bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute, sub‐acute and long‐term subjective consequences of ‘ecstasy’ (MDMA) consumption in 430 regular users
Authors: Verheyden Suzanne L. , Henry John A. , Curran H. Valerie 
Published: October 2003

AbstractThis study examined the reported psychological effects of different patterns of MDMA use in men and women, and how they are modified by use of other psychoactive substances. A semi‐structured interview was conducted with 466 regular MDMA users, exploring the perceived acute, sub‐acute and long‐term subjective effects of this drug. Factor analysis established three main categories of acute effects of MDMA: (i) positive and (ii) negative effects on mental health, and (iii) physical effects. In terms of subacute effects, 83% of participants reported experiencing low mood and 80% reported impaired concentration between ecstasy‐taking sessions. Factors affecting these effects included age, gender, extent of MDMA use and concomitant use of cocaine or amphetamine. The long‐term effects most frequently reported included the development of tolerance to MDMA (59%), impaired ability to concentrate (38%), depression (37%) and ‘feeling more open towards people’ (31%). In terms of what might persuade users to stop using MDMA, their most prominent concern was the drug's long‐term effects on mental health. Copyright © 2003 John Wiley & Sons, Ltd.
Donepezil in a chronic drug user—a potential treatment?
Authors: Jovanovski Diana , Zakzanis Konstantine K. 
Published: October 2003

AbstractThe objective of the current study was to explore the potential cognitive benefits of an anticholinesterase inhibitor, donepezil, in a former chronic drug user. A neuropsychological test battery composed of the vocabulary and matrix reasoning subtests of the Wechsler adult intelligence scale‐III, measures of everyday executive functioning (behavioural assessment of the dysexecutive syndrome [BADS]), and verbal learning and memory tasks (California verbal learning test‐II; Rivermead behavioural memory test) was completed at baseline, at 3 months after introducing donepezil, and at 3 months after donepezil was discontinued. After donepezil treatment, substantial improvements were found on tasks of nonverbal fluid reasoning (i.e. matrix reasoning) and other executive functioning tests (i.e. BADS). At entry into the study, poor academic performance and subjective problems with memory and concentration were reported, particularly after amphetamine use (i.e. MDMA and crystal methamphetamine); after donepezil treatment, dramatic increases in memory, concentration and academic achievement were observed. The finding of improvements in tests of executive functioning and in academic performance in this case study, together with the minimal adverse side effects of donepezil, warrants the investigation of controlled studies of cholinergic enhancement in chronic amphetamine and other drug users. Copyright © 2003 John Wiley & Sons, Ltd.
Induction of mania in depression by paroxetine
Authors: Morishita Shigeru , Arita Seizaburo 
Published: October 2003

AbstractIntroductionAn investigation of the proportion of patients who have experienced mania with antidepressant treatment and their characteristics would seem to be of clinical use.AimsThe purpose of this clinical study was to examine the predictors of induction of mania in depression patients as a result of paroxetine treatment.MethodA retrospective cohort analysis was carried out among depression patients treated in the Department of Psychiatry, Kawasaki Medical School Hospital, Kurashiki, Japan, in 2000 and 2001. Some 79 patients were identified who were receiving paroxetine to treat depression. A variety of clinical factors including gender, the type of depression, frequency of episodes, family history, age and daily dose were examined as possible predictors of induction of mania by paroxetine.ResultsSeven (8.86%) of the 79 paroxetine‐treated patients developed mania. A Cox proportional hazards analysis showed the type of depression and the history of family psychiatric illness to be independent predictive factors of the induction of mania by paroxetine treatment.ConclusionsThe rate of mania induction of paroxetine is not substantially different from that found for conventional antidepressants. The type of depression and the history of family psychiatric illness may be considered as predictors of mania induction in depression patients taking paroxetine treatment. Copyright © 2003 John Wiley & Sons, Ltd.
Saccade and cognitive impairment associated with kava intoxication
Authors: Cairney Sheree , Maruff Paul , Clough Alan R. , Collie Alex , Currie Jon , Currie Bart J. 
Published: October 2003

