bluuebunny/crossref_metadata_2025 huggingface dataset:
Loss of genetic variation and effective population size of Kirikuchi charr: implications for the management of small, isolated salmonid populations
Authors: Sato T. , Harada Y.
Published: March 2008

Small, isolated populations may face extinction due to a combination of inbreeding depression and other threats. Effective population size (Ne) is one comprehensive measure that allows us to evaluate the genetic status of a population, and to make management decisions regarding genetic viability. We simulated loss of genetic variation and estimated Ne for two small, isolated populations of Kirikuchi charr Salvelinus leucomaenis japonicus, the endangered, southernmost local populations of the genus Salvelinus in the world, using VORTEX, an individual‐based stochastic PVA model. Approximately half of the genetic variation was lost over 200 years regardless of census population size and demographic parameters, and Ne estimates were roughly 50 in each of the two populations, suggesting the possibility of inbreeding depression. The target population size of Ne>500, by securing long‐term viability, is several times that of the present size of each of the populations studied, and no local habitats maintaining such a target number are considered to exist. The results strongly indicate a need for recovering natural connections and potential gene flow among local populations. However, the impending threat to these populations from non‐native charr widely distributed throughout the drainage has prevented the recovery of the connections. Given the small Ne of the two populations, it would be necessary to retain gene flow artificially within or across local populations. This will be true of many other salmonid populations that have been isolated or fragmented recently.
Translocation and early post‐release demography of endangered Laysan teal
Authors: Reynolds M. H. , Seavy N. E. , Vekasy M.S. , Klavitter J. L. , Laniawe L. P.
Published: March 2008

In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic post‐release monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival and reproduction of all founders, and their first‐generation offspring using radio telemetry for 2 years after the first release. Forty‐two Laysan teal were sourced directly from the only extant population on Laysan Island and transported 2 days by ship to Midway Atoll. All birds survived the translocation with nutritional and veterinary support, and spent between 4 and 14 days in captivity. Post‐release survival of 42 founders was 0.857 (95% CI 0.86–0.99) during 2004–2006 or annualized 0.92 (95% CI 0.83–0.98). Seventeen of 18 founding hens attempted nesting in the first two breeding seasons. Fledgling success was 0.57 (95% CI 0.55–0.60) in 2005 and 0.63 (95% CI 0.62–0.64) in 2006. The effective founding female population (Ne) was 13. We applied these initial demographic rates to model population growth. The nascent population size increased to >100 after only 2 years post‐release (λ=1.73). If this growth rate continues, the size of the Midway population could surpass the source population before 2010.
The sleeping policeman: understanding issues of enforcement and compliance in conservation
Authors: Keane A. , Jones J. P. G. , Edwards‐Jones G. , Milner‐Gulland E. J.
Published: March 2008

Rules governing human behaviour are at the heart of every system of natural resource management. Without compliance, however, rules are meaningless so effective enforcement is essential if conservation is to be successful. There is a large body of theory concerning enforcement and compliance with rules spread over several disciplines, including psychology, economics and sociology. However, there have been few attempts to extend this theory to conservation applications and there is little practical guidance for managers and conservation planners on the optimal design of enforcement programmes. We review approaches to understanding why individuals break rules and how optimal policy choices can reduce rule‐breaking, highlighting research which has specifically dealt with natural resources. Because of the difficulty of studying rule‐breaking behaviour directly, modelling approaches have been particularly important and have been used to explore behaviour at the individual, group and institutional levels. We illustrate the application of models of enforcement and compliance to conservation using the African elephantLoxodonta africanaas a case study. Further work is needed to create practical tools which can be applied to the design of enforcement measures in conservation. Particular challenges include understanding the importance of violations of rationality assumptions and incorporating intertemporal choice in models of decision making. In conclusion, we argue that a new field of robust theory and practice is urgently needed to ensure that issues of enforcement and compliance do not undermine conservation initiatives.
The Trans‐Tasman Cable, the Australasian Bridgehead and Imperial History
Authors: Smithies James
Published: March 2008

The extension of the ‘All Red’ telegraph network to Australia and New Zealand during the 1870s greatly enhanced communication between the centre and periphery, consolidating British imperial expansion and offering the Australasian colonies the opportunity to engage more fully in imperial affairs. For contemporaries, the Trans‐Tasman cable between Australia and New Zealand provided the final link in a grand imperial chain of communications, which promised to bolster their significance in world affairs and offset the cultural isolation which appeared to be stifling their development. The cable represented an essential bond between the furthest‐flung imperial ‘bridgehead’ (John Darwin) and the cultural and strategic centre of London. In real terms, however, the promises of the new technology of submarine telegraphy failed to live up to expectations. Although quickly integrated into New Zealanders’ dawning cultural nationalist myth, the cable was expensive and underused for many years. Its real significance lies in its symbolic power as a symbol of imperial expansion, and as a case study in the vagaries of technology transfer.
Disaster: A Useful Category of Historical Analysis
Authors: Bergman Jonathan
Published: March 2008

