bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin and Human Chorionic Gonadotropin Cause a Shift in the Balance of Sterol Regulatory Element-Binding Protein (SREBP) Isoforms Toward the SREBP-1c Isoform in Cultures of Human Granulosa Cells
Authors: Richardson Malcolm C. , Cameron Iain T. , Simonis Chantal D. , Das Madhab C. , Hodge Tessa E. , Zhang Junlong , Byrne Christopher D.
Published: May 2005

The isoforms of sterol regulatory element-binding proteins (SREBP) (1a, 1c, and 2) are key transcriptional regulators of lipid biosynthesis. We examined their regulation by gonadotropin and insulin in human granulosa cells. After removal of leukocytes, granulosa cells were exposed to hormonal additions for 16 h starting on d 2 of culture. Progesterone, lactate, and IGF binding protein-1 were measured in culture medium and cellular mRNA measured by competitive RT-PCR. Addition of human chorionic gonadotropin (hCG) (100 ng/ml) stimulated progesterone production (7.0-fold, P < 0.001 vs. control), whereas lactate was increased by hCG (1.6-fold, P < 0.001) and insulin (1.4-fold, P < 0.001; 1000 ng/ml). Insulin decreased IGF binding protein-1 production by 85% (P < 0.001). There were no significant effects on the expression of SREBP-1a but significant increases in mRNA for SREBP-1c with insulin (6.3-fold), hCG (10.4-fold) and in combination (15.2-fold; P < 0.01 for all comparisons). No consistent effects on SREBP-2 were observed. The expression of mRNA for fatty acid synthase, a target gene for SREBP-1c, was increased by hCG (24-fold, P = 0.006) and insulin (19-fold, P = 0.024), which also increased the level of cellular, total fatty acid (1.34-fold; P = 0.03). Thus, hCG and insulin cause a switch toward expression of the SREBP-1c isoform with consequent effects on fatty acid synthesis. We suggest that high circulating insulin, associated with clinically defined insulin resistance, may up-regulate SREBP-1c expression in the ovary.
Effects of the Human Immunodeficiency Virus-Protease Inhibitor, Ritonavir, on Basal and Catecholamine-Stimulated Lipolysis
Authors: Adler-Wailes Diane C. , Liu Hanguan , Ahmad Faiyaz , Feng Ningping , Londos Constantine , Manganiello Vincent , Yanovski Jack A.
Published: May 2005

Several of the aspartic acid protease inhibitors used to treat HIV infection increase basal lipolysis in adipocytes, but the cellular mechanisms leading to this augmentation are not well understood. We therefore studied the effects of chronic exposure to the HIV protease inhibitor, ritonavir, on the lipolytic cascade in 3T3-L1 adipocytes.

Treatment of 3T3-L1 adipocytes with ritonavir for 14 d (during and after differentiation) enhanced basal, isoproterenol (Iso)-stimulated, and cAMP analog-stimulated lipolysis. Enhancement of lipolysis was observed after Iso at concentrations between 0.1 and 10 μm. Despite a significant decrease in cyclic nucleotide phosphodiesterase (PDE)3B activity and protein levels, there were no changes in Iso-stimulated intracellular cAMP, protein kinase A (PKA) expression, or PKA activity. Ritonavir-augmented lipolysis was also observed under conditions that reversed the effect on PDE3B activity via preincubation with 1 μm (-)-N6-(2-phenylisopropyl)adenosine. In ritonavir-treated cells, protein expression of the lipid droplet-protective protein, perilipin, was significantly decreased, whereas there was no change in hormone-sensitive lipase. Activation of ERK1/2 by Iso did not play a role in the augmentation. We conclude that ritonavir decreases PDE3B and perilipin protein expression and affects both basal and catecholamine-stimulated lipolysis in 3T3-L1 adipocytes primarily through actions at sites downstream of PKA.
Preproorexin and Orexin Receptors Are Expressed in Cortisol-Secreting Adrenocortical Adenomas, and Orexins Stimulate in Vitro Cortisol Secretion and Growth of Tumor Cells
Authors: Spinazzi R. , Rucinski M. , Neri G. , Malendowicz L. K. , Nussdorfer G. G.
Published: May 2005

Orexins A and B are hypothalamic peptides that originate from the proteolytic cleavage of preproorexin and act through two subtypes of receptors, named OX1-R and OX2-R. OX1-R almost exclusively binds orexin-A, whereas OX2-R is nonselective for both orexins. We previously found that orexin-A, via the OX1-R, stimulates cortisol secretion from dispersed human adrenocortical cells. In this study, we demonstrate that six of eight cortisol-secreting adenomas expressed preproorexin mRNA, and seven of 10 adenomas contained measurable amounts of orexin-A but not orexin-B. Normal adrenal cortexes neither expressed preproorexin nor contained orexins. All adenomas expressed OX1-R and OX2-R mRNAs, and real-time PCR showed that the expression of both receptors was up-regulated in adenomas, compared with normal adrenal cortex. Orexin-A concentration-dependently raised basal cortisol secretion from freshly dispersed normal and adenomatous cells, minimal and maximal effective concentrations being 10−10 and 10−8m, and the peptide efficacy (percent increase elicited by 10−8m orexin-A) was significantly higher in adenomas than in the normal adrenal cortex. Orexin-B was ineffective, thereby indicating that orexin secretagogue action is mediated by the OX1-R. In contrast, both orexins (10−8m) raised the proliferative activity of cultured normal and adenomatous cells, suggesting that this effect is mediated by OX2-R or both receptor subtypes. Collectively, our findings allow us to conclude that the orexin system is overexpressed in cortisol-secreting adenomas and suggest that orexin-A may act as an autocrine-paracrine regulator of the secretory activity and growth of some of these adrenal tumors.
The Leu7Pro Polymorphism of PreproNPY Is Associated with Decreased Insulin Secretion, Delayed Ghrelin Suppression, and Increased Cardiovascular Responsiveness to Norepinephrine during Oral Glucose Tolerance Test
Authors: Jaakkola Ulriikka , Kuusela Tom , Jartti Tuomas , Pesonen Ullamari , Koulu Markku , Vahlberg Tero , Kallio Jaana
Published: May 2005

