bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of occupational exposure to pesticides, polycyclic aromatic hydrocarbons, diesel exhaust, metal dust, metal fumes, and mineral oil on prostate cancer: a prospective cohort study
Authors: Boers D , Zeegers M P A , Swaen G M , Kant IJ , van den Brandt P A
Published: July 2005

Aims:To investigate the relation between exposure to pesticides, polycyclic aromatic hydrocarbons (PAHs), diesel exhaust, metal dust, metal fumes, and mineral oil in relation to prostate cancer incidence in a large prospective study.

Methods:This cohort study was conducted among 58 279 men in the Netherlands. In September 1986, cohort members (55–69 years) completed a self-administered questionnaire on potential cancer risk factors, including job history. Follow up for prostate cancer incidence was established by linkage to cancer registries until December 1995 (9.3 years of follow up). The analyses included 1386 cases of prostate cancer and 2335 subcohort members. A blinded case-by-case expert exposure assessment was carried out to assign cases and subcohort members a cumulative probability of exposure for each potential carcinogenic exposure.

Results:In multivariate analyses there was a significant negative association for pesticides (RR 0.60; 95% CI 0.37 to 0.95) when comparing the highest tertile of exposure to pesticides with no exposure. No association was found for occupational exposure to PAHs (RR 0.75; 95% CI 0.42 to 1.31), diesel exhaust (RR 0.81; 95% CI 0.62 to 1.06), metal dust (RR 1.01; 95% CI 0.72 to 1.40), metal fumes (RR 1.11; 95% CI 0.80 to 1.54), or mineral oil (RR 0.99; 95% CI 0.66 to 1.48) when comparing the highest tertile of exposure with no exposure. In subgroup analysis, with respect to tumour invasiveness and morphology, null results were found for occupational exposure to pesticides, PAH, diesel exhaust, metal dust, metal fumes, and mineral oil.

Conclusions:These results suggest a negative association between occupational exposure to pesticides and prostate cancer. For other carcinogenic exposures results suggest no association between occupational exposure to PAHs, diesel exhaust, metal dust, metal fumes, or mineral oil and prostate cancer.
Changes in hospitality workers’ exposure to secondhand smoke following the implementation of New York’s smoke-free law
Authors: Farrelly M C , Nonnemaker J M , Chou R , Hyland A , Peterson K K , Bauer U E
Published: July 2005

Objective:To assess the impact on hospitality workers’ exposure to secondhand smoke of New York’s smoke-free law that prohibits smoking in all places of employment, including restaurants, bars, and bowling facilities.

Design:Pre-post longitudinal follow up design.

Settings:Restaurants, bars, and bowling facilities in New York State.

Subjects:At baseline, 104 non-smoking workers in restaurants, bars, and bowling facilities were recruited with newspaper ads, flyers, and radio announcements. Of these, 68 completed a telephone survey and provided at least one saliva cotinine specimen at baseline. At three, six, and 12 month follow up studies, 47, 38, and 32 workers from the baseline sample of 68 completed a telephone survey and provided at least one saliva cotinine specimen.

Intervention:The smoke-free law went into effect 24 July 2003.

Main outcome measures:Self reported sensory and respiratory symptoms and exposure to secondhand smoke; self administered saliva cotinine specimens. Analyses were limited to subjects in all four study periods who completed a telephone survey and provided at least one saliva cotinine specimen.

Results:All analyses were limited to participants who completed both an interview and a saliva specimen for all waves of data collection (n  =  30) and who had cotinine concentrations ⩽ 15 ng/ml (n  =  24). Hours of exposure to secondhand smoke in hospitality jobs decreased from 12.1 hours (95% confidence interval (CI) 8.0 to 16.3 hours) to 0.2 hours (95% CI −0.1 to 0.5 hours) (p < 0.01) and saliva cotinine concentration decreased from 3.6 ng/ml (95% CI 2.6 to 4.7 ng/ml) to 0.8 ng/ml (95% CI 0.4 to 1.2 ng/ml) (p < 0.01) from baseline to the 12 month follow up. The prevalence of workers reporting sensory symptoms declined from 88% (95% CI 66% to 96%) to 38% (95% CI 20% to 59%) (p < 0.01); there was no change in the overall prevalence of upper respiratory symptoms (p < 0.16).

Conclusion:New York’s smoke-free law had its intended effect of protecting hospitality workers from exposure to secondhand smoke within three months of implementation. One year after implementation, the results suggest continued compliance with the law.
Public health measures to reduce smoking prevalence in the UK: how many lives could be saved?
Authors: Lewis S , Arnott D , Godfrey C , Britton J
Published: July 2005

Objective:To estimate the number of deaths that could be prevented in the UK by implementing population strategies to reduce smoking prevalence.

Design:A prospective analysis of future mortality using recent national smoking prevalence data and relative risks of mortality in current smokers, ex-smokers, and never-smokers.

Population:Smokers in the UK.

Interventions:Population measures of proven effectiveness assumed to reduce smoking prevalence by 1 percentage point per year for 10 years, or alternatively by 13% over 19 years (1 percentage point per annum for seven years, 0.5 percentage point per annum for 12 years) as considered to be achievable in a recent report to the UK Chancellor of the Exchequer.

