bluuebunny/crossref_metadata_2025 huggingface dataset:
Mentoring in the creative economy
Authors: Rautkorpi Tiina
Published: January 2008

Finland is among those countries leading research into the creative economy and co-configuration. A new economy preoccupied with intangible values and cultural meaning-making is being promoted in Finnish business and industry. This article argues that traditions of mentoring in business and education have much to offer in creating the necessary conditions for the new forms of work needed in this context. Mentoring as an area is ripe for development in art education also where attempts are under way to break down existing boundaries between the economy, society and the arts.
Antiapoptotic and Trophic Effects of Dominant-Negative Forms of Dual Leucine Zipper Kinase in Dopamine Neurons of the Substantia NigraIn Vivo
Authors: Chen Xiqun , Rzhetskaya Margarita , Kareva Tatyana , Bland Ross , During Matthew J. , Tank A. William , Kholodilov Nikolai , Burke Robert E.
Published: January 2008

There is extensive evidence that the mitogen-activated protein kinase (MAPK) signaling cascade mediates programmed cell death in neurons. However, current evidence that the mixed linage kinases (MLKs), upstream in this cascade, mediate cell death is based, in thein vivocontext, entirely on pharmacological approaches. The compounds used in these studies have neither complete specificity nor selectivity among these kinases. Therefore, to better address the molecular specificity of the MLKs in mediating neuron death, we used dominant-negative constructs delivered by AAV (adenoassociated virus) vector transfer. We assessed effects in a neurotoxin model of parkinsonism, in which neuroprotection by pharmacologic MLK inhibition has been reported. We find that two dominant-negative forms of dual leucine zipper kinase (DLK) inhibit apoptosis and enhance long-term survival of dopamine neurons, but a dominant negative of MLK3 does not. Interestingly, the kinase-dead form of DLK not only blocks apoptosis but also has trophic effects on dopamine neurons. Although the MAPK cascade activates a number of downstream cell death mediators, we find that inhibition of DLK correlates closely with blockade of phosphorylation of c-jun and prevention of cell death. We conclude that DLK acts primarily through c-jun phosphorylation to mediate cell death in this model.
Low-Pass Filter Properties of Basal Ganglia–Cortical–Muscle Loops in the Normal and MPTP Primate Model of Parkinsonism
Authors: Rivlin-Etzion Michal , Marmor Odeya , Saban Guy , Rosin Boris , Haber Suzanne N. , Vaadia Eilon , Prut Yifat , Bergman Hagai
Published: January 2008

Oscillatory bursting activity is commonly found in the basal ganglia (BG) and the thalamus of the parkinsonian brain. The frequency of these oscillations is often similar to or higher than that of the parkinsonian tremor, but their relationship to the tremor and other parkinsonian symptoms is still under debate. We studied the frequency dependency of information transmission in the cortex–BG and cortex–periphery loops by recording simultaneously from multiple electrodes located in the arm-related primary motor cortex (MI) and in the globus pallidus (GP) of two vervet monkeys before and after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment and induction of parkinsonian symptoms. We mimicked the parkinsonian bursting oscillations by stimulating with 35 ms bursts given at different frequencies through microelectrodes located in MI or GP while recording the evoked neuronal and motor responses. In the normal state, microstimulation of MI or GP does not modulate the discharge rate in the other structure. However, the functional-connectivity between MI and GP is greatly enhanced after MPTP treatment. In the frequency domain, GP neurons usually responded equally to 1–15 Hz stimulation bursts in both states. In contrast, MI neurons demonstrated low-pass filter properties, with a cutoff frequency above 5 Hz for the MI stimulations, and below 5 Hz for the GP stimulations. Finally, muscle activation evoked by MI microstimulation was markedly attenuated at frequencies higher than 5 Hz. The low-pass properties of the pathways connecting GP to MI to muscles suggest that parkinsonian tremor is not directly driven by the BG 5–10 Hz burst oscillations despite their similar frequencies.
Kainate Modulates Presynaptic GABA Release from Two Vesicle Pools
Authors: Mathew Seena S. , Pozzo-Miller Lucas , Hablitz John J.
Published: January 2008

Inhibitory control of local neuronal circuits is critical for prefrontal cortical functioning. Modulation of inhibitory circuits by several neuromodulators has been demonstrated, but the underlying mechanisms are unclear. Neuromodulator effects on synaptic vesicle recycling have received little attention. Controversy also exists whether different pools of synaptic vesicles underlie spontaneous and activity-dependent vesicle recycling. We therefore investigated the effects of kainate receptor activation on GABA release in rat prefrontal neocortex using electrophysiological and styryl dye imaging techniques in acute neocortical slices. Electrophysiological studies demonstrated that activation of kainate receptors increased the frequency, but not the amplitude of miniature IPSCs, suggesting a presynaptic action. Using styryl dye staining and multiphoton excitation microscopy, we visualized vesicular release from inhibitory GABAergic terminals in prefrontal cortical slices and demonstrate that kainate facilitates GABA release from presynaptic terminals. Our findings also indicate the presence of two pools of GABA-containing vesicles within inhibitory terminals. Kainate modulates both pools but only when vesicles are endocytosed and exocytosed by matching protocols of dye loading, i.e., spontaneous or evoked afferent activity.
Thrombin Induces Long-Term Potentiation of Reactivity to Afferent Stimulation and Facilitates Epileptic Seizures in Rat Hippocampal Slices: Toward Understanding the Functional Consequences of Cerebrovascular Insults
Authors: Maggio Nicola , Shavit Efrat , Chapman Joab , Segal Menahem
Published: January 2008