Disaster is one of those extraordinary phenomena that is ubiquitous yet indescribable. From supernatural occurrence to earthly force finally yielding to its present day configuration as a social event, disaster offers a unique lens with which to examine history. Beginning in the mid‐twentieth century, scholars set out to examine urban life, race, class, and politics through a variety of socially dislocating events. The historical literature is varied and deep. Conceptions of disaster are seldom the same, and often highlight the strained relationship between social and natural configurations. But historians examining disaster have not advocated a common creed of catastrophe, so much as sharing a familiar lexicon. That language is informed by social scientific literature, environmental studies, and topics such as urban life, race, class and politics. To be sure, the discourse of disaster has been quite supple, bridging disparate units of historical manufacture and blurring familiar categories of analysis. This article surveys the evolution of the term, its usage in American historiography and major scholarly trends. The article concludes with a cri de couer to bring greater visibility to disaster studies.
Victorian Psychology and the Novel
Authors: Stiles Anne
Published: March 2008

Over the last three decades, literary critics have evinced growing interest in nineteenth‐century psychology and its reciprocal relationship with the Victorian novel. The resulting body of interdisciplinary scholarship has yielded insight into how early and mid‐Victorian psychological movements (moral management, associationism, evolutionary psychology, and so forth) left their mark on realist authors like George Eliot and writers of sensation fiction such as Wilkie Collins or Mary Elizabeth Braddon. But these scholarly works have dealt less comprehensively with the psychological significance of late Victorian genres like the romance and neo‐Gothic novel. Moreover, literary critics are only beginning to explore the ways in which psychology subtly shaded into physiology during the late Victorian era. This materialist shift was felt most strongly after 1870, when cerebral localization experiments by David Ferrier, John Hughlings Jackson, and other neurologists linked specific emotions, faculties, and movements to discrete areas of the brain. These experiments suggested that human behavior amounted to the sum of various neurochemical impulses, a conclusion that raised hackles because it threatened cherished notions of the soul, will, and individual identity. Literary scholars have only recently discussed the ways in which late Victorian novels engaged with these unsettling neurological discoveries. Based on the early promise of these discussions, we might expect to see more work on Victorian brains than Victorian psyches in future literary criticism.
The Static Clock and the Old Manchild: Temporality in Twentieth‐Century African Literature
Authors: Barrows Adam
Published: March 2008

This essay provides an overview of critical trends in the study of time in twentieth‐century African and Diasporic African fiction. The pervasive tendency in Western historiography to treat Africa as occupying a space outside the narrative of historical progress and development has produced a critical counter‐reaction which celebrates the unique cultural rhythms and incommensurable experiences of African temporality. According to this influential critical model, most notably expressed by Bonnie J. Barthold in her 1981 study, Black Time, the project of African fiction is to attack the telos‐driven linearity of Western time, and to explore culturally indigenous temporal models of cyclicality, myth, and ritual which are fundamentally incomprehensible to the Western worldview. This critical model has been surprisingly inattentive, however, to competing tendencies in Diasporic African fiction which have insisted upon the pitfalls of temporal difference. Beginning with a survey of the ways in which theories of a uniquely African temporality have been both inherited and interrogated by contemporary critics, I turn to criticism of Ayi Kwei Armah's 1968 novel, The Beautyful Ones Are Not Yet Born, as a case study of a text that is particularly disserved by the prevailing critical paradigm.
Shakespeare's Books: Reading Dumb Eloquence and Speaking Breasts
Authors: Scott Charlotte
Published: March 2008

This paper is about the book in Shakespeare's plays; the book as an object, wherein the article may disclose narratives, corroborate stories, expose versions of reality and perspectives of presence; and the semiotic of the book, wherein the language of the book, of holding, touching, turning leaves, opening pages, reading, revealing and closing may simulate an idea of the body or mind in motion. This article is about how the metaphorical and material book appears on Shakespeare's stage, and how the physical and figurative presence of the book challenge the imaginative and representational conditions of Elizabethan theatre.
WT1 Expression Distinguishes Astrocytic Tumor Cells from Normal and Reactive Astrocytes
Authors: Schittenhelm Jens , Mittelbronn Michel , Nguyen Thai‐Dung , Meyermann Richard , Beschorner Rudi
Published: March 2008

Particularly in small brain biopsies, it might be difficult to distinguish reactive astrogliosis from low‐grade or infiltration zones of high‐grade astrocytomas. So far no immunohistochemical marker allows a reliable distinction. Recently, the over‐expression of Wilms' tumor gene product WT1 was reported in astrocytic tumor cells. However, no sufficient data on WT1 expression in normal or reactive astrocytes are available. Therefore, we investigated WT1 expression in paraffin‐embedded brain sections from 28 controls, 48 cases with astrogliosis of various etiology and 219 astrocytomas [World Health Organization (WHO) grades I–IV] by immunohistochemistry. In normal brains and in astrogliosis, expression of WT1 was restricted to endothelial cells. In astrocytomas, WT1‐positive tumor cells were found in pilocytic astrocytomas (66.7% of cases), diffuse astrocytomas (52.7%) WHO grade II (52.7%), anaplastic astrocytomas (83.4%) and glioblastomas (98.1%). Overall, the majority of all astrocytic neoplasms (84.5%) expressed WT1. Establishing a cut‐off value of 0% immunoreactive tumor cells served to recognize neoplastic astrocytes with 100% specificity and 68% sensitivity and was associated with positive and negative predictive values of 1 and 0.68, respectively. Therefore, WT1 expression in astrocytes indicates a neoplastic origin and might represent an important diagnostic tool to differentiate reactive from neoplastic astrocytes by immunohistochemistry.
Pineocytoma and Pineal Parenchymal Tumors of Intermediate Differentiation Presenting Cytologic Pleomorphism: A Multicenter Study
Authors: Fèvre‐Montange Michelle , Szathmari Alexandru , Champier Jacques , Mokhtari Karima , Chrétien Fabrice , Coulon Alix , Figarella‐Branger Dominique , Polivka Marc , Varlet Pascale , Uro‐Coste Emmanuelle , Fauchon François , Jouvet Anne
Published: March 2008