Main outcome measure:Estimated deaths from smoking prevented in the 35–75 year age group.

Results:Reducing the prevalence of smoking by 1 percentage point each year for 10 years would prevent 69 049 deaths at ages between 35 and 74 years during that period. The model of reduction by 13% over 19 years would prevent 54 308 and 194 493 deaths in 10 and 19 years, respectively. Continued prevalence reductions at the current rate of 0.4 percentage points each year will prevent 23 192 deaths over 10 years.

Conclusions:Full implementation of simple population measures to encourage smoking cessation could prevent substantial numbers of deaths in the UK.
The perimetric boycott: a tool for tobacco control advocacy
Authors: Offen N , Smith E A , Malone R E
Published: July 2005

Objectives:To propose criteria to help advocates: (1) determine when tobacco related boycotts may be useful; (2) select appropriate targets; and (3) predict and measure boycott success.

Methods:Analysis of tobacco focused boycotts retrieved from internal tobacco industry documents websites and other scholarship on boycotts.

Results:Tobacco related boycotts may be characterised by boycott target and reason undertaken. Most boycotts targeted the industry itself and were called for political or economic reasons unrelated to tobacco disease, often resulting in settlements that gave the industry marketing and public relations advantages. Even a lengthy health focused boycott of tobacco industry food subsidiaries accomplished little, making demands the industry was unlikely to meet. In contrast, a perimetric boycott (targeting institutions at the perimeter of the core target) of an organisation that was taking tobacco money mobilised its constituency and convinced the organisation to end the practice.

Conclusions:Direct boycotts of the industry have rarely advanced tobacco control. Perimetric boycotts of industry allies offer advocates a promising tool for further marginalising the industry. Successful boycotts include a focus on the public health consequences of tobacco use; an accessible point of pressure; a mutual interest between the target and the boycotters; realistic goals; and clear and measurable demands.
Actin microfilament and microtubule distribution patterns in the expanding root ofArabidopsis thaliana
Authors: Collings David A , Wasteneys Geoffrey O
Published: July 2005

Determination of the precise role(s) of actin microfilaments in the control of cell shape and elongation in the root tips of the model genetic system Arabidopsis thaliana (L.) Heynh is frustrated by inadequate microscopy imaging techniques. In this paper, we documented both microfilaments and microtubules in the root tips of Arabidopsis by double immunofluorescence labelling and computer-generated reconstruction of confocal image series. Our procedure, which complements the use of recently developed fluorescent reporter proteins, revealed hitherto undescribed aspects of the Arabidopsis microfilament cytoskeleton that may provide important clues about mechanisms behind cell elongation. We found that preservation of extensive arrays of transverse cortical microfilaments depends on unperturbed microtubule organization. Compared with ordinary epidermal cells, cells situated in the trichoblast or hair-forming cell files were comparatively devoid of endoplasmic microfilaments when in the distal elongation zone, well before hair formation begins. Computer-aided reconstructions also revealed that the nonexpanding end walls of cells in the distal elongation zone have radially oriented microtubules and randomly arranged microfilaments. In dividing cells, microfilaments became more prominent in the cell cortex, and subtle differences between microtubule and microfilament organization were seen within the phragmoplast. These observations will form the basis of understanding the roles of the cytoskeleton in controlling elongation in root tissues. In light of the many Arabidopsis mutants with altered root morphology, our methods offer a reliable approach to assess the function of cytoskeletal proteins and signalling systems in root morphogenesis.Key words: actin microfilaments, Arabidopsis thaliana, distal elongation zone, microtubules, phragmoplast, roots.
External symptoms and histopathological changes following inoculation of elms putatively resistant to Dutch elm disease with genetically close strains of Ophiostoma
Authors: Et-Touil Abdelali , Rioux Danny , Mathieu Fabienne M , Bernier Louis
Published: July 2005

To better characterize the hostpathogen interaction leading to Dutch elm disease, pathogenicity tests were carried out under controlled conditions. Putative resistant hybrid clones 2213 and 2245 from the same Ulmus parvifolia Jacq. × Ulmus americana L. cross and putative resistant U. americana clone 503, as well as saplings of U. americana grown from seeds, were inoculated with strains of Ophiostoma ulmi (Buism.) Nannf. or Ophiostoma novo-ulmi Brasier, including strains H327 and AST27, which carry different alleles at the Pat1 pathogenicity locus and display different levels of aggressiveness. The occurrence of wilted leaves and xylem streaks in inoculated elms indicated that the three clones tested were in fact susceptible to Dutch elm disease, although clones 2213 and 2245 were less susceptible than other elm material tested. In addition to the usual histopathological changes induced during the development of Dutch elm disease on clones 2213 and 2245, such as the formation of alveolar structures, tyloses, gels, and barrier zones, microscopic observations also revealed the presence of cells exhibiting a yellow autofluorescence under blue illumination around xylem vessels invaded by the pathogen. This may represent a new defence reaction against Dutch elm disease. The more aggressive H327 strain induced different levels of xylem responses than the less aggressive AST27 strain.Key words: Dutch elm disease, vascular wilt, histopathology.
Numerical modeling of rising-head permeability tests in monitoring wells after lowering the water level down to the screen
Authors: Chapuis Robert P
Published: July 2005

