bluuebunny/crossref_metadata_2025 huggingface dataset:
Glycemic index, glycemic load and risk of prostate cancer
Authors: Augustin Livia S.A. , Galeone Carlotta , Dal Maso Luigino , Pelucchi Claudio , Ramazzotti Valerio , Jenkins David J.A. , Montella Maurizio , Talamini Renato , Negri Eva , Franceschi Silvia , La Vecchia Carlo
Published: June 2004

Dietary carbohydrates have different glycemic and insulinemic potentials depending on type (glycemic index, GI) and amount (glycemic load, GL) of carbohydrate consumed or both. Insulin in turn has been implicated as a risk factor for several cancers, including that of the prostate. We assessed the relationship of GI and GL with prostate cancer risk in a multicenter case‐control study. Cases and controls were recruited between 1991 and 2002 in the network of major teaching and general hospitals in 4 Italian areas. Cases were 1,204 men (age range 46–74 years) admitted for incident, histologically confirmed prostate cancer. Controls were 1,352 men (age range 46–74 years) admitted for acute, nonmalignant conditions unrelated to long‐term modifications of diet. ORs of prostate cancer and the corresponding 95% CIs were derived using unconditional multiple logistic regression, including terms for age, study center, education, family history of prostate cancer, smoking, body mass index, physical activity, alcohol consumption, intake of energy, fiber and lycopenes. Compared to the lowest quintile of GI, the ORs were 1.23, 1.24, 1.47 and 1.57 for subsequent levels of GI. The corresponding values for GL were 0.91, 1.00, 1.20 and 1.41. No heterogeneity was found among strata of selected covariates. We found direct relations between dietary GI and GL and prostate cancer risk. Correcting for potential confounding factors did not substantially modify these associations. © 2004 Wiley‐Liss, Inc.
Childhood body mass index and later cancer risk: A 50‐year follow‐up of the Boyd Orr study
Authors: Jeffreys Mona , Davey Smith George , Martin Richard M. , Frankel Stephen , Gunnell David
Published: June 2004

Associations between childhood BMI and adult cancer risk were investigated in a historical cohort study based on the Carnegie (“Boyd Orr”) Survey of Diet and Health in Pre‐War Britain (1937–9). In 14 centres in England and Scotland, children had their height and weight measured. We included 2,347 individuals aged between 2 and 14 years 9 months at the time of measurement, who were traced through the National Health Service Central Register. Relative cancer risk (registration or death) was estimated in relation to age‐ and sex‐specific BMI SD scores. We studied associations with(i)all cancers,(ii)cancer groups stratified according to their relationship to smoking and(iii)certain site‐specific cancers. In the 50 years of follow‐up, 188 men and 192 women developed cancer. There was a 9% increase (95% CI –3 to 22%) in risk of cancer in adulthood per SD increase in BMI measured in childhood. There was no evidence of confounding by childhood or adulthood socioeconomic position, other anthropometric variables, childhood energy intake or birth order. There was a 30% increase (95% CI 10–54%) in risk of smoking‐related cancers per SD increase in childhood BMI. There was no relationship between BMI and cancers not related to smoking. Associations for all cancers and non‐smoking‐related cancers tended to be stronger in children who were measured at an older (>8 years) rather than a younger (≤8 years) age. We conclude that childhood BMI is related to increased risk of cancer in later life, particularly smoking‐related cancers. © 2004 Wiley‐Liss, Inc.
Electromagnetic imaging for a conducting cylinder buried in a slab medium by the genetic algorithm
Authors: Lin Chun Jen , Chou Chun‐Yuan , Chiu Chien‐Ching
Published: June 2004

This article presents a computational approach to the imaging of a perfectly conducting cylinder buried in a slab. A conducting cylinder of unknown shape buried in a slab scatters the incident wave from outside. The scattered field is recorded outside the slab. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived, and the imaging problem is reformulated into an optimization problem. The genetic algorithm is then employed to determine global extreme solution of the cost function. Numerical results demonstrated that, even when the initial guess is far removed from the exact one, good reconstruction can be obtained. In such a case, the gradient‐based methods often are trapped in a local extreme. In addition, the effect of Gaussian noise on the reconstruction is investigated. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 1–7, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20000
Super‐resolution of the undersampled and subpixel shifted image sequence by a neural network
Authors: Lu Yao , Inamura Minoru , del Carmen Valdes Maria
Published: June 2004

Numerous approaches to super‐resolution (SR) of sequentially observed images (image sequence) of low resolution (LR) have been presented in the past two decades. However, neural network methods are almost ignored for solving SR problems. This is because the SR problem traditionally has been regarded as the optimization of an ill‐posed large set of linear equations. A designed neural network based on this has a large number of neurons, thereby requiring a long learning time. Also, the deduced cost function is overly complex. These defects limit applications of a neural network to an SR problem. We think that the underlying meaning of the SR problem should refer to super‐resolving an imaging system by image sequence observation, instead of merely improving the image sequence itself. SR can be regarded as a pattern mapping from LR to SR images. The parameters of the pattern mapping can be learned from the imaging process of the image sequence. This article presents a neural network for SR based on learning from the imaging process of the image sequence. In order to speed up the convergence, we employ vector mapping to train the neural network. A mapping vector is composed of some neighbor subpixels. Such a well‐trained neural network has powerful generalization ability so that it can be used directly to estimate the SR image of the other image sequences without learning again. Our simulations show the effectiveness of the proposed neural network. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 8–15, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20001
Color adaptation for anomalous trichromats
Authors: Ro Yong Man , Yang Seungji
Published: June 2004

