54 research outputs found

    No evidence for reproductive isolation through sexual conflict in the bulb mite Rhizoglyphus robini

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    Sexual conflict leading to sexual antagonistic coevolution has been hypothesized to drive reproductive isolation in allopatric populations and hence lead to speciation. However, the generality of this speciation mechanism is under debate. We used experimental evolution in the bulb mite Rhizoglyphus robini to investigate whether sexual conflict promotes reproductive isolation measured comprehensively to include all possible pre- and post-zygotic mechanisms. We established replicate populations in which we either enforced monogamy, and hence removed sexual conflict by making male and female evolutionary interests congruent, or allowed promiscuity. After 35 and 45 generations of experimental evolution, we found no evidence of reproductive isolation between the populations in any of the mating systems. Our results indicate that sexual conflict does not necessarily drive fast reproductive isolation and it may not be a ubiquitous mechanism leading to speciation

    Mesolimbic dopamine D_{2} receptor plasticity contributes to stress resilience in rats subjected to chronic mild stress

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    RATIONALE: Few studies have investigated neurobiological and biochemical differences between stress-resilient and stress-vulnerable experimental animals. OBJECTIVES: We investigated alterations in mesolimbic dopamine D(2) receptor density and mRNA expression level in stressed rats at two time points, i.e. after 2 and 5 weeks of chronic mild stress (CMS). METHODS: We used the chronic mild stress paradigm because it is a well-established animal model of depression. Two groups of stressed rats were distinguished during CMS experiments: (1) stress reactive (70 %), which displayed a decrease in the drinking of a palatable sucrose solution during the stress regimen, and (2) stress resilient (30 %), which exhibited an unaltered drinking profile when compared with the unchallenged control group. [(3)H]Domperidone was used as a ligand to label dopamine D(2) receptors, and a mixture of three specific oligonucleotides was used to evaluate dopamine D(2) receptor mRNA changes in various regions of the rat brain. RESULTS: CMS strongly affected the mesolimbic dopamine circuit in stress-resilient group after 2 weeks and stress-reactive group of rats after 5 weeks which exhibited a decrease in the level of dopamine D(2) receptor protein without alterations in D(2) mRNA expression. Stress-resilient animals, but not stress-reactive animals, effectively adapted to the extended stress and coped with it. The increase in D(2) mRNA expression returned the dopamine D(2) receptor density to control levels in stress-resilient rats after 5 weeks of CMS, but not in stress-reactive animals. CONCLUSIONS: These results clearly demonstrate that, despite earlier blunting, the activation of dopamine receptor biosynthesis in the dopamine mesoaccumbens system in stress-resilient rats is involved in active coping with stressful experiences, and it exhibits a delay in time

    Radioguided surgery in patient with pancreatic neuroendocrine tumour followed by PET/CT scan as a new approach of complete resection evaluation — case report

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    Radioguided surgery using 68-gallium labelled somatostatin analogues is a promising method for detection of small, intra-abdominal, neuroendocrine neoplasm (NEN). However, due to high background activity (physiological uptake in e.g. spleen, adrenal glands and kidneys) tumours of the tail and body of pancreas might be impossible to detect with hand-held gamma probe. Therefore a new concept of intraoperative PET/CT scan of the resected tissue can be helpful in determining whether the tumour has been excised within the margins of healthy tissue. A 71-year-old woman with primary, non-metastatic NEN of the tail of pancreas is described. The tumour was diagnosed using MRI and PET/CT scan. Before operation patient was administered intravenously 80 MBq of 68Ga-DOTATATE. The surgery procedure was performed 60–180 minutes post injection. During the procedure pancreas was visualized, but the tumour could not be localized neither with palpation nor gamma probe. The tail of the pancreas was resected en bloc with spleen and adjacent lymph nodes. PET/CT scan of the tissue specimen was performed immediately followed by pathological examination. PET/CT scan of the resected tissue showed moderate activity in the tail of pancreas, and a small focus of high activity in the tail. Area of high SSTR expression in the tail corresponded with preoperative findings in MRI and whole-body PET/CT. Histopathological examination of the specimen confirmed the presence of neuroendocrine tumour grade 1. Immediate PET/CT scan of the surgical specimen can bring new quality to intraoperative assessment of completeness of resection of neuroendocrine tumours

    Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

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    We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

    Glioblastoma-derived spheroid cultures as an experimental model for analysis of EGFR anomalies

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    Glioblastoma cell cultures in vitro are frequently used for investigations on the biology of tumors or new therapeutic approaches. Recent reports have emphasized the importance of cell culture type for maintenance of tumor original features. Nevertheless, the ability of GBM cells to preserve EGFR overdosage in vitro remains controversial. Our experimental approach was based on quantitative analysis of EGFR gene dosage in vitro both at DNA and mRNA level. Real-time PCR data were verified with a FISH method allowing for a distinction between EGFR amplification and polysomy 7. We demonstrated that EGFR amplification accompanied by EGFRwt overexpression was maintained in spheroids, but these phenomena were gradually lost in adherent culture. We noticed a rapid decrease of EGFR overdosage already at the initial stage of cell culture establishment. In contrast to EGFR amplification, the maintenance of polysomy 7 resulted in EGFR locus gain and stabilization even in long-term adherent culture in serum presence. Surprisingly, the EGFRwt expression pattern did not reflect the latter phenomenon and we observed no overexpression of the tested gene. Moreover, quantitative analysis demonstrated that expression of the truncated variant of receptor—EGFRvIII was preserved in GBM-derived spheroids at a level comparable to the initial tumor tissue. Our findings are especially important in the light of research using glioblastoma culture as the experimental model for testing novel EGFR-targeted therapeutics in vitro, with special emphasis on the most common mutated form of receptor—EGFRvIII

