bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of vitamin D receptor gene polymorphisms in Chinese patients with generalized aggressive periodontitis
Authors: Li S. , Yang M. H. , Zeng C. A. , Wu W. L. , Huang X. F. , Ji Y. , Zeng J. Q.
Published: January 2008

Background and Objective:  The clinical features suggest that genetic factors may have a strong influence on susceptibility to aggressive periodontitis. The aim of this study was to investigate the association of vitamin D receptor gene polymorphisms with generalized aggressive periodontitis in Chinese patients.

Material and Methods:  A restriction fragment length polymorphism (RFLP) for 10,438,141 C to T (rs1544410, BsmI), 10,382,063 A to G (rs731236, TaqI), 10,382,143 C to A (rs7975232, ApaI) and 10,416,201 A to G (rs2228570, FokI) of vitamin D receptor gene was analysed by polymerase chain reaction, followed by digestion with restriction enzymes and gel electrophoresis. The genotypes of 51 generalized aggressive periodontitis patients and 53 periodontally healthy control subjects were analysed. The genotypic and allelic frequencies of each polymorphism site for the patients and control subjects were compared.

Results:  The distribution of vitamin D receptor FokI genotypes and alleles between the two groups was significantly different (p = 0.043 and p = 0.012, respectively). The F allele seemed to increase the susceptibility of aggressive periodontitis (odds ratio = 2.02, 95% confidence interval = 1.16–3.50) in Chinese patients. There was no significant difference in the genotype distribution or the allele frequencies of vitamin D receptor BsmI, ApaI and TaqI between two groups.

Conclusion:  The study indicates that FokI polymorphism of vitamin D receptor gene might be associated with generalized aggressive periodontitis in Chinese patients. In addition, the carriage of F allele increases the risk of developing generalized aggressive periodontitis.
Reattachment of Anterior Teeth Fragments: A Conservative Approach
Authors: MACEDO GEORGIA V. , DIAZ PATRICIA I. , DE O. FERNANDES CARLOS AUGUSTO , RITTER ANDRÉ V.
Published: January 2008

Coronal fractures of the anterior teeth are a common form of dental trauma that mainly affects children and adolescents. One of the options for managing coronal tooth fractures when the tooth fragment is available and there is no or minimal violation of the biological width is the reattachment of the dental fragment. Reattachment of fractured tooth fragments can provide good and long‐lasting esthetics (because the tooth’s original anatomic form, color, and surface texture are maintained). It also restores function, provides a positive psychological response, and is a relatively simple procedure. Patient cooperation and understanding of the limitations of the treatment is of utmost importance for good prognosis. This article reports on two coronal tooth fracture cases that were successfully treated using tooth fragment reattachment.

CLINICAL SIGNIFICANCE

Reattachment of fractured tooth fragments offers a viable restorative option for the clinician because it restores tooth function and esthetics with the use of a very conservative and cost‐effective approach.

(J Esthet Restor Dent 20:5–20, 2008)
Implant Replacement of the Maxillary Central Incisor Utilizing a Modified Ceramic Abutment (Thommen SPI ART) and Ceramic Restoration
Authors: SCHNEIDER ROBERT
Published: January 2008

The prosthetic restoration of a missing anterior tooth with a dental implant is a challenge. Treatment coordination with a multidisciplinary team is critical in the successful outcome of this type of patient treatment. Newer surgical treatment modalities in the management of hard and soft tissues are becoming common, with very good predictability and long‐term stability. Additionally, the use of advanced dental technology and materials such as sintered zirconium allows the restorative practitioner the opportunity to fabricate an esthetic, precise‐fitting, biocompatible, and strong definitive prosthesis for the patient, with good longevity.

CLINICAL SIGNIFICANCE

The use of an all‐ceramic abutment and restoration is described, along with the “soft tissue sculpting” procedure through the use of a custom provisional restoration. The relative ease and convenience of the procedure is also illustrated.

(J Esthet Restor Dent 20:21–28, 2008)
Long‐Term Antibacterial Effects and Physical Properties of a Chlorhexidine‐Containing Glass Ionomer Cement
Authors: TÜRKÜN L. S¸EBNEM , TÜRKÜN MURAT , ERTUG˘RUL FAHINUR , ATES¸ MUSTAFA , BRUGGER STEFAN
Published: January 2008

Statement of the Problem:  Many regions in the world do not have electricity, water, or access to dental facilities that allows the treatment of caries with dental handpieces and rotary burs. For restorative techniques used in these regions, an antibacterial self‐adherent glass ionomer material would contribute considerably.

Purpose:  This study aimed to test if chlorhexidine diacetate (Fluka BioChemika, Buchs, Switzerland)‐ or chlorhexidine digluconate (Sigma‐Aldrich, Steinheim, Germany)‐added ChemFil Superior glass ionomer cement (Dentsply DeTrey, Konstanz, Germany) had any long‐term antibacterial effect against certain oral bacteria and to test the new formulation’s physical properties.

Materials and Methods:  ChemFil Superior was used as a control. Chlorhexidine diacetate (powder) was added to the powder and chlorhexidine digluconate (liquid) was mixed with the powder in order to obtain 0.5, 1.25, and 2.5% concentrations of the respective groups. Setting time, compressive strength, and acid erosion were tested according to ISO 9917‐1. Working time, hardness, diametral tensile strength, and biaxial flexural strength were also determined. Long‐term antimicrobial activity against S. mutans, L. acidophilus, and C. albicans were tested with the agar diffusion method. Analysis of variance (ANOVA) was used for comparison (p < 0.05).

