bluuebunny/crossref_metadata_2025 huggingface dataset:
Building District-Level Capacity for Positive Behavior Support
Authors: George Heather Peshak , Kincaid Don K.
Published: January 2008

As more and more schools adopt school-wide positive behavior support (SWPBS) as a model for school improvement and the success of initial demonstration sites becomes evident, districts are faced with expansion and sustainability issues. Careful planning of these implementation efforts requires district personnel to be familiar with the resources and supports needed to implement and sustain such district-wide systems change efforts and build an infrastructure to support SWPBS initiatives. The purpose of this article is to expand upon School-wide Positive Behavior Support: Implementers' Blueprint and Self-Assessment (Sugai et al., 2005) by describing the how-to of the SWPBS implementation process with specific activities and providing user-friendly tools that can assist a district in “going to scale.” Obstacles to and future considerations for expanding the practice of SWPBS are also presented.
A Descriptive Analysis of Intervention Research Published in the Journal of Positive Behavior Interventions: 1999 Through 2005
Authors: Clarke Shelley , Dunlap Glen
Published: January 2008

The Journal of Positive Behavior Interventions (JPBI) has been publishing reports of empirical intervention research since 1999, with a commitment to serve as a vehicle for dissemination of data and perspectives pertinent to positive behavior support (PBS). PBS is distinguished by an emphasis on certain features of interventions, such as ecological and social validity. The current analysis was undertaken as an effort to describe the characteristics of intervention research published in JPBI from 1999 through 2005 and to provide a comparison with other peer-reviewed journals that publish a large number of articles reporting intervention research with children and youth with disabilities. The data indicate that JPBI has been publishing research with comparatively high levels of ecological validity, social validity, and assessment-based interventions. The authors note other distinctive aspects of JPBI's publication record and discuss the data with respect to the current and future character of PBS research.
The Influence of “Working Rules” on Police Suspicion and Discretionary Decision Making
Authors: Stroshine Meghan , Alpert Geoffrey , Dunham Roger
Published: January 2008

This study examines the role of “working rules” that define what officers interpret as suspicious people, places, and situations. Data were drawn from observational studies of police decision making in Savannah, Georgia and Miami-Dade, Florida. Current theory and research on the use of police discretion and biased policing is focused on the decision to stop, search, or arrest a suspect. Only a few studies focus on processes through which police determine behaviors to be suspicious that influence them to initiate official police action. An analysis of the “working rules” used by officers uncovered 12 substantive categories. The article concludes with a discussion of how this information can be useful in formulating training for police departments.
Psychometric Evaluation of the Shortened Resilience Scale Among Alzheimer's Caregivers
Authors: Wilks Scott E.
Published: January 2008

The purpose of this study was to evaluate psychometric properties of the shortened Resilience Scale (15-item version RS15) among a sample of Alzheimer's caregivers. Self-reported data were collected from 229 participants at 2 Alzheimer's caregiver conferences. RS15 principal axis factoring indicated a single-dimensional solution with all items loaded. Reliability was strong. Convergent validity for the RS15 was suggested through its correlations with stress, family suppport, and friend support. Odds ratios showed significant likelihoods of high resilience given low stress and high social support. The results confirmed the RS15 to be a psychometrically sound measure that can be used to appraise the efficacy of adaptability among Alzheimer's caregivers.
Platelet-mediated modulation of adaptive immunity: unique delivery of CD154 signal by platelet-derived membrane vesicles
Authors: Sprague Daniel L. , Elzey Bennett D. , Crist Scott A. , Waldschmidt Thomas J. , Jensen Robert J. , Ratliff Timothy L.
Published: January 2008

Although mounting evidence indicates that platelets participate in the modulation of both innate and adaptive immunity, the mechanisms by which platelets exert these effects have not been clearly defined. The study reported herein uses a previously documented adoptive transfer model to investigate the ability of platelet-derived membrane vesicles to communicate activation signals to the B-cell compartment. The findings demonstrate for the first time that platelet-derived membrane vesicles are sufficient to deliver CD154 to stimulate antigen-specific IgG production and modulate germinal center formation through cooperation with responses elicited by CD4+ T cells. The data are consistent with the hypothesis that platelets modulate inflammation and adaptive immunity at sites distant from the location of activation and that platelet-derived membrane vesicles are sufficient to mediate the effect.
Flow cytometric immunophenotyping for hematologic neoplasms
Authors: Craig Fiona E. , Foon Kenneth A.
Published: January 2008

