bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functions of corticotropin‐releasing hormone in anthropoid primates: From brain to placenta
Authors: Power Michael L. , Schulkin Jay 
Published: June 2006

AbstractCorticotropin‐releasing hormone (CRH) is an ancient regulatory molecule. The CRH hormone family has at least four ligands, two receptors, and a binding protein. Its well‐known role in the hypothalamic‐pituitary‐adrenal (HPA) axis is only one of many. The expression of CRH and its related peptides is widespread in peripheral tissue, with important functions in the immune system, energy metabolism, and female reproduction. For example, CRH is involved in the implantation of fertilized ova and in maternal tolerance to the fetus. An apparently unique adaptation has evolved in anthropoid primates: placental expression of CRH. Placental CRH stimulates the fetal adrenal zone, an adrenal structure unique to primates, to produce dehydroepiandrosterone sulfate (DHEAS), which is converted to estrogen by the placenta. Cortisol induced from the fetal and maternal adrenal glands by placental CRH induces further placental CRH expression, forming a positive feedback system that results in increasing placental production of estrogen. In humans, abnormally high placental expression of CRH is associated with pregnancy complications (e.g., preterm labor, intrauterine growth restriction (IUGR), and preeclampsia). Within anthropoid primates, there are at least two patterns of placental CRH expression over gestation: monkeys differ from great apes (and humans) by having a midgestational peak in CRH expression. The functional significance of these differences between monkeys and apes is not yet understood, but it supports the hypothesis that placental CRH performs multiple roles during gestation. A clearer understanding of the diversity of patterns of placental CRH expression among anthropoid primates would aid our understanding of its role in human pregnancy. Am. J. Hum. Biol. 18:431–447, 2006. © 2006 Wiley‐Liss, Inc.
Explaining sex differences in dental caries prevalence: Saliva, hormones, and “life‐history” etiologies
Authors: Lukacs John R. , Largaespada Leah L. 
Published: June 2006

AbstractWhen dental caries rates are reported by sex, females are typically found to exhibit higher prevalence rates than males. This finding is generally true for diverse cultures with different subsistence systems and for a wide range of chronological periods. Exceptions exist, but are not common. In this paper, we present new data for sex differences in dental caries rates among the Guanches (Tenerife, Canary Islands), summarize results of meta‐analyses of dental caries prevalence, and emphasize new research that stresses the critical role of female hormones and life‐history events in the etiology of dental caries. Among the Guanches, corrected tooth‐count caries rates for females (8.8%, 158/1,790) are approximately twice the frequency of caries among males (4.5%, 68/1,498). Higher caries prevalence among females is often explained by one of three factors: 1) earlier eruption of teeth in girls, hence longer exposure of girls' teeth to the cariogenic oral environment, 2) easier access to food supplies by women and frequent snacking during food preparation, and 3) pregnancy. Anthropologists tend to favor explanations involving behavior, including sexual division of labor and women's domestic role in food production. By contrast, the causal pathways through which pregnancy contributes to poorer oral health and higher caries rates are deemphasized or discounted. This paper presents recent research on physiological changes associated with fluctuating hormone levels during individual life histories, and the impact these changes have on the oral health of women. The biochemical composition of saliva and overall saliva flow rate are modified in several important ways by hormonal fluctuations during events such as puberty, menstruation, and pregnancy, making the oral environment significantly more cariogenic for women than for men. These results suggest that hormonal fluctuations can have a dramatic effect on the oral health of women, and constitute an important causal factor in explaining sex differences in caries rates. Am. J. Hum. Biol. 18:540–555, 2006. © 2006 Wiley‐Liss, Inc.
The mean‐field approximation in quantum electrodynamics: The no‐photon case
Authors: Hainzl Christian , Lewin Mathieu , Solovej Jan Philip 
Published: June 2006