To begin a rising-head permeability test in a monitoring well (MW), the water level is lowered in the pipe. If it is lowered down to the screen, the recovery graph may differ from the theoretical straight line, making it difficult to assess the mean field hydraulic conductivity. A numerical analysis (finite element method) of this type of test, considering the complete equations for saturated and unsaturated flow, is presented. The numerically obtained graphs are similar to those of real field tests. In an aquitard, when the filter pack is made of fine sand, which retains water by capillarity, the screen dewatering influence is hardly visible in the velocity graph and is undetected in the usual semilog graph. In an aquitard, when the filter pack cannot retain water by capillarity during dewatering, the semilog graph presents two straight-line portions. The velocity graph, a representation of the conservation equation, helps to distinguish the early time interval, when the groundwater fills the screen and the filter pack, and the later interval, when it fills only the pipe. The later portion of the graph must be used to calculate the hydraulic conductivity. In an unconfined aquifer, when there is no filter pack, dewatering down to the screen by pumping significantly lowers the water table around the MW. The usual semilog graph appears as a set of two straight lines. The velocity graph indicates that all calculations must consider a piezometric level that is lower than that measured before dewatering. In all cases, the velocity graph shows clearly what happened during the numerically simulated tests. The more complex case of an MW installed with a filter pack in an unconfined aquifer and tested using a mechanical slug was not numerically examined in this paper.Key words: hydraulic conductivity, rising head, monitoring well, numerical analysis.
A novel approach to estimating the bearing capacity stability of geosynthetic reinforced retaining walls constructed on yielding foundations
Authors: Skinner Graeme D , Rowe R Kerry
Published: July 2005

Yielding foundation conditions have been shown to adversely affect the stability and behaviour of overlying geosynthetic reinforced soil walls. To avoid serious problems and maintain a cost-effective design, careful consideration must be given to short-term stability. Previous research has shown that lengthening and stiffening the bottom reinforcement layer of the wall can increase the external stability, but the magnitude of this increase is not well understood. To provide insight regarding the potential benefit of lengthening and stiffening the bottom reinforcement layer, a numerical investigation is made of the plastic collapse mechanism due to bearing capacity failure of the foundation deposit for the case of a 6 m high geosynthetic reinforced retaining wall on a 10 m thick soft to firm visco plastic clay stratum. The calculated behaviour of the wall is compared with that from typical and novel design considerations for both a conventional reinforced wall and a wall where the bottom reinforcement layer has been extended and stiffened. A parametric study of the extended bottom reinforcement layer stiffness and interaction is reported, and the influence on the external stability is discussed.Key words: reinforced soil wall, soft yielding foundation, bearing capacity design, numerical analysis.
Influence de sollicitations hydriques et mécaniques complexes sur le comportement d'un sol gonflant compacté
Authors: Cuisinier Olivier , Masrouri Farimah
Published: July 2005

The main objective of the paper is to present a study on compacted expansive soil strains generated by complex hydric or mechanical loadings and their consequences on tested soil compressibility. In the first part of the paper, the suction-controlled testing devices are described (osmotic and salt solution methods). All the presented tests were performed in the range of suctions between 0 and 40 MPa. The consequences of the strains induced by wetting as a function of the applied mechanical stress were analyzed. The results showed that, under these conditions, strain depends on the followed hydraulic path, whereas the slope of the plastic compression line λ(s) was only affected by the suction applied during the mechanical loading. The second test series demonstrated that the stress path influenced both deformation and slope λ(s) if suction higher than the initial sample suction was imposed during the test. As a conclusion, it could be stated that the slope λ(s) depends on the suction applied during a mechanical loading and on the maximum suction experienced by an expansive material during its past "history".Key words: compacted soil, suction, hydric cycle, hydromechanical behaviour, expansive soil.
Computer simulation of the dynamic layered soilpilestructure interaction system
Authors: Lu Xilin , Li Peizhen , Chen Bo , Chen Yueqing
Published: July 2005

A three-dimensional finite element analysis of the soilpilestructure interaction system is presented in this paper. The analysis is based on data from shaking table model tests made in the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, China. The general finite element program ANSYS is used in the analysis. The surface-to-surface contact element is taken into consideration for the nonlinearity state of the soilpile interface, and an equivalent linear model is used for soil behavior. A comparison of the results of the finite element analysis with the data from the shaking table tests is used to validate the computational model. Furthermore, the reliability of the test result is also verified by the simulation analysis. It shows that separation, closing, and sliding exist between the pile foundation and the soil. The distribution of the amplitude of strains in the pile, the amplitude of contact pressure, and the amplitude of sliding at the soilpile interface are also discussed in detail in this paper.Key words: soilpilestructure interaction, shaking table model test, computer simulation, ANSYS program.
Initiation of static liquefaction and the role ofK0consolidation
Authors: Fourie A B , Tshabalala L
Published: July 2005