Cytologic pleomorphism has been described in a limited number of benign pineal tumors, namely pineocytoma (PC) and pineal parenchymal tumors (PPTs) of intermediate differentiation (PPTID). We examined the clinicopathologic features in a retrospective series of 14 cases (seven females and seven males aged from 10 to 65 years) of pleomorphic PPT. Seven cases were PC, with no mitoses and with areas of tumoral cells forming large pineocytomatous rosettes and other areas with giant cells containing hyperchromatic nuclei. The other seven were PPTID, presenting few mitoses (≤2), a Ki67 proliferation index between 3% and 7%, and predominantly composed of small neoplastic cells and scattered giant cells, sometimes multinucleated. In the 14 tumors, the proportion of pleomorphic areas was variable. Most tumoral cells showed extensive neuronal differentiation with strong expression of neuron‐specific enolase, synaptophysin and neurofilaments. Some of the neoplastic cells expressed S100 protein. The follow‐up period ranged from 1.2 to 13 years and only one PC and one PPTID progressed after stereotactic biopsy or incomplete resection. The lack of invasiveness and the low proliferation index of these tumors suggest a benign clinical course despite the marked pleomorphism, the latter of which can lead to upgrading.
Anaplastic Oligodendroglial Tumors: Refining the Correlation among Histopathology, 1p 19q Deletion and Clinical Outcome in Intergroup Radiation Therapy Oncology Group Trial 9402
Authors: Giannini Caterina , Burger Peter C. , Berkey Brian A. , Cairncross J. Gregory , Jenkins Robert B. , Mehta Minesh , Curran Walter J. , Aldape Ken
Published: March 2008

Intergroup Radiation Therapy Oncology Group Trial 9402 study, a phase III trial of chemotherapy plus radiotherapy (PCV‐plus‐RT) vs. radiotherapy alone for pure and mixed anaplastic oligodendroglioma confirmed the prognostic significance of 1p 19q deletion and showed that only progression‐free survival (PFS) was prolonged in PCV‐plus‐RT‐treated patients and only in association with 1p 19q deletion. We reviewed tumor histopathology, separating 115 tumors deemed to be classic for oligodendroglioma (CFO) from 132 lacking classic features of oligodendroglioma (NCFO) and evaluated the relationship of histopathology and 1p 19q status to treatment and outcome. The study disclosed: (i) overall survival (OS) of patients with CFO was significantly longer than for patients with NCFO (P < 0.0001) and was not affected by necrosis. Median OS for CFO patients with and without necrosis was 6.6 and 6.3 years (OS log‐rank P = not significant), respectively, in contrast to NCFO showing 1.9 and 3.3 years respectively (OS log‐rank P = 0.014). (ii) Classic oligodendroglial morphology was highly associated with 1p 19q deletion, present in 80% of CFO and only in 13% of NCFO. (iii) On multivariate analysis, both classic oligodendroglial morphology and 1p 19q deletion remained significantly associated with PFS and OS. (iv) Patients with CFO treated with PCV‐plus‐RT showed a trend toward increased survival compared with CFO treated with RT (P = 0.08). Median OS was not reached in the PCV‐plus‐RT group and was 6.3 years in RT group. These findings suggest that classic oligodendroglial morphology combined with 1p 19q deletion may in the future be predictive of chemotherapeutic response and survival.
CD133 Expression and Cancer Stem Cells Predict Prognosis in High‐grade Oligodendroglial Tumors
Authors: Beier Dagmar , Wischhusen Jörg , Dietmaier Wolfgang , Hau Peter , Proescholdt Martin , Brawanski Alexander , Bogdahn Ulrich , Beier Christoph P.
Published: March 2008

High‐grade oligodendroglial tumors, that is, anaplastic oligodendroglial tumors and glioblastomas with oligodendroglial component, differ significantly in terms of prognosis and response to chemotherapy. Differentiation might be difficult because the histological differences are vague and reliable markers are not established. We correlated the presence of putative cancer stem cells (CSC) in high‐grade oligodendroglial tumors (WHO grades III and IV) with clinical outcome. Tumors with favorable prognosis neither contained CSC nor did they show CD133 expression. Tumor cells resembled lineage‐restricted progenitor cells with limited proliferative capacity and differentiation profile. In contrast, CD133 expression and stem cell‐like tumor cells characterized tumors with poor prognosis. They showed neurosphere‐like growth, differentiated into cells of all neural lineages, and were tumorigenic in nude mice. In our series, CSC and expression of CD133 predicted the clinical course of disease better than the histological grading. To confirm these results, we retrospectively analyzed 36 high‐grade oligodendroglial tumors. Again, CD133 expression indicated shorter survival and predicted clinical outcome more reliable than the histological assessment.