Context: Neuropeptide Y (NPY) plays a role in angiogenesis, cardiovascular regulation, and hormone secretion. The leucine7 to proline7 (Leu7Pro) polymorphism of preproNPY is associated with vascular diseases and has an impact on hormone levels in healthy subjects.

Objective: The current study investigated the role of the Leu7Pro polymorphism in metabolic and cardiovascular autonomic regulation.

Design and Subjects: A 5-h oral glucose tolerance test was performed on 27 healthy volunteers representing two preproNPY genotypes (Leu7/Pro7 and Leu7/Leu7) matched for age, sex, body mass index and physical activity.

Main Outcome Measures: Simultaneously we performed cardiovascular autonomic function tests and plasma measurements of sympathetic transmitters, glucose, insulin, and ghrelin.

Results: The subjects with Leu7/Pro7 genotype had decreased plasma NPY, norepinephrine (NE), and insulin concentrations and insulin to glucose ratios. The suppression of ghrelin concentrations after glucose ingestion was delayed in these subjects. They also had increased heart rate variability indices and baroreflex sensitivity. However, they displayed significant negative association of NE concentration with variability of low-frequency R-R-intervals and with baroreflex sensitivity.

Conclusions: The Leu7Pro polymorphism of preproNPY is related to decreased level of basal sympathetic activity, decreased insulin secretion, and delayed ghrelin suppression during oral glucose tolerance test. The increased responsiveness of autonomic functions to NE associated with the polymorphism may be connected to increased cardiovascular vulnerability.
Focal adhesion kinase is required for the spatial organization of the leading edge in migrating cells
Authors: Tilghman Robert W. , Slack-Davis Jill K. , Sergina Natalia , Martin Karen H. , Iwanicki Marcin , Hershey E. Daniel , Beggs Hilary E. , Reichardt Louis F. , Parsons J. Thomas
Published: May 2005

The process of cell migration is initiated by protrusion at the leading edge of the cell, the formation of peripheral adhesions, the exertion of force on these adhesions, and finally the release of the adhesions at the rear of the cell. Focal adhesion kinase (FAK) is intimately involved in the regulation of this process, although the precise mechanism(s) whereby FAK regulates cell migration is unclear. We have used two approaches to reduce FAK expression in fibroblasts. Treatment of cells with FAK-specific siRNAs substantially reduced FAK expression and inhibited the spreading of fibroblasts in serum-free conditions, but did not affect the rate of spreading in the presence of serum. In contrast with the wild-type cells, the FAK siRNA-treated cells exhibited multiple extensions during cell spreading. The extensions appeared to be inappropriately formed lamellipodia as evidenced by the localization of cortactin to lamellipodial structures and the inhibition of such structures by expression of dominant-negative Rac. The wild-type phenotype was restored by reexpressing wild-type FAK in the knockdown cells, but not by expression of FAK containing a point mutation at the autophosphorylation site (FAK Y397F). In wound-healing assays, FAK knockdown cells failed to form broad lamellipodia, instead forming multiple leading edges. Similar results were obtained using primary mouse embryo fibroblasts from FAK-flox mice in which Cre-mediated excision was used to ablate the expression of FAK. These data are consistent with a role for FAK in regulating the formation of a leading edge during cell migration by coordinating integrin signaling to direct the correct spatial activation of membrane protrusion.
The formin family protein CaBni1p has a role in cell polarity control during both yeast and hyphal growth inCandida albicans
Authors: Li Chang Run , Wang Yan Ming , De Zheng Xin , Liang Hui Yan , Tang Jason Chih Wei , Wang Yue
Published: May 2005

Formins are conserved eukaryotic proteins playing key roles in regulating cell polarity. We have characterized the roles of a formin CaBni1p in the polymorphic fungus Candida albicans. CaBni1p localized persistently to hyphal tips during hyphal growth but to distinct growth sites at different cell cycle stages during yeast growth. Cabni1Δ yeast cells exhibited several morphological defects, such as round and enlarged cells, widened bud necks and a random budding pattern. Although Cabni1Δ cells could still undergo yeast-hypha growth switch, the hyphae were markedly swollen. Cabni1Δ also showed defects in spindle and cytoplasmic microtubule orientation and positioning. Coincidentally, the spindle orientation protein CaKar9p in Cabni1Δ yeast cells appeared as multiple random cortical spots, in contrast to the single spot at the bud tip of many wild-type cells. Interestingly, several defects manifested in Cabni1Δ yeast cells were partially corrected during hyphal growth. We found that the second formin CaBnr1p was recruited to hyphal tips, while it localized only to the bud neck during yeast growth. This behavior of CaBnr1p may play a key role in correcting Cabni1Δ defects during hyphal growth. Cabni1Δ exhibited reduced virulence in mice. These results indicate that the formins play an important role in Candida albicans polarized growth and CaBni1p's function is required for virulence.
HOXA3 induces cell migration in endothelial and epithelial cells promoting angiogenesis and wound repair
Authors: Mace Kimberly A. , Hansen Scott L. , Myers Connie , Young David M. , Boudreau Nancy
Published: May 2005

