1,110 research outputs found

    The dynamics of single spike-evoked adenosine release in the cerebellum

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    The purine adenosine is a potent neuromodulator in the brain, with roles in a number of diverse physiological and pathological processes. Modulators such as adenosine are difficult to study as once released they have a diffuse action (which can affect many neurones) and, unlike classical neurotransmitters, have no inotropic receptors. Thus rapid postsynaptic currents (PSCs) mediated by adenosine (equivalent to mPSCs) are not available for study. As a result the mechanisms and properties of adenosine release still remain relatively unclear. We have studied adenosine release evoked by stimulating the parallel fibres in the cerebellum. Using adenosine biosensors combined with deconvolution analysis and mathematical modelling, we have characterised the release dynamics and diffusion of adenosine in unprecedented detail. By partially blocking K+ channels, we were able to release adenosine in response to a single stimulus rather than a train of stimuli. This allowed reliable sub-second release of reproducible quantities of adenosine with stereotypic concentration waveforms that agreed well with predictions of a mathematical model of purine diffusion. We found no evidence for ATP release and thus suggest that adenosine is directly released in response to parallel fibre firing and does not arise from extracellular ATP metabolism. Adenosine release events showed novel short-term dynamics, including facilitated release with paired stimuli at millisecond stimulation intervals but depletion-recovery dynamics with paired stimuli delivered over minute time scales. These results demonstrate rich dynamics for adenosine release that are placed, for the first time, on a quantitative footing and show strong similarity with vesicular exocytosis

    Economic evaluations of travellers’ vaccinations

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    Erratum: A Survey of Paediatric Eye Diseases in a Tertiary Hospital, Southwest Nigeria

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    In the article titled “A Survey of Pediatric Eye Diseases in a Tertiary Hospital, South Western Nigeria”, published on pages 149-54, Issue 2, Volume 30 of Nigerian Journal of Medicine [1], the name of the second author is written incorrectly as “Ubah Josephine Ngozi” instead of “Ubah Josephine Nonye”.The “How to cite this article” section should read correctly as “Isawumi MA, Ubah JN. A survey of paediatric eye diseases in a tertiary hospital, Southwest Nigeria. Niger J Med 2021;30:149-54”

    The Word was the true light (Jn 1:9a). Jesus as the Light in the Prologue of the Fourth Gospel

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    This article aims to „The true light (Jn 1.9a). Jesus as the light in the Prologue of the Fourth Gospel”, was to explain the meaning of the symbol of the light connected with the person of Jesus Christ - the Logos in the Prologue of the Gospel of St John. The analysis of the text helped to establish that the author wanted to show the person o f Logos as a necessary condition of all life, and above all, the supernatural life (Jn 1,4). By revealing the divine life through the Incarnation, whose symbol is a light, he met with extreme hostility, which, however, is unable to destroy him (Jn 1,5). He is the light in an absolute sense (Jn 1,9). No one besides Him can not bestow the light, which in its fullest sense is identified with salvation. Father (John 5,31-32.37-38; 8,16-19), the Holy Spirit (Jn 15,26), the work of Jesus (Jn 5,36,10,25) and John the Baptist (Jn 1,7-8; 19nn) bear witness of His light, that people believed in him and thus have eternal life (Jn 20,31)