Our data show that detection of CSC and expression of CD133 is predictive of prognosis in high‐grade oligodendroglial tumors. The presence or absence of CD133+ CSC might explain the crucial biological difference between WHO grade III and IV oligodendroglial tumors.
The Evolution of Our Understanding on Glioma
Authors: Martin‐Villalba Ana , Okuducu Ali Fuat , Von Deimling Andreas
Published: March 2008

The description of neuroglia by Virchow in 1848 may be considered the starting point of our understanding of primary brain tumors. At the beginning of the 20th century, surgical removal of primary brain tumors became possible, and therefore, tissue for microscopic analysis and clinical data on survival became available. During this time, research on gliomas beyond improving surgical procedures focused on their classification. The classification schemes developed emphasized parameters for sorting tumors with regard to (i) cytological aspects; (ii) presumed tumor cell origin; (iii) histological appearance of the tissue; or (iv) clinical outcome. Over the years, experimental studies have greatly improved our knowledge on gliomas. Gliomas induced by viruses, chemicals, radiation, transgenes and knock‐out technology contributed to the understanding of their pathogenesis and still serve as preclinical models for the testing of novel therapies. Recent advances in developmental neurobiology and the identification of stem cells provided new insights into the origin of brain tumors and the molecular mechanisms of tumor formation. This review briefly compiles the evolution of our concepts on gliomas, focusing on the latest developments.
Amoeboid Microglia in the Periventricular White Matter Induce Oligodendrocyte Damage through Expression of Proinflammatory Cytokines via MAP Kinase Signaling Pathway in Hypoxic Neonatal Rats
Authors: Deng YiYu , Lu Jia , Sivakumar Viswanathan , Ling Eng Ang , Kaur Charanjit
Published: March 2008

Hypoxic injury in the perinatal period results in periventricular white matter (PWM) lesions with axonal damage and oligodendroglial loss. It also alters macrophage function by perpetuating expression of inflammatory mediators. Relevant to this is the preponderance of amoeboid microglial cells (AMC) characterized as active macrophages in the developing PWM. This study aimed to determine if AMC produce proinflammatory cytokines that may be linked to the oligodendroglial loss observed in hypoxic PWM damage (PWMD). Wistar rats (1 day old) were subjected to hypoxia, following which upregulated expression of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), TNF receptor 1 (TNF‐R1) and IL‐1 receptor 1 (IL‐1R1) was observed. This was coupled with apoptosis and expression of TNF‐R1 and IL‐1R1 in oligodendrocytes. Primary cultured microglial cells subjected to hypoxia (3% oxygen, 5% CO2 and 92% nitrogen) showed enhanced expression of TNF‐α and IL‐1β. Furthermore, mitogen‐activated protein (MAP) kinase signaling pathway was involved in the expression of TNF‐α and IL‐1β in microglia subjected to hypoxia. Our results suggest that following a hypoxic insult, microglial cells in the neonatal rats produce inflammatory cytokines such as TNF‐α and IL‐1β via MAP kinase signaling pathway. These cytokines are detrimental to oligodendrocytes resulting in PWM lesion.
Reduced Glioma Growth Following Dexamethasone or Anti‐Angiopoietin 2 Treatment
Authors: Villeneuve Jérôme , Galarneau Hugo , Beaudet Marie‐Josée , Tremblay Pierrot , Chernomoretz Ariel , Vallières Luc
Published: March 2008

All patients with glioblastoma, the most aggressive and common form of brain cancer, develop cerebral edema. This complication is routinely treated with dexamethasone, a steroidal anti‐inflammatory drug whose effects on brain tumors are not fully understood. Here we show that dexamethasone can reduce glioma growth in mice, even though it depletes infiltrating T cells with potential antitumor activity. More precisely, T cells with helper or cytotoxic function were sensitive to dexamethasone, but not those that were negative for the CD4 and CD8 molecules, including gammadelta and natural killer (NK) T cells. The antineoplastic effect of dexamethasone was indirect, as it did not meaningfully affect the growth and gene expression profile of glioma cells in vitro. In contrast, hundreds of dexamethasone‐modulated genes, notably angiopoietin 2 (Angpt2), were identified in cultured cerebral endothelial cells by microarray analysis. The ability of dexamethasone to attenuate Angpt2 expression was confirmed in vitro and in vivo. Selective neutralization of Angpt2 using a peptide‐Fc fusion protein reduced glioma growth and vascular enlargement to a greater extent than dexamethasone, without affecting T cell infiltration. In conclusion, this study suggests a mechanism by which dexamethasone can slow glioma growth, providing a new therapeutic target for malignant brain tumors.
Phenotypic and Genotypic Characterization of Orthotopic Human Glioma Models and Its Relevance for the Study of Anti‐glioma Therapy
Authors: Claes An , Schuuring Janneke , Boots‐Sprenger Sandra , Hendriks‐Cornelissen Sandra , Dekkers Marieke , Van Der Kogel Albert J. , Leenders William P. , Wesseling Pieter , Jeuken Judith W.
Published: March 2008