Wound repair requires both the recruitment and coordination of numerous cell types including inflammatory cells, fibroblasts, endothelial and epithelial cells. Each cell type has a distinct set of cell behavior such as formation of granulation tissue and basement membrane, migration, proliferation and redifferentiation. These processes are dependent on cell-cell and cell-ECM signaling, intracellular signal transduction cascades, and ultimately, changes in gene transcription. We have investigated the role of the transcription factor HOXA3 in wound repair and angiogenesis. Here we show that HOXA3 increases endothelial cell migration, induces angiogenesis in vivo, and leads to increased expression of the matrix metalloproteinase-14 (MMP-14) and urokinase-type plasminogen activator receptor (uPAR) genes in endothelial cells in culture and in vivo in response to injury. We find that HOXA3 gene expression is upregulated during wound healing in angiogenic endothelial cells and keratinocytes, and that HOXA3 is not induced in genetically diabetic mice that have impaired angiogenesis and wound repair. We demonstrate that gene transfer of HOXA3 into diabetic mouse wounds leads to dramatic improvements in both angiogenesis and wound closure. In addition, we show that HOXA3 promotes migration of endothelial cells and keratinocytes in a uPAR-dependent manner. Together these findings illustrate how the morphoregulatory protein, HOXA3 can facilitate tissue remodeling via coordinated changes in both epithelial and endothelial cell gene expression and behavior in adult tissues during wound repair.
Rab18 localizes to lipid droplets and induces their close apposition to the endoplasmic reticulum-derived membrane
Authors: Ozeki Shintaro , Cheng Jinglei , Tauchi-Sato Kumi , Hatano Naoya , Taniguchi Hisaaki , Fujimoto Toyoshi
Published: May 2005

Lipid droplets (LDs) are organelles that store neutral lipids, but their regulatory mechanism is not well understood. In the present study, we identified Rab18 as an LD component of HepG2 cells by proteomic analysis, and confirmed its localization by immunohistochemistry and western blotting. Wild-type and dominant-active Rab18 localized to LDs but the dominant-negative form did not. Endogenous Rab18 coexisted with adipocyte differentiation-related protein (ADRP) in LDs, but the labeling intensity of the two proteins showed clear reciprocity. Consistent with this observation, overexpression of Rab18 induced a decrease in the amounts of ADRP in LDs in HepG2 and BALB/c 3T3 cells. Furthermore, Rab18 overexpression caused close apposition of LDs to membrane cisternae connected to the rough ER. Two other procedures that decrease ADRP, i.e. RNA interference and brefeldin A treatment, induced the same morphological change, indicating that decrease in ADRP was the cause of the LD-ER apposition. In accordance with similar structures found between ER and other organelles, we propose that the ER membrane apposed to LDs should be named the LD-associated membrane, or LAM. The present results suggested that Rab18 regulates LAM formation, which is likely to be involved in mobilizing lipid esters stored in LDs.
Structural characterization of an anti-gp120 RNA aptamer that neutralizes R5 strains of HIV-1
Authors: DEY ANTU K. , GRIFFITHS CARLA , LEA SUSAN M. , JAMES WILLIAM
Published: May 2005

We recently described the isolation of 2′-fluoropyrimidine-substituted RNA aptamers that bind specifically to the surface glycoprotein (gp 120) of the R5 strain, HIV-1Ba-L, as presented in a previous study. These aptamers potently neutralize HIV-1 infectivity in human peripheral blood mononuclear cells of both tissue culture lab-adapted strains and diverse R5 clinical isolates from multiple clades. Here, we report a detailed structural characterization of one such neutralizing aptamer, B40, using enzymatic and chemical probing methods. We identify the minimal region of the aptamer essential for binding gp120 and accordingly design a 77-nucleotide truncated aptamer, B40t77. We then quantitatively analyze the binding affinity and neutralization potency of the parental and truncated (minimal) aptamer, and show them to be comparable. Furthermore, using results from secondary structure analysis, RNA mutagenesis and BIAcore surface plasmon resonance (SPR) binding assays, we hypothesize that a folded RNA structure is required to present specific nucleotide sequences to allow gp120-recognition and binding. The information gained from this study may provide leads for development of novel anti-HIV-1 therapies and can be used to extend our understanding of the molecular interactions between the virus and its host cell.
Sequence characteristics of functional siRNAs
Authors: JAGLA BERND , AULNER NATHALIE , KELLY PETER D. , SONG DA , VOLCHUK ALLEN , ZATORSKI ANDRZEJ , SHUM DAVID , MAYER THOMAS , DE ANGELIS DINO A. , OUERFELLI OUATHEK , RUTISHAUSER URS , ROTHMAN JAMES E.
Published: May 2005