In this article, we propose a content‐based color adaptation method for color vision impairment, especially for anomalous trichromats, to improve color information accessibility. Color degradation caused by anomalous trichromacy is compensated in digital color content with a range of the visible spectrum corresponding to color deficiency characteristics. To verify the usefulness of the proposed method, we performed clinical experiments as well as computer simulations. The results of both the experiments and the simulations show that the proposed adaptation could convey better color information to anomalous trichromats. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 16–20, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20002
Parameter estimation in Bayesian reconstruction of SPECT images: An aid in nuclear medicine diagnosis
Authors: López Antonio , Molina Rafael , Katsaggelos Aggelos K. , Rodriguez Antonio , López José M. , Llamas José M.
Published: June 2004

Despite the adequacy of Bayesian methods to reconstruct nuclear medicine SPECT (single‐photon emission computed tomography) images, they are rarely used in everyday medical practice. This is primarily because of their computational cost and the need to appropriately select the prior model hyperparameters. We propose a simple procedure for the estimation of these hyperparameters and the reconstruction of the original image and test the procedure on both synthetic and real SPECT images. The experimental results demonstrate that the proposed hyperparameter estimation method produces satisfactory reconstructions. Although we have used generalized Gaussian Markov random fields (GGMRF) as prior models, the proposed estimation method can be applied to any priors with convex potential and tractable partition function with respect to the scale hyperparameter. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 21–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20003
Synthetic‐aperture assessment of a dispersive surface
Authors: Cheney Margaret
Published: June 2004

This article considers Synthetic Aperture Radar and other synthetic‐aperture imaging systems in which a backscattered wave is measured from a variety of locations. We focus on the case in which the ground‐reflectivity function depends on frequency as well as on position. We begin with a (linearized) mathematical model, based on a scalar approximation to Maxwell's equations, which includes the effects of the source waveform and the antenna beam pattern. The model can also accommodate other effects such as antenna steering and motion. For this mathematical model, we use the tools of microlocal analysis to develop and analyze a three‐dimensional inversion algorithm that uses measurements made on a surface and determines the frequency‐dependent ground reflectivity. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 28–34, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20004
The potential role for economic instruments in drought management
Authors: Merrett Stephen
Published: June 2004

Climate change in the twenty‐first century will likely reduce the return period of drought events, indicating that drought management will be even more important in the future than it is already. In the case of England's Anglian region it is shown that two principal institutions are responsible for drought management—the Environment Agency and Anglian Water Services (AWS). The region has a fast‐growing population of more than 5 million people, it has 58% of the most productive agricultural land in England and Wales, and in some summers irrigation can make up 50% of water use.

An examination of the drought plans of the Agency and AWS demonstrates that in both cases the policy instruments that they deploy to manage drought are informational, infrastructural and regulatory. In neither case would they use water pricing as a management tool. Moreover, the government's drought plan guidelines for the water utilities make no reference to economic instruments of drought management nor do they suggest that utilities should review the economic impact on their customers of regulatory action.

The principal issues that would arise if water charging were to be deployed as a drought management instrument are then reviewed. The paper concludes by proposing that national government should evaluate the feasibility, costs, benefits and risks of replacing the regulatory instruments of drought management by economic instruments. Copyright © 2004 John Wiley & Sons, Ltd.
Microrough implant surface topographies increase osteogenesis by reducing osteoclast formation and activity
Authors: Lossdörfer S. , Schwartz Z. , Wang L. , Lohmann C. H. , Turner J. D. , Wieland M. , Cochran D. L. , Boyan B. D.
Published: June 2004

Titanium implant surfaces with rough microtopographies exhibit increased pullout strength in vivo suggesting increased bone‐to‐implant contact. This is supported by in vitro studies showing that as surface microroughness increases, osteoblast proliferation decreases whereas differentiation increases. Differentiation is further enhanced on microrough surfaces by factors stimulating osteogenesis including 1α,25(OH)2D3. Levels of PGE2 and TGF‐β1 are increased in cultures grown on rough microtopographies; this surface effect is enhanced synergistically by 1α,25(OH)2D3‐treatment. PGE2 and TGF‐β1 regulate osteoclasts as well as osteoblasts, suggesting that surface microtopography may modulate release of other factors from osteoblasts that regulate osteoclasts. To test this hypothesis, we examined the effects of substrate microarchitecture on production of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL), which have been identified as a key regulatory system of bone remodeling. We also examined the production of 1α,25(OH)2D3, which regulates osteoblast differentiation and osteoclastogenesis. MG63 osteoblast‐like cells were grown on either tissue culture plastic or titanium disks of different surface microtopographies: PT (Ra < 0.2 μm), SLA (Ra = 4 μm), and TPS (Ra = 5 μm). At confluence, cultures were treated for 24 h with 0, 10−8 M or 10−7 M 1α,25(OH)2D3. RANKL and OPG were determined at the transcriptional level by RT‐PCR and real time PCR and soluble RANKL, OPG and 1α,25(OH)2D3 in the conditioned media were measured using immunoassay kits. Cell number was reduced on SLA and TPS surfaces and 1α,25(OH)2D3 caused further decreases. OPG mRNA levels increased on rougher surfaces and 1α,25(OH)2D3 treatment caused a further synergistic increase. While the cells expressed RANKL mRNA, levels were low and independent of surface microtopography. OPG protein was greater when cells were grown on SLA and TPS. 1α,25(OH)2D3 increased OPG by 50% on the smooth Ti surface but on SLA, 10−8 M 1α,25(OH)2D3 caused a 100% increase and 10−7 M 1α,25(OH)2D3 increased OPG by 200%. On TPS 10−7 M 1α,25(OH)2D3 increased OPG 350%. Soluble RANKL was not detected in the conditioned media of any of the cultures. 1α,25(OH)2D3 was produced endogenously and levels were positively correlated with surface roughness. Thus, on surfaces with rough microtopographies, osteoblasts secrete factors that enhance osteoblast differentiation while decreasing osteoclast formation and activity. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 361–369, 2004
Electrostatic interactions as a predictor for osteoblast attachment to biomaterials
Authors: Smith I. O. , Baumann M. J. , McCabe L. R.
Published: June 2004