Results:  Regarding the immediate antibacterial effect for S. mutans, all the tested groups showed inhibitions of the strain compared with the control group (p < 0.05), with larger zones for the higher concentration groups and all the diacetates. For L. acidophilus, all the groups were effective compared with the control, but the greatest antibacterial effect was observed with the 2.5% diacetate group. The 2.5% group of chlorhexidine diacetate showed antibacterial activity up to 90 days against S. mutans and up to 60 days against L. acidophilus. The working and setting time, acid erosion test, diametral tensile strength, and biaxial flexural strength of the tested groups were not different from the control ChemFil group. However, the 1.25 and 2.5% groups of chlorhexidine diacetate had significantly lower compressive strengths than the control group. Lower hardness values were obtained with the 0.5 and 2.5% chlorhexidine digluconate groups in comparison with the control group.

CLINICAL SIGNIFICANCE

The results of this in vitro investigation demonstrated that chlorhexidine diacetate or digluconate added to the ChemFil Superior glass ionomer material can exhibit long‐term antibacterial effects against S. mutans and L. acidophilus without compromising the physical properties of the material.

(J Esthet Restor Dent 20:29–45, 2008)
Cytochrome b6f is a dimeric protochlorophyll a binding complex in etioplasts
Authors: Reisinger Veronika , Hertle Alexander P. , Plöscher Matthias , Eichacker Lutz A.
Published: January 2008

The cytochrome b6f complex is a dimeric protein complex that is of central importance for photosynthesis to carry out light driven electron and proton transfer in chloroplasts. One molecule of chlorophyll a was found to associate per cytochrome b6f monomer and the structural or functional importance of this is discussed. We show that etioplasts which are devoid of chlorophyll a already contain dimeric cytochrome b6f. However, the phytylated chlorophyll precursor protochlorophyll a, and not chlorophyll a, is associated with subunit b6. The data imply that a phytylated tetrapyrrol is an essential structural requirement for assembly of cytochrome b6f.
Polymorphism of the interleukin‐10 gene in polycystic ovary syndrome
Authors: Karadeniz M. , Erdogan M. , Zengi A. , Tamsel S. , Berdeli A. , Saygili F. , Yilmaz C.
Published: January 2008

Interleukin (IL)‐10 is a major anti‐inflammatory cytokine that has been associated with obesity and type 2 diabetes. We aimed to evaluate the IL‐10 gene polymorphisms in polycystic ovary syndrome (PCOS) and control subjects. Ninety‐one young women with PCOS and 74 healthy control women were included in our study. All subjects underwent venous blood drawing for complete hormonal assays, lipid profile, glucose, insulin and IL‐10 gene polymorphism genetic analysis and carotid intimae media thickness (CIMT) were measured. The genotype and allele frequencies showed similar ratios between both the control and the patient group. The AA and AG genotypes in IL‐10 polymorphism seemed to be relatively high, but statistically no significant difference has been detected in GG genotype. Our results show that IL‐10 gene polymorphism of PCOS patients has no effect on inflammatory markers, metabolic parameters (fasting insulin, fasting glucose, HOMA‐IR), carotid intimae media thickness and Ferriman‐ Gallwey scoring. These data will be different in PCOS patients with different ethnical origin.
Aspherical supernova explosions and formation of compact black hole low-mass X-ray binaries
Authors: Li Xiang-Dong
Published: January 2008

It has been suggested that black hole low-mass X-ray binaries (BHLMXBs) with short orbital periods may have evolved from BH binaries with an intermediate-mass secondary, but the donor star seems to always have higher effective temperatures than measured in BHLMXBs. Here we suggest that the secondary star is originally an intermediate-mass (∼2–5 M⊙) star, which loses a large fraction of its mass due to the ejecta impact during the aspherical suparnova explosion that produced the BH. The resulted secondary star could be of low mass (≲1 M⊙). Magnetic braking would shrink the binary orbit and drive mass transfer between the donor and the BH, producing a compact BHLMXB.
INTEGRAL observations of PSR J1811−1925 and its associated pulsar wind nebula
Authors: Dean A. J. , De Rosa A. , McBride V. A. , Landi R. , Hill A. B. , Bassani L. , Bazzano A. , Bird A. J. , Ubertini P.
Published: January 2008