AbstractKava is an extract from the Piper methysticum Forst. f. plant that has social and spiritual importance in Pacific islands societies. Herbal remedies that contain kava are used for the psychiatric treatment of anxiety and insomnia. Laboratory studies have found only subtle, if any, changes on cognitive or motor functions from the acute effects of consuming small clinical doses of kava products. Intoxication from recreational doses of kava has not been studied. The performance of individuals intoxicated from drinking kava (n=11) was compared with a control group (n=17) using saccade and cognitive tests. On average, intoxicated individuals had consumed 205 g of kava powder each (approximately 150 times clinical doses) in a group session that went for 14.4 h and ended 8 h prior to testing. Intoxicated kava drinkers showed ataxia, tremors, sedation, blepharospasm and elevated liver enzymes (GGT and ALP), together with saccadic dysmetria, saccadic slowing and reduced accuracy performing a visual search task that only became evident as the task complexity increased. Kava intoxication is characterized by specific abnormalities of movement coordination and visual attention but normal performance of complex cognitive functions. Saccade abnormalities suggest disruption of cerebellar and GABAergic functions. Copyright © 2003 John Wiley & Sons, Ltd.
Computing motif correlations in proteins
Authors: Horng Jorng‐Tzong , Huang Hsien‐Da , Wang Shih‐Hsien , Chen Ming‐You , Huang Shir‐Ly , Hwang Jenn‐Kang 
Published: October 2003

AbstractProtein motifs, which are specific regions and conserved regions, are found by comparing multiple protein sequences. These conserved regions in general play an important role in protein functions and protein folds, for example, for their binding properties or enzymatic activities. The aim here is to find the existence correlations of protein motifs. The knowledge of protein motif/domain sharing should be important in shedding new light on the biologic functions of proteins and offering a basis in analyzing the evolution in the human genome or other genomes. The protein sequences used here are obtained from the PIR‐NREF database and the protein motifs are retrieved from the PROSITE database. We apply data mining approach to discover the occurrence correlations of motif in protein sequences. The correlation of motifs mined can be used in evolution analyses and protein structure prediction. We discuss the latter, i.e., protein structure prediction in this study. The correlations mined are stored and maintained in a database system. The database is now available at http://bioinfo.csie.ncu.edu.tw/ProMotif/. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2032–2043, 2003
A point‐charge force field for molecular mechanics simulations of proteins based on condensed‐phase quantum mechanical calculations
Authors: Duan Yong , Wu Chun , Chowdhury Shibasish , Lee Mathew C. , Xiong Guoming , Zhang Wei , Yang Rong , Cieplak Piotr , Luo Ray , Lee Taisung , Caldwell James , Wang Junmei , Kollman Peter 
Published: October 2003

AbstractMolecular mechanics models have been applied extensively to study the dynamics of proteins and nucleic acids. Here we report the development of a third‐generation point‐charge all‐atom force field for proteins. Following the earlier approach of Cornell et al., the charge set was obtained by fitting to the electrostatic potentials of dipeptides calculated using B3LYP/cc‐pVTZ//HF/6‐31G** quantum mechanical methods. The main‐chain torsion parameters were obtained by fitting to the energy profiles of Ace‐Ala‐Nme and Ace‐Gly‐Nme di‐peptides calculated using MP2/cc‐pVTZ//HF/6‐31G** quantum mechanical methods. All other parameters were taken from the existing AMBER data base. The major departure from previous force fields is that all quantum mechanical calculations were done in the condensed phase with continuum solvent models and an effective dielectric constant of ε = 4. We anticipate that this force field parameter set will address certain critical short comings of previous force fields in condensed‐phase simulations of proteins. Initial tests on peptides demonstrated a high‐degree of similarity between the calculated and the statistically measured Ramanchandran maps for both Ace‐Gly‐Nme and Ace‐Ala‐Nme di‐peptides. Some highlights of our results include (1) well‐preserved balance between the extended and helical region distributions, and (2) favorable type‐II poly‐proline helical region in agreement with recent experiments. Backward compatibility between the new and Cornell et al. charge sets, as judged by overall agreement between dipole moments, allows a smooth transition to the new force field in the area of ligand‐binding calculations. Test simulations on a large set of proteins are also discussed. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1999–2012, 2003
Theoretical approach to the mechanism of reactions between halogen atoms and unsaturated hydrocarbons: The Cl + propene reaction
Authors: Braña Pedro , Sordo José A. 
Published: October 2003