The present study utilizes zeta (ζ)‐potential analysis as an indicator of bonding of osteoblasts and whole bone to various biomaterials. Common metal alloys (316L stainless steel, CoCrMo, and Ti6Al4V) and bioceramics (hydroxyapatite and β‐tricalcium phosphate) used in orthopedic applications were suspended in particulate form in physiologic saline, both as‐received and supplemented with bovine serum albumin (BSA). Metal alloys were also treated with NaOH washing to study the effect of such a surface treatment on the ζ‐potential. The NaOH wash was found to increase the ζ‐potential for CoCrMo and Ti6Al4V, but there was a decrease in the magnitude of the ζ‐potential for 316L stainless steel. When the metal alloy powders were suspended in BSA‐supplemented physiologic saline, the ζ‐potential as a function of pH increased, thereby increasing the electronegativity gap and increasing the propensity for bonding between each of the metal alloys and bone. This increase is likely due to matrix proteins in the BSA, which adsorb onto the metal alloy surfaces, promoting bone growth. With the addition of BSA to each bioceramic system, a uniform decrease in ζ‐potential was observed. However, the electronegativity gap remained large in each case, maintaining the anticipation of bonding. ζ‐Potential analysis is an effective predictor of biomaterial attraction to osteoblasts and bone, providing a useful in vitro method for predicting such interactions. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 436–441, 2004
Osteoblast‐like cell response to bioactive composites—Surface‐topography and composition effects
Authors: Rea Susan M. , Brooks Roger A. , Schneider Andreas , Best Serena M. , Bonfield William
Published: June 2004

Two bioactive composites, containing 40 vol % filler in high‐density polyethylene (HDPE), were investigated to examine the effects of different filler compositions and different surface patterning. The first composite, known as HAPEX™, consists of hydroxyapatite within HDPE, and the second composite, known as AWPEX, consists of glass‐ceramic apatite‐wollastonite in HDPE. Surface topography effects at 5–50 and 100–150 μm were explored, with cell morphology analyzed with the use of scanning electron microscopy and confocal laser scanning microscopy (CLSM). Biochemical assays of adenosine triphosphate and alkaline phosphatase were used to analyze osteoblast‐like cell proliferation and differentiation. For both composites, cell alignment was seen along grooves, pillars, and wells, with preferential cell attachment to ceramic particles within the polymer matrices. HAPEX™ showed significantly increased cell proliferation over AWPEX (P < 0.005). However, greater cell differentiation occurred for AWPEX over HAPEX™ (P < 0.005). Polishing significantly increased osteoblast‐like cell response over as‐cut samples, but surface‐topography changes above 50 μm had no consistent effect. Smaller‐scale features also showed no significant trend in terms of cell proliferation, but did show significant differences in cell differentiation (P < 0.05). CLSM imaging of actin and vinculin localization within cells showed the greatest change in comparison to polished surface controls for cells cultured on samples with surface features below 50 μm. The fact that similar observations were made for both HAPEX™ and AWPEX indicated that, for these experiments, the effects of surface topography more strongly influenced cell response than chemical composition. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 250–261, 2004
Leaching and mechanical properties characterization of dental composites
Authors: Drummond James L. , Andronova Ksenia , Al‐Turki Lulwa I. , Slaughter Leslee D.
Published: June 2004

The objective of this study was to determine the leaching of Ba, Si, and Sr from four dental composites: Restolux (RX), Micronew (M), Renew (RW), and Choice (C) and to correlate the effects of such leaching with flexure strength and modulus of elasticity. The specimens were 3 × 3 × 25‐mm bars, polished with 120‐ and 240‐grit SiC paper, and were aged for 4, 6, and 8 months in artificial saliva, distilled water, and a 50/50 mixture of ethanol and distilled water. Inductively coupled plasma with mass spectroscopy (ICP/MS) was used to determine the ion concentrations after aging. The greatest release of Ba and Sr occurred after aging in 50/50 volume fraction mixture of ethanol/water and for Si in artificial saliva. The 50/50 solution caused a breakdown of the resin and glass matrix, resulting in an increase of Ba and Sr, whereas aging in artificial saliva resulted in an ion charge balance, which allowed an elevated and continuous release of Si. The flexure strength and the elastic modulus showed a gradual decrease over time, with the greatest decreases occurring following aging in the 50/50 water/ethanol solution, but little correlation with the leaching of the filler ions. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 172–180, 2004
Bisphenol A from dental polycarbonate crown upregulates the expression of hTERT
Authors: Takahashi Akiko , Higashino Fumihiro , Aoyagi Mariko , Kyo Satoru , Nakata Takashi , Noda Mamoru , Shindoh Masanobu , Kohgo Takao , Sano Hidehiko
Published: June 2004