RNA interference in mammalian cells is actively used to conduct genetic screens, to identify and to validate targets, and to elucidate regulators and modifiers of cellular pathways. To ensure the specificity and efficacy of the active 21mer siRNA molecules, it is pertinent to develop a strategy for their rational design. Here we show that most functional siRNAs have characteristic sequence features. We tested 601 siRNAs targeting one exogenous and three endogenous genes. The efficacy of the siRNAs was determined at the protein level. Using a decision tree algorithm in combination with information analysis, our analyses revealed four sets of rules with a mean knockdown efficacy ranging from 60% to 73%. (To distinguish between percentages used to describe the quality of an siRNA and the percentages used to describe parts of data sets we underlined the former throughout this paper.) The best rule comprises an A/U at positions 10 and 19, a G/C at position 1, and more than three A/Us between positions 13 and 19, in the sense strand of the siRNA sequence. Using these rules, there is a 99.9% chance of designing an effective siRNA in a set of three with more than 50% knockdown efficiency in a biological readout.
Conservative Accounting Choices
Authors: Bagnoli Mark , Watts Susan G.
Published: May 2005

Managers have sufficient discretion under generally accepted accounting principles (GAAP) to adopt more or less conservative financial reporting policies. In this paper, we develop a signaling model to provide insight into managers’ decisions to be conservative in their accounting. We provide conditions under which the market can use the manager’s exercise of discretion to infer her private information about the future prospects of the firm and thus firm value. Under these conditions, we also show that there are meaningful differences between earnings response coefficients for firms whose managers choose a conservative reporting policy and those whose managers do not. Finally, we use our theoretical model to provide intuition for some established empirical results on earnings response coefficients.
Evolution of R&D Capabilities: The Role of Knowledge Networks Within a Firm
Authors: Nerkar Atul , Paruchuri Srikanth
Published: May 2005

In this paper, we suggest that the characteristics of individual positions in an intraorganizational network of inventors or intrafirm knowledge network predict the likelihood with which knowledge created by an inventor is used in the firm’s research and development (R&D) activities. Such choices lead to path dependence and subsequent specialization. We provide empirical evidence that a firm’s R&D is concentrated in those areas where it chooses to recombine knowledge, offering support for the path-dependent evolution of capabilities. We test this theory by analyzing the R&D networks in DuPont, a highly regarded Fortune 500 chemical company. Cox Proportional Regression models of intrafirm citations on network characteristics offer strong empirical support for our theory.
Market for Software Vulnerabilities? Think Again
Authors: Kannan Karthik , Telang Rahul
Published: May 2005

Software vulnerability disclosure has become a critical area of concern for policymakers. Traditionally, a Computer Emergency Response Team (CERT) acts as an infomediary between benign identifiers (who voluntarily report vulnerability information) and software users. After verifying a reported vulnerability, CERT sends out a public advisory so that users can safeguard their systems against potential exploits. Lately, firms such as iDefense have been implementing a new market-based approach for vulnerability information. The market-based infomediary provides monetary rewards to identifiers for each vulnerability reported. The infomediary then shares this information with its client base. Using this information, clients protect themselves against potential attacks that exploit those specific vulnerabilities.

The key question addressed in our paper is whether movement toward such a market-based mechanism for vulnerability disclosure leads to a better social outcome. Our analysis demonstrates that an active unregulated market-based mechanism for vulnerabilities almost always underperforms a passive CERT-type mechanism. This counterintuitive result is attributed to the market-based infomediary’s incentive to leak the vulnerability information inappropriately. If a profit-maximizing firm is not allowed to (or chooses not to) leak vulnerability information, we find that social welfare improves. Even a regulated market-based mechanism performs better than a CERT-type one, but only under certain conditions. Finally, we extend our analysis and show that a proposed mechanism—federally funded social planner—always performs better than a market-based mechanism.
Quantifying the Value of Leadtime Information in a Single-Location Inventory System
Authors: Chen Fangruo , Yu Bin
Published: May 2005

This article studies a single-location inventory model with random leadtimes. Inventory is replenished by a single supplier who, at the time a replenishment order is received, knows exactly when the order will be delivered. In other words, the supplier knows the leadtime for every replenishment order. Suppose the single-location inventory system is managed by a retailer. The objective of this article is to quantify the value of the information about leadtimes to the retailer. This is achieved by considering and comparing the performances of two scenarios whether or not the supplier shares his leadtime information with the retailer. Numerical evidence suggests that the value of leadtime information can be significant.
An Optimal Production and Shutdown Strategy when a Supplier Offers an Incentive Program
Authors: Chao Xiuli , Chen Frank Y.
Published: May 2005

Motivated by the incentive programs that have been offered by energy companies under tight market conditions in the past few years, we consider a production control problem in which time alternates randomly between peak and nonpeak periods. During peak periods, the energy supplier offers the manufacturing firm—the energy user—an incentive program to reduce its energy usage by shutting down its production facility. Participation in the incentive program, however, is totally voluntary, and the user firm is rewarded for each unit of time that it participates in the program. We consider two problems that face the manufacturing firm. The first is whether it is worth shutting down production to participate in the incentive program when it is offered, and in which part (portion) of the peak period the firm should participate. The second problem is how the firm should decide on its production policy in both the peak and nonpeak periods in the presence of such an incentive program. In this paper, we provide simple models to give insight into the nature of these problems. Two cases are studied. In the first case, the peak duration is assumed to be exponentially distributed, and in the second, its length becomes known at the beginning of a peak period. In both cases, the occurrence times of the peak periods are uncertain. We characterize the optimal production and shutdown policy for both the peak and nonpeak periods. We also study the effect of seasonality on the optimal control policies.
Decentralized Serial Supply Chains Subject to Order Delays and Information Distortion: Exploiting Real-Time Sales Data
Authors: Watson Noel , Zheng Yu-Sheng
Published: May 2005

Decentralized supply chains are traditionally order focused: stage managers focus on meeting replenishment orders of downstream stages; market demand information is relayed up through these orders, and therefore is subject to costly delay and distortion. This paper shows that sharing real-time sales data across all stages and a change in focus to meeting customer demand can mitigate performance impairment caused by the order focus.