AbstractWe study the mean‐field approximation of quantum electrodynamics (QED) by means of a thermodynamic limit. The QED Hamiltonian is written in Coulomb gauge and does not contain any normal ordering or choice of bare electron/positron subspaces. Neglecting photons, we properly define this Hamiltonian in a finite box [−L/2; L/2)3, with periodic boundary conditions and an ultraviolet cutoff λ. We then study the limit of the ground state (i.e., the vacuum) energy and of the minimizers as L goes to infinity, in the Hartree‐Fock approximation.In the case with no external field, we prove that the energy per volume converges and obtain in the limit a translation‐invariant projector describing the free Hartree‐Fock vacuum. We also define the energy per unit volume of translation‐invariant states and prove that the free vacuum is the unique minimizer of this energy.In the presence of an external field, we prove that the difference between the minimum energy and the energy of the free vacuum converges as L goes to infinity. We obtain in the limit the so‐called Bogoliubov‐Dirac‐Fock functional. The Hartree‐Fock (polarized) vacuum is a Hilbert‐Schmidt perturbation of the free vacuum and it minimizes the Bogoliubov‐Dirac‐Fock energy. © 2006 Wiley Periodicals, Inc.
Branch to colony trajectory in a modular organism: Pattern formation in the Indo‐Pacific coral Stylophora pistillata
Authors: Shaish Lee , Abelson Avigdor , Rinkevich Baruch 
Published: June 2006

AbstractThe architecture of the colony in a branching coral is an iterative process in which new layers of calcium carbonate compile atop existing structures that remain unchanged. Colony growth and development, known as astogeny, is believed to be a continuous process, characterized by replication of lower rank unites, polyps, and branches. This study seeks to explore the genetic blueprint of branch‐to‐colony developmental trajectory in the branching coral Stylophora pistillata, within an astogeny period of 1 year. One hundred small branches (initially 2–4 cm long) were sampled from 10 colonies. A year later, 63 remaining colonies were analyzed for their architectural rules by using 15 morphometric parameters. Multivariate statistical tests were preformed. Cluster and two‐dimensional nonmetric Multi‐Dimensional Scaling analyses revealed that the 10 genotypes could be divided into two major morphometric groups and two intermediate groups, whereas SIMPER analyses (a similarity percentage test) on within‐genet similarities showed high similarity between the ramets developed from each of the 10 genotypes. Although, at first, it seemed that different colonies exhibited variable and different architectural designs (each characterized by specific morphometric parameters), a comprehensive analysis revealed that all 10 coral genotypes exhibited a single common developmental plan that was characterized by a continuum of architectural design with several distinct stages. Each stage is marked by its own characteristic morphometric parameters. Changing of developmental rules during the trajectory from branch to coral colony may help the colony to cope better with environmental constraints. Developmental Dynamics 235:2111–2121, 2006. © 2006 Wiley‐Liss, Inc.
The biocompatibility and osteoconductivity of a cement containing β–TCP for use in vertebroplasty
Authors: Goto K. , Shinzato S. , Fujibayashi S. , Tamura J. , Kawanabe K. , Hasegawa S. , Kowalski R. , Nakamura T. 
Published: June 2006

AbstractA new composite bone cement designated “G2B1” was developed for percutaneous transpedicular vertebroplasty. G2B1 contains beta tricalcium phosphate particles and methylmethacrylate–methylacrylate copolymer as the powder components, and methylmethacrylate, urethane dimethacrylate, and tetrahydrofurfuryl methacrylate as the liquid components. Biocompatibility and osteoconductivity were evaluated using scanning electron microscopy, contact microradiography, and Giemsa surface staining 4, 8, 12, 26, and 52 weeks after implantation into rat tibiae. To evaluate osteoconductivity, affinity indices (%) were calculated. Scanning electron microscopy and contact microradiography revealed that bone contact with G2B1 was attained within 4 weeks (affinity index: 50.2 ± 11.8 at 4 weeks) and at most of the margin within 26 weeks (affinity index: 87.4 ± 7.2 at 26 weeks). Specifically, G2B1 contacted bone via a wide calcium–phosphate‐rich layer, and its degradation started within 8 weeks, mainly in the marginal area. Giemsa surface staining showed that there was almost no inflammatory reaction around the G2B1. These results indicate that G2B1 is a biocompatible and osteoconductive bone cement. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthesis and characterization of uniform radiopaque polystyrene microspheres for X‐ray imaging by a single‐step swelling process
Authors: Galperin Anna , Margel David , Margel Shlomo 
Published: June 2006