Flow cytometric immunophenotyping remains an indispensable tool for the diagnosis, classification, staging, and monitoring of hematologic neoplasms. The last 10 years have seen advances in flow cytometry instrumentation and availability of an expanded range of antibodies and fluorochromes that have improved our ability to identify different normal cell populations and recognize phenotypic aberrancies, even when present in a small proportion of the cells analyzed. Phenotypically abnormal populations have been documented in many hematologic neoplasms, including lymphoma, chronic lymphoid leukemias, plasma cell neoplasms, acute leukemia, paroxysmal nocturnal hemoglobinuria, mast cell disease, myelodysplastic syndromes, and myeloproliferative disorders. The past decade has also seen refinement of the criteria used to identify distinct disease entities with widespread adoption of the 2001 World Health Organization (WHO) classification. This classification endorses a multiparametric approach to diagnosis and outlines the morphologic, immunophenotypic, and genotypic features characteristic of each disease entity. When should flow cytometric immunophenotyping be applied? The recent Bethesda International Consensus Conference on flow cytometric immunophenotypic analysis of hematolymphoid neoplasms made recommendations on the medical indications for flow cytometric testing. This review discusses how flow cytometric testing is currently applied in these clinical situations and how the information obtained can be used to direct other testing.
Using Generalized Procrustes Analysis (GPA) for normalization of cDNA microarray data
Authors: Xiong Huiling , Zhang Dapeng , Martyniuk Christopher J , Trudeau Vance L , Xia Xuhua
Published: January 2008

Background

Normalization is essential in dual-labelled microarray data analysis to remove non-biological variations and systematic biases. Many normalization methods have been used to remove such biases within slides (Global, Lowess) and across slides (Scale, Quantile and VSN). However, all these popular approaches have critical assumptions about data distribution, which is often not valid in practice.

Results

In this study, we propose a novel assumption-free normalization method based on the Generalized Procrustes Analysis (GPA) algorithm. Using experimental and simulated normal microarray data and boutique array data, we systemically evaluate the ability of the GPA method in normalization compared with six other popular normalization methods including Global, Lowess, Scale, Quantile, VSN, and one boutique array-specific housekeeping gene method. The assessment of these methods is based on three different empirical criteria: across-slide variability, the Kolmogorov-Smirnov (K-S) statistic and the mean square error (MSE). Compared with other methods, the GPA method performs effectively and consistently better in reducing across-slide variability and removing systematic bias.

Conclusion

The GPA method is an effective normalization approach for microarray data analysis. In particular, it is free from the statistical and biological assumptions inherent in other normalization methods that are often difficult to validate. Therefore, the GPA method has a major advantage in that it can be applied to diverse types of array sets, especially to the boutique array where the majority of genes may be differentially expressed.
The amphioxus (Branchiostoma floridae) genome contains a highly diversified set of G protein-coupled receptors
Authors: Nordström Karl JV , Fredriksson Robert , Schiöth Helgi B
Published: January 2008

Background

G protein-coupled receptors (GPCRs) are one of the largest families of genes in mammals. Branchiostoma floridae (amphioxus) is one of the species most closely related species to vertebrates.

Results

Mining and phylogenetic analysis of the amphioxus genome showed the presence of at least 664 distinct GPCRs distributed among all the main families of GPCRs; Glutamate (18), Rhodopsin (570), Adhesion (37), Frizzled (6) and Secretin (16). Surprisingly, the Adhesion GPCR repertoire in amphioxus includes receptors with many new domains not previously observed in this family. We found many Rhodopsin GPCRs from all main groups including many amine and peptide binding receptors and several previously uncharacterized expansions were also identified. This genome has however no genes coding for bitter taste receptors (TAS2), the sweet and umami (TAS1), pheromone (VR1 or VR2) or mammalian olfactory receptors.

Conclusion

The amphioxus genome is remarkably rich in various GPCR subtypes while the main GPCR groups known to sense exogenous substances (such as Taste 2, mammalian olfactory, nematode chemosensory, gustatory, vomeronasal and odorant receptors) in other bilateral species are absent.
Protein interactions in human genetic diseases
Authors: Schuster-Böckler Benjamin , Bateman Alex
Published: January 2008

We present a novel method that combines protein structure information with protein interaction data to identify residues that form part of an interaction interface. Our prediction method can retrieve interaction hotspots with an accuracy of 60% (at a 20% false positive rate). The method was applied to all mutations in the Online Mendelian Inheritance in Man (OMIM) database, predicting 1,428 mutations to be related to an interaction defect. Combining predicted and hand-curated sets, we discuss how mutations affect protein interactions in general.
Factors Predicting the Near-Final Height in Growth Hormone-Treated Children and Adolescents with Chronic Kidney Disease
Authors: Nissel Richard , Lindberg Anders , Mehls Otto , Haffner Dieter
Published: January 2008

Context: GH therapy is an accepted measure to increase adult height in young prepubertal patients suffering from growth failure related to chronic kidney disease (CKD). The impact of GH therapy on final height (FH) in CKD patients of pubertal age is unclear.

Objective: This study set out to analyze near-FH in a cohort of GH-treated CKD patients.

Design, Settings, and Patients: Of 240 evaluable patients in the Pfizer International Growth Database (KIGS) with CKD, 39% were prepubertal and 61% were pubertal at baseline; 45% were on conservative treatment for CKD, 28% were on dialysis, and 27% were in the period after renal transplantation.

Main Outcome Measures: Near-FH, relation to pubertal stage, and factors predictive of growth response were the main outcome measures.

Results: Mean height sd scores increased continuously during GH treatment until near-FH by 1.2 and 1.6 in boys and girls, respectively. Mean near-FH differed significantly from prepubertal patients showing severely delayed puberty (−3.6), late pubertal patients (−2.9), early pubertal patients (−2.2), and prepubertal patients with normal onset of puberty (−2.0). The initial degree of stunting, degree of bone age retardation, duration of GH therapy, time spent on conservative treatment/dialysis, pubertal delay (>2 sd), gender, and age at start of GH treatment were significant predictors of growth response to GH therapy, explaining between 33 and 61% of the overall variability.