We present spectral measurements made in the soft (20–100 keV) γ-ray band of the region containing the composite supernova remnant G11.2-0.3 and its associated pulsar PSR J1811−1925. Analysis of INTEGRAL/IBIS data allows characterization of the system above 10 keV. The IBIS spectrum is best fitted by a power law having photon index Γ= 1.8+0.4−0.3 and a 20–100 keV flux of 1.5 × 10−11 erg cm−2 s−1. Analysis of archival Chandra data over different energy bands rules out the supernova shell as the site of the soft γ-ray emission while broadband (1–200 keV) spectral analysis strongly indicates that the INTEGRAL/IBIS photons originate in the central zone of the system which contains both the pulsar and its nebula. The composite X-ray and soft γ-ray spectrum indicates that the pulsar provides around half of the emission seen in the soft γ-ray domain; its spectrum is hard with no sign of a cut off up to at least 80 keV. The other half of the emission above 10 keV comes from the pulsar wind nebula; with a Γ= 1.7 its spectrum is softer than that of the pulsar. From the IBIS/ISGRI mosaics we are able to derive 2σ upper limits for the 20–100 keV flux from the location of the nearby TeV source HESS J1809−193 to be 4.8 ×10−12 erg cm−2 s−1. We have also examined the likelihood of an association between PSR J1811−1925 and HESS J1809−193. Although PSR J1811−1925 is the most energetic pulsar in the region, the only one detected above 10 keV and thus a possible source of energy to fuel the TeV fluxes, there is no morphological evidence to support this pairing, making it an unlikely counterpart.
Novel Druggable Hot Spots in Avian Influenza Neuraminidase H5N1 Revealed by Computational Solvent Mapping of a Reduced and Representative Receptor Ensemble
Authors: Landon Melissa R. , Amaro Rommie E. , Baron Riccardo , Ngan Chi Ho , Ozonoff David , Andrew McCammon J. , Vajda Sandor
Published: January 2008

The influenza virus subtype H5N1 has raised concerns of a possible human pandemic threat because of its high virulence and mutation rate. Although several approved anti‐influenza drugs effectively target the neuraminidase, some strains have already acquired resistance to the currently available anti‐influenza drugs. In this study, we present the synergistic application of extended explicit solvent molecular dynamics (MD) and computational solvent mapping (CS‐Map) to identify putative ‘hot spots’ within flexible binding regions of N1 neuraminidase. Using representative conformations of the N1 binding region extracted from a clustering analysis of four concatenated 40‐ns MD simulations, CS‐Map was utilized to assess the ability of small, solvent‐sized molecules to bind within close proximity to the sialic acid binding region. Mapping analyses of the dominant MD conformations reveal the presence of additional hot spot regions in the 150‐ and 430‐loop regions. Our hot spot analysis provides further support for the feasibility of developing high‐affinity inhibitors capable of binding these regions, which appear to be unique to the N1 strain.
A Structural Informatics Study on Collagen
Authors: Bolboaca Sorana D. , Jäntschi Lorentz
Published: January 2008

The study integrates knowledge resulting from structure–activity relationships analysis of amino acids with respect to the characterization of α1 and α2 type I collagen chains. Specifically, 15 amino acids and 14 properties were investigated and their structure–activity relationship models were obtained. The models were integrated into a web application and were used to predict the properties of a set of six amino acids. The similarities in α1 and α2 type I collagen chains has been investigated starting from the observed and predicted properties of amino acids by using two‐step cluster analysis.
Analysis of Crystal Structures of LXRβ in Relation to Plasticity of the Ligand‐Binding Domain upon Ligand Binding
Authors: Malini Nagulapalli , Rajesh Hariharan , Berwal Pooja , Phukan Samiron , Balaji Vittukudi Narayanaiyengar
Published: January 2008

Liver X receptors (LXRs) are a member of the nuclear hormone receptor superfamily of ligand activated transcription factors. LXRs have gained importance as therapeutic targets because of their involvement in many diseases. Analysis of the protein–ligand complexes of X‐ray crystallography‐derived structures revealed that residues His435 and Trp457 act as a switch that mediates ligand activation. These residues show conservation for main chain (φ, ψ) in His435 and moderate movement for Trp457. His435 in Helix11 (H11) is conserved in relation to Trp457 in Helix12 (H12). This shows that some induced fit effect can be incorporated while designing ligands for activation of LXR with relation to Trp457 rather than that of His435. Similarly, main chain movement in Phe329 and Leu330 showed significant conformational mobility leading to flexibility in the ligand‐binding domain (LBD) along with Arg319 which has a moderate movement in (φ and ψ) angles. It is interesting to know that for some sequence–ligand complex crystallizations using different conditions show considerable main chain and side chain mobility indicating plasticity in LBD of LXRβ. This study supports our understanding the relative movement of residues in the LBD of LXRs upon ligand binding which can provide insight for designing of LXRs modulators.
Three‐dimensional Quantitative Structure–activity Relationship Modeling of γ‐Secretase Inhibitors using Molecular Field Analysis
Authors: Sammi Tarnvir , Silakari Om , Ravikumar Muttineni
Published: January 2008

Three‐dimensional quantitative structure–activity relationship analysis of a set of 79 analogs of γ‐secretase inhibitors was performed by molecular field analysis with genetic partial least squares method to investigate the substitutional requirements to derive a predictive model and for the favorable receptor–drug interaction that may be used for the designing of a novel γ‐secretase inhibitors. The developed molecular field analysis model has a good fit, with r2 value of 0.952 and cross‐validated coefficient, r2cv, value of 0.931. Predictive ability of the developed model was further assessed using test set of 19 compounds and r2pred was found to be 0.665.
Drug Use Patterns and Trends in Rural Communities
Authors: Gfroerer Joseph C. , Larson Sharon L. , Colliver James D.
Published: January 2008