The potential for static liquefaction of hydraulically placed sands and silts is now well recognised. A particular category of this type of operation, tailings disposal facilities constructed using the upstream method, has come under increased scrutiny due to the large number of failures of these structures. Although the conditions that render a particular deposit susceptible to potential liquefaction are now well known, being a combination of void ratio and mean effective stress that places the material state above its steady state value, the same cannot be said about our ability to predict the stresses at which liquefaction will be initiated. The concept of a collapse surface, derived from the locus of peak shear stress values from undrained compression tests on isotropically consolidated specimens, attempts to provide a method for predicting the onset of liquefaction. As confirmed in this paper, however, application of the collapse surface concept to actual tailings dam facilities results in factors of safety based on an effective stress approach that are significantly less than unity for facilities that have not failed. On the other hand, shear strength values derived from ultimate state conditions are unconservative, predicting factors of safety significantly in excess of unity for facilities that have failed. A comparison of monotonic undrained triaxial compression tests on both isotropically- and K0-consolidated specimens of gold tailings suggests that the resolution to this dilemma lies in the recognition that a kinematic yield surface, which is a function of the consolidation stress path followed, develops in stress space. The collapse surface derived from undrained loading of K0-consolidated loose specimens is shown to provide a greatly improved capacity for predicting the onset of liquefaction under undrained loading conditions.Key words: static liquefaction, tailings, collapse surface, anisotropic.
Quick clay from the Mink Creek landslide near Terrace, British Columbia: Geotechnical properties, mineralogy, and geochemistry
Authors: Geertsema Marten , Torrance J Kenneth
Published: July 2005

A flowslide involving more than 2.5 million m3 of sensitive glaciomarine sediment occurred near Terrace, British Columbia (54° 27′ N, 128° 37′ W) sometime between 1 December 1993 and 9 January 1994. Geotechnical measurements confirm the presence of quick clay at the site; mineralogical and geochemical investigations reveal its similarities to the quick clays in eastern Canada, Scandinavia, and Japan.Key words: quick clay, flowslide, glaciomarine sediment, rheology, British Columbia.
CHARACTERISTICS OF ISOTOPE EFFECT AND DOUBLE-BODY STRUCTURE MODEL
Authors: CHEN YU , HUANG XINMIN , FU MING XING , WANG JIANWU
Published: July 2005

The characteristics of the oxygen-isotope effect (16 O /18 O ) are studied with the double-body structure physical model in high-Tc copper oxide superconductors. With the double-body structure physical model, some reasonable explanations are given to the phenomena of high-Tc copper oxide superconductor's isotope effect, weak isotope effect, and abnormal isotope effect.
VIBRATION SPECTRA OF DISORDERED CRYSTALLINE SURFACE CLUSTER
Authors: TIGRINE R. , KHATER A. , RAFIL O. , BELHADI M.
Published: July 2005

A method is presented for the determination of the energies of the localized vibration modes around isolated inhomogeneity, inside a square crystalline surface. The defect breaks the translational symmetry in two directions and gives rise to localized phonons on its neighborhood. Typical dispersion curves for modes of energies along the inhomogeneity are given with their polarizations. These localized modes energies are compared with the vibration modes of the free molecule. The vibration Green's functions are determined for the system and the spectral and state densities are presented numerically for atomic sites that constitute a minimum representation set in the neighborhood of the defect. A hyperfine resonance structure that permits the analysis of the evolution of the dynamics from half-space to others is obtained. This analytic approach is applicable to different surface cluster configurations for the same underlying substrate square symmetry in the present model, which underlies the general character of the method.
THE DOPPLER FACTORS AT X-RAY BAND OF THE BLAZARS
Authors: MEI D. C. , ZHANG L.
Published: July 2005

We study the Doppler factors for a group blazars at soft X-ray band. In our estimates, we have made the assumptions that (i) blazars can be divided into high-energy-peaked (HEP) objects whose synchrotron peak frequencies νp > 1014.7 Hz , and the low-energy-peaked (LEP) objects whose synchrotron peak frequencies νp≤1014.7 Hz , and (ii) the intrinsic radiation from a blazar in the energy range from radio to soft X-ray bands is the synchrotron radiation for HEP objects and the soft X-ray emission comes from inverse Compton scattering for LEP objects. Under the above assumptions, we estimate Doppler factors at optical (δO) and X-rays (δx) for 54 blazars by using the known radio Doppler factors and the observed flux densities in radio, optical and X-ray bands, and Doppler factors [Formula: see text] at X-ray band in which X-rays are assumed to be produced only by the synchrotron radiation. We get [Formula: see text] . The Doppler factors are different in various wavebands, and on average, the Doppler factor decreases with frequency from radio to X-ray bands.
THE FATE OF THE FALSE VACUUM IN EINSTEIN GRAVITY THEORY WITH NONMINIMALLY-COUPLED SCALAR FIELD
Authors: LEE WONWOO , LEE CHUL H.
Published: July 2005

The decay of false vacuum via the true vacuum bubble nucleation has been explored in Einstein theories of gravity with nonminimally-coupled scalar field using Coleman–De Luccia's semiclassical instanton approximation. In this case the false vacuum decay rates and the radius of the bubbles in Coleman's thin-wall approximation have been computed analytically and numerically with several values of nonminimal coupling constant and compared with the standard result obtained by Coleman–De Luccia in the context of scalar field minimally-coupled to Einstein gravity.
Kidneys extract BNP and NT-proBNP in healthy young men
Authors: Schou Morten , Dalsgaard Mads K. , Clemmesen Otto , Dawson Ellen A. , Yoshiga Chie C. , Nielsen Henning B. , Gustafsson Finn , Hildebrandt Per R. , Secher Niels H.
Published: July 2005