Conclusions: Long-term GH therapy of CKD patients in prepubertal and pubertal age results in an increased adult height, but response is diminished in patients on dialysis and/or with severely delayed puberty.
On the connectivity and diameter of small-world networks
Authors: Ganesh Ayalvadi , Xue Feng
Published: January 2008

We consider two different models of small-world graphs on nodes whose locations are modelled by a stochastic point process. In the first model each node is connected to a fixed number of its nearest neighbours, while in the second model each node is connected to all nodes located within some fixed distance. In both models, nodes are additionally connected via shortcuts to other nodes chosen uniformly at random. We obtain sufficient conditions for connectivity in the first model, and necessary conditions in the second model. Thereby, we show that connectivity is achieved at a smaller value of total degree (nearest neighbours plus shortcuts) in the first model. We also obtain bounds on the diameter of the graph in this model.
Congestion-dependent pricing in a stochastic service system
Authors: Maoui Idriss , Ayhan Hayriye , Foley Robert D.
Published: January 2008

We study a service facility modeled as a queueing system with finite or infinite capacity. Arriving customers enter if there is room in the facility and if they are willing to pay the price posted by the service provider. Customers belong to one of a finite number of classes that have different willingnesses-to-pay. Moreover, there is a penalty for congestion in the facility in the form of state-dependent holding costs. The service provider may advertise class-specific prices that may fluctuate over time. We show the existence of a unique optimal stationary pricing policy in a continuous and unbounded action space that maximizes the long-run average profit per unit time. We determine an expression for this policy under certain conditions. We also analyze the structure and the properties of this policy.
Graphs with specified degree distributions, simple epidemics, and local vaccination strategies
Authors: Britton Tom , Janson Svante , Martin-Löf Anders
Published: January 2008

Consider a random graph, having a prespecified degree distribution F, but other than that being uniformly distributed, describing the social structure (friendship) in a large community. Suppose that one individual in the community is externally infected by an infectious disease and that the disease has its course by assuming that infected individuals infect their not yet infected friends independently with probability p. For this situation, we determine the values of R0, the basic reproduction number, and τ0, the asymptotic final size in the case of a major outbreak. Furthermore, we examine some different local vaccination strategies, where individuals are chosen randomly and vaccinated, or friends of the selected individuals are vaccinated, prior to the introduction of the disease. For the studied vaccination strategies, we determine Rv, the reproduction number, and τv, the asymptotic final proportion infected in the case of a major outbreak, after vaccinating a fraction v.
An epidemic model with infector-dependent severity
Authors: Ball Frank , Britton Tom
Published: January 2008

A stochastic epidemic model is defined in which infected individuals have different severities of disease (e.g. mildly and severely infected) and the severity of an infected individual depends on the severity of the individual he or she was infected by; typically, severe or mild infectives have an increased tendency to infect others severely or, respectively, mildly. Large-population properties of the model are derived, using branching process approximations for the initial stages of an outbreak and density-dependent population processes when a major outbreak occurs. The effects of vaccination are considered, using two distinct models for vaccine action. The consequences of launching a vaccination program are studied in terms of the effect it has on reducing the final size in the event of a major outbreak as a function of the vaccination coverage, and also by determining the critical vaccination coverage above which only small outbreaks can occur.
Perfectly random sampling of truncated multinormal distributions
Authors: Fernández Pedro J. , Ferrari Pablo A. , Grynberg Sebastian P.
Published: January 2008

The target measure μ is the distribution of a random vector in a box ℬ, a Cartesian product of bounded intervals. The Gibbs sampler is a Markov chain with invariant measure μ. A ‘coupling from the past’ construction of the Gibbs sampler is used to show ergodicity of the dynamics and to perfectly simulate μ. An algorithm to sample vectors with multinormal distribution truncated to ℬ is then implemented.
Transformations of Galton-Watson processes and linear fractional reproduction
Authors: Klebaner F. C. , Rösler U. , Sagitov S.
Published: January 2008

By establishing general relationships between branching transformations (Harris-Sevastyanov, Lamperti-Ney, time reversals, and Asmussen-Sigman) and Markov chain transforms (Doob's h-transform, time reversal, and the cone dual), we discover a deeper connection between these transformations with harmonic functions and invariant measures for the process itself and its space-time process. We give a classification of the duals into Doob's h-transform, pathwise time reversal, and cone reversal. Explicit results are obtained for the linear fractional offspring distribution. Remarkably, for this case, all reversals turn out to be a Galton-Watson process with a dual reproduction law and eternal particle or some kind of immigration. In particular, we generalize a result of Klebaner and Sagitov (2002) in which only a geometric offspring distribution was considered. A new graphical representation in terms of an associated simple random walk on N2 allows for illuminating picture proofs of our main results concerning transformations of the linear fractional Galton-Watson process.
Functional limit theorems for critical processes with immigration
Authors: Rahimov I.
Published: January 2008