ABSTRACT: Context and Purpose:This study examines the prevalence of tobacco, alcohol, and illicit drug use among adolescents and adults in 3 types of counties: “rural” (nonmetropolitan counties with urban population less than 20,000), “urbanized nonmetropolitan” (nonmetropolitan counties with urban population 20,000 or higher), and “metropolitan” (counties in metropolitan areas).Methods: Data from the 2002‐2004 National Surveys on Drug Use and Health are used to compare residents of the 3 county types. Descriptive findings and a multivariate model of marijuana use among adolescents are presented by county type.Findings:Past year illicit drug use is generally similar among adolescents in rural, urbanized nonmetropolitan, and metropolitan counties, except that Ecstasy use is higher among youth in metropolitan and urbanized nonmetropolitan counties than rural counties, while rural youth have a higher prevalence of stimulant and methamphetamine use than metropolitan youth. Gender, race/ethnicity, and family income functioned differentially across the 3 county types as predictors of youth marijuana use during the past year. Rural adults had generally lower rates of illicit drug use than metropolitan adults, but adults in rural and urbanized nonmetropolitan areas had higher rates of methamphetamine use than those in metropolitan areas. Rural youth had a higher prevalence of past month use of tobacco and alcohol. Rural adults had higher rates of tobacco use but lower rates of alcohol use.Conclusions:This study dispels the notion that substance abuse is only an urban problem and provides information useful in developing and implementing interventions that consider the unique characteristics of rural residents.
Examining the Effects of School‐Based Drug Prevention Programs on Drug Use in Rural Settings: Methodology and Initial Findings
Authors: Hendricks Brown C. , Guo Jing , Terri Singer L. , Downes Katheryne , Brinales Joseph M.
Published: January 2008

ABSTRACT: 
Context: Although there have been substantial advances in knowledge about drug prevention over the last decade, the majority of school‐based drug prevention studies have been conducted in urban settings. There is little knowledge about the effectiveness of such programs when they are implemented in rural populations. Purpose: To examine the prevention effects of school‐based drug prevention programs implemented in rural populations. Methods: Mixed model or 2‐level meta‐analysis of trials based on school‐based drug prevention programs that included rural populations. A total of 182 trials were coded for urbanicity of schools and 22 separate trials were selected for the analysis conducted in this paper. A total of 435 distinct analyses were examined from these 22 trials. Findings: We found a modest but consistent beneficial impact of drug prevention programs on later use as well as level of use. Regarding later drug use, the largest impact was on those who were not using at baseline and those exposed to an interactive program; the results were much larger for marijuana and other drugs compared to alcohol or tobacco, while inhalant use was less affected than other drug categories. Regarding level of use, the impact was greatest 6 months after the trial ended, with diminishing effects thereafter. Conclusions: Evidence exists for a small but systematic beneficial effect of drug prevention programs in rural settings. It is likely that these programs have produced a mild reduction in new use of substances but have had little impact on those already using substances.
Opportunities to Meet Challenges in Rural Prevention Research: Findings From an Evolving Community‐University Partnership Model
Authors: Spoth Richard
Published: January 2008

ABSTRACT:  Various rural prevention research challenges have been articulated through a series of sessions convened since the mid 1990s by the National Institutes of Health, particularly the National Institute on Drug Abuse. Salient in this articulation was the need for effective collaboration among rural practitioners and scientists, with special consideration of accommodating the diversity of rural areas and surmounting barriers to implementation of evidence‐based interventions. This paper summarizes the range of challenges in rural prevention research and describes an evolving community‐university partnership model addressing them. The model entails involvement of public school staff and other rural community stakeholders, linked with scientists by Land Grant University‐based Extension system staff. Examples of findings from over 16 years of partnership‐based intervention research projects include those on engagement of rural residents, quality implementation of evidence‐based interventions, and long‐term community‐level outcomes, as well as factors in effectiveness of the partnerships. Findings suggest a future focus on building capacity for practitioner‐scientist collaboration and developing a network for more widespread implementation of the partnership model in a manner informed by lessons learned from partnership‐based research to date.
Stimulant Use and Sexual Risk Behaviors for HIV in Rural North Carolina
Authors: Zule William A. , Costenbader Elizabeth , Coomes Curtis M. , Meyer William J. , Riehman Kara , Poehlman Jon , Wechsberg Wendee M.
Published: January 2008

ABSTRACT: 
Context: While literature exists on sexual risks for HIV among rural populations, the specific role of stimulants in increasing these risks has primarily been studied in the context of a single drug and/or racial group. Purpose: This study explores the use of multiple stimulants and sexual risk behaviors among individuals of different races and sexual identities in rural North Carolina. Methods: In‐depth interviews were conducted with 41 individuals in 3 rural North Carolina counties between June 2004 and December 2005. Interviews were audiotaped, transcribed and reviewed for accuracy. Edited interviews were imported into Atlas.ti and askSam for analysis. Findings: Along with marijuana, stimulants—including powder cocaine, crack, and methamphetamine—were the most frequently used illicit drugs in these counties. Powder cocaine use was more closely associated with white participants, crack with African Americans, and both were more commonly used by female participants. Participants reported 3 overlapping behaviors involving stimulant use that may be associated with increased risk of HIV infection: engaging in sex while using drugs, sex trading and group sex. Nearly half of participants reported engaging in group sex activity. Conclusions: HIV risk through injection appears to be low in these rural counties. However, nearly all study participants reported some form of sexual risk behavior that may increase transmission of HIV and other sexually transmitted infections. Further research is warranted focusing on the nexus between substance abuse and risky sexual behaviors.
Adolescent Substance Abuse Treatment Resource Allocation in Rural and Frontier Conditions: The Impact of Including Organizational Readiness to Change
Authors: Minugh P. Allison , Janke Susan L. , Lomuto Nicoletta A. , Galloway Diane K.
Published: January 2008