Most human gliomas are characterized by diffuse infiltrative growth in the brain parenchyma. Partly because of this characteristic growth pattern, gliomas are notorious for their poor response to current therapies. Many animal models for human gliomas, however, do not display this diffuse infiltrative growth pattern. Furthermore, there is a need for glioma models that represent adequate genocopies of different subsets of human gliomas (e.g., oligodendrogliomas). Here, we assessed the intracerebral growth patterns and copy number changes [using multiplex ligation‐dependent probe amplification (MLPA)/comparative genomic hybridization (CGH)] of 15 human glioma lines in nude mice. Most xenografts present with compact growing lesions intracerebrally. Only the E98 and, to a lesser degree, E106 xenograft lines (propagated through subcutaneous growth) consistently produced intracerebral tumors, displaying diffuse infiltrative growth in the brain parenchyma. In contrast, four xenograft lines (E434, E468, E473 and E478), established by direct intracerebral inoculation of human glioma cells and serially propagated intracerebrally, consistently showed extensive diffuse infiltration throughout the brain. After several passages, the neoplastic cells still carry typical chromosomal aberrations [(−1p/−19q in oligodendroglioma, +7/−10 in glioblastoma multiforme (GBM)]. Especially these latter four models and the E98 line thus represent adequate geno‐ and phenocopies of human gliomas and form an attractive platform to investigate different therapeutic approaches in a preclinical setting.
Adrenomedullin Expression is Up‐regulated by Acute Hypobaric Hypoxia in the Cerebral Cortex of the Adult Rat
Authors: Serrano Julia , Fernández Ana Patricia , Sánchez Jaime , Rodrigo José , Martínez Alfredo
Published: March 2008

Hypobaric hypoxia can produce neuropsychological disorders such as insomnia, dizziness, memory deficiencies, headache and nausea. Here we report the changes in adrenomedullin (AM) expression observed in rats exposed to hypobaric hypoxia and different times of reoxygenation. AM immunoreactivity was transiently elevated in the cerebral cortex after 7 h of exposure to a simulated altitude of 8325 m (27 000 ft). This higher expression was seen in all pyramidal cells and in a subset of small interneurons. AM‐positive nonpyramidal neurons contained also calbindin and calretinin, but no parvalbumin immunoreactivity, thus identifying them as bipolar and double bouquet cells. Small blood vessels and related astroglia also became immunoreactive following the hypobaric insult. AM up‐regulation decreased progressively with the time of reoxygenation, reaching almost control levels after 5 days. Real‐time PCR quantification of AM mRNA and Western blotting confirmed the up‐regulation of AM expression following hypobaria. In addition, hypobaria modulates alternative splicing of the AM gene resulting in a higher production of AM. Our data show that AM expression regulation constitutes a cortical response to hypobaria, suggesting that AM modulation may provide new therapeutic avenues to prevent and/or treat the symptoms produced by hypobaria.
Interactional Influence of Ability Perception and Task Demand on Cardiovascular Response: Appetitive Effects at Three Levels of Challenge1
Authors: Annis Shannon , Wright Rex A. , Williams Barry J.
Published: March 2008

Participants received feedback that they had low ability (n= 16) or moderate ability (n= 17) on a memory task and were given the chance to attain more and less challenging performance standards in subsequent work periods. Myocardial contractility and stroke volume responses were in an interactional pattern reflecting (a) a positive relationship between demand and heart performance for moderate ability participants in contrast with a nonmonotonic relationship between demand and heart performance for low ability participants and (b) stronger heart performance for the low ability group than for the moderate ability group when the standard was low and moderate, but the reverse of that when the standard was high. Blood pressure responses were similar, although systolic responses provided no evidence of a reversed perceived‐ability/cardiovascular‐response relationship when demand was high.
Is the Glass Half‐Full or Half‐Empty? The Relationship of Big and Little Optimism With Acute and Longer Term Exercise‐Related Social Cognitions
Authors: Gyurcsik Nancy C. , Brawley Lawrence R.
Published: March 2008

Big optimism reflects generalized expectations about longer term positive outcomes. Little optimism reflects specific expectations about acute positive outcomes. This study examined the relationships among big optimism, little optimism, and acute (decisional struggle, coping self‐efficacy) and longer term exercise‐related social cognitions (scheduling self‐efficacy, intention). Participants were 85 fitness‐setting exercisers. Measures were obtained concurrently. Regression analyses indicated that, as expected, big optimism predicted the longer term social cognitions and little optimism predicted struggle. Big optimism also predicted coping self‐efficacy and modestly predicted struggle. A multivariate analysis of variance (MANOVA) indicated that, as expected, big optimists differed from big pessimists on the longer term social cognitions. Groups also differed on coping self‐efficacy. A second MANOVA indicated that, as expected, little optimists differed from little pessimists on the acute social cognitions.
Environmental response of Galium palustre s. lat. in a coastal area in Central Sweden
Authors: Apelgren Karin
Published: March 2008

Galium palustre s. lat. is a polymorphic taxon. The differences in morphology are correlated with the level of ploidy, but there is also a certain amount of phenotypic plasticity. The plasticity probably contributes to this taxon's successful colonization of a wide variety of habitats. The amount of plasticity was studied for plants from different kinds of habitats in Sweden, both for diploids (G. palustre s. str.) and octoploids (G. elongatum), which were cloned. This cloned material was then transplanted to three different localities in Sweden: a sunny exposed sea‐shore, a ditch, and a shady alder swamp. The general pattern of morphology was similar for all material, independent of its origin and level of ploidy, with smaller plants (smaller in several vegetative characters) and a more abundant flowering on the exposed seashore than in the ditch, and the largest plants with a fairly sparse flowering in the alder swamp. The octoploid plants originating from the wooded wetland are the least plastic ones but are very variable within the localities. G. palustre var. balneum shows a similar variation pattern as the others, but there are also genetically fixed differences in some characters between it and G. palustre var. palustre. The changes in morphology of the plants in the different localities occur fairly rapidly (in one month), although the differences are more spectacular one year later.
Basananthe aciphylla (Passifloraceae), a new species from Somalia
Authors: Thulin Mats
Published: March 2008