Renal metabolism of the cardiac marker NH2-terminal-pro-brain natriuretic peptide (NT-proBNP) has been suggested. Therefore, we determined the renal extraction ratios of NT-proBNP and its bioactive coproduct brain natriuretic peptide (BNP) at rest and during exercise. In addition, the cerebral ratios were evaluated. Ten young healthy men were investigated at baseline, during moderate cycle exercise (heart rate: 140, Borg scale: 14–15), and in the recovery with BNP and NT-proBNP measured from the brachial artery and the jugular and renal veins, and the renal and cerebral extraction ratios (Ext-Ren and Ext-Cer, respectively) were calculated. Cardiac output, stroke volume, heart rate, mean arterial pressures, and estimated glomerular filtration were determined. BNP and NT-proBNP were extracted by the kidneys but not by the brain. We observed no effect of exercise. The mean values (± SE) of Ext-Ren of NT-proBNP were similar (0.19 ± 0.05, 0.21 ± 0.06, and 0.12 ± 0.03, respectively) during the three sessions ( P > 0.05). Also the Ext-Ren of BNP were similar (0.18 ± 0.07, 0.15 ± 0.11, and 0.14 ± 0.06, respectively; P > 0.05). There were no significant differences between Ext-Ren of BNP and NT-proBNP during the three sessions ( P > 0.05). The Ext-Cer of both peptides varied insignificantly between −0.21 ± 0.15 and 0.11 ± 0.08. The renal extraction ratio of both BNP and NT-proBNP is ∼0.15–0.20. There is no cerebral extraction, and short-term moderate exercise does not affect these values. Our findings suggest that the kidneys extract BNP and NT-proBNP to a similar extent in healthy young men.
Reverse transcription in genome evolution
Authors: Mourier T.
Published: July 2005

As reverse transcription is predominantly performed by retrotransposable elements, the process is often entirely associated with the propagation of these elements. However, as a unique tool for transmitting information from the dynamic RNA to the more inert DNA, reverse transcription has been instrumental in shaping extant genomes. This review aims at presenting the diversity by which reverse transcription has influenced modern genomic structures.
Genome evolution mediated by Ty elements in Saccharomyces
Authors: Garfinkel D.J.
Published: July 2005

How mobile genetic elements molded eukaryotic genomes is a key evolutionary question that gained wider popularity when mobile DNA sequences were shown to comprise about half of the human genome. Although Saccharomyces cerevisiae does not suffer such “genome obesity”, five families of LTR-retrotransposons, Ty1, Ty2, Ty3, Ty4, and Ty5 elements, comprise about 3% of its genome. The availability of complete genome sequences from several Saccharomyces species, including members of the closely related sensu stricto group, present new opportunities for analyzing molecular mechanisms for chromosome evolution, speciation, and reproductive isolation. In this review I present key experiments from both the pre- and current genomic sequencing eras suggesting how Ty elements mediate genome evolution.
Polymorphic Alu insertions within the Major Histocompatibility Complex class I genomic region: a brief review
Authors: Kulski J.K. , Dunn D.S.
Published: July 2005

Most polymorphic Alu insertions (POALINs) belong to a subgroup of the Alu multicopy retrotransposon family of short interspersed nucleotide elements (SINEs) that are categorized as AluYb8 and AluYa5. The number of AluYb8/AluYa5 members (∼4,492 copies) is significantly less than the ∼one million fixed Alu copies per human genome. We have studied the presence of POALINs within the Major Histocompatibility Complex (MHC) class I region on the short arm of chromosome 6 (6p21.3) because this region has a high gene density, many genes with immune system functions, large sequence variations and diversity, duplications and redundancy, and a strong association with more than 100 different diseases. Since little is known about POALINs within the MHC genomic region, we undertook to identify some of the members of the AluYb8/AluYa5 subfamily and to study their frequency of distribution and genetic characteristics in different populations. As a result of our comparative genomic analyses, we identified the insertion sites for five POALINs distributed within the MHC class I region. This brief review outlines the locations of the insertions and sequence features of the five MHC POALINs, their single site and haplotype frequencies in different geographic populations, and their association with different HLA class I genes and disease. We show that the MHC POALINs have a potential value as lineage and linkage markers for the study of human population genetics, disease associations, genomic diversity and evolution.
Stress activation and genomic impact of Tnt1 retrotransposons in Solanaceae
Authors: Grandbastien M.-A. , Audeon C. , Bonnivard E. , Casacuberta J.M. , Chalhoub B. , Costa A.-P.P. , Le Q.H. , Melayah D. , Petit M. , Poncet C. , Tam S.M. , van Sluys M.-A. , Mhiri C.
Published: July 2005