ABSTRACT: 
Context: Rural and frontier states are significantly affected by substance abuse and poverty. The high rate of substance abuse coupled with high levels of dependence on state‐funded treatment systems places a burden on rural treatment systems and makes resource allocation a central planning issue. Purpose: The goal of this study was to combine substance abuse treatment need data with organizational readiness to change data to create a rank‐ordered listing of residential treatment providers to answer the following questions: Do program priority rankings change when organizational readiness to change is included in a need‐based resource allocation algorithm?Methods: Three methodological procedures were used to determine program priority rankings among 14 residential adolescent treatment programs in 8 Wyoming counties: (1) a social indicators analysis of crime data, (2) synthetic estimates of substance abuse treatment need, and (3) analysis of organizational change data from the directors and staff at adolescent residential treatment programs. Findings: Program need rankings based on crime data and synthetic estimates of substance abuse treatment need shifted when organizational readiness to change data was added to the algorithm. Conclusions: There is much to be gained from considering organizational readiness to change when selecting programs for funding. It plays a central role in the successful diffusion of evidence‐based practices within and among programs. Including this measure in the resource allocation process can help planners identify programs that will be more apt to adopt a best practice. This is critical for making decisions about where to allocate scarce treatment resources.
Survival and maturation rates of the African rodent, Mastomys natalensis: density‐dependence and rainfall
Authors: SLUYDTS Vincent , CRESPIN Laurent , DAVIS Stephen , LIMA Mauricio , LEIRS Herwig
Published: January 2008

Survival and maturation rates of female Mastomys natalensis were analysed based on a ten‐year monthly capture‐recapture data set. We investigated whether direct and delayed density dependent and independent (rainfall) variables accounted for the considerable variation in demographic traits. It was estimated that seasonal and annual covariates accounted for respectively 29 and 26% of the total variation in maturation rates and respectively 17 and 11% of the variation in survival rates. Explaining the between‐year differences in maturation rates with annual past rainfall or density did not improve the model fit. On the other hand we showed that maturation rates were correlated negatively with density the previous month and positively to cumulative rainfall over the past three months. Survival estimates of both adults and subadults varied seasonally, with higher estimates during the increase phase (dry season). The subadults were characterised by a very high survival rate (> 0.95) during this phase. In the decrease phase only minor differences were found between survival rates of subadults and adults. We found that 39% of the between‐year variation in survival can be explained by accumulated rainfall over the past year.
Unwanted and unintended effects of culling: A case for ecologically‐based rodent management
Authors: SINGLETON Grant R. , BROWN Peter R. , JACOB Jens , APLIN Ken P. , SUDARMAJI
Published: January 2008

In this study, the ecological effects of culling programs are considered in the context of rodent pest management. Despite the escalation of rodent problems globally, over the past quarter of a century there have not been many new developments in culling programs directed at managing these populations. There is a strong reliance on broad scale use of chemical rodenticides or other lethal methods of control. The ecological consequences of culling programs based on chemical rodenticides and bounty systems are considered. Although rodents cause tremendous economic hardship to people on a continental scale, usually less than 10% of species cause substantial impacts. Indeed, many species of rodent provide important “ecological services” and, given that culling programs rarely distinguish between rodent species, often the non‐pest rodents are at grave risk. Rodent control is conducted with little appreciation of what proportion of the population would need to be culled for a significant reduction in economic damage. In Indonesian rice fields, once rodent densities are high then a reduction in yield loss from 30% to 15% would require more than 75% of the population to be culled; a reduction to less than 5% yield loss would require more than a 95% cull. The negative ecological consequences of culling can be better managed if the method is specifically tailored to the species that need to be managed. A greater emphasis on ecologically‐based rodent management would assist markedly in reducing the unwanted and unintended effects of culling.
Temporally stable genetic structure and low migration in an Atlantic salmon population complex: implications for conservation and management
Authors: Vähä Juha‐Pekka , Erkinaro Jaakko , Niemelä Eero , Primmer Craig R.
Published: January 2008

The evolutionary potential of a population is closely related to two key population genetic parameters, namely the effective population size (Ne) and migration rate (m). Furthermore, knowledge of these parameters is required in order to assess potential constraints on local adaptation and for the development of biologically sound management strategies. We addressed these key issues by investigating the temporal and spatial genetic structure of over 2000 adult Atlantic salmon (Salmo salar) collected from 17 sites in the Teno and Näätämö rivers in northernmost Europe with up to five time points spanning temporal intervals up to 24 years (∼4 generations). In all cases except one, local populations were found to be temporally stable within the river system. Estimates of Ne were generally a magnitude larger for the mainstem and headwater populations (MS+HW, Ne∼340–1200) than for the tributary populations (Ne∼35–160), thus explaining the higher genetic diversity and lower divergence of the MS+HW populations compared to tributaries. The overall migration rates to tributaries were low, and in some cases, low enough for local adaptations to potentially evolve, despite their lower Ne. Signs of a population bottleneck and natural recruitment from nearby populations were detected in one local population. This highlights a fact which is relevant for the conservation and management of highly substructured population systems in general: that even when the overall census size is large, local populations can be vulnerable to perturbations. To preserve the current and to regain the historical distribution of salmon within the river system, we propose that the status of the total population complex should be evaluated at the local population level rather than from descriptive statistics at the system level.
Conservation genetics as applied evolution: from genetic pattern to evolutionary process
Authors: Latta Robert G.
Published: January 2008