The effects of thrombin, a blood coagulation serine protease, were studied in rat hippocampal slices, in an attempt to comprehend its devastating effects when released into the brain after stroke and head trauma. Thrombin acting through its receptor, protease-activated receptor 1 (PAR1), produced a long-lasting enhancement of the reactivity of CA1 neurons to afferent stimulation, an effect that saturated the ability of the tissue to undergo tetanus-induced long-term potentiation. This effect was mediated by activation of a PAR1 receptor, because it was shared by a PAR1 agonist, and was blocked by its selective antagonist. An independent effect of thrombin involved the lowering of the threshold for generating epileptic seizures in CA3 region of the hippocampus. Thus, the experiments in a slice mimicked epileptic and cognitive dysfunction induced by thrombin in the brain, and suggest that these effects are mediated by activation of the PAR1 receptor.
Cumulative Activation of Voltage-Dependent KVS-1 Potassium Channels
Authors: Rojas Patricio , Garst-Orozco Jonathan , Baban Beravan , de Santiago-Castillo Jose Antonio , Covarrubias Manuel , Salkoff Lawrence
Published: January 2008

In this study, we reveal the existence of a novel use-dependent phenomenon in potassium channels, which we refer to as cumulative activation (CA). CA consists of an increase in current amplitude in response to repetitive depolarizing step pulses to the same potential. CA persists for up to 20 s and is similar to a phenomenon called “voltage-dependent facilitation” observed in some calcium channels. The KVS-1 K+channel, which exhibits CA, is a rapidly activating and inactivating voltage-dependent potassium channel expressed in chemosensory and other neurons ofCaenorhabditis elegans. It is unusual in being most closely related to the Shab (Kv2) family of potassium channels, which typically behave like delayed rectifier K+channels in other species. The magnitude of CA depends on the frequency, voltage, and duration of the depolarizing step pulse. CA also radically changes the activation and inactivation kinetics of the channel, suggesting that the channel may undergo a physical modification in a use-dependent manner; thus, a model that closely simulates the behavior of the channel postulates the existence of two populations of channels, unmodified and modified. Use-dependent changes in the behavior of potassium channels, such as CA observed in KVS-1, could be involved in functional mechanisms of cellular plasticity such as synaptic depression that represent the cellular basis of learning and memory.
Glial Dysfunction in Parkin Null Mice: Effects of Aging
Authors: Solano Rosa M. , Casarejos Maria J. , Menéndez-Cuervo Jamie , Rodriguez-Navarro Jose A. , García de Yébenes Justo , Mena Maria A.
Published: January 2008

Parkin mutations in humans produce parkinsonism whose pathogenesis is related to impaired protein degradation, increased free radicals, and abnormal neurotransmitter release. The role of glia in parkin deficiency is little known. We cultured midbrain glia from wild-type (WT) and parkin knock-out (PK-KO) mice. After 18–20 din vitro, PK-KO glial cultures had less astrocytes, more microglia, reduced proliferation, and increased proapoptotic protein expression.

PK-KO glia had greater levels of intracellular glutathione (GSH), increased mRNA expression of the GSH-synthesizing enzyme γ-glutamylcysteine synthetase, and greater glutathioneS-transferase and lower glutathione peroxidase activities than WT. The reverse happened in glia cultured in serum-free defined medium (EF12) or in old cultures. PK-KO glia was more susceptible than WT to transference to EF12 or neurotoxins (1-methyl-4-phenylpyridinium, blockers of GSH synthesis or catalase, inhibitors of extracellular signal-regulated kinase 1/2 and phosphatidylinositol 3 kinases), aging of the culture, or combination of these insults. PK-KO glia was less susceptible than WT to Fe2+plus H2O2and less responsive to protection by deferoxamine.

Old WT glia increased the expression of heat shock protein 70, but PK-KO did not. Glia conditioned medium (GCM) from PK-KO was less neuroprotective and had lower levels of GSH than WT. GCM from WT increased the levels of dopamine markers in midbrain neuronal cultures transferred to EF12 more efficiently than GCM from PK-KO, and the difference was corrected by supplementation with GSH. PK-KO-GCM was a less powerful suppressor of apoptosis and microglia in neuronal cultures. Our data prove that abnormal glial function is critical in parkin mutations, and its role increases with aging.
Transient Receptor Potential Channels in Sensory Neurons Are Targets of the Antimycotic Agent Clotrimazole
Authors: Meseguer Victor , Karashima Yuji , Talavera Karel , D'Hoedt Dieter , Donovan-Rodríguez Tansy , Viana Felix , Nilius Bernd , Voets Thomas
Published: January 2008