We show that a change of managerial focus in a decentralized chain can be made by measuring stages’ performance based on their respective echelon stocks, which only depends on how well they respond to the market demand. A demand-focused measurement scheme can be made incentive compatible with the knowledge of the demand distribution; a heuristic scheme independent of the demand distribution can be used to achieve near incentive compatibility.
Acute Myopathy in a Patient with Concomitant Use of Pravastatin and Colchicine
Authors: Alayli Gamze , Cengiz Kivanç , Cantürk Ferhan , Durmuş Dilek , Akyol Yeşim , Menekşe Elif B
Published: May 2005

OBJECTIVE

To report a case of acute myopathy after concomitant use of colchicine and pravastatin.

CASE SUMMARY

A 65-year-old woman was admitted to the hospital with an acute episode of gout. She had been taking pravastatin 20 mg once daily for 6 years. On admission, blood urea nitrogen and serum creatinine levels were 48 mg/dL and 1.3 mg/dL, respectively. Colchicine 1.5 mg/day was added to the treatment regimen, but 20 days after the initiation of colchicine therapy, symmetrical proximal muscle weakness developed in the woman's legs. Physical examination, laboratory findings, and electromyelogram findings suggested myopathy. The Naranjo probability scale indicated a probable relationship between myopathy and combined therapy. Seven days after discontinuation of colchicine and pravastatin, the patient's weakness improved and enzyme levels returned to normal. Colchicine was restarted at 1.0 mg/day 5 days later; no myopathy occurred.

DISCUSSION

Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) and colchicine are known to cause myopathy. Most of the statins and colchicine are biotransformed in the liver primarily by the CYP3A4 system, which may increase the risk of myopathy when concurrent therapy is used. However, pravastatin is not primarily metabolized by cytochrome P450 isoenzymes. The cause of myopathy in our patient may be related to the interaction of colchicine and pravastatin via P-glycoprotein. In addition, the presence of mild renal dysfunction could have contributed to the development of myopathy.

CONCLUSIONS

We suggest that clinicians be aware that neuromuscular toxicity can occur in patients with mild renal dysfunction with combined use of colchicine and pravastatin.
Molecular basis of the complex formation between the two calcium-binding proteins S100A8 (MRP8) and S100A9 (MRP14)
Authors: Leukert Nadja , Sorg Clemens , Roth Johannes
Published: May 2005

S100 proteins form characteristic homo- and/or heterodimers that play a role in calcium-mediated signaling. We characterized the formation of the human S100A8/S100A9 heterodimer using the yeast two-hybrid system. Employing site-directed mutagenesis we found that distinct hydrophobic amino acids of helix I/I′ are located at a crucial site of the S100A8/S100A9 dimer interface, whereas conserved residues within helix IV/IV′ are not important for heterodimerization. Furthermore, amino acids Y16 and F68 prevent homodimerization of human S100A8. These data demonstrate for the first time the functional relevance of distinct hydrophobic amino acids for human S100A8/S100A9 complex formationin vivo.
An extracellular carboxylesterase from the basidiomycete Pleurotus sapidus hydrolyses xanthophyll esters
Authors: Zorn Holger , Bouws Henning , Takenberg Meike , Nimtz Manfred , Getzlaff Rita , Breithaupt Dietmar E. , Berger Ralf G.
Published: May 2005

An extracellular enzyme capable of efficient hydrolysis of xanthophyll esters was purified from culture supernatants of the basidiomycetePleurotus sapidus. Under native conditions, the enzyme exhibited a molecular mass of 430 kDa, and SDS-PAGE data suggested a composition of eight identical subunits. Biochemical characterisation of the purified protein showed an isoelectric point of 4.5, and ideal hydrolysis conditions were observed at pH 5.8 and 40°C. Partial amino acid sequences were derived from N-terminal Edman degradation and from mass spectrometricab initiosequencing of internal peptides. An 1861-bp cDNA containing an open reading frame of 1641 bp was cloned from a cDNA library that showed ca. 40% homology toCandida rugosalipases. TheP. sapiduscarboxylesterase represents the first enzyme of the lipase/esterase family from a basidiomycetous fungus that has been characterised at the molecular level.
The anti-inflammatory compound curcumin inhibits Neisseria gonorrhoeae-induced NF-κB signaling, release of pro-inflammatory cytokines/chemokines and attenuates adhesion in late infection
Authors: Wessler Silja , Muenzner Petra , Meyer Thomas F. , Naumann Michael
Published: May 2005