The new species Basananthe aciphylla, a thorny shrublet from central Somalia, is described and illustrated. Its closest relative is the likewise spinescent NE African endemic B. berberoides.
On the ecology of Thelypteris limbosperma — a synecological investigation of T. limbosperma‐dominated stands in W Norway
Authors: Odland Arvid
Published: March 2008

The investigation is based on phytosociological and ecological analyses of T. limbosperma‐dominated stands from different parts of W Norway. The distribution and floristical composition of the stands are related to different environmental parameters, such as climate, soil and topography. The data are analysed by numerical methods, of which two‐way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. The broad‐scale distribution of T. limbosperma stands is determined by climatic factors. Within its distribution area soil factors and human influence govern the floristic composition and development of different types of such stands. Based on the TWINSPAN classification 9 different stand types are distinguished.

The first major division of the TWINSPAN classification is mainly correlated with soil factors. Most of the stands growing on the richest soils are interpreted as representing regeneration stages after intensive human influence. Divisions at lower levels are well correlated with altitude and temperature conditions.

The stands are all characterized by low pH and base saturation. Some types are concentrated to certain geographical regions, indicating that both altitudinal and west‐east‐gradients are important in influencing the floristic composition of the different types. The investigations indicate that T. limbosperma has a rather narrow realised phytosociological niche. It is mainly concentrated to stands that are floristically most related to the poorest part of Vaccinio‐Piceion communities. Occasionally it is also dominant in Alno‐Padion and Lactucion alpinae communities.
The Swedish taxa of Laccaria (Tricholomataceae) with notes on their distribution
Authors: Mueller Gregory M.
Published: March 2008

Ten taxa of Laccaria are recognized from Sweden: L. amethystina, L. bicolor, L. laccata var. laccala, L. laccala var. moelleri, L. laccata var. pallidifolia, L. maritima, L. montana, L. proximo, L. pumila, and L. tortilis. A key to treated taxa, descriptions of macro‐ and micromorphology of these taxa and a discussion of their distribution in northern Europe and boreal and arctic North America are presented.
Sea ice diatoms (Bacillariophyceae) of the Canadian Arctic. 2. A taxonomic, morphological and geographical study of Gyrosigma concilians
Authors: Poulin Michel
Published: March 2008

A taxonomic account of the sea ice diatom, Gyrosigma concilians, is presented with the designation of a neotype from modern collections. Detailed morphological data of Canadian Arctic specimens, based on light (LM) and, for the first time, scanning electron (SEM) microscopy, confirm the slightly oblique nature of the transapical striae which are intersected by a more finely striated longitudinal pattern, and the presence of small, thin central bars on the internal valve face. Valves of G. concilians range from 57–109 μm in length, 6.5–11 μm in width and have 22–27 transapical striae in 10 μm crossed by a closer longitudinal pattern of 38–44 in 10 μm. Relationships with another species in the genus are discussed and the circumpolar Arctic distribution of G. concilians is demonstrated.
Functional contributions of synaptically localized NR2B subunits of the NMDA receptor to synaptic transmission and long‐term potentiation in the adult mouse CNS
Authors: Miwa Hideki , Fukaya Masahiro , Watabe Ayako M. , Watanabe Masahiko , Manabe Toshiya
Published: March 2008

The NMDA‐type glutamate receptor is a heteromeric complex composed of the NR1 and at least one of the NR2 subunits. Switching from the NR2B to the NR2A subunit is thought to underlie functional alteration of the NMDA receptor during synaptic maturation, and it is generally believed that it results in preferential localization of NR2A subunits on the synaptic site and that of NR2B subunits on the extracellular site in the mature brain. It has also been proposed that activation of the NR2A and NR2B subunits results in long‐term potentiation (LTP) and long‐term depression (LTD), respectively. Furthermore, recent reports suggest that synaptic and extrasynaptic receptors may have distinct roles in synaptic plasticity as well as in gene expression associated with neuronal death. Here, we have investigated whether NR2B subunit‐containing receptors are present and functional at mature synapses in the lateral nucleus of the amygdala (LA) and the CA1 region of the hippocampus, comparing their properties between the two brain regions. We have found, in contrast to the above hypotheses, that the NR2B subunit significantly contributes to synaptic transmission as well as LTP induction. Furthermore, its contribution is greater in the LA than in the CA1 region, and biophysical properties of NMDA receptors and the NR2B/NR2A ratio are different between the two brain regions. These results indicate that NR2B subunit‐containing NMDA receptors accumulate on the synaptic site and are responsible for the unique properties of synaptic function and plasticity in the amygdala.
Selective regulation of spontaneous activity of neurons of the deep cerebellar nuclei by N‐type calcium channels in juvenile rats
Authors: Alviña Karina , Khodakhah Kamran
Published: March 2008