Clotrimazole (CLT) is a widely used drug for the topical treatment of yeast infections of skin, vagina, and mouth. Common side effects of topical CLT application include irritation and burning pain of the skin and mucous membranes. Here, we provide evidence that transient receptor potential (TRP) channels in primary sensory neurons underlie these unwanted effects of CLT. We found that clinically relevant CLT concentrations activate heterologously expressed TRPV1 and TRPA1, two TRP channels that act as receptors of irritant chemical and/or thermal stimuli in nociceptive neurons. In line herewith, CLT stimulated a subset of capsaicin-sensitive and mustard oil-sensitive trigeminal neurons, and evoked nocifensive behavior and thermal hypersensitivity with intraplantar injection in mice. Notably, CLT-induced pain behavior was suppressed by the TRPV1-antagonist BCTC [(N-(-4-tertiarybutylphenyl)-4-(3-cholorpyridin-2-yl)tetrahydropyrazine-1(2H)-carboxamide)] and absent in TRPV1-deficient mice. In addition, CLT inhibited the cold and menthol receptor TRPM8, and blocked menthol-induced responses in capsaicin- and mustard oil-insensitive trigeminal neurons. The concentration for 50% inhibition (IC50) of inward TRPM8 current was ∼200 nm, making CLT the most potent known TRPM8 antagonist and a useful tool to discriminate between TRPM8- and TRPA1-mediated responses. Together, our results identify TRP channels in sensory neurons as molecular targets of CLT, and offer means to develop novel CLT preparations with fewer unwanted sensory side effects.
Kalirin-7 Is an Essential Component of both Shaft and Spine Excitatory Synapses in Hippocampal Interneurons
Authors: Ma Xin-Ming , Wang Yanping , Ferraro Francesco , Mains Richard E. , Eipper Betty A.
Published: January 2008

Kalirin, a multifunctional Rho GDP/GTP exchange factor, plays a vital role in cytoskeletal organization, affecting process initiation and outgrowth in neurons. Through alternative splicing, theKaliringene generates multiple functionally distinct proteins. Kalirin-7 (Kal7) is the most prevalent isoform in the adult rat hippocampus; it terminates with a postsynaptic density-95 (PSD-95)/Discs large/zona occludens-1 (PDZ) binding motif, is localized to the postsynaptic density, interacts with PSD-95, and causes the formation of dendritic spines when overexpressed in pyramidal neurons. Levels of Kal7 are low in the dendrites of hippocampal aspiny interneurons. In these interneurons, Kal7 is localized to the postsynaptic side of excitatory synapses onto dendritic shafts, overlapping clusters of PSD-95 and NMDA receptor subunit NR1. Selectively decreasing levels of Kal7 decreases the density of PSD-95-positive, bassoon-positive clusters along the dendritic shaft of hippocampal interneurons. Overexpression of Kal7 increases dendritic branching, inducing formation of spine-like structures along the dendrites and on the soma of normally aspiny hippocampal interneurons. Essentially all of the spine-like structures formed in response to Kal7 are apposed to vesicular glutamate transporter 1-positive, bassoon-positive presynaptic endings; GAD-positive, vesicular GABA transporter-positive inhibitory endings are unaffected. Almost every Kal7-positive dendritic cluster contains PSD-95 along with NMDA (NR1) and AMPA (GluR1 and GluR2) receptor subunits. Kal7-induced formation of spine-like structures requires its PDZ binding motif, and interruption of interactions between the PDZ binding motif and its interactors decreases Kal7-induced formation of spine-like structures. Kal7 thus joins Shank3 and GluR2 as molecules with a level of expression at excitatory synapses that titrates the number of dendritic spines.
Very Austen: Accounting for the Language of Emma
Authors: Barchas Janine
Published: January 2008

Jane Austen uses the word “very” in Emma (1815) at a surprisingly high frequency, one that significantly outpaces its appearance in her other novels as well as in the works of her contemporaries. This essay resists dismissing this smallish word as a nugatory accidental and explores its possible interpretive functions, especially in light of the novel's dominant concerns with confinement and isolation. The essay argues that the “very”-studded language of Emma indicts truth-telling in the novel, bears the linguistic fingerprint of Austen's own idiolect, and bespeaks her interest in early linguistics. The essay finds in the novel's incessant “very”s the shaping of a subtle imagined linguistic quirk that marks small-town life. Isolation asserts itself as a dominant subtext of Emma—isolation through mechanisms as various as illness, weather, physical space, social circumstances, and, this essay argues, language. If the application of “very” mimics the dulling repetition of life in Highbury and the slow linguistic isolation of country-living, it also reflects Austen's extraordinary control over her own idiolect.
Pulmonary infections after lung transplantation
Authors: Czebe Krisztina , Antus Balázs , Varga Marina , Csiszér Eszter
Published: January 2008

A tüdőtranszplantáció napjainkban már rutinszerűen végzett beavatkozássá vált a végstádiumú parenchymás és vascularis tüdőbetegségekben. Az elmúlt két évtized során több mint 20 ezer tüdőtranszplantációt végeztek a világon. Az immunszuppresszív szerek fejlődésének eredményeként az életet veszélyeztető akut rejekciók száma jelentősen csökkent, az első éven belüli halálozás csupán 2%-át okozza. A legnagyobb arányban az infekciók felelősek a korai és a késői morbiditásért és mortalitásért. A posztoperatív első 30 napon belüli halálozás 21,2%-a, az első éven belüli halálozás 40%-a infekciós eredetű. Az első hónapban a betegek 35–70%-ánál bakteriális pneumónia alakul ki, amelynek kb. felét Gram-negatív pálcák okozzák, dominálóan Pseudomonas-törzsek. A betegek a műtétet követően antibiotikus profilaxisban részesülnek, amit aztán a donortüdőből kimutatott törzs rezisztenciatesztje alapján módosíthatunk. A korai posztoperatív időszakban az invazív gomba- (Aspergillus-, Candida-) és CMV-infekciók a 100 napig tartó inhalatív amphotericin és szisztémás valganciklovir-profilaxis hatására kevesebb mint 10–10%-ban lépnek fel. Számuk a profilaxis befejezte után emelkedik. A későbbiekben kialakuló bronchiolitis obliterans szindróma (BOS) szintén hajlamosít a fertőzésekre. Ennek jelentőségét az adja, hogy 5 évvel a műtét után a betegek kb. 50%-ánál detektálható a BOS. Az infekciók sikeres leküzdésének alapja a rutinszerűen, illetve a tünetek fellépte után minél hamarabb elvégzett kontroll (laboratóriumi, radiológiai, légzésfunkciós, köpet- és bronchoszkópos vizsgálatok), majd a célzott terápia bevezetése. A munka célja a tüdőtranszplantáltaknál jelentkező leggyakoribb infekciók klinikai manifesztációjának, diagnosztikájának és kezelésének áttekintése.
A new possible strategy of prevention and preventive treatment of age-related macular degeneration
Authors: Fischer Tamás
Published: January 2008