AbstractThe potential energy surface for the Cl + propene reaction was analyzed at the MP2 level using Pople's 6‐31G(d,p) and 6‐311+G(d,p), and Dunning's cc‐pVDZ and aug‐cc‐pVDZ basis sets. Two different channels for the addition reaction leading to chloroalkyl radicals and five alternative channels for the abstraction reaction leading to C3H + HCl were explored. The corresponding energy profiles were computed at the QCISD(T)/aug‐cc‐pVDZ//MP2/aug‐cc‐pVDZ level of theory. Theoretical results suggest that the previously established mechanism consisting of (1) direct abstraction and (2) addition–elimination steps is instead made up of (1) addition through an intermediate and (2) two‐step abstraction processes. No direct abstraction mechanism exists on the potential energy surface. The kinetic equations derived for the new mechanism are consistent with the pressure dependence experimentally observed for this reaction. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2044–2062, 2003
Siliceous spicules and skeleton frameworks in sponges: Origin, diversity, ultrastructural patterns, and biological functions
Authors: Uriz María‐J. , Turon Xavier , Becerro Mikel A. , Agell Gemma 
Published: October 2003

AbstractSilica deposition is a fundamental process in sponges. Most sponges in the Classes Demospongiae and Hexactinellida secrete siliceous elements, which can subsequently fuse, interlock with each other, or form three‐dimensional structures connected by spongin. The resulting skeletal frameworks allow sponges to grow upwards and facilitate water exchange with minimal metabolic cost. Several studies on sponge skeletogenesis have been published. We are beginning to understand the mechanisms of spicule secretion and the role of spicules and skeletal frameworks in the biology, ecology, and evolution of sponges. Molecular techniques and ecological experiments have demonstrated the genetic control of the process and the contribution of environmental factors to the expression of a sponge spicule, respectively. However, other classic topics such as the role of membranes in silicon transport or whether spicules are formed in situ or secreted anywhere in the sponge mesohyl and then transported to the skeletal framework require further investigation. We review the process of silica deposition in sponges at the molecular and cellular levels, as well as the biological and ecological functions of spicules and skeletons. The genetic control of spicule shapes makes them useful in the reconstruction of sponge phylogeny, although recent experiments have demonstrated the influence of environmental factors in modulating spicule size, shape, and the presence or absence of one or more spicule types. The implications of such variations in sponge taxonomy may be important. Besides supporting sponge cells, spicules can help larvae stay buoyant while in the plankton or reach the bottom at settlement, enhance reproduction success, or catch prey. Conversely, the role of spicules and skeletons in deterring predation has not been demonstrated. Knowledge of several aspects is still based on a single or a few species and extrapolations should be made only with caution. With the advent of new molecular techniques, new lines of research are presently open and active in this field. Microsc. Res. Tech. 62:279–299, 2003. © 2003 Wiley‐Liss, Inc.
Comparative study of spiculogenesis in demosponge and hexactinellid larvae
Authors: Leys S.P. 
Published: October 2003

AbstractSpicule deposition was studied by electron microscopy in fixed embryos and larvae of the haplosclerid spongeRenierasp. and the hexactinellidOopsacas minuta. Spicules form in centrally located vacuoles within cells and within syncytia, as in the adult sponges. InReniera, scleroblasts differentiate from micromeres prior to gastrulation. At gastrulation the scleroblasts migrate to the periphery of the embryo and commence spicule deposition around a hexagonal axial filament. Sclerocytes have numerous pseudopodia and migrate to the posterior pole where they become aligned along the antero‐posterior axis in the free‐swimming larva.Renieralarvae possess some 40–50 oxeas, each 70–75 μm long and 1 μm wide. MatureOopsacaslarvae have up to 14 stauractin spicules, which are produced on a rectangular axial filament in tissues that lie under the smooth epithelium at the posterior pole of the larva. Young sclerocytes have many pseudopodia. The 4‐rayed spicules elongate along both the antero‐posterior and medial axes, until the longitudinal rays become anchored in a lipid‐filled cytoplasm at the anterior of the larva and the lateral rays intersect around the midline. The length of the transverse rays of the stauractins in free‐swimming larvae are 27–45 μm each, while the length of the two longitudinal rays is 40–80 μm. Although spicule deposition begins in cells with a similar morphology in both cellular and syncytial sponges, the elaboration and organization of the spicules differ markedly in cellular and syncytial sponges and appear to be an outcome of the very distinct cellular differentiation and larval morphogenesis that occur in each of these groups. Microsc. Res. Tech. 62:300–311, 2003. © 2003 Wiley‐Liss, Inc.
Some aspects of silica deposition in lithistid demosponge desmas
Authors: Pisera Andrzej 
Published: October 2003