Tnt1 elements are a superfamily of LTR-retrotransposons distributed in the Solanaceae plant family and represent good model systems for studying regulatory and evolutionary controls established between hosts and transposable elements. Tnt1 retrotransposons tightly control their activation, by restricting expression to specific conditions. The Tnt1A element, originally discovered in tobacco, is expressed in response to stress, and its activation by microbial factors is followed by amplification, demonstrating that factors of pathogen origin can generate genetic diversity in plants. The Tnt1A promoter has the potential to be activated by various biotic and abiotic stimuli but a number of these are specifically repressed in tobacco and are revealed only when the LTR promoter is placed in a heterologous context. We propose that a tobacco- and stimulus-specific repression has been established in order to minimize activation in conditions that might generate germinal transposition. In addition to tight transcriptional controls, Tnt1A retrotransposons self-regulate their activity through gradual generation of defective copies that have reduced transcriptional activity. Tnt1 retrotransposons found in various Solanaceae species are characterized by a high level of variability in the LTR sequences involved in transcription, and have evolved by gaining new expression patterns, mostly associated with responses to diverse stress conditions. Tnt1A insertions associated with genic regions are initially favored but seem subsequently counter-selected, while insertions in repetitive DNA are maintained. On the other hand, amplification and loss of insertions may result from more brutal occurrences, as suggested by the large restructuring of Tnt1 populations observed in tobacco compared to each of its parental species. The distribution of Tnt1 elements thus appears as a dynamic flux, with amplification counterbalanced by loss of insertions. Tnt1 insertion polymorphisms are too high to reveal species relationships in the Nicotiana genus, but can be used to evaluate species relationships in the Lycopersicon and Capsicum genera. This also demonstrates that the behavior of Tnt1 retrotransposons differs between host species, most probably in correlation to differences in expression conditions and in the evolutionary and environmental history of each host.
A family of neofunctionalized Ty3/gypsy retrotransposon genes in mammalian genomes
Authors: Brandt J. , Veith A.M. , Volff J.-N.
Published: July 2005

A family of at least eleven genes called Mar related to long terminal repeat retrotransposons from the Ty3/gypsy group, including two genes previously identified as such, is present in human and mouse genomes. Single orthologous copies were identified for most Mar genes in different mammals. All of them have lost essential structural features necessary for autonomous retrotransposition before divergence between mouse and human. Three Mar genes also have introns at identical positions in human and mouse. Hence, Mar genes do not correspond to functional retrotransposons. Mar genes evolved under purifying selection, strongly suggesting that they are not pseudogenic relics but rather neofunctionalized retrotransposon genes. All putative Mar proteins display sequence similarity to the capsid-like domain of the Gag protein of Tf1/Sushi retrotransposons. In addition, three Mar proteins have conserved the Gag CCHC zinc finger motif, suggesting a role in nucleic acid binding. Some Mar genes have also retained from their retrotransposon origin a –1 ribosomal frameshifting between the gag-related open reading frame and a region encoding a putative aspartyl protease domain. EST analysis revealed that the majority of Mar genes are expressed in brain as well as in other tissues and organs. Some Mar proteins might function as transcription factors or be involved in the control of cell proliferation and apoptosis. Strikingly, as many as eight Mar genes are located on the X chromosome in human, mouse and other mammals, and at least two of the autosomal genes are subject to imprinting. We suggest that retrotransposons might be a source for epigenetically regulated genes. Epigenetic regulation of these neogenes might be derived from the cellular defense mechanisms having controlled their retrotransposon ancestor.
Transposable elements donate lineage-specific regulatory sequences to host genomes
Authors: Mariño-Ramírez L. , Lewis K.C. , Landsman D. , Jordan I.K.
Published: July 2005

The evolutionary implications of transposable element (TE) influences on gene regulation are explored here. An historical perspective is presented to underscore the importance of TE influences on gene regulation with respect to both the discovery of TEs and the early conceptualization of their potential impact on host genome evolution. Evidence that points to a role for TEs in host gene regulation is reviewed, and comparisons between genome sequences are used to demonstrate the fact that TEs are particularly lineage-specific components of their host genomes. Consistent with these two properties of TEs, regulatory effects and evolutionary specificity, human-mouse genome wide sequence comparisons reveal that the regulatory sequences that are contributed by TEs are exceptionally lineage specific. This suggests a particular mechanism by which TEs may drive the diversification of gene regulation between evolutionary lineages.
Mobile genetic elements and sexual reproduction
Authors: Arkhipova I.R.
Published: July 2005

Transposable elements (TE) are prominent components of most eukaryotic genomes. In addition to their possible participation in the origin of sexual reproduction in eukaryotes, they may be also involved in its maintenance as important contributors to the deleterious mutation load. Comparative analyses of transposon content in the genomes of sexually reproducing and anciently asexual species may help to understand the contribution of different TE classes to the deleterious load. The apparent absence of deleterious retrotransposons from the genomes of ancient asexuals is in agreement with the hypothesis that they may play a special role in the maintenance of sexual reproduction and in early extinction for which most species are destined upon the abandonment of sex.
Repbase Update, a database of eukaryotic repetitive elements
Authors: Jurka J. , Kapitonov V.V. , Pavlicek A. , Klonowski P. , Kohany O. , Walichiewicz J.
Published: July 2005

Repbase Update is a comprehensive database of repetitive elements from diverse eukaryotic organisms. Currently, it contains over 3600 annotated sequences representing different families and subfamilies of repeats, many of which are unreported anywhere else. Each sequence is accompanied by a short description and references to the original contributors. Repbase Update includes Repbase Reports, an electronic journal publishing newly discovered transposable elements, and the Transposon Pub, a web-based browser of selected chromosomal maps of transposable elements. Sequences from Repbase Update are used to screen and annotate repetitive elements using programs such as Censor and RepeatMasker. Repbase Update is available on the worldwide web at http://www.girinst.org/Repbase_Update.html.
Retrons, msDNA, and the bacterial genome
Authors: Lampson B.C. , Inouye M. , Inouye S.
Published: July 2005