The cerebellum coordinates movement and maintains body posture. The main output of the cerebellum is formed by three deep nuclei, which receive direct inhibitory inputs from cerebellar Purkinje cells, and excitatory collaterals from mossy and climbing fibres. Neurons of deep cerebellar nuclei (DCN) are spontaneously active, and disrupting their activity results in severe cerebellar ataxia. It is suggested that voltage‐gated calcium channels make a significant contribution to the spontaneous activity of DCN neurons, although the exact identity of these channels is not known. We sought to delineate the functional role and identity of calcium channels that contribute to pacemaking in DCN neurons of juvenile rats. We found that in the majority of cells blockade of calcium currents results in avid high‐frequency bursting, consistent with the notion that the net calcium‐dependent current in DCN neurons is outward. We showed that the bursting seen in these neurons after block of calcium channels is the consequence of reduced activation of small‐conductance calcium‐activated (SK) potassium channels. With the use of selective pharmacological blockers we showed that L‐, P/Q‐, R‐ and T‐type calcium channels do not contribute to the spontaneous activity of DCN neurons. In contrast, blockade of high‐threshold N‐type calcium channels increased the firing rate and caused the cells to burst. Our results thus suggest a selective coupling of N‐type voltage‐gated calcium channels with calcium‐activated potassium channels in DCN neurons. In addition, we demonstrate the presence of a cadmium‐sensitive calcium conductance coupled with SK channels, that is pharmacologically distinct from L‐, N‐, P/Q‐, R‐ and T‐type calcium channels.
Brainstem modulation of locomotion in the neonatal mouse spinal cord
Authors: Gordon Ian T. , Whelan Patrick J.
Published: March 2008

During development, descending projections to the spinal cord are immature. Available data suggest that even though these projections are not fully formed, they contribute to activation of spinal circuitry and promote development of network function. Here we examine the modulation of sacrocaudal afferent‐evoked locomotor activity by descending pathways. We first examined the effects of brainstem transection on the afferent evoked locomotor‐like rhythm using an isolated brainstem–spinal cord preparation of the mouse. Transection increased the frequency and stability of the locomotor‐like rhythm while the phase remained unchanged. We then made histologically verified lesions of the ventrolateral funiculus and observed similar effects on the stability and frequency of the locomotor rhythm. We next tested whether these effects were due to downstream effects of the transection. A split‐bath was constructed between the brainstem and spinal cord. Neural activity was suppressed in the brainstem compartment using cooled high sucrose solutions. This manipulation led to a reversible change in frequency and stability that mirrored our findings using lesion approaches. Our findings suggest that spontaneous brainstem activity contributes to the ongoing modulation of afferent‐evoked locomotor patterns during early postnatal development. Our work suggests that some of the essential circuits necessary to modulate and control locomotion are at least partly functional before the onset of weight‐bearing locomotion.
Slow‐ and fast‐twitch rat hind limb skeletal muscle phenotypes 8 months after spinal cord transection and olfactory ensheathing glia transplantation
Authors: Negredo Pilar , Rivero José‐Luis L. , González Beatriz , Ramón‐Cueto Almudena , Manso Rafael
Published: March 2008

Paralysed skeletal muscle of rats with spinal cord injury (SCI) undergoes atrophy and a switch in gene expression pattern which leads to faster, more fatigable phenotypes. Olfactory ensheathing glia (OEG) transplants have been reported to promote axonal regeneration and to restore sensory‐motor function in animals with SCI. We hypothesized that OEG transplants could attenuate skeletal muscle phenotypic deterioration and that this effect could underlie the functional recovery observed in behavioural tests. A variety of morphological, metabolic and molecular markers were assessed in soleus (SOL) and extensor digitorum longus (EDL) muscles of spinal cord transected (SCT), OEG‐transplanted rats 8 months after the intervention and compared with non‐transplanted SCT rats and sham‐operated (without SCT) controls (C). A multivariate analysis encompassing all the parameters indicated that OEG‐transplanted rats displayed skeletal muscle phenotypes intermediate between non‐transplanted and sham‐operated controls, but different from both. A high correlation was observed between behaviourally tested sensory‐motor functional capacity and expression level of slow‐ and fast‐twitch hind limb skeletal muscle phenotypic markers, particularly the histochemical glycerol‐3‐phosphate dehydrogenase activity (−0.843, P < 0.0001) and the fraction of variant 2s of the slow regulatory myosin light chain isoform (0.848, P < 0.0001) in SOL. Despite the mean overall effect of OEG transplants in patterning skeletal muscle protein expression towards normal, in 6 out of 9 animals they appeared insufficient to overcome fibre type switching and to support a consistent and generalized long‐term maintenance of normal skeletal muscle characteristics. The interplay of OEG and exercise‐mediated neurotrophic actions is a plausible mechanism underlying OEG transplantation effects on paralysed skeletal muscle.
Restrictions in systemic and locomotor skeletal muscle perfusion, oxygen supply andVO2during high‐intensity whole‐body exercise in humans
Authors: Mortensen Stefan P. , Damsgaard Rasmus , Dawson Ellen A. , Secher Niels H. , González‐Alonso José
Published: March 2008