AbstractTransmitted light microscope and SEM observations of various growth stages, including very young forms, of lithistid demosponge spicules called desmas provided a wealth of new observations on silica deposition in desmas of most lithistid demosponge groups. In typical (pachastrellid) demosponges a basic feature of silica deposition in young spicules is the formation of silica granules (100–160 nm in diameter) deposited in more or less regular concentric layers. Further growth stages in typical demosponges are similar, only silica granules are smaller and more densely packed. The shape of the spicule is controlled by an organic axial filament, while features of the outer spicule surface are also determined by silicalemma. In lithistid desmas the early stage of silica deposition is controlled by an organic axial filament or, in some cases, dispersed organic molecules only. The next step, after early arrest of axial filament growth and its total encasing by silica, is the deposition of various silica granules (40–300 nm in diameter), spheres, and/or cylinders (1,300–3,330 nm), which are either the result of precipitation or the effect of templating by organic molecules (proteins and polysaccharides), without direct control by the silicalemma. The later stages of desma growth are under direct control of the silicalemma, which molds secondary branches and/or elements of sculpture of the desmas. The tips of desmas, which articulate with older desmas, are also controlled by local spatial relationships. Differentiation of morphological forms of silica in desmas, which is at least genus‐specific, clearly supports the polyphyletic nature of lithistid sponges. Microsc. Res. Tech. 62:312–326, 2003. © 2003 Wiley‐Liss, Inc.
Sponge cell reactivity to various forms of silica
Authors: Bavestrello Giorgio , Benatti Umberto , Cattaneo‐Vietti Riccardo , Cerrano Carlo , Giovine Marco 
Published: October 2003

AbstractSeveral sponge species incorporate a wide range of foreign material. Whether such material is actively selected by the sponge is controversial. Here we compare the available suspended matter and the sediment incorporated in the tissue of the demosponge Chondrosia reniformis. Field observations and laboratory experiments indicate that this species selects and incorporates only siliceous materials, in particular quartz particles and opal sponge spicules, avoiding carbonate particles. The reaction of ectosome cells of Chondrosia depends on the forms of silica: after settlement of crystalline quartz particles on the sponge surface, the pinacocytes contract uniformly, giving rise to a ruffled surface that remains throughout the incorporation of foreign material. In contrast, the opal spicules elicit a motile response in pinacocytes, which cover the spicules as a result. After incorporation, while the opal spicules remain unaltered within sponge tissue, the engulfed quartz particles are quickly etched, reduced in size, and released from the sponge. The etching of quartz particles by C. reniformis is produced by ascorbic acid, and is the first evidence of such activity from the animal kingdom. Ascorbic acid has been found to change the quartz surface features, which leads to an increased radical production and a consequent dissolution of quartz. This process does not occur on opal spicules. Microsc. Res. Tech. 62:327–335, 2003. © 2003 Wiley‐Liss, Inc.
Physical and chemical analysis of the siliceous skeletons in six sponges of two groups (demospongiae and hexactinellida)
Authors: Sandford Floyd 
Published: October 2003

