterns can change dramatically. Various parameters such as RNA degradation, shipment time, sample purity, and patient age can principally influence measured gene expression. However, thus far, no information has been available on the robustness of a diagnostic gene expression signature. We demonstrate here that for a subset of acute leukemia, expression profiling is applicable in a diagnostic setting, considering various influencing parameters. With the use of a set of differentially expressed genes, that is, a diagnostic gene expression signature, four genetically defined acute myeloid leukemia subtypes with recurrent chromosomal aberrations can clearly be identified. In addition, we show that preparation by different operators and using different sample‐handling procedures did not impair the robustness of diagnostic expression signatures. In conclusion, our results provide additional support for the applicability of microarrays in a diagnostic setting, and we have been encouraged to enroll patients in a prospective study in which microarrays will be tested as an additional routine diagnostic method in parallel with standard diagnostic procedures. © 2004 Wiley‐Liss, Inc.
A novel candidate region linked to development of both pheochromocytoma and head/neck paraganglioma
Authors: Cascón Alberto , Ruiz‐Llorente Sergio , Rodríguez‐Perales Sandra , Honrado Emiliano , Martínez‐Ramírez Ángel , Letón Rocío , Montero‐Conde Cristina , Benítez Javier , Dopazo Joaquín , Cigudosa Juan C. , Robledo Mercedes
Published: December 2004

Although the histologic distinction between pheochromocytomas and head and neck paragangliomas is clear, little is known about the genetic differences between them. To date, various sets of genes have been found to be involved in inherited susceptibility to developing both tumor types, but the genes involved in sporadic pathogenesis are still unknown. To define new candidate regions, we performed CGH analysis on 29 pheochromocytomas and on 24 paragangliomas mainly of head and neck origin (20 of 24), which allowed us to differentiate between the two tumor types. Loss of 3q was significantly more frequent in pheochromocytomas, and loss of 1q appeared only in paragangliomas. We also found gain of 11q13 to be a significantly frequent alteration in malignant cases of both types. In addition, recurrent loss of 8p22–23 was found in 62% of pheochromocytomas (including all malignant cases) versus in 33% of paragangliomas, suggesting that this region contains candidate genes involved in the pathogenesis of this abnormality. Using FISH analysis on tissue microarrays, we confirmed genomic deletion of this region in 55% of pheochromocytomas compared to 12% of paragangliomas. Loss of 8p22–23 appears to be an important event in the sporadic development of these tumors, and additional molecular studies are necessary to identify candidate genes in this chromosomal region. © 2004 Wiley‐Liss, Inc.
A deterministic method to characterize canopy radiative transfer properties
Authors: Link Timothy E. , Marks Danny , Hardy Janet P.
Published: December 2004

Investigations of snowcover dynamics beneath vegetation canopies require either measured or estimated solar and thermal radiation values at the snow surface. A deterministic method is presented that uses portable arrays of pyranometers and pyrgeometers to quantify the amount of incoming radiation at the snow surface. Example solar and thermal radiation datasets are presented from boreal deciduous, boreal coniferous and temperate coniferous forest stands. The data indicate that the canopies transmitted 33% (4–8 March), 15% (6–10 February), and 3% (22–24 September) of the above‐canopy radiation. In the boreal deciduous and temperate conifer stands, thermal radiation is increased by 25% and 34% respectively. Thermal gains partially offset solar reduction, such that incoming all‐wave radiation is decreased by 22% and 25% respectively for each of these stands. When recorded at a high temporal resolution, array data can estimate below‐canopy diffuse solar radiation values for estimation techniques that treat direct and diffuse transmission independently. We provide examples of how radiometer array data are used to derive simple canopy radiation transmissivity parameters for global, beam and diffuse radiation. Radiometer arrays also provide data for detailed investigations to assess within‐stand radiation variability, or to investigate radiation variations across land cover discontinuities, to advance our understanding of snowcover energetics in complex environments. Copyright © 2004 John Wiley & Sons, Ltd.
Trends in incidence and prognosis for head and neck cancer in the United States: A site‐specific analysis of the SEER database
Authors: Carvalho André Lopes , Nishimoto Inês Nobuko , Califano Joseph A. , Kowalski Luiz Paulo
Published: December 2004

Despite recent advances in the diagnosis and treatment of head and neck cancer, there has been little evidence of improvement in 5‐year survival rates over the last few decades. To determine more accurate trends in site‐specific outcomes as opposed to a more general overview of head and neck cancer patients, we analyzed the site‐specific data collected in the Surveillance, Epidemiology, and End Results—SEER Public‐Use Database 1973–1999. Based on the selection criteria, 96,232 cases were evaluated for trend analysis in incidence, clinical stage, treatment and 5‐year survival. During the period 1973–1999, site‐specific incidence rates for head and neck cancer changed significantly. Site‐specific analysis of survival from 1974–1997 showed significant improvements in 5‐year survival rates for cancers of the nasopharynx, oropharynx and hypopharynx (38.1% to 56.7% for nasopharynx, p < 0.001; 36.3% to 49.1% for oropharynx, p = 0.001 and 28.3% to 33.3% for hypopharynx, p = 0.015). The prognosis for early‐stage salivary gland cancer during 1983–1997 and late‐stage larynx cancer during 1974–1997 also demonstrated improvement (82.7% to 88.5%, p = 0.012 and 22.2% to 38.3%, p = 0.013, respectively). On the other hand, the prognosis for regional stage oral cavity cancer as well as early‐stage larynx cancer patients declined during 1983–1997 (49.2% to 43.8%, p = 0.032 and 82.3% to 74.3%, p = 0.002, respectively). Site‐specific changes in treatment and staging were also noted. Site‐specific analysis allows for a more accurate description of incidence, staging, treatment, and prognostic trends for head and neck cancer. © 2004 Wiley‐Liss, Inc.