Neisseria gonorrhoeae(Ngo) is a Gram-negative pathogenic bacterium responsible for an array of diseases ranging from urethritis to disseminated gonococcal infections. Early events in the establishment of infection involve interactions betweenNgoand the mucosal epithelium, which induce a local inflammatory response. Here we analyzed the molecular mechanism involved in theNgo-induced induction of the proinflammatory cytokines tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and IL-8. We identified the immediate early response transcription factor nuclear factor κB (NF-κB) as a key molecule for the induction of cytokine release.Ngo-induced activation of direct upstream signaling molecules was demonstrated for IκB kinase α and β (IKKα and IKKβ) by phosphorylation of IκBα as a substrate and IKK autophosphorylation. Using dominant negative cDNAs encoding kinase-dead IKKα, IKKβ, and NF-κB-inducing kinase (NIK),Ngo-induced NF-κB activity was significantly inhibited. Curcumin, the yellow pigment derived fromCurcuma longa, inhibited IKKα, IKKβ and NIK, indicating its strong potential to block NF-κB-mediated cytokine release and the innate immune response. In addition to the inhibition ofNgo-induced signaling, curcumin treatment of cells completely abolished the adherence of bacteria to cells in late infection, underlining the high potential of curcumin as an anti-microbial compound without cytotoxic side effects.
Uptake and Neuritic Transport of Scrapie Prion Protein Coincident with Infection of Neuronal Cells
Authors: Magalhães Ana Cristina , Baron Gerald S. , Lee Kil Sun , Steele-Mortimer Olivia , Dorward David , Prado Marco A. M. , Caughey Byron
Published: May 2005

Invasion of the nervous system and neuronal spread of infection are critical, but poorly understood, steps in the pathogenesis of transmissible spongiform encephalopathies or prion diseases. To characterize pathways for the uptake and intraneuronal trafficking of infectious, protease-resistant prion protein (PrP-res), fluorescent-labeled PrP-res was used to infect a neuronally derived murine cell line (SN56) and adult hamster cortical neurons in primary culture. Concurrent with the establishment of persistent scrapie infection, SN56 cells internalized PrP-res aggregates into vesicles positive for markers for late endosomes and/or lysosomes but not synaptic, early endocytic, or raft-derived vesicles. Internalized PrP-res was then transported along neurites to points of contact with other cells. Similar trafficking was observed with dextran, Alzheimer's Aβ1-42 fibrils and noninfectious recombinant PrP fibrils, suggesting that PrP-res is internalized by a relatively nonspecific pinocytosis or transcytosis mechanism. Hamster cortical neurons were also capable of internalizing and disseminating exogenous PrP-res. Similar trafficking of exogenous PrP-res by cortical neurons cultured from the brains of PrP knock-out mice showed that uptake and neuritic transport did not require the presence of endogenous cellular PrP. These experiments visualize and characterize the initial steps associated with prion infection and transport within neuronal cells.
Pigment-Dispersing Factor and GABA Synchronize Cells of the Isolated Circadian Clock of the CockroachLeucophaea maderae
Authors: Schneider Nils-Lasse , Stengl Monika
Published: May 2005

Pigment-dispersing factor-immunoreactive circadian pacemaker cells, which arborize in the accessory medulla, control circadian locomotor activity rhythms inDrosophilaas well as in the cockroachLeucophaea maderaevia unknown mechanisms. Here, we show that circadian pacemaker candidates of the accessory medulla of the cockroach produce regular interspike intervals. Therefore, the membrane potential of the cells oscillates with ultradian periods. Most or all oscillating cells within the accessory medulla are coupled via synaptic and nonsynaptic mechanisms, forming different assemblies. The cells within an assembly share the same ultradian period (interspike interval) and the same phase (timing of spikes), whereas cells between assemblies differ in phase. Apparently, the majority of these assemblies are formed by inhibitory GABAergic synaptic interactions. Application of pigment-dispersing factor phase locked and thereby synchronized different assemblies. The data suggest that pigment-dispersing factor inhibits GABAergic interneurons, resulting in disinhibition and phase locking of their postsynaptic cells, which previously belonged to different assemblies. Our data suggest that phase control of action potential oscillations in the ultradian range is a main task of the circadian pacemaker network. We hypothesize that neuropeptide-dependent phase control is used to gate circadian outputs to locomotor control centers.
Functional Architecture of Spatial Attention in the Parietal Cortex of the Behaving Monkey
Authors: Raffi Milena , Siegel Ralph M.
Published: May 2005

Functional architectures facilitate orderly transmittal of representations between cortices, allow for local interactions between neurons, and ensure a uniform distribution of feature representations with respect to larger-scale topographies. We sought to correlate such topographies with internal cognitive states. A psychophysical task for which the monkey was required to detect a change in one of two identical peripheral expanding flow fields tested for spatial shifts of attention. The monkey was cued as to which flow would change with a small cue near the fixation points. Reaction time data indicate that the monkey's performance in the optic flow detection task depended on the location of the cue. Using optical imaging of intrinsic signals, we show that a monkey's internally generated locus of attention is correlated with an 800-860 μm patchy topological architecture across the cortical surface of the inferior parietal lobule. The attentional patches vary in location but are stable in spatial frequency. The patches are embedded in a larger-scale and stable representation of eye position. Trial-by-trial analysis of the images indicates that the organizational scheme with simultaneous stable and variable subcomponents occurs within the experiment of 1 d, as well as across days. This novel functional architecture is the first to be correlated with attentional mechanisms and could support a fine-scale functional architecture underlying hemispatial neglect, an attentional deficit caused by parietal lesions.
Synergy, Redundancy, and Independence in Population Codes, Revisited
Authors: Latham Peter E. , Nirenberg Sheila
Published: May 2005