Az időskori maculadegeneratio (AMD) létrejöttében és későbbi alakulásában az endothel-diszfunkciónak (ED) kulcsszerepe van. Az endothelfunkció-zavarra, illetve annak következményes kóros működésbeli, strukturális és anyagcsere-elváltozásaira különböző gyógyszerek (ACE-inhibitorok, AR-blokkolók, statinok, acetilszalicilsav, trimetazidin) kedvező hatással vannak. Az ED kedvező befolyásolásának, sikeres kezelésének jótékony hatása, az idült vascularis, cardiovascularis betegségekben mára már evidencia: az ACE-gátlók, az AR-blokkolók és a statinok helyreállítják az oxidatív stressz (OS) indukálta ED-ban a felborult egyensúlyt a vasoconstrictorok és vasodilatatorok, a növekedési faktorok és azok gátlói, a proinflammatorok és antiinflammatorok, valamint a prothromboticus és fibrinolyticus tényezők között, gátolják az OS kifejlődését, illetve káros hatásainak kialakulását; a thrombocyta-antiaggregatiós pleiotrop aspirin az endothel nyugalmi állapotának helyreállításában működik hatásosan közre, a trimetazidin pedig segít normalizálni, helyreállítani az elégtelenül funkcionáló szervszövet kóros anyagcserestátuszát. Mivel a humán érrendszer egységes, konszubsztanciális, ezért az ED-ban kedvezően ható gyógyszerek a szem, illetve a retina ereiben is előnyösen hatnak. A fentiek alapján logikus a feltevés, hogy elsődleges és másodlagos prevenciós tevékenység részeként adjunk ilyen gyógyszereket 1) azoknak, akiknek ugyan nincsen maculopathiájuk, de fennállnak az ED-t indukáló AMD-rizikótényezők, és 50 évesek elmúltak; 2) azoknak a betegeknek – a másik szem maculadegeneratiós károsodásának kialakulását megelőzendő –, akiken egyoldali maculopathiát állapítottak meg; 3) végül azoknak – a rosszabbodás kivédése és az esetleges javulás reményében –, akiknél mindkét szemen maculadegeneratiót diagnosztizáltak. – Természetesen emellett törekedjünk az OS-t és konszekutív ED-t indukáló maculadegeneratiós rizikótényezők teljes kiiktatására. – Dolgozatomban a fenti, indirekt bizonyítékokon is alapuló következtetéseket tárgyalom meg.
Seasonal variation of polychlorinated biphenyl congeners in surficial sediment, trapped settling material, and suspended particulate material in Lake Michigan, USA
Authors: Robinson Sander D , Landrum Peter F , van Hoof Patricia L , Eadie Brian J
Published: January 2008

A unique time series of surface sediment, trapped settling material, and suspended particulate material polychlorinated biphenyl (PCB) samples were collected at a 45-m deep site off Grand Haven (MI, USA) over a 14-month period. Both concentrations and congener distributions remained constant for the sediments, although there were seasonal and interannual variability in the other matrices. Trapped settling material and suspended particulate material PCB concentrations were substantially lower (∼50%) in 1997 than in the samples from December 1997 through July 1998. The cause could not be determined from the data collected, but there were some very large storms during the winter–spring period of 1998, resulting in major sediment resuspension throughout the southern basin. Observed seasonal variation in PCB concentration and congener distribution on particles likely was due to the changes in particle composition. These include particle size and the source of particles (such as the amount of resuspended sediment in trapped settling material), and the role of diagenesis of the organic matter on particles.
Ultra-trace analysis of multiple endocrine-disrupting chemicals in municipal and bleached kraft mill effluents using gas chromatography–high-resolution mass spectrometry
Authors: Ikonomou Michael G , Cai Sheng-Suan , Fernandez Marc P , Blair Joel D , Fischer Maike
Published: January 2008