AbstractUniform radiopaque polystyrene microspheres of ∼2.3 ± 0.2 μm were prepared by a single‐step swelling of 2.3 ± 0.2 μm polystyrene template microspheres, dispersed in an aqueous solution with methylene chloride emulsion droplets containing 2,3,5‐triiodobenzoylethyl ester. After completing the swelling process, the methylene chloride was evaporated in order to lock the 2,3,5‐triiodobenzoylethyl ester in the polystyrene microspheres. The influence of the weight ratio [2,3,5‐triiodobenzoylethyl ester]/[polystyrene] on the % of entrapped 2,3,5‐triiodobenzoylethyl ester was elucidated. Characterization of the radiopaque polystyrene microspheres was accomplished by light microscope, FTIR, TGA, SEM, XPS, and elemental analysis. The radiopacity of the microspheres was demonstrated by an imaging technique based on X‐ray absorption usually used in hospitals. This novel method of encapsulation of 2,3,5‐triiodobenzoylethyl ester within polystyrene microspheres by a single‐step swelling process may be used as a model for encapsulation of various hydrophobic radiopaque drugs within uniform polystyrene template particles of various diameters for different X‐ray imaging needs, e.g., blood pool, body organs, embolization, dental composition, implants, protheses, and nanocomposites. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Molecular cloning and characterization of alpha‐class glutathione S‐transferase gene from the liver of silver carp, bighead carp, and other major chinese freshwater fishes
Authors: Liao Wan‐Qin , Liang Xu‐Fang , Wang Lin , Lei La‐Mei , Han Bo‐Ping 
Published: June 2006

AbstractTwo full‐length cDNAs encoding glutathione S‐transferase (GST) were cloned and sequenced from the hepatopancreas of planktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis). The silver carp and bighead carp GST cDNA were 920 and 978 bp in length, respectively, and both contained an open reading frame that encoding 223 amino acids. Partial GST cDNA sequences were also obtained from the liver of grass carp (Ctenopharyngodon idellus), crucian carp (Carassius auratu), mud carp (Cirrhinus molitorella), and tilapia (Oreochromis nilotica). All these GSTs could be classified as alpha‐class GSTs on the basis of their amino acid sequence identity with other species. The three‐dimensional structure of the silver carp GST was predicted using a computer program, and was found to fit the classical two‐domain GST structure. Using the genome walker method, a 875‐bp 5′‐flanking region of the silver carp GST gene was obtained, and several lipopolysaccharide (LPS) response elements were identified in the promoter region of the phytoplanktivorous fish GST gene, indicating that the GST gene expression of this fish might be regulated by LPS, released from the toxic blue‐green algae producing microcystins. To compare the constitutive expression level of the liver GST gene among the six freshwater fishes with completely different tolerance to microcystins, beta‐actin was used as control and the ratio GST/beta‐actin mRNA (%) was determined as 130.7 ± 6.6 (grass carp), 103.1 ± 8.9 (bighead carp), 92.6 ± 15.0 (crucian carp), 72.3 ± 7.8 (mud carp), 58.8 ± 11.5 (silver carp), and 33.6 ± 13.7 (tilapia). The constitutive expression level of the liver GST gene clearly shows that all the six freshwater fishes had a negative relationship with their tolerance to microcystins: high‐resistant fishes (phytoplanktivorous silver carp and tilapia) had the lowest tolerance to microcystins and the high‐sensitive fish (herbivorous grass carp) had the highest tolerance to microcystins. Taken together with the reciprocal relationship of constitutive and inducible liver GST expression level in some of the tested fish species to microcystin exposure, a molecular mechanism for different microcystin detoxification abilities of the warm freshwater fishes was discussed. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:114–126, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20125
Systematic QM/MM investigation of factors that affect the cytochrome P450‐catalyzed hydrogen abstraction of camphor
Authors: Altun Ahmet , Shaik Sason , Thiel Walter 
Published: June 2006