Decoding the activity of a population of neurons is a fundamental problem in neuroscience. A key aspect of this problem is determining whether correlations in the activity, i.e., noise correlations, are important. If they are important, then the decoding problem is high dimensional: decoding algorithms must take the correlational structure in the activity into account. If they are not important, or if they play a minor role, then the decoding problem can be reduced to lower dimension and thus made more tractable. The issue of whether correlations are important has been a subject of heated debate. The debate centers around the validity of the measures used to address it. Here, we evaluate three of the most commonly used ones: synergy, ΔIshuffled, and ΔI. We show that synergy and ΔIshuffledare confounded measures: they can be zero when correlations are clearly important for decoding and positive when they are not. In contrast, ΔIis not confounded. It is zero only when correlations are not important for decoding and positive only when they are; that is, it is zero only when one can decode exactly as well using a decoder that ignores correlations as one can using a decoder that does not, and it is positive only when one cannot decode as well. Finally, we show that ΔIhas an information theoretic interpretation; it is an upper bound on the information lost when correlations are ignored.
Fuel-Optimal Control of Rendezvous Maneuvers for Passenger Cars (Treibstoffoptimale Annäherung von Straßenfahrzeugen)
Authors: Sciarretta Antonio , Guzzella Lino
Published: May 2005

In this paper fuel-optimal rendezvous maneuvers for passenger cars will be analyzed. The results are obtained using simplified yet realistic descriptions of the vehicles and their internal combustion engines. Both the mathematical arguments leading to and the physical interpretations deriving from the optimal solution are shown. Implementation issues (computational burden, convergence, feedforward versus feedback, etc.) are discussed as well.
Extracellular Ca2+-sensing receptor expression and hormonal regulation in rat uterus during the peri-implantation period
Authors: Xiao Li-Juan , Yuan Jin-Xiang , Li Yin-Chuan , Wang Rui , Hu Zhao-Yuan , Liu Yi-Xun
Published: May 2005

The extracellular Ca2+-sensing receptor (CaR) is a member of the superfamily of G protein-coupled receptors (GPCRs). It is an important mediator of a wide range of Ca2+-dependent physiological responses in various tissues. In reproductive tissues it has been reported to play a significant role in promoting or maintaining placentation. Meanwhile, another Ca2+regulated gene stanniocalcin-1 (STC-1) has been documented to be involved in decidualization and uterine remodelling. The phenomenon that CaR mediates STC-1’s transcription responding to extracellular calcium in fish urges us to suppose that CaR, like STC-1, may also play a role in implantation and decidualization. To resolve this conjecture, we have examined the expression and hormonal regulation of the CaR gene in rat uterus during peri-implantation period.

CaR mRNA was expressed at a moderate level in the luminal epithelium of the early stage of pregnancy (from day 1 to day 3). From day 2–3 it began to be expressed more strongly in the stromal cells immediately underneath the luminal epithelium, but decreased to a basal level on day 4. From day 6 to day 9 continuously, both CaR mRNA and protein were highly expressed in the primary decidua. Expression of CaR mRNA and protein in these cells was also observed when a delayed implantation was terminated by estrogen treatment to allow the embryo implantation. In contrast, only basal level expression of the molecules was detected in the cells of animals subjected to a normal-delayed implantation or the pseudopregnant condition.

Embryo transplantation experiment confirmed that CaR expression at the implantation site was induced by the implanting blastocyst. Consistent with the normal pregnant process, CaR mRNA and protein in the cells were also induced by an artificial decidualization procedure. Further experiments demonstrated that treatment of the ovariectomized rat with estrogen or/and progesterone stimulated a high level expression of CaR mRNA in the uterine epithelial and glandular epithelium. In conclusion, CaR was specifically induced during the processes of implantation and subsequent decidualization and may play a role in these processes.
Pathogen Levels, Lysozyme, and Cortisol Response in Channel Catfish with Susceptibility Differences to Edwardsiella ictaluri
Authors: Bilodeau A. L. , Small B. C. , Wise D. J. , Wolters W. R.
Published: May 2005

Differences in bacterial loads, clearance rates, nonspecific immune response, and cortisol response were measured for three family groups of channel catfish Ictalurus punctatus susceptible to enteric septicemia of catfish (ESC) and three ESC-resistant families. Resistant families had lower mortality during challenge (P < 0.0001). Bacterial loads on day 5 postexposure were higher (P < 0.01) in susceptible families than resistant families for blood, kidney, and spleen. Blood, kidney, and spleen bacterial levels were highly correlated. Pathogen clearance was evident by day 12 in fish from the susceptible families and measurable only in kidney and spleen from resistant families on day 20. Lysozyme activity increased on day 1 (P = 0.0074) in resistant fish and on day 2 in susceptible fish (P < 0.0001). An acute stress response was evident for both resistant (21.4 ± 1.7 ng/mL [mean ± SD]) and susceptible families (30.0 ± 1.6 ng/mL). Plasma cortisol levels were elevated in susceptible fish throughout challenge, except for day 12, but in resistant fish they recovered to near basal levels immediately after an acute response on day 2. There was no correlation between cortisol and lysozyme levels. Differences in lysozyme activity and pathogen levels suggest that the nonspecific immune response was effective during the early stages of infection in resistant fish.
Considerations for manufacture of irrigation pipe
Authors: Tock Richard Wm. , A'hern Daniel W.
Published: May 2005

On January 18, 1977 the United States Patent Office granted James E. Turner the rights to Patent Number 4,003,408 entitled “Underground Irrigation Porous Pipe.” The porous pipe was claimed to be made entirely from reclaimed rubber and recycled plastic binder. The weight percent of binder materials ranged from 10% to 40%. The wall of the porous pipe was reported to contain labyrinthine apertures of such size and number so as to provide a leak rate of 12 to 20 gallons per hour of water per one hundred feet of length of 1/2 inch pipe when subjected to internal pressures of 5 to 10 psig. The pores were claimed to have been blown into the walls by venting vapors and water associated with the rubber during the extrusion process.