A comprehensive gas chromatographic–high-resolution mass spectrometric (GC-HRMS)–based method was developed that permitted the simultaneous determination of 30 estrogenic endocrine-disrupting chemicals (EDCs) and related compounds, including surfactants, biogenic and synthetic steroids, fecal sterols, phytoestrogens, and plasticizers, in wastewater. Features of the method include low sample volume (∼40 ml), optimized Florisil® cleanup to minimize matrix interferences and optimized analyte derivatization to improve sensitivity via GC-HRMS. Detection limits were in the low- to mid-ng/L range, and recoveries were greater than 60% for most target analytes. This new method allows for high throughput analysis of many organic wastewater contaminants in a complex matrix with relative standard deviation of less than 15% for most measurable compounds. The applicability of the method was demonstrated by examining wastewater samples from different origins. Compounds such as di(2-ethylhex-yl)phthalate, cholesterol, cholestanol, and other cholesterol derivatives were measured in much higher concentrations in untreated sewage and were reduced substantially in concentration by the treatment process. However, steroidal compounds, particularly estrone (E1), 17β-estradiol (E2), and estriol (E3), as well as plant sterols (except stigmastanol), were greater in the treated municipal wastewater versus the untreated effluent. Plant and fungi sterols, stigmastanol and ergosterol, were found largely associated with bleached kraft mill effluent (BKME) as compared to the municipal effluents.
Relative impact of coexposure compared to single-substance exposure on the biotransformation and toxicity of benzo[a]pyrene and fluoranthene in the marine polychaete Capitella sp. I
Authors: Palmqvist Annemette , Rasmussen Lene Juel , Forbes Valery E
Published: January 2008

Most biotransformation studies to date have concentrated on single-substance exposures. The biotransformation ability of organisms exposed to a single substance, however, may differ from that of organisms coexposed to binary or complex mixtures. The marine polychaete Capitella sp. I was exposed to either 31 μg/g dry weight sediment of benzo[a]pyrene (BaP) in a single-substance exposure or to a mixture of 31 and 28 μg/g dry weight sediment of BaP and fluoranthene (Flu), respectively (coexposure). Biotransformation capability and DNA damage were compared between treatments. Worms exposed to BaP alone accumulated total BaP equivalents to a significantly higher degree than coexposed worms (final body burden: 117.14 ± 3.52 μg BaP equivalents/g dry wt tissue and 69.78 ± 8.58 μg BaP equivalents/g dry wt tissue, respectively), probably because of a higher degree of BaP biotransformation in the latter. In addition, a larger percentage of the accumulated BaP equivalents was in the form of parent compound in worms exposed to BaP alone compared to coexposed worms on day 10 (87 and 56%, respectively). In coexposed worms, Flu was both accumulated and biotransformed to a considerably greater degree than BaP (final Flu body burden: 181.85 ± 18.46 μg Flu equivalents/g dry wt tissue, 24% as parent compound). Neither treatment resulted in significant effects on growth or DNA damage. The present study shows that the extent to which bioaccumulation factors estimated from single-substance exposures have relevance for the field situation will depend on the degree to which accumulation is influenced by the presence of other contaminants. These results therefore are relevant for assessing risks from contaminated sediments.
Early life-stage toxicity test for copper pyrithione and induction of skeletal anomaly in a teleost, the mummichog (Fundulus heteroclitus)
Authors: Mochida Kazuhiko , Ito Katsutoshi , Harino Hiroya , Onduka Toshimitsu , Kakuno Akira , Fujii Kazunori
Published: January 2008

We used a teleost fish, the mummichog (Fundulus heteroclitus), to conduct early life-stage toxicity testing for copper pyrithione (CuPT). Fertilized mummichog eggs were exposed to CuPT at various concentrations for 50 d under continuous flow-through conditions. Hatchability, survival, growth, and morphologic abnormalities were measured. Hatchability did not differ significantly between any experimental group and control groups. Survival and growth were significantly reduced at 50 d in the groups exposed to 2 or 4 μg/L CuPT. During the test, morphologic abnormalities, such as vertebral deformity and formation of inflammatory masses in the lateral muscles, occurred in fish exposed to CuPT. Light and electron microscopic studies indicated that muscle dysfunction played a role in the vertebral deformity and revealed that the inflammatory mass was composed mainly of macrophages and necrotic myocytes. We consider that macrophages infiltrated and phagocytized necrotic cells, thus forming the inflammatory mass. In addition, acetylcholinesterase activity was markedly decreased in the 2- and 4-μg/L exposure groups, suggesting the skeletal deformity was due to mechanisms similar to those proposed for organophosphorous pesticide exposure.
Effects of dietary selenium on reproduction and body mass of captive lesser scaup
Authors: DeVink Jean-Michel A , Clark Robert G , Slattery Stuart M , Scheuhammer Tony M
Published: January 2008

The continental population of scaup has declined over the last three decades to levels that remain well below conservation goals. One proposed hypothesis for this decline is that increasing exposure to contaminants has led to decreased fitness in scaup, and selenium (Se) has been identified as a contaminant of concern. We conducted an experiment with captive scaup to simulate late spring migration exposure to environmentally relevant doses of dietary Se (control [<1 μg/g total Se], and 7.5 μg/g and 15 μg/g Se as selenomethionine) for 30 d, after which excess Se was removed from the diets prior to laying. Overall, we found no treatment effect on body mass, breeding probability, or clutch initiation dates. Egg Se concentrations of the 15 μg/g and 7.5 μg/g groups decreased rapidly after Se-supplemented diets were removed and within 12 and 8 d post treatment, respectively, were below the suggested egg teratogenicity threshold of 9 μg/g (dry wt). We found no significant intraclutch variation in egg Se deposition. Blood Se concentrations differed between groups in proportion to dose, with a half-life of 16 and 22 d for females when removed from the 15 and 7.5 μg/g treatments, respectively. Our findings suggest that exposure to dietary Se concentrations representative of spring-staging environments is insufficient to adversely affect body mass or reproduction in scaup that subsequently migrate to uncontaminated breeding areas (e.g., in prairie-parklands and boreal forest). Further studies of Se effects on scaup should focus on wintering birds in contaminated habitats.
Intercalibration exercise using a stickleback endocrine disrupter screening assay
Authors: Allen Yvonne T , Katsiadaki Ioanna , Pottinger Tom G , Jolly Cecile , Matthiessen Peter , Mayer Ian , Smith Andy , Scott Alexander P , Eccles Paul , Sanders Matthew B , Pulman Kim G.T , Feist Stephen
Published: January 2008