Retrons are distinct DNA sequences that code for a reverse transcriptase (RT) similar to the RTs produced by retroviruses and other types of retroelements. Retron DNAs are commonly associated with prophage DNA and are found in the genomes of a wide variety of different bacteria. The retron RT is used to synthesize a strange satellite DNA known as msDNA. msDNA is actually a complex of DNA, RNA, and probably protein. It is composed of a small, single-stranded DNA, linked to a small, single-stranded RNA molecule. The 5′ end of the DNA molecule is joined to an internal guanosine residue of the RNA molecule by a unique 2′-5′ phosphodiester bond. msDNA is produced in many hundreds of copies per cell, but its function remains unknown. Although retrons are absent from the genome of most members of a population of related bacteria, retrons may not be entirely benign DNAs. Evidence is beginning to suggest that retron elements may produce small but potentially significant effects on the host cell. This includes the generation of repeated copies of the msDNA sequence in the genome, and increasing the frequency of spontaneous mutations. Because these events involve the retron RT, this may represent a source of reverse transcription in the bacterial cell. Thus, the process of reverse transcription, a force that has profoundly affected the content and structure of most eukaryotic genomes, may likewise be responsible for changes in some prokaryotic genomes.
The evolution of transposons in Schizosaccharomyces pombe
Authors: Kelly F.D. , Levin H.L.
Published: July 2005

Recent studies of the LTR-retrotransposons of Schizosaccharomyces pombe have shed considerable light on their evolution and function. The sequencing of the S. pombe genome allowed analysis of its transposon content. This analysis provides information about the maintenance and loss of transposons in the genome. The results of transposition assays and biochemical analyses demonstrate that the N-terminal protein of Tf1 is functionally equivalent to the Gag proteins of retroviruses and retrotransposons. Despite this conservation of function, the N-terminal protein of Tf1 lacks any sequence similarity to other known Gag proteins. Sequence analysis and experimental data also indicate that the Tf1 transposons of S. pombe target their integration into specific sites in the host genome. Transposition events resulting from the expression of Tf1 reveal a strong preference for intergenic regions, specifically at pol II promoters in a window 100–400 bp upstream of open reading frames. The complete and partial copies of Tf transposons in the sequenced genome of S. pombe show the same association of integration with promoter regions. This body of work explores how the transposon interacts with the host, the balance between the transposons propagation and loss, and how different families of transposons evolve.
Working-Class Children’s Experience through the Prism of Personal Storytelling
Authors: Miller Peggy J. , Cho Grace E. , Bracey Jeana R.
Published: July 2005

Framed within recent developments in genre theory, this paper examines personal storytelling as practiced by working-class children and their families. Although both working-class and middle-class children encounter versions of oral storytelling that embody a personal perspective, these versions privilege different slants on experience. Drawing on a program of research that spans several decades and two European American working-class communities, we attempt to characterize the working-class slant on its own terms, not simply as a departure from a middle-class standard. We conclude that the working-class slant encourages children to see that they have the right and resources to narrate their own experiences in self-dramatizing ways, but that the right to be heard and to have one’s point of view accepted cannot be taken for granted.
Endoscopic Enucleation of Leiomyoma of the Bladder
Authors: Ninan Andrews C. , St.Luce Serena , Kimberl I.Jane , Petros John A. , Issa Muta M.
Published: July 2005

A case of benign leiomyoma of the urinary bladder was discovered incidentally and treated successfully with endoscopic enucleation. We describe the technique of this new surgical approach and discuss its advantages. We recommend this minimally invasive approach over open surgical resection.
Effect of Acute Alcohol Intake on Prostate Tissue and Serum PSA-Like Protein Levels in Rats
Authors: Gumus Eyup , Solakoglu Seyhun , Mutus Rıfat , Altay Bulent , Kiziler Ali Riza , Miroglu Cengiz
Published: July 2005

Objective: To investigate both the possible changes induced by acute alcohol intake on prostate tissue at the ultrastructural level and its effect on serum prostate-specific-antigen (PSA)-like protein levels in rats. Materials and Methods: 44 male Wistar rats were included in the study in four separate groups; 7 treatment and 4 control animals were selected for each group. The treatment group received 40% ethanol (6 g/kg) while the control group was injected with the same dose of intraperitoneal isotonic saline. The first group was sacrificed after 3 h, the second group after 24 h, the third group after 72 h and the fourth group on day 7. Samples were examined by light and Jeol-100 electron microscope. Total serum PSA-like protein levels were determined by a Tosoh immunoenzymometric analyzer AIA 600. Results: In groups 1–3, electron microscopy showed dilatations in the endoplasmic reticulum cisternae of prostatic acinar cells, disarrangements in apparent Golgi complex and apertures belonging to the basal labyrinth. It was also observed that there was a mass of debris cells inside the acinar lumen, and the secretory epithelium was detached from the basal membrane in some places. No pathology was found in group 4 by light and electron microscopy. In group 1, significant levels of increased serum total PSA-like protein were found compared to controls and other treatment groups (p = 0.006). Conclusions: The fundamental effect of acute alcohol intake on prostate tissue was observed in intermediate stages participating in the exocrine secretion process in the cellular organelles. At the same time, this influences the levels of serum PSA-like protein.
Testicular Granulocytic Sarcoma without Systemic Leukemia
Authors: Lagerveld B.W. , Wauters C.A.P. , Karthaus H.F.M.
Published: July 2005