Bisphenol A (BPA) is one of the endocrine‐disrupting chemicals (EDCs) that possess estrogen‐like biologic activity. Many dental materials have been reported to release BPA. However, there are few reports available on the release of BPA from dental polycarbonates. The purpose of this study was to investigate the release of BPA from dental polycarbonate crowns and to evaluate the estrogenic activity of BPA. Polycarbonate crowns were immersed in five solvents (water, ethanol, n‐hepthane, acetic acid, and acetonitrile) at 37 or 65°C for 24 h. The elution from the material was analyzed by high‐performance liquid‐chromatography (HPLC) and mass‐spectrometry (MS) analysis. BPA release was detected corresponding to the degradation of dental polycarbonates under the some storage conditions (ethanol, acetic acid, and acetonitrile). A previous report proved that estrogen increased human telomerase catalytic subunit (hTERT) mRNA, whereas the effect of EDCs on the hTERT promoter has never been reported. The estrogenic activity of BPA was analyzed by luciferase assay with the use of the hTERT promoter. This assay revealed that BPA was a positive regulator of hTERT transcription. In addition, quantitative real‐time PCR analysis showed that BPA increased the expression level of hTERT mRNA in MCF7 cells. Herein, it is demonstrated that hTERT is a new target of BPA. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 214–221, 2004
Prolonged cytotoxic effect of colchicine released from biodegradable microspheres
Authors: Muvaffak Asli , Gurhan Ismet , Hasirci Nesrin
Published: June 2004

One the main problems of cancer chemotherapy is the unwanted damage to normal cells caused by the high toxicities of anticancer drugs. Any system of controlled drug delivery that would reduce the total amount of drug required, and thus reduce the side effects, would potentially help to improve chemotherapy. In this respect, biodegradable gelatin microspheres were prepared by water/oil emulsion polymerization and by crosslinking with glutaraldehyde (GTA) as the drug‐carrier system. Microspheres were loaded with colchicine, a model antimitotic drug, which was frequently used as an antimitotic agent in cancer research involving cell cultures. Microsphere sizes, swelling and degradation properties, drug‐release kinetics, and cytotoxities were studied. Swelling characteristics of microspheres changed upon changing GTA concentration. A decrease in swelling values was recorded as GTA crosslink density was increased.In vitrodrug release in PBS (0.01M, pH 7.4) showed rapid colchicine release up to ∼83% (att= 92 h) for microspheres with low GTA (0.05% v/v), whereas a slower release profile (only ∼39%) was obtained for microspheres with high GTA (0.50% v/v) content, for the same period. Cytotoxicity tests with MCF‐7, HeLa and H‐82 cancer cell lines showed that free colchicine was very toxic, showing an ∼100% lethal effect in both HeLa and H‐82 cell lines and more than 50% decrease in viability in MCF‐7 cells in 4 days. Indeed, entrapped colchicine indicated similar initial high toxic effect on cell viability in MCF‐7 cell line and this effect became more dominant as colchicine continued to be released from microspheres in the same period. In conclusion, the control of the release rate of colchicine from gelatin microspheres was achieved underin vitroconditions by gelatin through the alteration of crosslinking conditions. Indeed, the results suggested the potential application of gelatin microspheres crosslinked with GTA as a sustained drug‐delivery system for anticancer drugs for local chemotherapy administrations. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 295–304, 2004
Evaluation of hot‐pressed hydroxyapatite/poly‐L‐lactide composite biomaterial characteristics
Authors: Ignjatovic Nenad , Suljovrujic Edin , Budinski‐Simendic Jaroslava , Krakovsky Ivan , Uskokovic Dragan
Published: June 2004

Hydroxyapatite/poly‐L‐lactide (HAp/PLLA) is a ceramic/polymer composite, whose application as a resorbable biomaterial for the substitution and repair of hard bone tissue is widely promising in orthopedic, oral, maxillofacial, and reconstructive surgery. Hot processing is a necessary step for obtaining HAp/PLLA composite blocks with mechanical properties similar to those of bones. In this article, the changes in structure and physicochemical properties of HAp/PLLA composite, hot pressed for different pressing times (5, 15, 30, 45, and 60 min), were studied. Because the morphology of HAp/PLLA composite biomaterial is very sensitive to this procedure, its surface microstructure was analyzed by scanning electron microscopy (SEM) coupled with an energy‐dispersive X‐ray (EDX) detector system. Structural changes occurring in the material, mostly changes in crystallinity of PLLA, were studied by wide‐angle X‐ray structural analyses (WAXS) and infrared (FTIR) spectroscopy. Using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC), the influence of hot pressing on the properties, crystallization kinetics, and decomposition of HAp/PLLA composite biomaterial was analyzed. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 284–294, 2004
Analysis of mesenchymal cells derived from an chondrodysplasia punctuate patient and donors
Authors: Shur Irena , Reish Orit , Ezra Eli , Benayahu Dafna
Published: June 2004