Perfusion to exercising skeletal muscle is regulated to match O2delivery to the O2demand, but this regulation might be compromised during or approaching maximal whole‐body exercise as muscle blood flow for a given work rate is blunted. Whether muscle perfusion is restricted when there is an extreme metabolic stimulus to vasodilate during supramaximal exercise remains unknown. To examine the regulatory limits of systemic and muscle perfusion in exercising humans, we measured systemic and leg haemodynamics, O2transport, and, and estimated non‐locomotor tissue perfusion during constant load supramaximal cycling (498 ± 16 W; 110% of peak power; mean ±s.e.m.) in addition to both incremental cycling and knee‐extensor exercise to exhaustion in 13 trained males. During supramaximal cycling, cardiac output (), leg blood flow (LBF), and systemic and leg O2delivery andreached peak values after 60–90 s and thereafter levelled off at values similar to or ∼6% (P< 0.05) below maximal cycling, while upper body blood flow remained unchanged (∼5.5 l min−1). In contrast,and LBF increased linearly until exhaustion during one‐legged knee‐extensor exercise accompanying increases in non‐locomotor tissue blood flow to ∼12 l min−1. At exhaustion during cycling compared to knee‐extensor exercise,, LBF, leg vascular conductance, leg O2delivery and legfor a given power were reduced by 32–47% (P< 0.05). In conclusion, locomotor skeletal muscle perfusion is restricted during maximal and supramaximal whole–body exercise in association with a plateau inand limb vascular conductance. These observations suggest that limits of cardiac function and muscle vasoconstriction underlie the inability of the circulatory system to meet the increasing metabolic demand of skeletal muscles and other tissues during whole‐body exercise.
AMP‐activated protein kinase signalling pathways are down regulated and skeletal muscle development impaired in fetuses of obese, over‐nourished sheep
Authors: Zhu Mei J. , Han Bin , Tong Junfeng , Ma Changwei , Kimzey Jessica M. , Underwood Keith R. , Xiao Yao , Hess Bret W. , Ford Stephen P. , Nathanielsz Peter W. , Du Min
Published: March 2008

Maternal obesity and over‐nutrition give rise to both obstetric problems and neonatal morbidity. The objective of this study was to evaluate effects of maternal obesity and over‐nutrition on signalling of the AMP‐activated protein kinase (AMPK) pathway in fetal skeletal muscle in an obese pregnant sheep model. Non‐pregnant ewes were assigned to a control group (Con, fed 100% of NRC nutrient recommendations, n= 7) or obesogenic group (OB, fed 150% of National Research Council (NRC) recommendations, n= 7) diet from 60 days before to 75 days after conception (term 150 days) when fetal semitendinosus skeletal muscle (St) was sampled. OB mothers developed severe obesity accompanied by higher maternal and fetal plasma glucose and insulin levels. In fetal St, activity of phosphoinositide‐3 kinase (PI3K) associated with insulin receptor substrate‐1 (IRS‐1) was attenuated (P < 0.05), in agreement with the increased phophorylation of IRS‐1 at serine 1011. Phosphorylation of AMP‐activated protein kinase (AMPK) at Thr 172, acetyl‐CoA carboxylase at Ser 79, tuberous sclerosis 2 at Thr 1462 and eukaryotic translation initiation factor 4E‐binding protein 1 at Thr 37/46 were reduced in OB compared to Con fetal St. No difference in energy status (AMP/ATP ratio) was observed. The expression of protein phosphatase 2C was increased in OB compared to Con fetal St. Plasma tumour necrosis factor α (TNFα) was increased in OB fetuses indicating an increased inflammatory state. Expression of peroxisome proliferator‐activated receptor γ (PPARγ) was higher in OB St, indicating enhanced adipogenesis. The glutathione: glutathione disulphide ratio was also lower, showing increased oxidative stress in OB fetal St. In summary, we have demonstrated decreased signalling of the AMPK system in skeletal muscle of fetuses of OB mothers, which may play a role in altered muscle development and development of insulin resistance in the offspring.
20‐HETE increases renal sympathetic nerve activity via activation of chemically and mechanically sensitive muscle afferents
Authors: Gao Zhaohui , Koba Satoshi , Sinoway Lawrence , Li Jianhua
Published: March 2008

Arachidonic acid and its metabolites produced via cyclooxygenase (COX) and lipoxygenase pathways have been reported to contribute to the cardiovascular reflexes evoked by stimulating thin fibre muscle afferents during muscle contraction. 20‐Hydroxyeicosatetraenoic acid (20‐HETE), a primarily metabolized product of arachidonic acid by cytochrome P450 enzymes, can be accumulated in contracting muscles. Thus, the purpose of this study was to determine the role of 20‐HETE in modulating the reflex sympathetic responses to activation of chemically and mechanically sensitive muscle afferents. The renal sympathetic nerve activity (RSNA) and cardiovascular responses were examined after injections of 20‐HETE into the arterial blood supply of the hindlimb muscles of decerebrated rats. This induced a dose‐dependent increases in RSNA and mean arterial pressure (MAP). We also tested the hypothesis that 20‐HETE would sensitize muscle afferents and, thereby, augment the RSNA and blood pressure response to muscle stretch. The results show that arterial infusion of 20‐HETE significantly enhanced the RSNA and MAP responses to muscle stretch. In contrast, N‐hydroxy‐N′‐(4‐butyl‐2‐methylphenyl)formamidine, a potent inhibitor of 20‐HETE production, attenuated the reflex muscle responses. Furthermore, the sensitizing effect of 20‐HETE on the muscle reflex was significantly attenuated after blocking COX activity with indomethacin. Our data suggest that 20‐HETE plays a role in modulating muscle afferent‐mediated sympathetic responses, probably through engagement of a COX‐dependent mechanism.