Conservation genetics can be seen as the effort to influence the evolutionary process in ways that enhance the persistence of populations. Much published research in the field applies genetic sampling techniques to infer population parameters from the patterns of variation in threatened populations. The limited resolution of these inferences seems to yield limited confidence which results in conservative policy recommendations. As an alternative, I suggest that conservation genetics focus on the relationships between those variables conservationists can control, and the probability of desirable evolutionary outcomes. This research would involve three phases – a greater use of existing evolutionary theory; testing management options using experimental evolution; and ‘field trials’ under an adaptive management framework. It would take a probabilistic approach that recognizes the stochasticity inherent in evolutionary change. This would allow a more nuanced approach to conservation policy than rule of thumb guidelines. Moreover, it would capitalize on the fact that evolution is a unifying theory in biology and draw on the substantial body of evolutionary knowledge that has been built up over the last half a century.
Consequences of sexual selection for fisheries‐induced evolution: an exploratory analysis
Authors: Hutchings Jeffrey A. , Rowe Sherrylynn
Published: January 2008

Reproductive behaviour and mating system complexity may influence fisheries‐induced evolution. Mate choice and intrasexual competition might favour late‐, large‐maturing genotypes in contrast to the selection imposed by many fisheries. Here, we simulate changes to the mean and variance in body size of Atlantic cod (Gadus morhua) concomitant with increased fishing intensity. Comparing selection differentials (S) for length under the assumptions that size does and does not affect reproductive success, we find that the strength of selection for smaller body size associated with increased fishing pressure depends on: (i) the initial variance in body size; (ii) changes to the variance in size with increasing fishing intensity; and (iii) the influence of size on reproductive success. If the initial variability in length is sufficiently high and its coefficient of variation (CV) increases with fishing intensity, the predicted evolutionary shift towards smaller size generated by fishing is less than that expected under the assumption that reproductive success is independent of size. However, if size influences reproduction and if the CV in body size declines as fishing pressure increases, a trend that may be characteristic of many intensively exploited populations, the strength of selection for smaller size is predicted to be comparatively rapid. We conclude that fisheries‐induced evolution can be influenced by changes to the mean and variance of traits under sexual selection, and that the benefits of maintaining broad phenotypic variability in traits such as body size may be greater than previously thought.
Genetic, ecological, behavioral and geographic differentiation of populations in a thistle weevil: implications for speciation and biocontrol
Authors: Olivieri Isabelle , Singer Michael C. , Magalhães Sara , Courtiol Alexandre , Dubois Yvain , Carbonell David , Justy Fabienne , Beldade Patrícia , Parmesan Camille , Michalakis Yannis
Published: January 2008

Because weevils are used as biocontrol agents against thistles, it is important to document and understand host shifts and the evolution of host‐specificity in these insects. Furthermore, such host shifts are of fundamental interest to mechanisms of speciation. The mediterranean weevil Larinus cynarae normally parasitizes either one of two thistle genera, Onopordum and Cynara, being locally monophagous. In Sardinia, however, both host genera are used. We used three types of data to help understand this complex host use: (i) weevil attack rates on the two host genera among 53 different populations in Sardinia and nearby Corsica, (ii) host preference in a lab setting, and (iii) genetic (allozyme) differentiation among weevil populations exploiting the same or different hosts. Using a subset of populations from northern Sardinia, we attempted to relate interpopulation differences in host preference to gene flow among populations by comparing pairwise differences in oviposition preference (Qst) and in allozyme frequencies (Fst). Overall, Qst and Fst were positively correlated. Fst was positively correlated with geographic distance among pairs of populations using the same host, but not among different‐host population pairs. As mating occurs on the hosts, this result suggests reinforcement. Genetic evidence indicates Cynara as the ancestral host of the weevils from both islands and our current studies suggest repeated attempts to colonize Onopordum, with a successful shift in Corsica and a partial shift in Sardinia. This scenario would explain why in Sardinia the level of attack was higher on Cynara than on Onopordum and why, when given a choice in the laboratory, Sardinian weevils preferred Cynara even when sampled from Onopordum. The lability of host shifts in L. cynarae supports caution in using these or related weevils as biocontrol agents of exotic thistles.
Case report of a focal nodular hyperplasia‐like nodule present in cirrhotic liver
Authors: Takahashi Sho , Miyanishi Koji , Takada Kohichi , Kawano Yutaka , Sagawa Tamotsu , Sato Yasushi , Takimoto Rishu , Takayama Tetsuji , Kato Junji , Omatsu Mutsuko , Hasegawa Tadashi , Kojiro Masamichi , Niitsu Yoshiro
Published: January 2008