Conradi–Hunermann syndrome (CDPX2) is X‐linked dominant disorder appeared with aberrant punctuate calcification. The skeletal cells derived from the marrow stroma are active in maintaining the skeletal formation. We obtained mesenchymal stem cells from a patient with CDPX2 and studied the formation of colony forming unit‐fibroblast (CFU‐F) in vitro in comparison cells obtained from normal donors. Cultured cells were studied morphologically and subjected to gene expression analysis. Marrow stromal cells (MSC)‐chondrodysplasia punctuate (CDP) cells from CDPX2 were identified by their mosaic morphology formed three phenotypically distinct types of CFU‐F colonies. One type consisted of normal fibroblasts with developed cell body and cellular processes; the second type contained pathological small cells without processes; and the third type comprised of mixed cells. We compared gene expression by the MSC‐CDP to cells from normal donors. Transcription factors analyzed proliferation potential were similar in both normal and mixed colonies of MSC‐CDP and similar to normal MSCs. The message expression for cytokines and extra cellular matrix (ECM) proteins revealed similar expression for biglycan, osteocalcin, and osteonectin, while IL‐6, IL‐11, and M‐CSF mRNA levels were significantly higher in normal cells than in MSC‐CDP. Mixed cells had elevated levels for IL‐6 and M‐CSF mRNA, but expressed IL‐11 at the normal range. The studied genes were expressed at lower levels by the pathological (MSC‐CDP) cells compared to normal ones. Hence, MSC‐CDP was demonstrated to display abnormal morphology and transcription of several investigated genes. This study further illuminates the basis of the mosaic pattern of mesenchymal cells derived from a patient affected with CDPX2, and their gene expression involvement. © 2004 Wiley‐Liss, Inc.
A3 adenosine receptor deficiency does not influence atherogenesis
Authors: Jones Matthew R. , Zhao Zhihui , Sullivan Christopher P. , Schreiber Barbara M. , Stone Phillip J. , Toselli Paul A. , Kagan Herbert M. , Cohen Richard A. , Ravid Katya
Published: June 2004

Atherosclerosis is a multifactorial disease, the progression of which is modulated by several factors, including inflammation and hypercholesterolemia. The A3 adenosine receptor (A3AR) has been reported to affect mast cell degranulation leading to inflammation, as well as to influence cardiovascular homeostasis. Here, we show that its deletion can also impact vascular smooth muscle cell (VSMC) proliferation in vitro. Based on these observations, we hypothesized that A3AR deficiency would affect atheromatous lesion development in vivo. Our results indicate that the expression of the matrix enzyme lysyl oxidase (LO) is increased while the proliferation potential of VSMC is decreased in A3AR‐null aortas. This is in accordance with the previously reported inverse correlation between LO level and proliferation. Nevertheless, we found that A3‐deficiency does not protect vessels against atherogenesis. This was demonstrated in mouse models of high fat diet‐induced atherosclerosis and guidewire‐induced femoral artery injury. We conclude that the contributions of the A3AR to inflammation and to modulating LO levels are not significant enough to control vascular response to injury. © 2004 Wiley‐Liss, Inc.
Inhibition of phenylephrine‐induced cardiac hypertrophy by docosahexaenoic acid
Authors: Siddiqui Rafat A. , Shaikh Saame Raza , Kovacs Richard , Stillwell William , Zaloga Gary
Published: June 2004

Many of the cardiovascular benefits of fish oil result from the antiarrhythmic actions of the n‐3 polyunsaturated lipids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The beneficial effects of DHA/EPA in patients with coronary artery disease and myocardial infarction may also result from modulation of the myocardial hypertrophic response. Hypertrophy was assessed in neonatal cardiomyocytes exposed to phenylephrine (PE) by measuring cell surface area, total protein synthesis (14C leucine incorporation), and the organization of sarcomeric α‐actinin and by monitoring expression of atrial natriuretic factor (ANF). We report that PE induced a twofold increase in cell surface area and protein synthesis in cardiomyocytes. The hypertrophied cardiomyocytes also exhibited increased expression of ANF in perinuclear regions and organization of sarcomeric α‐actinin into classical z‐bands. Treatment of cardiomyocytes with 5 μM DHA effectively prevented PE‐induced hypertrophy as shown by inhibition of surface area expansion and protein synthesis, inhibition of ANF expression, and prevention of α‐actinin organization into z‐bands. DHA treatment prevented PE‐induced activation of Ras and Raf‐1 kinase. The upstream inhibition of Ras → Raf‐1 effectively prevented translocation and nuclear localization of phosphorylated extracellularly regulated kinase 1 and 2 (Erk1/2). These effects consequently led to inhibition of nuclear translocation, and hence, activation of the downstream signaling enzyme p90 ribosomal S6 kinase (p90rsk). These results indicate that PE‐induced cardiac hypertrophy can be minimized by DHA. Our results suggest that inhibition of Ras → Raf‐1 → Erk1/2 → p90rsk → hypertrophy is one possible pathway by which DHA can inhibit cardiac hypertrophy. In vivo studies are needed to confirm these in vitro effects of DHA. © 2004 Wiley‐Liss, Inc.
Mitochondrial P2Y‐Like receptors link cytosolic adenosine nucleotides to mitochondrial calcium uptake
Authors: Belous Andrey , Wakata Aya , Knox Clayton D. , Nicoud Ian B. , Pierce Janene , Anderson Christopher D. , Pinson C. Wright , Chari Ravi S.
Published: June 2004