AbstractThe hydrogen abstraction reaction of camphor in cytochrome P450cam has been investigated in the native enzyme environment by combined quantum mechanical/molecular mechanical (QM/MM) calculations and in the gas phase by density functional calculations. This work has been motivated by contradictory published QM/MM results. In an attempt to pinpoint the origin of these discrepancies, we have systematically studied the factors that may affect the computed barriers, including the QM/MM setup, the optimization procedures, and the choice of QM region, basis set, and protonation states. It is found that the ChemShell and QSite programs used in the published QM/MM calculations yield similar results at given geometries, and that the discrepancies mainly arise from two technical issues (optimization protocols and initial system preparation) that need to be well controlled in QM/MM work. In the course of these systematic investigations, new mechanistic insights have been gained. The crystallographic water 903 placed near the oxo atom of Compound I lowers the hydrogen abstraction barrier by ca. 4 kcal/mol, and thus acts as a catalyst for this reaction. Spin density may appear at the A‐propionate side chain of the heme if the carboxylate group is not properly screened, which might be expected to happen during protein dynamics, but not in static equilibrium situations. There is no clear correlation between the computed A‐propionate spin density and the hydrogen abstraction barrier, and hence, no support for a previously proposed side‐chain mediated transition state stabilization mechanism. Standard QM/MM optimizations yield an A‐propionate environment close to the X‐ray structure only for protonated Asp297, and not for deprotonated Asp297, but the computed barriers are similar in both cases. An X‐ray like A‐propionate environment can also be obtained when deprotonated Asp297 is included in the QM region and His355 is singly protonated, but this Compound II‐type species with a closed‐shell porphyrin ring has a higher hydrogen abstraction barrier and should thus not be mechanistically relevant. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1324–1337, 2006
Photodynamic therapy of brain tumors—A work in progress
Authors: Muller Paul J. , Wilson Brian C. 
Published: June 2006

AbstractBackground and ObjectivesPDT has been used in the treatment of malignant brain tumors. This communication updates our series of unselected malignant gliomas treated with Photofrin‐PDT.Study Design and MethodsWe examined the records of 112 patients with malignant gliomas, metastatic brain tumors and meningiomas treated with Photofrin‐PDT at St. Michael's Hospital, Toronto. These patients were treated prior to the onset of ongoing randomized trials in Photofrin PDT or had pathology that excluded them from such trials.ResultsThe overall post‐PDT survival of 96 patients with supratentorial gliomas was 42 weeks, with a 40 and 22% 1‐ and 2‐year survival, respectively. The greater the degree of oligodendroglial involvement the longer was the survival. Seventy‐five percent of patients had no significant post‐operative complications.ConclusionsPhotofrin‐PDT was safe. However, higher light doses than were used in these patients may be required for improved responses. Lasers Surg. Med. 38:384–389, 2006. © 2006 Wiley‐Liss, Inc.
Multicell tumor spheroids in photodynamic therapy
Authors: Madsen Steen J. , Sun Chung‐Ho , Tromberg Bruce J. , Cristini Vittorio , De Magalhães Nzola , Hirschberg Henry 
Published: June 2006