We consider a critical discrete-time branching process with generation dependent immigration. For the case in which the mean number of immigrating individuals tends to ∞ with the generation number, we prove functional limit theorems for centered and normalized processes. The limiting processes are deterministically time-changed Wiener, with three different covariance functions depending on the behavior of the mean and variance of the number of immigrants. As an application, we prove that the conditional least-squares estimator of the offspring mean is asymptotically normal, which demonstrates an alternative case of normality of the estimator for the process with nondegenerate offspring distribution. The norming factor iswhere α(n) denotes the mean number of immigrating individuals in thenth generation.
Uniform renewal theory with applications to expansions of random geometric sums
Authors: Blanchet J. , Glynn P.
Published: January 2008

Consider a sequence X = (Xn: n ≥ 1) of independent and identically distributed random variables, and an independent geometrically distributed random variable M with parameter p. The random variable SM = X1 + ∙ ∙ ∙ + XM is called a geometric sum. In this paper we obtain asymptotic expansions for the distribution of SM as p ↘ 0. If EX1 > 0, the asymptotic expansion is developed in powers of p and it provides higher-order correction terms to Renyi's theorem, which states that P(pSM > x) ≈ exp(-x/EX1). Conversely, if EX1 = 0 then the expansion is given in powers of √p. We apply the results to obtain corrected diffusion approximations for the M/G/1 queue. These expansions follow in a unified way as a consequence of new uniform renewal theory results that are also developed in this paper.
Optimal boarding policies for thin passengers
Authors: Bachmat Eitan , Berend Daniel , Sapir Luba , Skiena Steven
Published: January 2008

We deal with the problem of seating an airplane's passengers optimally, namely in the fastest way. Under several simplifying assumptions, whereby the passengers are infinitely thin and react within a constant time to boarding announcements, we are able to rewrite the asymptotic problem as a calculus of variations problem with constraints. This problem is solved in turn using elementary methods. While the optimal policy is not unique, we identify a rigid discrete structure which is common to all solutions. We also compare the (nontrivial) optimal solutions we find with some simple boarding policies, one of which is shown to be near-optimal.
Estimation for Nonnegative Lévy-Driven Ornstein-Uhlenbeck Processes
Authors: Brockwell Peter J. , Davis Richard A. , Yang Yu
Published: January 2008

Continuous-time autoregressive moving average (CARMA) processes with a nonnegative kernel and driven by a nondecreasing Lévy process constitute a very general class of stationary, nonnegative continuous-time processes. In financial econometrics a stationary Ornstein-Uhlenbeck (or CAR(1)) process, driven by a nondecreasing Lévy process, was introduced by Barndorff-Nielsen and Shephard (2001) as a model for stochastic volatility to allow for a wide variety of possible marginal distributions and the possibility of jumps. For such processes, we take advantage of the nonnegativity of the increments of the driving Lévy process to study the properties of a highly efficient estimation procedure for the parameters when observations are available of the CAR(1) process at uniformly spaced times 0,h,…,Nh. We also show how to reconstruct the background driving Lévy process from a continuously observed realization of the process and use this result to estimate the increments of the Lévy process itself when h is small. Asymptotic properties of the coefficient estimator are derived and the results illustrated using a simulated gamma-driven Ornstein-Uhlenbeck process.
Moments of Random Allocation Processes Reaching a Boundary
Authors: Tsitsiashvili G. S.
Published: January 2008

In this paper we develop some results presented by Gani (2004), deriving moments for random allocation processes. These moments correspond to the allocation processes reaching some domain boundary. Exact formulae for means, variances, and probability generating functions as well as some asymptotic formulae for moments of random allocation processes are obtained. A special choice of the asymptotics and of the domain allows us to reduce a complicated numerical procedure to a simple asymptotic one.
On a Theorem of Breiman and a Class of Random Difference Equations
Authors: Denisov Denis , Zwart Bert
Published: January 2008

We consider the tail behavior of the product of two independent nonnegative random variables X and Y. Breiman (1965) has considered this problem, assuming that X is regularly varying with index α and that E{Yα+ε} < ∞ for some ε > 0. We investigate when the condition on Y can be weakened and apply our findings to analyze a class of random difference equations.
A Unifying Conservation Law for Single-Server Queues
Authors: Ayesta Urtzi
Published: January 2008

We develop a conservation law for a multi-class GI/GI/1 queue operating under a general work-conserving scheduling discipline. For single-class single-server queues, conservation laws have been obtained for both nonanticipating and anticipating disciplines with general service time distributions. For multi-class single-server queues, conservation laws have been obtained for (i) nonanticipating disciplines with exponential service time distributions and (ii) nonpreemptive nonanticipating disciplines with general service time distributions. The unifying conservation law we develop generalizes already existing conservation laws. In addition, it covers popular nonanticipating multi-class time-sharing disciplines such as discriminatory processor sharing (DPS) and generalized processor sharing (GPS) with general service time distributions. As an application, we show that the unifying conservation law can be used to compare the expected unconditional response time under two scheduling disciplines.
PLD regulates myoblast differentiation through the mTOR-IGF2 pathway
Authors: Yoon Mee-Sup , Chen Jie
Published: January 2008