ATP is a known extracellular ligand for cell membrane purinergic receptors. Intracellular ATP can work also as a regulatory ligand via binding sites on functional proteins. We report herein the existence of P2Y1‐like and P2Y2‐like receptors in hepatocyte mitochondria (mP2Y1 and mP2Y2), which regulate mCa2+ uptake though the uniporter. Mitochondrial P2Y1 activation stimulates mCa2+ uptake; whereas, mP2Y2 activation inhibits mCa2+ uptake. ATP acts preferentially on mP2Y2 receptors, while ADP and AMP‐PNP stimulate both the mP2Y1 and mP2Y2. PPADS inhibits ADP stimulated mP2Y1‐mediated mCa2+ uptake. In addition, UTP, a selective P2Y2 agonist, strongly inhibits mCa2+ uptake. The newly discovered presence and function of these receptors is significant because it explains increased mCa2+ uptake in the setting of low cytosolic [ATP] and, therefore, establishes a mechanism for direct feedback in which cytosolic [ATP] governs mitochondrial ATP production through regulation of mCa2+ uptake. © 2004 Wiley‐Liss, Inc.
Increased density of retinal pigment epithelium in cd81−/− mice
Authors: Song Bong K. , Levy Shoshana , Geisert Eldon E.
Published: June 2004

Our laboratories have focused on the role of the tetraspanin CD81 in the regulation of mitotic activity. Previously we have shown that antibodies directed against CD81 can block the proliferation of cultured retinal pigment epithelial (RPE) cells. The present study investigates the role of this protein by analyzing the structure of the adult retina in mice with a null mutation of cd81. Adult cd81−/− mice were produced by crossing two inbred strains, NIHS‐BC/Tac and 129X1/SvJ, carrying the cd81 mutation as heterozygotes (+/−). Seven cd81−/− mice and 11 wildtype (cd81+/+) littermates were anesthetized and perfused with paraformaldehyde. The eyes were removed and processed for examination by light and electron microscopy. In general, the retinas of the cd81−/− mice appeared normal. However, upon close examination, there was an 18% increase in the number of RPE nuclei in the cd81−/− mice. The photoreceptor layer of the cd81−/− mice was significantly thinner than that of the wild‐type mice, even though there was no difference in the total thickness of the retinas in the two groups of mice. At the electron microscopic level we did not observe any differences in cell–cell junctions in the retinas of the cd81−/− mice as compared to their wild‐type littermates. These data support a role for CD81 controlling cell‐cycle and the number of RPE nuclei in the mouse retina. © 2004 Wiley‐Liss, Inc.
Radiation‐induced genomic instability: A role for secreted soluble factors in communicating the radiation response to non‐irradiated cells
Authors: Sowa Resat Marianne B. , Morgan William F.
Published: June 2004

Radiation induced genomic instability can be described as the increased rate of genomic alterations occurring in the progeny of an irradiated cell. Its manifestations are the dynamic ongoing production of chromosomal rearrangements, mutations, gene amplifications, transformation, microsatellite instability, and/or cell killing. In this prospectus, we present the hypothesis that cellular exposure to ionizing radiation can result in the secretion of soluble factors by irradiated cells and/or their progeny, and that these factors can elicit responses in other cells thereby initiating and perpetuating ongoing genomic instability. © 2004 Wiley‐Liss, Inc.
In vitro and in vivo prevention of HIV protease inhibitor‐induced insulin resistance by a novel small molecule insulin receptor activator
Authors: Cheng Mingshan , Chen Seiyu , Schow Steven R. , Manchem Vara Prasad , Spevak Wayne R. , Cristobal Cristina P. , Shi Songyuan , Macsata Robert W. , Lum Robert T. , Goldfine Ira D. , Keck James G.
Published: June 2004

Protease inhibitor (PI) therapy for the treatment of patients infected with human immunodeficiency virus is frequently associated with insulin resistance and diabetic complications. These adverse effects of PI treatment result to a large extent from their inhibition of insulin‐stimulated glucose transport. Insulin receptor (IR) activators that enhance the insulin signaling pathway could be effective in treating this resistance. However, there are no agents reported that reverse inhibition of insulin action by PIs. Herein, we describe the effects of TLK19781. This compound is a non‐peptide, small molecule, activator of the IR. We now report in cultured cells, made insulin resistant HIV by PI treatment, that TLK19781 both increased the content of insulin‐stimulated GLUT4 at the plasma membrane, and enhanced insulin‐stimulated glucose transport. In addition, oral administration of TLK19781 with the PI, indinavir improved glucose tolerance in rats made insulin resistant. These results suggest, therefore, that IR activators such as TLK19781 may be useful in treating the insulin resistance associated with PIs. © 2004 Wiley‐Liss, Inc.
Dual effect of heparin on cultured adult rat cardiomyocytes
Authors: Rezgui Nebil , Stefano Corda , Françoise Marotte , Jane‐Lise Samuel
Published: June 2004

Heparin has been widely reported to inhibit the growth of several cell types including neonatal rat cardiac myocyte (NRCM) but its effect on adult rat ventricular myocyte (ARVM) is unknown. To determine whether heparin is able to modulate ARVM protein synthesis capacity and if so which pathway is involved in this response, ARVM were cultured in presence or absence of 5% human serum and exposed to heparin (2–2,000 μg/ml) or its analogue xylan (0.5 and 50 μg/ml), and either the Ca2+ chelator BAPTA/AM (10 μg/ml), or the calcineurin inhibitor FK506 (10 μg/ml), and heparinase I (0.1–10 U/ml) for 2 days. The protein synthesis (PS) was measured after 24 h incorporation of [14C]‐Phenylalanine in ARVM. Independently of the serum presence, heparin and xylan altered PS in a bimodal dose‐dependent manner. At high doses, heparin and xylan (2,000 and 50 μg/ml, respectively) either had no effect (without serum) or inhibited PS (with serum). In absence of serum, low doses of heparin or xylan (20 and 0.5 μg/ml, respectively) amplified the PS process in ARVM (2‐fold, P < 0.05). FK506 inhibited the trophic response to 20 μg/ml heparin alone (−39%, P < 0.05). In presence of serum, the heparin induced‐trophic effect, that was not significantly altered by FK506, was inhibited by BAPTA/AM (−32%, P < 0.05). Finally, heparinase I that increased PS in NRCM had no effect on ARVM growth. This study strongly suggests that heparin dose‐dependently modulated PS in ARVM, this result being not observed in neonatal cells. Different mechanisms involving intracellular Ca2+ play a role in the PS response of ARVM to low concentrations of heparin, the intracellular pathways depending on the presence of serum. © 2004 Wiley‐Liss, Inc.
Heme oxygenase‐1 protects against apoptosis induced by tumor necrosis factor‐α and cycloheximide in papillary thyroid carcinoma cells
Authors: Chen George G. , Liu Z.M. , Vlantis A.C. , Tse G.M.K. , Leung B.C.H. , van Hasselt C.A.
Published: June 2004