The Organisation for Economic Cooperation and Development (OECD) is currently validating a short-term fish screening protocol for endocrine disrupters (estrogens, androgens, and their antagonists and aromatase inhibitors), using three core species: fathead minnow, Japanese medaka, and zebrafish. The main endpoints proposed for the first phase of validation of the screen are vitellogenin (VTG) concentration, gross morphology (secondary sexual characteristics and gonado-somatic index), and gonadal histopathology. A similar protocol is concurrently being developed in the United Kingdom using the three-spined stickleback, with identical endpoints to those for the core species and, in addition, a unique androgen-specific endpoint in the form of spiggin (glue protein) induction. To assess the suitability of this species for inclusion in the OECD protocol alongside the core species, an intercalibration was conducted using 17β-estradiol (a natural estrogen) and trenbolone (a synthetic androgen), thus mimicking a previous intercalibration with the core species. All three participating laboratories detected statistically significant increases in VTG in males after 14 d exposure to nominal concentrations of 100 ng/L 17β-estradiol and statistically significant increases in spiggin in females after 14 d exposure to nominal concentrations of 5,000 ng/L trenbolone. The stickleback screen is reliable, possessing both relevant and reproducible endpoints for the detection of potent estrogens and androgens. Further work is underway to assess the relevance and suitability of the screen for weakly acting estrogens, anti-androgens, and aromatase inhibitors.
Comparison of pesticide concentrations in streams at low flow in six metropolitan areas of the United States
Authors: Sprague Lori A , Nowell Lisa H
Published: January 2008

To examine the effect of urban development on pesticide concentrations in streams under low-flow conditions, water samples were collected at stream sites along an urban land use gradient in six environmentally heterogeneous metropolitan areas of the United States. In all six metropolitan areas, total insecticide concentrations generally increased significantly as urban land cover in the basin increased, regardless of whether the background land cover in the basins was agricultural, forested, or shrub land. In contrast, the response of total herbicide concentrations to urbanization varied with the environmental setting. In the three metropolitan areas with predominantly forested background land cover (Raleigh–Durham, NC, USA; Atlanta, GA, USA; Portland, OR, USA), total herbicide concentrations increased significantly with increasing urban land cover. In contrast, total herbicide concentrations were not significantly related to urban land cover in the three remaining metropolitan areas, where total herbicide concentrations appeared to be strongly influenced by agricultural as well as urban sources (Milwaukee–Green Bay, WI, USA; Dallas–Fort Worth, TX, USA), or by factors not measured in the present study, such as water management (Denver, CO, USA). Pesticide concentrations rarely exceeded benchmarks for protection of aquatic life, although these low-flow concentrations are likely to be lower than at other times, such as during peak pesticide-use periods, storm events, or irrigation discharge. Normalization of pesticide concentrations by the pesticide toxicity index—an index of relative potential toxicity—for fish and cladocerans indicated that the pesticides detected at the highest concentrations (herbicides in five of the six metropolitan areas) were not necessarily the pesticides with the greatest potential to adversely affect aquatic life (typically insecticides such as carbaryl, chlorpyrifos, diazinon, and fipronil).
Changes in serum biochemical parameters of freshwater fish Oreochromis niloticus following prolonged metal (Ag, Cd, Cr, Cu, Zn) exposures
Authors: Öner Muazzez , Atli Gülüzar , Canli Mustafa
Published: January 2008

Fish serum may reflect status of many biochemical processes in the metabolism. Heavy metals, as environmental stressors, may alter serum biochemical parameters in fishes. Thus, freshwater fish, Oreochromis niloticus, were exposed to low levels (0.05 mg/L) of metals (silver [Ag], cadmium [Cd], copper [Cu], chromium [Cr], zinc [Zn]) to investigate responses of serum biochemical parameters over different exposure periods (0, 5, 10, 20, 30 d). Fish mortality occurred only in Ag exposure, as all fish died between days 12 to 16. Activities of alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) were altered only in Cu- and Cd-exposed fish. Both Cd and Cu exposures decreased the activity of ALP, although they increased the activities of ALT and AST. Glucose concentrations increased in Ag-, Cd-, and Cu-exposed fish, with a sharp increase occurring in Ag-exposed fish before mortality began. Total protein and triglyceride concentrations increased in Ag-exposed fish, although they decreased in Cu-exposed ones. However, all metal exposures increased cholesterol concentration in the serum. Concentration of blood urea nitrogen increased in Ag-, Cd-, and Cu-exposed fish, although it decreased in Cr-exposed ones. Calcium level decreased only in Cu-exposed fish, and Cl− level decreased in Ag-exposed fish. Silver and Cu exposures also decreased Na+ level in the serum. Cadmium and Cu exposures increased serum K+ levels. The present study, investigating the effects of environmentally realistic metal exposures on serum biochemical parameters, demonstrated that fish serum could sensitively reflect environmental metal stress. Thus, it suggests that serum biochemical parameters could be used as important and sensitive biomarkers in ecotoxicological studies concerning the effects of metal contamination and fish health.
Influence of contamination by organochlorine pesticides and polychlorinated biphenyls on the breeding of the Spanish Imperial Eagle (Aquila adalberti)
Authors: Hernández Mauro , González Luis M , Oria Javier , Sánchez Roberto , Arroyo Beatriz
Published: January 2008