A mammalian target of rapamycin (mTOR) pathway is essential for the differentiation of cultured skeletal myoblasts in response to growth factor withdrawal. Previously, phospholipase D (PLD) has been found to play a role in cell growth regulation and mitogenic activation of mTOR signaling. However, a role for PLD in the autocrine regulation of myoblast differentiation is not known. Here we show that upon induction of differentiation in mouse C2C12 satellite cells, the expression of both PLD1 and PLD2 is upregulated. C2C12 differentiation is markedly inhibited by 1-butanol, an inhibitor of the PLD-catalyzed transphosphatidylation reaction, and also by the knockdown of PLD1, but not PLD2. Further investigation has revealed that PLD1 is unlikely to regulate myogenesis through modulation of the actin cytoskeleton as previously suggested. Instead, PLD1 positively regulates mTOR signaling leading to the production of IGF2, an autocrine factor instrumental for the initiation of satellite cell differentiation. Furthermore, exogenous IGF2 fully rescues the differentiation defect resulting from PLD1 knockdown. Hence, PLD1 is critically involved in skeletal myogenesis by regulating the mTOR-IGF2 pathway.
The Potential for β-Structure in the Repeat Domain of Tau Protein Determines Aggregation, Synaptic Decay, Neuronal Loss, and Coassembly with Endogenous Tau in Inducible Mouse Models of Tauopathy
Authors: Mocanu Maria-Magdalena , Nissen Astrid , Eckermann Katrin , Khlistunova Inna , Biernat Jacek , Drexler Dagmar , Petrova Olga , Schönig Kai , Bujard Hermann , Mandelkow Eckhard , Zhou Lepu , Rune Gabriele , Mandelkow Eva-Maria
Published: January 2008

We describe two new transgenic mouse lines for studying pathological changes of Tau protein related to Alzheimer's disease. They are based on the regulatable expression of the four-repeat domain of human Tau carrying the FTDP17 (frontotemporal dementia and parkinsonism linked to chromosome 17) mutation ΔK280 (TauRD/ΔK280), or the ΔK280 plus two proline mutations in the hexapeptide motifs (TauRD/ΔK280/I277P/I308P). The ΔK280 mutation accelerates aggregation (“proaggregation mutant”), whereas the proline mutations inhibit Tau aggregationin vitroand in cell models (“antiaggregation mutant”). The inducible transgene expression was driven by the forebrain-specific CaMKIIα (calcium/calmodulin-dependent protein kinase IIα) promoter. The proaggregation mutant leads to Tau aggregates and tangles as early as 2–3 months after gene expression, even at low expression (70% of endogenous mouse Tau). The antiaggregation mutant does not aggregate even after 22 months of gene expression. Both mutants show missorting of Tau in the somatodendritic compartment and hyperphosphorylation in the repeat domain [KXGS motifs, targets of the kinase MARK (microtubule affinity regulating kinase)]. This indicates that these changes are related to Tau expression rather than aggregation. The proaggregation mutant causes astrogliosis, loss of synapses and neurons from 5 months of gene expression onward, arguing that Tau toxicity is related to aggregation. Remarkably, the human proaggregation mutant TauRDcoaggregates with mouse Tau, coupled with missorting and hyperphosphorylation at multiple sites. When expression of proaggregation TauRDis switched off, soluble and aggregated exogenous TauRDdisappears within 1.5 months. However, tangles of mouse Tau, hyperphosphorylation, and missorting remain, suggesting an extended lifetime of aggregated wild-type Tau once a pathological conformation and aggregation is induced by a proaggregation Tau species.
Cellular Dynamics of Cholinergically Induced α (8–13 Hz) Rhythms in Sensory Thalamic NucleiIn Vitro
Authors: Lörincz Magor L. , Crunelli Vincenzo , Hughes Stuart W.
Published: January 2008

Although EEG α (8–13 Hz) rhythms are traditionally thought to reflect an “idling” brain state, they are also linked to several important aspects of cognition, perception, and memory. Here we show that reactivating cholinergic input, a key component in normal cognition and memory operations, in slices of the cat primary visual and somatosensory thalamus, produces robust α rhythms. These rhythms rely on activation of muscarinic receptors and are primarily coordinated by activity in the recently discovered, gap junction-coupled subnetwork of high-threshold (HT) bursting thalamocortical neurons. By performing extracellular field recordings in combination with intracellular recordings of these cells, we show that (1) the coupling of HT bursting cells is sparse, with individual neurons typically receiving discernable network input from one or very few additional cells, (2) the phase of oscillatory activity at which these cells prefer to fire is readily modifiable and determined by a combination of network input, intrinsic properties and membrane polarization, and (3) single HT bursting neurons can potently influence the local network state. These results substantially extend the known effects of cholinergic activation on the thalamus and, in combination with previous studies, show that sensory thalamic nuclei possess powerful and dynamically reconfigurable mechanisms for generating synchronized α activity that can be engaged by both descending and ascending arousal systems.
Minimally invasive direct cardiac surgery with jakoscope retractor
Authors: Galajda Zoltán , Jakó Géza , von Jakó Ronald , Péterffy Árpád
Published: January 2008