Heme oxygenase‐1 (HO‐1) plays a role in the resistance to apoptosis of several types of cells, but its role in the development of thyroid cancer is unknown. In this study, we investigated the regulation of HO‐1 in human papillary thyroid carcinoma cells (KAT5). The results show that HO‐1 is significantly induced by hemin and cadmium. In addition to inducing HO‐1, hemin and cadmium also cause a rise in the levels of p21, a cyclin‐dependent kinase inhibitor. Cells with increased levels of HO‐1 and p21 were more resistant to apoptotic stimuli than cells with normal levels. The cells resistant to apoptosis also displayed an increased arrest at the G0/G1 phase of the cell‐cycle. The induced levels of HO‐1 and p21 were significantly reduced by p38 mitogen‐activated protein kinase (p38 MAPK) and extracellular‐regulated kinase (ERK) inhibitors. More importantly, KAT5 cells regained their sensitivity to apoptotic stimuli after they were treated with these kinase inhibitors, indicating that p38 MAPK and ERK are required for the resistance to apoptosis conferred by HO‐1. Furthermore, we demonstrated that increased levels of HO‐1 and p21 expression are associated with an increase in the activity of NF‐kappaB and that inhibiting NF‐kappaB leads to a block in the induction of HO‐1 and p21. In summary, this study reveals that an increase in the level of HO‐1 markedly reduces the sensitivity of papillary thyroid carcinoma cells to apoptotic stimuli. The HO‐1 pathway of apoptosis resistance is associated with an increase in the levels of p21, involves a p38 MAPK and ERK‐mediated mechanism and can be suppressed by inhibiting NF‐kappaB. © 2004 Wiley‐Liss, Inc.
Application of ab initio theory to QSAR study of 1,4‐dihydropyridine‐based calcium channel blockers using GA‐MLR and PC‐GA‐ANN procedures
Authors: Hemmateenejad Bahram , Safarpour Mohammad A. , Miri Ramin , Taghavi Fariba
Published: June 2004

The usefulness of the quantum chemical descriptors, calculated at the level of the RHF theory using 6‐31G basis set for QSAR study of 1,4‐dihydropyridine‐based calcium channel antagonist was examined. A data set containing 45 dihydropyridine derivatives with known activity was used. Multiple linear regressions combined with genetic algorithm for variable selection and an artificial neural network model combined with principal component analysis for dimension reduction and genetic algorithm for factor selection (PC‐GA‐ANN) were employed. Some multiparametric MLR equations with good statistical quality were obtained for different classes of dihydropyridine derivatives. The resulting equations suggest that the electronic properties of the atoms belonging to the backbone of the molecules as well as the conformation of the molecules affect the binding of these molecules with their receptor. In the PC‐GA‐ANN, The principal components of the descriptors data matrix were used as the input of the neural network and then genetic algorithm was applied to select the most relevant set of principal components. Two ANN models with five selected principal components were obtained. These models, which have high statistical qualities, can predict the activity of the molecules with prediction errors lower than ±5%. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1495–1503, 2004
CHARMM fluctuating charge force field for proteins: II Protein/solvent properties from molecular dynamics simulations using a nonadditive electrostatic model
Authors: Patel Sandeep , Mackerell Alexander D. , Brooks Charles L.
Published: June 2004

A fluctuating charge (FQ) force field is applied to molecular dynamics simulations for six small proteins in explicit polarizable solvent represented by the TIP4P‐FQ potential. The proteins include 1FSV, 1ENH, 1PGB, 1VII, 1H8K, and 1CRN, representing both helical and β‐sheet secondary structural elements. Constant pressure and temperature (NPT) molecular dynamics simulations are performed on time scales of several nanoseconds, the longest simulations yet reported using explicitly polarizable all‐atom empirical potentials (for both solvent and protein) in the condensed phase. In terms of structure, the FQ force field allows deviations from native structure up to 2.5 Å (with a range of 1.0 to 2.5 Å). This is commensurate to the performance of the CHARMM22 nonpolarizable model and other currently existing polarizable models. Importantly, secondary structural elements maintain native structure in general to within 1 Å (both helix and β‐strands), again in good agreement with the nonpolarizable case. In qualitative agreement with QM/MM ab initio dynamics on crambin (Liu et al. Proteins 2001, 44, 484), there is a sequence dependence of average condensed phase atomic charge for all proteins, a dependence one would anticipate considering the differing chemical environments around individual atoms; this is a subtle quantum mechanical feature captured in the FQ model but absent in current state‐of‐the‐art nonpolarizable models. Furthermore, there is a mutual polarization of solvent and protein in the condensed phase. Solvent dipole moment distributions within the first and second solvation shells around the protein display a shift towards higher dipole moments (increases on the order of 0.2–0.3 Debye) relative to the bulk; protein polarization is manifested via the enhanced condensed phase charges of typical polar atoms such as backbone carbonyl oxygens, amide nitrogens, and amide hydrogens. Finally, to enlarge the sample set of proteins, gas‐phase minimizations and 1 ps constant temperature simulations are performed on various‐sized proteins to compare to earlier work by Kaminsky et al. (J Comp Chem 2002, 23, 1515). The present work establishes the feasibility of applying a fully polarizable force field for protein simulations and demonstrates the approach employed in extending the CHARMM force field to include these effects. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1504–1514, 2004
Pharmacotherapy for performance anxiety disorders: Occasionally useful but typically contraindicated
Authors: Birk Lee
Published: June 2004