This paper reports on an analysis of such a “leaky pipe” as described by Patent Number 4,003,408. The leakage phenomenon is shown to be a natural occurrence which arises from the adhesion of rubber particles with insufficient binder to fill the voids between particles. This observation means that the reclaimed rubber must have a very narrow size range if the leak rate is to be predictable. In addition, the binder material may be restricted to virgin LLDPE feed stock if a reproducible product is to be continuously extruded. Finally, using technology developed for sintered‐porous metal objects, it was demonstrated that the leak rate can be predicted a priori. This evidence suggests that the occurrence of the porosity as claimed in U.S. Patent Number 4,003,408 is not confirmed by practical experience. Moreover, although a leaky pipe can be produced in accordance with the teachings of the patent, the properties and performance of that pipe will probably not meet the specification of potential users.
Silylation and dry procession
Authors: Roland Bruno
Published: May 2005

The issues of dry development and self‐developing resists are addressed in this paper by way of an introduction to the main topic of surface imaging, in which diffusion‐enhanced vapour plhase silylation chemistries and their mechanisms are developed with specific reference to resists that function through the DESIRE process. More recent liquid phase silylation processes are also considered.
Electron beam and X‐ray resists
Authors: Jones Richard G. , Tate Philip C. Miller
Published: May 2005

The optimisation of the lithographic performance of negative‐working electron beam resists is developed through consideration of the radiation chemistry of crosslinking of representative materials, typically epoxy‐functionalised polymers and polystyrene and its derivatives. Similarly, the lithographic behaviour of positive‐working systems based on radiation‐induced chain scission reactions is discussed with reference to acrylate and methacrylate polymers and polysulphones. The difficulties encountered in devising desirable working systems based on novolacs are considered and contrasted with the promise offered by recent developments arising from the extension of chemical amplification techniques to the electron beam lithographic domain.
Mitochondrial metabolism following bilateral cerebral ischemia in the gerbil
Authors: Ginsberg Myron D. , Mela Leena , Wrobel‐Kuhl Krystyna , Reivich Martin
Published: May 2005

Following periods of bilateral cerebral ischemia in urethane‐anesthetized Mongolian gerbils, the metabolism of isolated brain mitochondria was assessed in an in vitro oxygenated medium in the presence of the substrates glutamate‐malate. Mitochondria from both control and ischemic brains were well coupled. Urethane‐anesthetized controls showed an early mild depression and a subsequent enhancement of State 3 respiration (ADP present) relative to awake controls. Respiratory activity in State 3, calculated per mol of cytochrome oxidase, was first depressed below control values following 60 minutes of ischemia; and a further decline, to 46 to 58% of control values, followed 90 to 120 minutes of ischemia. Mitochondrial calcium ion accumulation was depressed by ischemia of 2 hours in moribund animals. In contrast, a significant degree of cerebral edema was observed with ischemia of only 30 minutes' duration. Respiration of brain mitochondria appears relatively resistant to irreversible impairment following cerebral ischemia.
Far‐field somatosensory evoked potentials in the cat: Correlation with depth recording
Authors: Iragui‐Madoz V. J. , Wiederholt W. C.
Published: May 2005

We have previously identified, with surface‐recording techniques, four potentials (I, II, III, IV) preceding the cortical component of the somatosensory evoked potential (SEP) in the cat. In the present study, we correlated surface and depth activity in the cat by recording SEPs simultaneously from skull electrodes and from depth electrodes placed in the cervical posterior columns, cuneate nucleus, medial lemniscus, inferior cerebellar peduncle, ventral posterior thalamus, and sensory radiation. Latencies and amplitudes of surface‐ and depth‐recorded potentials and their responses to repetitive stimulation were analyzed. Our findings indicate that: (1) component I originates in cervical posterior columns and nucleus cuneatus; (2) component II reflects postsynaptic activity in nucleus cuneatus, medial lemniscus, and inferior cerebellar peduncle; (3) component III‐A probably originates in the cerebellar hemispheres; (4) component III‐B consists of component III‐A and superimposed activity in the ventral posterior thalamus and sensory radiation; and (5) component IV originates in the sensory radiation.
Lead poisoning and brain tumors in children: A report of 2 cases
Authors: Schreier Herbert A. , Sherry Norman , Shaughnessy Elizabeth
Published: May 2005

Lead poisoning and subclinical body lead elevations have become increasingly widespread findings in children, not only in the inner cities but in the suburbs and rural areas as well. This paper reports on 2 institutionalized children with elevated urinary lead levels who subsequently developed astrocytomas. Lead toxicity may play a role in causing mental retardation, hyperactivity, and more subtle neuropsychological dysfunction in children. It has been shown to have a direct toxic effect on neurons, causing astrocytic proliferation in humans and central nervous system neoplasms in rats.