We evaluated temporal and regional trends of organochlorine (OC) pesticide (including polychlorinated biphenyl [PCB]) levels in eggs of the Spanish Imperial Eagle (Aquila adalberti) collected in Spain between 1972 and 2003. Levels of p,p′-dichlorodiphenyldichloroethylene (DDE) and PCBs varied significantly (p = 0.022) among regions (central, western, and Doñana), being higher in Doñana than in the central and western populations (DDE: 1.64 ± 5.56, 0.816 ± 1.70, and 1.1 ± 2.66 μg/g, respectively; PCBs: 1.189 ± 5.0, 0.517 ± 1.55, and 0.578 ± 1.75 μg/g, respectively). Levels of DDE decreased with time, but a significant interaction was observed between region and time. In Doñana, egg volume and breadth as well as Ratcliffe Index were significantly lower after DDT use (p = 0.0018) than during the pre-DDT period (p = 0.0018); eggs were significantly smaller overall than in the other two regions (p = 0.04) and were smaller when DDE levels increased, even when controlling for regional differences (p = 0.04). Productivity in Doñana was significantly lower than in the other regions (p < 0.001). Clutch size in Doñana varied according to DDE concentrations (p = 0.01), with the highest DDE concentrations found in clutches consisting of one egg. When considering eggs with DDE levels greater than 3.5 μg/g, a significant effect of DDE on fertility was found (p = 0.03). Clutches with DDE levels greater than 4.0 μg/g had a higher probability of hatching failure (p = 0.07) and produced fewer fledglings (p = 0.03). If we consider 3.5 μg/g as the lowest-observable-adverse-effect level, the proportion of sampled clutches that exceeded that level in Doñana (29%) was significantly higher than in other regions (p < 0.001). These eggs showed a mean percentage of thinning of 16.72%. Contamination by OCs, mainly DDE, could explain, at least in part, the low productivity of the Spanish Imperial Eagles in Doñana.
Toxicity of human pharmaceuticals and personal care products to benthic invertebrates
Authors: Dussault Ève B , Balakrishnan Vimal K , Sverko Ed , Solomon Keith R , Sibley Paul K
Published: January 2008

Despite concerns about potential risks associated with the presence of pharmaceuticals and personal care products (PPCPs) in the environment, few toxicological data address the effects of these compounds. In aquatic systems, which often represent the final repository for PPCPs, increasing toxicological information regarding aquatic biota is improving our capacity to assess potential risks. However, responses of key biota, such as benthic invertebrates, have not been investigated as widely. In the present study, we examined the toxicity of four PPCPs—the lipid regulator atorvastatin (ATO), the antiepileptic drug carbamazepine (CBZ), the synthetic hormone 17α-ethinylestradiol (EE2), and the antimicrobial triclosan (TCS)—to the midge Chironomus tentans and the freshwater amphipod Hyalella azteca in 10-d waterborne exposures. The toxicity of the four compounds varied between 0.20 and 47.3 mg/L (median lethal concentration), with a relative toxicity ranking of TCS > EE2 > ATO > CBZ. Hyalella azteca was more sensitive than C. tentans to these compounds. The toxicity data were used in a hazard quotient approach to evaluate the risk posed by the four PPCPs to benthic invertebrates and other aquatic organisms. For each compound, a hazard quotient was calculated by dividing the lowest toxicity value by the highest exposure value found in the literature, to which an uncertainty factor was applied. With hazard quotients of 3.55 to 11.5, we conclude that potential risks exist toward benthic invertebrates for the toxicity of TCS and CBZ and that further investigations of these compounds are required to characterize more completely the risks to benthic organisms. In contrast, our data also indicate that considering the low concentrations currently detected in the environment, ATO and EE2 pose negligible risks to benthic invertebrates.
Envisioning the Future of Veterinary Medical Education: The Association of American Veterinary Medical Colleges Foresight Project, Final Report
Authors: Willis Norman G. , Monroe Fonda A. , Potworowski J. Andre , Halbert Gary , Evans Brian R. , Smith John E. , Andrews Kenneth J. , Spring Lynelle , Bradbrook Andrea
Published: January 2008

This report of the Association of American Veterinary Medical Colleges’ 2006 Foresight Project, developed under the leadership of an AAVMC Steering Committee, drew on the experience, imagination, and energetic participation of more than 95 participants from across the United States and Canada.

The environment of veterinary medicine is one of profound change. The current number of veterinarians is inadequate to address the present and future needs of society. To remain relevant, academic veterinary medicine must prepare veterinarians for what may come in the future. In order to be recognized and remunerated for their knowledge, compassion, integrity, and judgment, veterinarians must first demonstrate their relevance to new societal trends.