An 81‐year‐old female was referred to Sapporo Medical University Hospital because of a nodular lesion 20 mm in diameter found in the liver S8 during follow‐up for type C liver cirrhosis. Abdominal ultrasonography showed a capsule‐like structure, and contrast computed tomography revealed hypervascularity at the early phase and inner pooling of the contrast medium with ring enhancement at the late phase. Magnetic resonance T2‐weighted imaging (T2WI) demonstrated a hyperintensity nodule with further hyperintensity signals in some parts of the nodule, and the signal pattern differed from that of typical fibrosis. SPIO‐magnetic resonance imaging showed partial hypointensity signals by T2WI, which indicated the presence of Kupffer cells. Angiography did not show a spoke‐wheel pattern. The results by imaging modalities indicated that the nodule was atypical for hepatocellular carcinoma (HCC) and focal nodular hyperplasia (FNH), and liver nodule biopsy was performed for histological diagnosis. Compared with the background liver, the nodule revealed high cellular density, cellular dysplasia at the periphery, a pseudo‐crypt structure and irregular hepatic cord arrangement in some parts of the nodule. Among them, there was immature fibrous tissue containing arterioles with muscular hypertrophy. There has been no report of well‐differentiated HCC with a central scar, and this case was presumed to be an FNH‐like nodule with dysplasia physically associated with cirrhotic tissue.
Cytoplasmic Na+‐dependent modulation of mitochondrial Ca2+ via electrogenic mitochondrial Na+–Ca2+ exchange
Authors: Kim Bongju , Matsuoka Satoshi
Published: January 2008

To clarify the role of mitochondrial Na+–Ca2+ exchange (NCXmito) in regulating mitochondrial Ca2+ (Ca2+mito) concentration at intact and depolarized mitochondrial membrane potential (ΔΨmito), we measured Ca2+mito and ΔΨmito using fluorescence probes Rhod‐2 and TMRE, respectively, in the permeabilized rat ventricular cells. Applying 300 nm cytoplasmic Ca2+ (Ca2+c) increased Ca2+mito and this increase was attenuated by cytoplasmic Na+ (Na+c) with an IC50 of 2.4 mm. To the contrary, when ΔΨmito was depolarized by FCCP, a mitochondrial uncoupler, Na+c enhanced the Ca2+c‐induced increase in Ca2+mito with an EC50 of about 4 mm. This increase was not significantly affected by ruthenium red or cyclosporin A. The inhibition of NCXmito by CGP‐37157 further increased Ca2+mito when ΔΨmito was intact, while it suppressed the Ca2+mito increase when ΔΨmito was depolarized, suggesting that ΔΨmito depolarization changed the exchange mode from forward to reverse. Furthermore, ΔΨmito depolarization significantly reduced the Ca2+mito decrease via forward mode, and augmented the Ca2+mito increase via reverse mode. When the respiratory chain was attenuated, the induction of the reverse mode of NCXmito hyperpolarized ΔΨmito, while ΔΨmito depolarized upon inducing the forward mode of NCXmito. Both changes in ΔΨmito were remarkably inhibited by CGP‐37157. The above experimental data indicated that NCXmito is voltage dependent and electrogenic. This notion was supported theoretically by computer simulation studies with an NCXmito model constructed based on present and previous studies, presuming a consecutive and electrogenic Na+–Ca2+ exchange and a depolarization‐induced increase in Na+ flux. It is concluded that Ca2+mito concentration is dynamically modulated by Na+c and ΔΨmito via electrogenic NCXmito.
α‐Adrenergic inhibition increases collateral circuit conductance in rats following acute occlusion of the femoral artery
Authors: Taylor Jessica C. , Li Zeyi , Yang H. T. , Laughlin M. Harold , Terjung Ronald L.
Published: January 2008

This study evaluated whether α‐adrenergic activation contributes to collateral circuit vascular resistance in the hindlimb following acute unilateral occlusion of the femoral artery in rats. Blood pressures (BPs) were measured above (caudal artery) and below (distal femoral artery) the collateral circuit. Arterial BPs were reduced (15–35 mmHg) with individual (prazosin, rauwolscine) or combined (phentolamine) α‐receptor inhibition. Blood flows (BFs) were measured using microspheres before and after α inhibition during the same treadmill speed. α1 inhibition increased blood flow by ∼40% to active muscles that were not affected by femoral occlusion, whereas collateral‐dependent BFs to the calf muscles were reduced by 29 ± 8.4% (P < 0.05), due to a decrease in muscle conductance with no change in collateral circuit conductance. α2 inhibition decreased both collateral circuit (39 ± 6.0%; P < 0.05) and calf muscle conductance (36 ± 7.3%; P < 0.05), probably due to residual α1 activation, since renal BF was markedly reduced with rauwolscine. Most importantly, inhibiting α2 receptors in the presence of α1 inhibition increased (43 ± 12%; P < 0.05) collateral circuit conductance. Similarly, non‐selective α inhibition with phentolamine increased collateral conductance (242 ± 59%; P < 0.05). We interpret these findings to indicate that both α1‐ and α2‐receptor activation can influence collateral circuit resistance in vivo during the high flow demands caused by exercise. Furthermore, we observed a reduced maximal conductances of active muscles that were ischaemic. Our findings imply that in the presence of excessive sympathetic activation, which can occur in the condition of intermittent claudication during exertion, an exaggerated vasoconstriction of the existing collateral circuit and active muscle will occur.
Decreased activity of the smooth muscle Na+/Ca2+ exchanger impairs arteriolar myogenic reactivity
Authors: Raina Hema , Ella Srikanth R. , Hill Michael A.
Published: January 2008