Cikkükben a szerzők egy olyan sebészi feltárót (ún. jakoszkóp) mutatnak be, amely hasi, urológiai, mellkasi, ér- és szívsebészeti területen egyaránt használhatónak bizonyult. Az eszköz sokoldalú használhatósága a felépítésének köszönhető, és lehetővé teszi a fenti sebészeti szakmákban a minimálisan invazív direkt feltárást. Ezzel a műszerrel a szerzők sikeresen végeztek aortaműbillentyű-beültetést jobb oldali mini-thoracotomiából, koszorúér-áthidalást mini-thoracotomiából dobogó szíven, illetőleg elektrofiziológiai beavatkozások során bal kamrai elektródaimplantációt és radiofrekvenciás pulmonalis vénaablatiót. Jelen közleményükben elsőként szeretnék közölni szívsebészetben szerzett tapasztalataikat. Az előbb említett beavatkozásoknál a jakoszkóp minimális behatolás mellett megfelelő direkt feltárást biztosított, szövődmény egyik esetben sem lépett fel.
Watershed and land use–based sources of trace metals in urban storm water
Authors: Tiefenthaler Liesl L , Stein Eric D , Schiff Kenneth C
Published: January 2008

Trace metal contributions in urban storm water are of concern to environmental managers because of their potential impacts on ambient receiving waters. The mechanisms and processes that influence temporal and spatial patterns of trace metal loading in urban storm water, however, are not well understood. The goals of the present study were to quantify trace metal event mean concentration (EMC), flux, and mass loading associated with storm water runoff from representative land uses; to compare EMC, flux, and mass loading associated with storm water runoff from urban (developed) and nonurban (undeveloped) watersheds; and to investigate within-storm and within-season factors that affect trace metal concentration and flux. To achieve these goals, trace metal concentrations were measured in 315 samples over 11 storm events in five southern California, USA, watersheds representing eight different land use types during the 2000 through 2005 storm seasons. In addition, 377 runoff samples were collected from 12 mass emission sites (end of watershed) during 15 different storm events. Mean flux at land use sites ranged from 24 to 1,238, 0.1 to 1,272, and 6 to 33,189 g/km2 for total copper, total lead, and total zinc, respectively. Storm water runoff from industrial land use sites contained higher EMCs and generated greater flux of trace metals than other land use types. For all storms sampled, the highest metal concentrations occurred during the early phases of storm water runoff, with peak concentrations usually preceding peak flow. Early season storms produced significantly higher metal flux compared with late season storms at both mass emission and land use sites.
Dose-related effects following oral exposure of 2,4-dinitrotoluene on the western fence lizard, Sceloporus occidentalis
Authors: Suski Jamie G , Salice Christopher , Houpt John T , Bazar Matthew A , Talent Larry G
Published: January 2008

2,4-dintitrotoluene (2,4-DNT) is an explosive frequently found in the soil of military installations. Because reptiles can be common on these sites, ecological risk assessments for compounds such as 2,4-DNT could be improved with toxicity data specific to reptiles. Western fence lizards, Sceloporus occidentalis, were used to develop a laboratory toxicity model for reptiles. A hierarchical approach was used; acute to subchronic studies were conducted to provide toxicity data relevant to short- and long-term exposures. First, a modified median lethal dose (LD50) study was conducted on male and female lizards using a stage-wise probit model. The LD50 was 577 mg/kg for female and 380 mg/kg for male lizards. Subsequently, a subacute experiment was conducted to further assess 2,4-DNT toxicity to male lizards and to define exposure levels for a longer term, subchronic study. The subchronic study was conducted for 60 consecutive days; male lizards were exposed to 0, 9, 15, 25, 42, 70 mg/kg/d. Dose-dependent mortality was observed in the three highest dose groups (25, 42, and 70 mg/kg/d); all other animals survived the study duration. Benchmark dose model calculations based on mortality indicated a 5% effect level of 15.8 mg/kg/d. At study termination, a gross necropsy was performed, organ weights were taken, and blood was collected for clinical and hematological analysis. Body weight, kidney weight, food consumption, postdose observations, and blood chemistries all were found to be significantly different from controls at doses above 9 mg/kg/d. Also, preliminary results suggest behavioral observations, and reduced food consumption may be a sensitive indicator of toxicity. The present study indicates Sceloporus occidentalis is suitable for evaluating toxicity of compounds to reptilian species.
Reproductive toxicity of vinclozolin in the fathead minnow: Confirming an anti-androgenic mode of action
Authors: Martinović Dalma , Blake Lindsey S , Durhan Elizabeth J , Greene Katie J , Kahl Michael D , Jensen Kathleen M , Makynen Elizabeth A , Villeneuve Daniel L , Ankley Gerald T
Published: January 2008