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    The Meaning and the Letter. On a vicissitude of the Interpretation in Psychoanalysis

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    Przedmiotem niniejszej pracy są konsekwencje, jakie niesie dla psychoanalitycznej teorii i praktyki interpretacji włączenie do swojego aparatu strukturalistycznego ujęcia mowy, w szczególności w nauczaniu Jacquesa Lacana oraz w pracach psychoanalityków orientacji lacanowskiej. W tym celu w pracy zostaje: 1) zrekonstruowana Lacanowska lektura Freuda i Kartezjusza jako dwóch myślicieli, którzy umocowali swoją pewność na wątpieniu; 2) zostają przedstawione oraz porównane językoznawcze i psychoanalityczne pojęcia znaczącego, znaczonego, metafory i metonimii; 3) zostaje rozważona kwestia różnicy pomiędzy przedmiotem językoznawstwa strukturalnego i psychoanalizy; 4) omówione zostają relacje pomiędzy sensem, znaczącym oraz literą oraz status psychoanalizy jako metody koniekturalnej; 5) dochodzi do odniesienia do siebie pojęć seksualności, znaczenia i interpretacji; 6) zostaje rozważona relacja pomiędzy poza-sensem a funkcją odpowiedzi. Na koniec zagadnienia omówione w pracy zostają odniesione do aktualnej debaty na temat statusu interpretacji w szkołach orientacji lacanowskiej.The subject of the following thesis is the consequences of incorporating a structuralist account of speech into the apparatus of psychoanalysis for its theory and practice of interpretation, particularly in the teaching of Jacques Lacan and in other texts of psychoanalysts of the Lacanian orientation. To this end, author of the thesis: 1) reconstructs the Lacanian reading of Freud and Descartes as two thinkers who anchored their certainty on doubt; 2) presents and compares linguistic and psychoanalytic concepts of signifier, signified, metaphor and metonymy; 3) considers the difference between the subject matter of structural linguistics and psychoanalysis; 4) discusses the relationship between meaning, signifier and letter and the status of psychoanalysis as a conjunctural method; 5) explores the links between the notions of sexuality, signification and interpretation; 6) considers the relationship between the non-sense and the function of response. Finally, the issues discussed in the paper are related to the current debate on the status of interpretation in the schools of Lacanian orientation

    Position of the Notion of Understanding in the Early Teaching of Lacan; Reconstruction of the Critique and a Commentary Based on Selected Psychoanalytic Concepts

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    Praca ta obrała za cel umieszczenie uwag padających z ust Lacana w kierunku kategorii rozumienia, używanej niekiedy w psychiatrii, psychoterapii, psychologii czy psychoanalizie, w kontekście pozwalającym na uchwycenie ich sensu, to jest na tle: 1) koncepcji rozumienia przedstawionej przez Jaspersa w "Psychopatologii ogólnej", stanowiącej szczególne, zaawansowane opracowanie tej ogólnej kategorii, 2) aparatu teoretycznego porządkującego doświadczenie płynące z praktyki psychoanalizy, w szczególności tego sformułowanego podczas pierwszego czasu nauczania Lacana wraz z wcześniejszym okresem jego publicznej aktywności intelektualnej, to jest w latach 1936-1964. W tym celu w pracy zostaje zwięźle zrekonstruowana koncepcja rozumienia z "Psychopatologii ogólnej", w tym zwłaszcza jej aspekt dotyczący rozumienia genetycznego i jego związków z przyczynowością. Następnie zostają przytoczone wspomniane wyżej uwagi, które w dalszej kolejności są rozpatrywane w ramach wybranych koncepcji psychoanalitycznych: identyfikacji, relacji wyobrażeniowych, schematu dialektyki intersubiektywnej, mowy pustej i mowy pełnej, psychoanalitycznego ujęcia mowy, języka i mówienia, w tym: algorytmu de Saussure'a, punktu zapikowania, metafory, metonimii, znaczenia oraz sensu. Na koniec krytykowana koncepcja rozumienia zostaje zestawiona z psychoanalityczną formą interpretacji oraz zostaje poruszony wątek eksplikacyjnego nastawienia psychoanalizy.The following thesis aims to provide context for remarks made by Lacan towards the category of understanding, which is sometimes used in psychiatry, psychotherapy, psychology, or psychoanalysis, that would allow the reader to grasp their meaning, that is: 1) the conception of understanding portrayed by Jaspers in his "General Psychopathology", which is a specific, advanced formulation of this general category, 2) theoretical apparatus of psychoanalysis which organizes the experience resulting from its praxis, particularly the one that was formulated during the first time of the teaching of Lacan together with the period of his public intellectual activity that was prior to it, that is between 1936 and 1964. For this purpose, the thesis includes a concise reconstruction of the conception of meaning found in “General Psychopathology”, with a special focus on its aspect concerning genetic understanding and its links with causality. Subsequently, the remarks mentioned above are introduced and considered within the framework of selected psychoanalytic concepts: identification, imaginary relations, the schema of the intersubjective dialectic, full speech [parole], empty speech [parole], psychoanalytic approach to speech [langage], language [langue] and speaking [parole] including: de Saussure’s algorithm, quilting point, metaphor, metonymy, signification, and meaning. Finally, the conception of understanding that is subjected to critique is juxtaposed with the psychoanalytic form of interpretation and the topic of the explanatory nature of psychoanalysis is raised
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