Arteriolar myogenic vasoconstriction occurs when stretch or increased membrane tension leads to smooth muscle cell (SMC) depolarization and opening of voltage‐gated Ca2+ channels. While the mechanism underlying the depolarization is uncertain a role for non‐selective cation channels has been demonstrated. As such channels may be expected to pass Na+, we hypothesized that reverse mode Na+/Ca2+ exchange (NCX) may act to remove Na+ and in addition play a role in myogenic signalling through coupled Ca2+ entry. Further, reverse (Ca2+ entry) mode function of the NCX is favoured by the membrane potential found in myogenically active arterioles. All experiments were performed on isolated rat cremaster muscle first order arterioles (passive diameter ∼150 μm) which were pressurized in the absence of intraluminal flow. Reduction of extracellular Na+ to promote reverse‐mode NCX activity caused significant, concentration‐dependent vasoconstriction and increased intracellular Ca2+. This vasoconstriction was attenuated by the NCX inhibitors KB‐R7943 and SEA 04000. Western blotting confirmed the existence of NCX protein while real‐time PCR studies demonstrated that the major isoform expressed in the arteriolar wall was NCX1. Oligonucleotide knockdown (24 and 36 h) of NCX inhibited the vasoconstrictor response to reduced extracellular Na+ while also impairing both steady‐state myogenic responses (as shown by pressure–diameter relationships) and acute reactivity to a 50 to 120 mmHg pressure step. The data are consistent with reverse mode activity of the NCX in arterioles and a contribution of this exchanger to myogenic vasoconstriction.
Diversity dynamics of Early Jurassic ostracods of the Cordillera Ibérica (Spain) and the re-evaluation of the Pliensbachian–Toarcian mass extinction
Authors: Arias Carmen
Published: January 2008

The extinction and recovery of Ostracoda at the Pliensbachian–Toarcian (P–T) boundary are analyzed based on a database of taxonomically revised Pliensbachian to Toarcian transition ostracod assemblages. In contrast to earlier assertions, the results of this study indicate that ostracod extinction rates were significant in comparison with other marine invertebrates. An extinction rate of 54% has been calculated for upper Pliensbachian ostracod species occurring in more than one section. Diversification took place in the latest Pliensbachian (Spinatum Zone) and early Toarcian (Tenuicostatum Zone), whereas diversity decrease occurred in the middle early Toarcian (Strangewaysi Subzone, Serpentinus Zone). This notable diversity decline in the early Toarcian corresponds to a global mass extinction time, whose peak has been documented in the Tenuicostatum Zone. Meanwhile, the ostracod mass extinction occurred within the Serpentinus Zone and was followed by radiation and recovery in the succeeding Bifrons Zone. Similar diversity changes of ostracods are observed in other European areas, although in the Cordillera Ibérica, the demise began later. Many aspects of this event are still debated, and there is no common cause or single set of climatic or environmental changes common to this event. The supposed extinction-causing environmental changes resulting from anoxia episodes are unclear and are unlikely to have been of sufficient intensity or geographic extent to cause this global extinction. In this paper, the decrease in marine species diversity is explained by a new palaeoceanographic scenario, in which a rapid global cooling episode is regarded as the ultimate cause.
Petrology, age, and tectonic setting of the Seal Island Pluton, offshore southwestern Nova Scotia
Authors: Moran Patrick C , Barr Sandra M , White Chris E , Hamilton Michael A
Published: January 2008

The Seal Island Pluton outcrops only on small islands located on the continental shelf 45 km south of Nova Scotia, although geophysical data indicate that the pluton is part of large granitoid units that cover thousands of square kilometres farther offshore. Based on the island outcrops, the Seal Island Pluton consists of biotite monzogranite and muscovite–biotite monzogranite of uncertain relative age. Metasedimentary xenoliths combined with characteristic magnetic patterns indicate that the pluton intruded the Cambrian–Ordovician Meguma Group. Compared with the biotite monzogranite, the muscovite–biotite monzogranite is higher in SiO2, more peraluminous, and more depleted in heavy rare-earth elements, and also has lower εNd (–1.39 versus +0.82), possibly the result of more contamination by Meguma Group sedimentary rocks. The biotite monzogranite yielded a Late Devonian U–Pb (zircon) age of 362.8 ± 0.7 Ma. Although the relatively minor petrological differences between the two units do not preclude a co-magmatic relationship, the muscovite–biotite monzogranite could be 10–15 Ma older than the biotite monzogranite, based on its petrological similarities to parts of the onshore ca. 376–372 Ma Shelburne and Port Mouton plutons. Comparison with granite samples in offshore drill core indicates that granitoid rocks similar to those exposed on Seal and surrounding islands form part of large plutons farther offshore in the Meguma terrane. The age and petrochemical data from both onshore and offshore plutons indicate that peraluminous granitoid rocks in the Meguma terrane were derived from similar sources over a span of at least 20 million years. Magma genesis may have been related to mantle upwelling and stepping back of the subduction zone to the southeast subsequent to docking of Meguma terrane with adjacent Avalonia.