AbstractThe siliceous skeletons of six hexactinellids and demosponges were compared using a series of physical and chemical tests. The sponges were two hermit‐crab sponges (Class Demospongiae, family Suberitidae), one from Scotland, Suberites domuncula, and the other, Pseudospongosorites suberitoides, from the Gulf of Mexico, and four hexactinellids, Hyalonema sp., Euplectella aspergillum, Rhabdocalyptus dawsoni, and Aphrocallistes vastus. The operating hypothesis was that differences in the amorphous hydrated silica skeletons in Demosponges and Hexactinellids might prove taxonomically useful. Physical properties studied included SEM, glass density, glass transition temperature (Tg), TG/DTA to determine water content, and FTIR spectra. Chemical determinations were made using energy dispersive X‐ray fluorescence (EDXRF). Spicular skeletal material is deposited in concentric layers around the axial canal. With the exception of differences at several bands in the IR spectra, the siliceous skeletons in demosponges and hexactinellids are largely indistinguishable. Density was similar in all sponges (range 2.03–2.13 g/cc) and similar to the density of opal (SiO2 · 1.5H2O) (mean = 2.09 g/cc). IR spectra were similar, with prominent absorption bands at 460–470, 800, and 1,090–1,100 cm−1 (due to different vibrational modes of Si‐O‐Si linkages) and at 1,650 and 3,450–3,560 cm−1 (due to water). The skeletons of all six showed similar spectra to that of silica gel both before and after heating to 1,200°C. Water comprised 10–14% of the skeleton by weight, slightly higher in the demosponges. Average spicule chemical composition was 85.2% SiO2, 12.3% water, and 2.5% other elements (mainly S, Al, K, Ca, and Na). The percent amounts of Si did not differ significantly between the demosponges and the hexactinellids. Microsc. Res. Tech. 62:336–355, 2003. © 2003 Wiley‐Liss, Inc.
Molecular biology of demosponge axial filaments and their roles in biosilicification
Authors: Weaver James C. , Morse Daniel E. 
Published: October 2003

AbstractFor hundreds of years, the skeletal elements of marine and freshwater sponges have intrigued investigators with a diverse array of remarkably complex morphologies. Early studies of demosponge monaxonal megascleres revealed the presence of a central organic axial filament running their entire length. Until recently, however, the precise function of these axial filaments was largely unknown. The spicules from the temperate Eastern Pacific demosponge, Tethya aurantia, comprise ∼75% of the dry weight of this species, facilitating the large‐scale isolation and purification of the biosilica‐associated proteins. Silicateins, the most abundant proteins comprising the axial filaments of these spicules, prove to be members of a well‐known superfamily of proteolytic and hydrolytic enzymes and can be easily collected after silica demineralization with hydrofluoric acid. Consistent with these findings, the intact filaments are more than simple, passive templates; in vitro, they actively catalyze and spatially direct the hydrolysis and polycondensation of silicon alkoxides to yield silica at neutral pH and low temperature. Catalytic activity also is exhibited by the monomeric subunits obtained by disaggregation of the protein filaments and those produced from recombinant DNA templates cloned in bacteria. These proteins also can be used to direct the polymerization of organosilicon polymers (silicones) from the corresponding organically functionalized silicon alkoxides. Based on these observations, the silicateins are currently being used as models for the design of biomimetic agents with unique catalytic and structure‐directing properties. The presence of axial filaments in a diversity of spicule types and the evolutionary implications of these findings are also discussed. Microsc. Res. Tech. 62:356–367, 2003. © 2003 Wiley‐Liss, Inc.
Biochemistry and cell biology of silica formation in sponges
Authors: Müller Werner E.G. , Krasko Anatoli , Le Pennec Gaël , Schröder Heinz C. 
Published: October 2003

AbstractThe main inorganic material forming the skeletal elements in Demospongiae as well as in Hexactinellida, the spicules, is amorphous silica. The spicules occur in the cytoplasm and the extracellular space and also in the nucleus (as silicate crystals) of some sponge cells; the function in the latter compartment is unknown. Recent evidence shows that the formation of spicules is mediated by the enzyme silicatein. The cDNA as well as the gene encoding this enzyme was cloned from Suberites domuncula. The recombinant silicatein catalyzes the synthesis of amorphous silicate using tetraethoxysilane as substrate. The enzyme is dependent on ferric iron. Silicatein also has proteolytic (cathepsin‐like) activity. Incubation of primmorphs, a special form of 3D‐cell aggregates, with silicon resulted in a strong increase of their size from 1–7 mm to ∼10 mm. The morphogenetic activity of silicate is underscored by the finding that this ion increases gene expression of silicatein and collagen. Based on these findings, it is concluded that both iron and silicate stimulate the activity of silicatein. Furthermore, it is proposed that the growing spicules are surrounded by the scavenger receptor which might be considered as a docking molecule for the collagen matrix into which the spicules are embedded. Microsc. Res. Tech. 62:368–377, 2003. © 2003 Wiley‐Liss, Inc.