AbstractBackground and ObjectivesMulticell spheroids (MCSs) represent a simple in vitro system ideally suited for studying the effects of a wide variety of investigational treatments including photodynamic therapy (PDT).Study Design/Materials and MethodsIn the first section of this review study, an overview of the current literature on MCS in PDT will be presented. Knowledge of basic PDT parameters has been gained from numerous MCS studies, in particular, the mechanisms of sensitizer photobleaching have been elucidated. MCSs have also proven useful for the study of complex PDT treatment regimens including multiple treatments and combined therapies involving PDT and ionizing radiation or hyperthermia. The purpose of the second part of this review is to present results from recent studies in our laboratory aimed at developing MCS models suitable for investigating tumor cell invasion and angiogenesis—processes characteristic of high‐grade gliomas.Results and ConclusionTo that end, progress has recently been made to develop a more accurate in vivo brain tumor model consisting of biopsy‐derived human tumor spheroids implanted into the brains of immunodeficient rats. Finally, recent work suggests that computer simulations may prove useful to describe the growth of MCS and predict the effects of investigational therapies including PDT. Such in silico models have made a number of counterintuitive predictions that have been verified in vitro and, as such, could guide the development of improved therapeutics. Lasers Surg. Med. 38:555–564, 2006. © 2006 Wiley‐Liss, Inc.
Nature: A rich source for developing multifunctional agents. tumor‐imaging and photodynamic therapy
Authors: Pandey Ravindra K. , Goswami Lalit N. , Chen Yihui , Gryshuk Amy , Missert Joseph R. , Oseroff Allan , Dougherty Thomas J. 
Published: June 2006

AbstractThe purpose of this review is to call attention in the use of chlorophyll‐a and bacteriochlorophyll‐a to develop more than 600 photosensitizers (λ max 660 nm–800 nm) during the last 15 years (1990–2005) at the Photodynamic Therapy Center, Roswell Park Cancer Institute, Buffalo. This article mainly includes the chemistry, preclinical results, and brief clinical data of some of the most effective photosensitizers. The utility of the tumor‐avid photosensitizers in developing multimodality agents (imaging and therapy) is also presented. Lasers Surg. Med. 38:445–467, 2006. © 2006 Wiley‐Liss, Inc.
Local physiological changes during photodynamic therapy
Authors: Busch Theresa M. 
Published: June 2006

AbstractBackground and ObjectiveHerein an overview is provided of the causes, consequences, and significance of photodynamic therapy (PDT)‐mediated effects on tumor oxygenation and blood flow during illumination.Study Design/Materials and MethodsTechniques particularly valuable to this research have included tissue oxygen tension measurement by the Eppendorf pO2 Histograph; spatial quantification of hypoxia by EF3 and EF5; and tissue oxygenation/blood flow monitoring by diffuse reflectance/correlation spectroscopy.ResultsSevere hypoxia was measured in vivo during PDT and is shown to be a consequence of photochemical oxygen consumption and/or compromised vascular perfusion. Oxygen depletion can be controlled by treatment regimen, occurs in a spatially‐definable pattern, and is therapy‐limiting. PDT‐induced changes in tumor oxygenation during illumination are correlated with outcome. In PDT‐treated tissues, blood flow also is determined by treatment regimen and correlates with treatment response.ConclusionsPhotodynamic therapy creates distinct, measurable changes in tumor oxygen and blood flow during illumination. These physiological changes may ultimately affect treatment efficacy. Lasers Surg. Med. 38:494–499, 2006. © 2006 Wiley‐Liss, Inc.
Control of pesticide residues by liquid chromatography‐mass spectrometry to ensure food safety
Authors: Picó Yolanda , Font Guillermina , José Ruiz María , Fernández Mónica 
Published: June 2006

AbstractLiquid chromatography‐mass spectrometry (LC‐MS) has become an invaluable technique for the control of pesticide residues to ensure food safety. After an introduction about the regulations that highlights its importance to meet the official requirements on analytical performance, the different mass spectrometers used in this field of research, as well as the LC‐MS interfaces and the difficulties associated with quantitative LC‐MS determination, are discussed. The ability to use practical data for quantifying pesticides together with the option of obtaining structural information to identify target and non‐target parent compounds and metabolites are discussed. Special attention is paid to the impact of sample preparation and chromatography on the ionization efficiency of pesticides from food. The last section is devoted to applications from a food safety point of view. © 2006 Wiley Periodicals, Inc.