    Development of adenosine signalling in the cerebellum

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    The release and clearance of adenosine are reasonably well-documented in the mature CNS but relatively little is known about how adenosine signalling changes during postnatal development. The activation of presynaptic A1 receptors (A1R) at cerebellar parallel fibre terminals is known to inhibit synaptic transmission and the expression of A1R has been observed in mature rat cerebellar slices. However its distribution during development or in relation to parallel fibre–Purkinje cell (PF-PC) synapses has not previously been described. In the mature cerebellum blockade of presynaptic A1R at PF-PC synapses enhances synaptic transmission suggesting an inhibitory adenosine tone and an extracellular purine tone is detectable with microelectrode biosensors under basal conditions. The active release of adenosine can be stimulated with trains of activity in the molecular layer of mature slices although this does not appear to be a source of the basal extracellular adenosine tone. This study used immunohistochemistry to determine the distribution of A1R at PFPC synapses in cerebellar slices at postnatal day 3 prior to PF-PC synapse formation, postnatal days 8-14 and postnatal days 21-28. This study also used cerebellar slices from rats at postnatal days 9-14 to investigate the pharmacological profile of the immature rat PF-PC synapse with electrophysiology and microelectrode biosensors. The immunohistochemistry suggests that A1R are widely distributed across Purkinje cell bodies and their dendrites and within the granule layer of the cerebellum and that its expression does not change during development. The same staining patterns were also observed prior to PF-PC synapse formation. Application of adenosine resulted in a variable A1R-mediated inhibition at immature PF-PC synapses. This did not appear to be gender-specific or correlated with age of rat and the synapses otherwise appeared identical in their properties. The comparison of log concentration-response curves generated for an A1R agonist suggested that some A1R may have a lower efficacy at this stage of development. Blockade of presynaptic A1R at immature PF-PC synapses suggested that an inhibitory adenosine tone is low or absent at this stage of development and is not the result of a low A1R expression or developmental differences in A1R efficacy. Inhibition of adenosine clearance via adenosine deaminase, adenosine kinase and equilibrative transporters had little effect on synaptic transmission suggesting that little adenosine is moving between the intracellular and extracellular spaces under basal conditions in immature slices. Active adenosine release measured by electrophysiology and microelectrode biosensors could be stimulated with hypoxia in immature slices but this was delayed and slower in comparison to the release observed in mature slices. Adenosine could not be actively released at immature PFPC synapses in response to electrical stimulation in the molecular layer

    "I give my life for the sheep." (Jn 10:11): an exegetical analysis of Jn 10:11-18 and the Good Shepherd in priestly identity and priestly mission

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    V magistrski nalogi z naslovom »Svoje življenje dam za ovce.« (Jn 10,11): eksegetska analiza Jn 10,11-18 in dobri pastir v duhovniški identiteti in duhovniškem poslanstvu želi avtor predstaviti, kako je duhovniku pri njegovem življenju in poslanstvu v zgled podoba dobrega pastirja kot ga predstavi evangelist Janez v odlomku Jn 10,11-18. Ta odlomek avtor v prvem delu eksegetsko analizira, v drugem pa se poglobi v njegovo starozavezno ozadje. Pri tem pride do ugotovitve, da Jn 10,11-18 naredi odločilen korak naprej s tem, ko dobrega pastirja označi za tistega, ki je pripravljen dati življenje za ovce. Kaj to konkretno pomeni v sedanjem družbenem in cerkvenem kontekstu ter kdo je danes dobri pastir, pa želi osvetliti tretje poglavje, kjer se avtor poglobi v nekatere koncilske in pokoncilske dokumente, ki govorijo o duhovništvu ter nekaterih delih sodobnejših katoliških teologov in dušnih pastirjev. Jezus Kristus je Dobri pastir in tega poslanstva so po posvečenju deležni vsi duhovniki, ki se morajo v svojem življenju truditi, da se Jezusu čim bolj priličijo. Na tej poti jih spremljajo tudi nevarnosti, da ne bi oznanjevali Boga, ampak sebe, česar se je treba zavedati. Da bi se temu izognili, je pomemben trden odnos s Kristusom, ki je edini in najvišji Pastir.In the Master\u27s thesis, "I give my life for the sheep." (Jn 10:11): an exegetical analysis of Jn 10:11-18 and the Good Shepherd in priestly identity and priestly mission, the author aims to present how the image of the Good Shepherd, as presented by the Evangelist John in the passage Jn 10:11-18, is an example for the priest in his life and mission. In the first part of the paper the author analyses the passage exegetically, and in the second part of the paper he looks into its Old Testament background. In doing so, he concludes that Jn 10:11-18 takes a decisive step forward by identifying the Good Shepherd as the one who is willing to lay down his life for the sheep. What this means concretely in the present social and ecclesial context, and who the good shepherd is today, is what chapter 3 aims to shed light on, where the author looks at some conciliar and post-conciliar documents on the priesthood and at some of the works of more contemporary Catholic theologians and of shepherds of the pastoral community. Jesus Christ is the Good Shepherd, and all priests share in this mission after ordination and must strive to be as like Jesus as possible in their lives. On this journey, they are also accompanied by the danger of preaching not God but themselves, and this must be borne in mind. To avoid this, it is important to have a strong relationship with Christ, who is the only and supreme Shepherd

    Cure of the Criple at Bet-Hesed (Jn 5, 1—9)