The objective of the study reported here was to determine a future direction for academic veterinary medicine using Foresight technology. The tools employed were challenge questions and the development of eight future possible scenarios. The study supported the need for change. This report recommends an adaptive and responsive system of veterinary medical education, achieved by defining those areas of professional focus that would address all the anticipated needs of society. An area of professional focus signifies a pathway leading to a DVM degree. Colleges would choose to offer selected areas of professional focus most appropriate to their capabilities, according to a binational plan. Veterinary medicine is integral to the well-being of any future society. This is a pivotal moment for the veterinary profession and for veterinary medical education. Leadership, collaboration, and a shared vision will determine the destiny of the profession.
How Useful Is Plastination in Learning Anatomy?
Authors: Latorre Rafael M. , García-Sanz Mari P. , Moreno Matilde , Hernández Fuensanta , Gil Francisco , López Octavio , Ayala Maria D. , Ramírez Gregorio , Vázquez Jose M. , Arencibia Alberto , Henry Robert W.
Published: January 2008

In recent years plastination has begun to revolutionize the way in which human and veterinary gross anatomy can be presented to students. The study reported here assessed the efficacy of plastinated organs as teaching resources in an innovative anatomy teaching/learning system. The main objective was to evaluate whether the use of plastinated organs improves the quality of teaching and learning of anatomy. For this purpose, we used an interdepartmental approach involving the departments of Veterinary Anatomy, Human Anatomy, Veterinary Surgery, and Education Development and Research Methods. The knowledge base of control and experimental student groups was examined before and after use of the fixed or plastinated resources, respectively, to gather information evaluating the effectiveness of these teaching resources. Significant differences (p < 0.001) between control and experimental groups of Human and Veterinary Anatomy were observed in the post-test results. The Veterinary Surgery students had the most positive opinion of the use of plastinated specimens. Using these data, we were able to quantitatively characterize the use of plastinated specimens as anatomy teaching resources. This analysis showed that all the plastinated resources available were heavily used and deemed useful by students. Although the properties of plastinated specimens accommodate student needs at various levels, traditional material should be used in conjunction with plastinated resources.
Teaching Histology to First-Year Veterinary Science Students Using Virtual Microscopy and Traditional Microscopy: A Comparison of Student Responses
Authors: Mills Paul C. , Bradley Andrew P. , Woodall Peter F. , Wildermoth Michael
Published: January 2008

Virtual microscopy (VM) is a comparatively recent innovation that is revolutionizing both the teaching of microscopic structure in human medicine and the concept of online diagnosis and telemedicine. The interactivity of the various commercially available browsers attempts to simulate the experience of looking down a microscope while offering advantages over traditional microscopy that include clarity of image, reduced infrastructure, and high flexibility, as the images are accessible online. We developed our own VM system, including customized software and a browser that was simple and intuitive to use, with the added advantage of further modifications possible to assist student learning. In this article, we report on a preliminary study wherein VM was introduced to veterinary science students in one course and directly compared to traditional microscopy to determine whether students would readily accept this new technology and which aspects of VM were advantageous. Responses from a survey form showed that students rated VM significantly higher than traditional microscopy as a tool to learn histology because it offers clearer images, the ability to learn collaboratively, more effective use of time, and the flexibility of online learning. Students also indicated a strong preference for the use of VM in future courses. These results suggest that VM is a flexible and enjoyable resource that could be useful to enhance the learning of microscopic structure in veterinary science courses.
Improving Response Rates: Introducing an Anonymous Longitudinal Survey Research Protocol for Veterinary Medical Students
Authors: Reisbig Allison M. J. , Hafen McArthur , White Mark B. , Rush Bonnie R.
Published: January 2008

With the Journal of Veterinary Medical Education's recent summer 2005 theme issue on stress, the mental-health concerns of veterinary medical students has been brought to the forefront of the field. Since it is anticipated that research on this topic will continue and that educational institutions may implement changes based upon these results, it is of the utmost importance that this research be of the highest quality. Of particular concern with human-subject inquiries are response rates and confidentiality. In order to accommodate these concerns, an example of a survey research protocol that promotes high response rates and minimizes threats to internal validity influenced by student mistrust in assurances of confidentiality is presented. Specifically, the protocol is designed to ensure anonymity and to preserve the ability to track students longitudinally through the use of anonymous longitudinal identifiers. This protocol was tested with the first-year class of veterinary medical students at Kansas State University in October 2004 and March 2005. The two data collection periods yielded 90% and 76% response rates, respectively. The matching rate of participants, according to the anonymous longitudinal identifiers from Time 1 to Time 2, was 88%.
Change in Higher Education: Understanding and Responding to Individual and Organizational Resistance
Authors: Lane India F.
Published: January 2008

In many fields, the ability of educators and practitioners to cope with rapid change is essential to sustained success. In veterinary medical education, as in other scientific disciplines, meaningful change is challenging to achieve and subject to resistance from many individual and organizational norms. Individual concerns often relate to fears of instability or uncertainty, loss of current status, or effects on individual time and workload. Sources of organizational resistance may include a conservative culture, fierce protection of current practices, and prevalence of disciplinary or territorial viewpoints. In academia, especially in scientific or medical fields, individuals appear to be strongly independent and conservative in nature, and generally skeptical of educational change. In this environment, a highly participatory process, with regular communication strategies and demonstrations or evidence that supports proposed changes, can be useful in facilitating change. An understanding of the nature of complex change, as well as of the reasons underlying resistance to change, and some methods to overcome these barriers are highly valuable tools for educational leaders.
Distance Education: Its Concepts and Constructs
Authors: Matkin Gary W.
Published: January 2008

The use of technology to provide improved access to higher education has a long history, but now, in addition to improved access, Internet-based technologies are truly transforming higher education, making learning and teaching more effective than ever before. The notion that distance education is inferior to classroom-based education is being countered by millions of student experiences every day. By now, patterns of the adoption of new instructional technology are clear. In this article, 10 “axioms” designed to provide guidance for leaders in higher education are presented and discussed. The implications of these axioms to veterinary medicine education are described.