The objective of the present study was to characterize responses of the reproductive endocrine system of the fathead minnow (Pimephales promelas) to the fungicide vinclozolin (VZ), using a 21-d reproduction assay, and a shorter-term (approximately two weeks) test in which fish were cotreated with the VZ (a putative anti-androgen) and the androgen 17β-trenbolone (TB). Effects on fecundity, gonadal histology, secondary sexual characteristics, reproductive hormones, and relative abundance of androgen receptor (AR) and 11 β-hydroxysteroid dehydrogenase (11 βHSD) mRNA transcripts were evaluated in one or both of these studies. Fecundity of VZ-exposed fish was decreased in a concentration-dependent manner in the 21-d test, culminating in complete reproductive failure at a concentration of 700 μg/L. Exposure to VZ decreased expression of male secondary sexual characteristics— an effect typical of anti-androgens. The finding that exposure of females to TB-induced expression of prominent, male-like tubercles, which could be effectively blocked with VZ, provides powerful evidence of the anti-androgenic activity of VZ in vivo. In the two experiments VZ produced several responses possibly indicative of compensation or adaptation of the fish to the anti-androgen, including increases in gonad weight, AR and 11 βHSD mRNA transcript abundance, and ex vivo gonadal production of testosterone and 11-ketotestosterone. Overall, our results demonstrate that the model anti-androgen VZ, which also is an environmental contaminant, impairs reproductive success of fathead minnows and elicits endocrine responses consistent with an anti-androgenic mode of action.
Use of pollution-induced community tolerance of the bacterial community to detect phenol toxicity in soil
Authors: Demoling Louise Aldén , Bååth Erland
Published: January 2008

Pollution-induced community tolerance (PICT) was used to study effects of phenol on soil bacteria. Phenol was added to an agricultural soil in a microcosm experiment. The effects were studied for up to four months. Bacterial growth rates were estimated with the leucine incorporation technique. This technique was also used as detection method for PICT. Changes in community structure were studied using the phospholipid fatty acid (PLFA) pattern. Increased phenol PICT of the bacterial community was found at phenol concentrations above 1 μmol/g wet weight soil. Direct inhibiting effect on bacterial growth rates 1 d after adding phenol was correlated to PICT. Phenol toxicity was reflected by changes in the structure of the bacterial community, although PICT appeared more sensitive than the PLFA method. In soil amended with 1 to 10 μmol phenol/g soil, bacterial growth recovered within one week. In the soil amended with the highest phenol concentration (30 μmol/g soil), bacterial growth rate recovered from total inhibition after 27 d, eventually reaching values six times higher than in the control. However, PICT did not change during the four months the experiment was performed. The specificity of PICT was also studied by examining cotolerance to 2-chlorophenol, 2,4-dichlorophenol, 2,3,6-trichlorophenol, Cu, and Zn. Adding phenol induced cotolerance of the bacterial community to the other phenols, although always at a lover level than to phenol. No cotolerance was found to metals in phenol-polluted soil. We conclude that the PICT concept is a valuable tool in determining phenol toxicity to bacterial communities, especially in situations where bacterial growth has recovered. Cotolerance between different phenols can, however, make interpretations of PICT more complicated.
A screening method for toxicity identification evaluation on an industrial effluent using Chelex®-100 resin and chelators for specific metals
Authors: Onikura Norio , Kishi Katsuyuki , Nakamura Akiko , Takeuchi Shinichi
Published: January 2008

Toxicity of an industrial effluent was characterized using a toxicity identification method established at our research institute. Toxicity was evaluated using the Ceriodaphnia dubia survival test. The industrial effluent chosen in the present study had toxic effects on C. dubia before treatment. The effluent was first filtered to remove suspended solids (F-treatment). Activated charcoal was then added to the effluent to adsorb organic substances (AC-treatment), followed by treatment of the supernatant with Chelex®-100 resin to remove di- and trivalent cations, including transition metals (C100-treatment). The effluent exhibited atoxic effect on C. dubia even after the AC-treatment, but it was no longer toxic after the C100-treatment, indicating that the effluent contained cations that affect C. dubia survival. To further identify the metals responsible for the toxicity, benzoin-α-oxime or dimethylglyoxime was added to the effluent to chelate specific cations. The toxicity of the effluent was eliminated by addition of dimethylglyoxime but not significantly so by addition of benzoin-α-oxime, suggesting that the toxicants in the effluent strongly formed complexes with dimethylglyoxime. These results combined with those of metal analysis strongly suggest that nickel might be the noxious agent. The toxicity identification method described in this paper is effective for the identification of metal toxicants in industrial effluents. The method using insoluble chelating resins and chelators for specific metals would serve as a useful addition to the standard toxicity identification evaluation procedure.
Congener-specific characterization and sources of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in marine sediments from industrialized bays of Korea
Authors: Moon Hyo-Bang , Choi Hee-Gu , Lee Pil-Yong , Ok Gon
Published: January 2008