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    Tree main strains of the modern egzegese deny the historical character of the recite of Jn 5, 1—9. The first affirms that the healing of paralytic of Bet-Hesed is identical to the healing of the paralytic of Kefar-Nahum (Mk 2, 3 —12 and par.). The author of Jn has altered it only. The second sees only a symbol of the final .spiritual healing of Israel after his spiritual symbolic therty eight years wandering in the era of NT. The author of Jn would have created a merely symbolic substratum. The third affirms that the recite is a illustrative narrative in order to introduce the sabbatical dispute and the revelatory discourse. The author of the article analyses the recite contently and philologicaly also in part. On the ground of the analysis he argues for the impossibility of identity of Johannine and synoptic recite. The Johannine recite differs substantialy from the synoptic. Even if the recites were more similar, we could speak of two different healings on the ground of Mt 8, 17 and Lk 5, 15: Jesus has heald many paralytics. The analysis shows also that the author of Jn purses not a symbolic aim but a really historical purpose. In the background of his recite we can percieve the historical sources he has used. He spoke in his preached gospel on the first christian assemblies how he saw and heard Jesus when he heald the paralytic. The other disciples and many of those people who were present at the healing and became christians confirmed his preaching. The strongest confirmation of his preaching however cames from the heald man who has experienced the miracle and was present also on the assemblies. The evangelist's documented preached gospel becames then his documented written gospel. The author of the article stresses especially on the ground of the two participles idon kai gnous (v. 6) that the motiv which moved Jesus to performe the miracle was his divine mercy and pity toward the unfortunate sick man. The sabbatical dispute has non occasioned the miracle but the healing on Saturdy has created the occasion for the sabbatical dispute and the revelatory discourse, which is a self-defense for the dealing on Saturday. The evangelist has produced the motiv on the healing, the sabbatical dispute and the revelatory discourse in this light

    Attention to attributes and objects in working memory

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    It has been debated on the basis of change-detection procedures whether visual working memory is limited by the number of objects, task-relevant attributes within those objects, or bindings between attributes. This debate, however, has been hampered by several limitations, including the use of conditions that vary between studies and the absence of appropriate mathematical models to estimate the number of items in working memory in different stimulus conditions. We reexamined working memory limits in 2 experiments with a wide array of conditions involving color and shape attributes, relying on a set of new models to fit various stimulus situations. In Experiment 2, a new procedure allowed identical retrieval conditions across different conditions of attention at encoding. The results show that multiple attributes compete for attention, but that retaining the binding between attributes is accomplished only by retaining the attributes themselves. We propose a theoretical account in which a fixed object capacity limit contains within it the possibility of the incomplete retention of object attributes, depending on the direction of attention.</p

    Las comparecencias de «phaneróō» en Jn 21 y 1Jn, señal de una andadura teológica (II)

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    In the first installment of this contribution, we concluded that 1 John, on the one hand, retains the usage that John 1-20 assigns to phaneróō, used technically to refer the earthly ministry of Jesus as the Revealer of the Father (cf. 1 John 1:2; 3:5, 8; 4:9). On the other, the Johannine author represents a new advance in qualifying the event of the parousia as an act of definitive revelation (1 John 2:28; 3:2). The resurrection as an act of revelation does not appear in 1 John’s use of phaneróō. This suggests that the theme of resurrection as revelation (John 21:1, 14) points to an enlargement of the semantic field. This enlargement points to a different stage in the path of theological reflection of the Johannine community: in the post-Easter period, Jesus prolongs the effects of the revelation of the saving God’s love (Jn 3:16; 19:30) through his community of disciples, as Jesus’ resurrection has brought to completion the process of revelation narrated in the Gospel (Jn 20, 19-29).En la primera entrega de esta contribución concluimos que 1Jn mantenía los usos que el cuerpo del evangelio (Jn 1-20) asignaba a phaneróō (cf. 1Jn 1,2; 3,5.8; 4,9), término empleado técnicamente para referirse al ministerio terreno de Jesús como Revelador del Padre. Pero, por otra parte, 1Jn ensanchaba el campo semántico de phaneróō extendiéndolo al acontecimiento de la parusía (cf. 1Jn 2,28; 3,2). La resurrección, como acto de revelación, no encontró espacio entre los usos que 1Jn asigna a phaneróō.  Lo cual sugiere que las comparecencias de este término en Jn 21,1.14 deben situarse en un estadio distinto de la andadura teológica de la comunidad joánica: en el tiempo postpascual, Jesús prolonga los efectos de la revelación del amor salvífico de Dios (cf. Jn 3,16; 13,1; 19,30) mediante su comunidad de discípulos, pues su resurrección ha llevado a culmen el proceso de revelación narrado en el relato (cf. Jn 20,19-29)
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