Pharmacotherapy is an effective part of treatment for most anxiety disorders, but not for specific phobia or performance anxiety. In them it is contraindicated, because it interferes with the effectiveness of exposure therapies and the extinction of fear responses. Interference with exposure–extinction is a drug side effect that should rarely if ever be tolerated in treating them. This article reviews the many indications for pharmacotherapy in treating most anxiety disorders and contrasts its usefulness in treatment of anxiety disorders with its relatively rare usefulness in treating specific phobias and performance anxiety. In both the latter disorders, benzodiazepines interfere with exposure and generally are best avoided, although temporary use, with safeguards, can sometimes be helpful for a specific phobia. The recent discovery that d‐cycloserine (DCS) facilitates exposure and the extinction of anxiety offers promise that it could in the future be usefully and broadly employed to catalyze and enhance exposure therapies. © 2004 Wiley Periodicals, Inc. J Clin Psychol/In Session.
Characterization of adhesion and differentiation markers of osteogenic marrow stromal cells
Authors: Marom R. , Shur I. , Solomon R. , Benayahu Dafna
Published: June 2004

Marrow stroma cells (MSC) play a major role in osteogenesis. The potential of the MSC to differentiate to bone‐forming cells relies upon molecular regulation. This study analyzed MBA‐15 cells for the expression of genes and proteins that are key regulators of osteoblast differentiation. These cells express Cbfa1 and c‐fos transcription factors (TF) of osteoprogenitor proliferating cells. RT‐PCR and immunohistochemistry were used to demonstrate the message and protein expression of extracellular matrix proteins that are a prerequisite for matrix formation and mineralization, including alkaline phosphatase (ALP), osteocalcin, osteopontin, biglycan, and bone sialoprotein (BSP). The activity of ALP was correlated at various cell densities with co‐expression of osteocalcin or osteopontin. Adhering cells must attach to the appropriate matrix to enable survival and differentiation. Using attachment assays, we demonstrated that MBA‐15 cells adhered to collagenous matrix and the effect on survival measured by changes in intracellular calcium (Ca) levels. The cells' adhesion to matrix is mediated via cell surface molecules. We quantified the expression of cells surface molecules that are important players in mediating cell–matrix interaction. Flow cytometry analysis (FACS) was used to determine the expression of CD‐31 (36%), and lower levels were identified for CD‐62E and CD11b. In summary, the present study demonstrates the expression of molecular markers that are distinctive for the osteoblastic phenotype in MBA‐15 marrow stroma cells and have crucial role in cell–matrix interaction, in establishing the cellular osteogenic phenotype and their survival. © 2005 Wiley‐Liss, Inc.
High‐dose retinoic acid modulates rat calvarial osteoblast biology
Authors: Song HanJoon M. , Nacamuli Randall P. , Xia Wei , Bari Ali S. , Shi Yun‐Ying , Fang Tony D. , Longaker Michael T.
Published: June 2004

Retinoic acid has been shown to adversely affect craniofacial development. Cleft palate and craniosynostosis are two examples of craniofacial defects associated with prenatal exposure to this agent. Although the effects of retinoic acid on cephalic neural crest‐derived tissues have previously been studied, the specific effects of retinoic acid on the cellular biology of osteoblasts remain unclear. The purpose of this study was to analyze in detail the effects of pharmacologic doses of retinoic acid on the differentiation and proliferation of osteoblasts derived from an intramembranous source. Primary rat calvarial osteoblasts were established in culture and treated with 1 or 10 μM all‐trans‐retinoic acid. Retinoic acid treatment markedly increased expression of osteopontin up to 48 h after stimulation. Consistent with this early stage of differentiation, both mRNA and protein analysis of FGF receptor isoforms demonstrated a switch in predominance from fibroblast growth factor receptor 2 (fgfr2) to fgfr1. Analysis of PCNA protein confirmed inhibition of proliferation by retinoic acid. To determine whether these alterations in osteoblast biology would lead to increased differentiation, we examined short term [alkaline phosphatase (AP) activity] and long term (von Kossa staining) surrogates of bone formation in vitro. These assays confirmed that retinoic acid increased osteogenesis, with a 4‐fold increase in bone nodule formation in cells treated with 10 μM retinoic acid after 28 days. Overall, our results demonstrated that pharmacologic doses of all‐trans‐retinoic acid decreased osteoblast proliferation and increased differentiation, suggesting that retinoic acid may effect craniofacial development by pathologically enhancing osteogenesis. © 2005 Wiley‐Liss, Inc.