This case report describes a unilateral testicular granulocytic sarcoma or chloroma. Because of the relatively immature nature of the tumor cells, the histological diagnosis can be difficult. Granulocytic sarcomas are well known in patients with systemic leukemia and can sometimes precede a systemic leukemic outcome. A solitary granulocytic sarcoma not followed by a hematological proliferation of the myelocytic stem cells is very rare. No prognostic factors that are able to predict a systemic outcome are known. Therefore, in this case with no signs of systemic disease, we adopted a wait-and-see policy after radical orchidectomy. Up to now, after a follow-up period of 7 years, the patient is still free of disease. Diagnosis and therapy of this urologic disease are discussed and the literature is reviewed.
Perinatal Hypoxic-Ischemic Brain Damage: Evolution of an Animal Model
Authors: Vannucci Robert C. , Vannucci Susan J.
Published: July 2005

Early research in the Vannucci laboratory prior to 1981 focused largely on brain energy metabolism in the developing rat. At that time, there was no experimental model to study the effects of perinatal hypoxia-ischemia in the rodent, despite the tremendous need to investigate the pathophysiology of perinatal asphyxial brain damage in infants. Accordingly, we developed such a model in the postnatal day 7 rat, using a modification of the Levine preparation in the adult rat. Rat pups underwent unilateral common carotid artery ligation followed by exposure to systemic hypoxia (8% oxygen) at a constant temperature of 37°C. Brain damage, seen histologically, was generally confined to the cerebral hemisphere ipsilateral to the arterial occlusion, and consisted of selective neuronal death or infarction, depending on the duration of the systemic hypoxia. Tissue injury was observed in the cerebral cortex, hippocampus, striatum, and thalamus. Subcortical and periventricular white matter injury was also observed. This model was originally described in the Annals of Neurology in 1981, and during the more than 20 years since that publication numerous investigations utilizing the model have been conducted in our laboratories as well as laboratories around the world. Cerebral blood flow and metabolic correlates have been fully characterized. Physiologic and pharmacologic manipulations have been applied to the model in search of neuroprotective strategies. More recently, molecular biologic alterations during and following the hypoxic-ischemic stress have been ascertained and the model has been adapted to the immature mouse for specific use in genetically altered animals. As predicted in the original article, the model has proven useful for the study of the short- and long-term effects of hypoxic-ischemic brain damage on motor activity, behavior, seizure incidence, and the process of maturation in the brain and other organ systems.
Induction of Reproducible Focal Ischemic Lesions in Neonatal Mice by Photothrombosis
Authors: Maxwell Kimberley A. , Dyck Richard H.
Published: July 2005

Focal stroke during the perinatal and neonatal period is a significant cause of cognitive and behavioral deficits. Currently, the number of models available to study neonatal brain injury is limited and many are technically difficult to induce in neonatal rodents. We demonstrate a reproducible method to induce a focal ischemic injury in the cerebral cortex of neonatal mice that utilizes the principle of photothrombosis. Postnatal day 7 pups were anesthetized and systemically administered rose bengal (50 mg/kg). Permanent focal ischemia was induced in the medial frontal cortex and somatosensory cortex by irradiating surface blood vessels with a laser (532 nm). By placing a mask having an aperture of defined shape and size on the skull surface, we were able to reliably and reproducibly induce infarcts in discretely defined cortical regions. Further, we demonstrate explicit control of infarct volume by modifying the duration of laser exposure. This tool will provide a means for researchers to safely, easily and noninvasively induce reproducible ischemic lesions in specified regions of the neonatal cortex.
Strain Variability, Injury Distribution, and Seizure Onset in a Mouse Model of Stroke in the Immature Brain
Authors: Comi Anne M. , Johnston Michael V. , Wilson Mary Ann
Published: July 2005

Neonatal stroke is an important cause of neurologic morbidity and cerebral palsy. Recently, we have determined that in postnatal day 12 CD1 mice unilateral carotid ligation alone results in seizures and brain injury. We have shown that, in this model, seizure scores correlate with brain injury scores. We have applied this model to another strain of mice to assess strain-related differences in vulnerability to seizures and brain injury after unilateral carotid ligation. Under isoflurane anesthesia, unilateral right-sided carotid ligation was performed in postnatal day 12 C3HeB/FeJ mice followed by a 4-hour period of observation in a 35°C incubator. Seizure scores and brain jury scores were assigned and compared to scores in mice receiving sham surgery. Timing of seizure onset and regional distribution of brain injury were compared in the CD1 and C3HeB/FeJ mice. Unilateral carotid ligation in postnatal day 12 C3HeB/FeJ mice resulted in seizure behavior and brain injury in some animals, with similar time to seizure onset and regional injury distribution, but affected a significantly smaller percentage of C3HeB/FeJ pups than that observed in postnatal day 12 CD1 mice, indicating strain-related vulnerability in this model.