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DLPCBs) were determined in 122 coastal sediments from heavily industrialized areas in Korea. Toxic equivalent (TEQ) concentrations of PCDD and PCDF (PCDD/F) and DLPCB ranged from 0.44 to 38.5 pg/g dry weight and from 0.01 to 38.4 pg/g dry weight, respectively. Overall PCDD/F and DLPCB concentrations were elevated in estuarine and inner bay locations close to industrial complexes, indicating that these contaminants derived from local discharges. Concentrations of PCDD/F measured in the present study were comparable to those in industrialized areas of other countries. Nonparametric multidimensional scaling ordination and congener-specific characterization showed that combustion processes occurring in industrial complexes, including the steel industry, are the major source of PCDD/Fs in Korean coastal waters. There were no significant correlations among PCDD/Fs, DLPCBs, and total organic carbon; however, there was moderate correlation between PCDD/Fs and DLPCBs in some coastal bays, suggesting that these chemicals have similar sources and movements in these locations.
Dose-dependent enantiomeric enrichment of 2,2′,3,3′,6,6′-hexachlorobiphenyl in female mice
Authors: Kania-Korwel Izabela , Hornbuckle Keri C , Robertson Larry W , Lehmler Hans-Joachim
Published: January 2008

Nineteen of the 209 possible polychlorinated biphenyl (PCB) congeners are chiral and stable to racemization at ambient temperature. Chiral PCB congeners are important components of technical and environmental PCB mixtures, and some are highly toxic. Both environmental and laboratory studies have shown that these chiral PCB congeners undergo enantiomeric enrichment in many species; however, the processes and factors influencing the extent of this enantiomeric enrichment are poorly understood. We hypothesized that the exposure levels are an important factor affecting the extent of enantiomeric enrichment. To test this hypothesis, we investigated the levels and enantiomeric fractions of (±)-PCB 136 in selected tissues, feces, and urine of female C57Bl/6 mice 3 d after oral administration of 2.5, 10, or 50 mg/kg body weight of (±)-PCB 136. The PCB 136 tissue levels typically increased with increasing dose. The extent of the enrichment of (+)-PCB 136 in tissues and feces, however, decreased with increasing dose, an observation that suggests a saturation of the disposition process responsible for the enantiomeric enrichment. Overall, the present study demonstrates that in addition to species, exposure source, exposure frequency, and other factors, levels of PCB exposure are an important determinant of the enantiomeric enrichment of PCBs in mice and, most likely, other species.
Why Dissection Videos Should Not Replace Cadaver Prosections in the Gross Veterinary Anatomy Curriculum: Results from a Comparative Study
Authors: Theoret Christine Laura , Carmel Éric-Norman , Bernier Sonia
Published: January 2008

The goal of our study was to evaluate the impact of a tool intended to eliminate large-animal cadavers from the anatomy laboratory, in view of their prohibitive cost and the logistic difficulties they pose. We sought to determine whether a commented video of the bovine abdominal cavity could effectively replace a prosection of this region. The hypothesis was that students receiving video instruction would achieve lower scores on a post-instructional exam than those benefiting from a commented cadaver prosection.

A commented video of the bovine abdominal cavity was compared to a prosection covering identical material. Seventy-five first-year students, having received no prior instruction on the region of interest, were divided into two groups of equivalent knowledge: group A received prosection instruction (N = 38) and group B, video instruction (N = 37). Following instruction, students completed a test on a cadaver, requiring that they correctly match 15 labeled structures with a list of 40 possible answers. Statistical analysis consisted of a repeated-measures linear model with group (A vs. B) as a between-subject factor and time (pre- vs post-test) as a within-subject factor, with significance at p ≤ 0.05.

Students in group A achieved mean scores of 9.21 ± 0.31, while those in group B scored 7.65 ± 0.31. Although both groups significantly improved following instruction, there was a statistically significant difference in the post-instruction scores between groups A and B (p = 0.0007), in favor of the prosection group. The major comment in favor of cadaver prosection pertained to the sensory experience; in favor of video instruction, students stressed accessibility to the pedagogical material for autonomous learning and revision as well as superior viewing compared to the setup adopted for prosections.

In conclusion, while our data suggest that cadaver prosections are superior to video demonstrations, it is apparent that students can learn bovine abdominal anatomy by both methods. Future investigations on the subject of alternative teaching methods are warranted.
Meat Inspection Education in Finnish Veterinary Curriculum
Authors: Lundén Janne , Björkroth Johanna , Korkeala Hannu
Published: January 2008

This article describes the Finnish meat-inspection curriculum and presents an expert-panel evaluation of meat-inspection education. The work tasks of the meat-inspection veterinarian are challenging and include classical meat inspection, meat hygiene, hygiene control, and animal disease and welfare. The meat-inspection veterinarian is not only an inspector, which by itself is very demanding, but also an expert or “consultant” on food safety. The significant role of the meat-inspection veterinarian in society puts high demands on meat-inspection education, which should provide veterinary students with sufficient tools to perform meat inspection and hygiene control in slaughterhouses, cutting premises, and further processing plants. To be of high quality, such education must be evaluated from time to time. An expert panel evaluated Finnish undergraduate meat-inspection education and found that it provides veterinary students with good knowledge of meat inspection. The structure of the curriculum, with theoretical studies followed by four weeks of practice in a slaughterhouse, was considered vital for learning and for creating interest in meat inspection. The evaluation also revealed that certain subjects should receive greater emphasis and some new subjects should be introduced. Hygiene-control tasks, in particular, have increased and should receive more emphasis in education. Personnel management and interaction skills should be introduced into the curriculum as these skills influence all the duties of the meat-inspection veterinarian. This article outlines the subjects to be included in the modern, high-quality meat-inspection curriculum recommended by the expert panel.