112 research outputs found
In vitro modell a csapfejlĆdĂ©sben szerepet jĂĄtszĂł faktorok tanulmĂĄnyozĂĄsĂĄra = In vitro model to study retinal cone photoreceptor differentiation
Az emlĆsök többsĂ©gĂ©nek retinĂĄjĂĄban kĂ©tfĂ©le csapot talĂĄlunk, az egyik a kĂ©k- (S-csap), mĂg a mĂĄsik a zöld, vagy a vörös fĂ©nyre Ă©rzĂ©keny (M/L-csap). E kĂ©t csaptĂpus nem egymĂĄstĂłl fĂŒggetlenĂŒl fejlĆdik. Mindegyik csap elĆször S-opszint expresszĂĄl, többsĂ©gĂŒk azonban kĂ©sĆbb ĂĄtĂĄll az M/L-pigment termelĂ©sĂ©re. Keveset tudunk arrĂłl, mely faktorok vehetnek rĂ©szt a pigment vĂĄltĂĄs szabĂĄlyozĂĄsĂĄban. A pĂĄlyĂĄzatban bemutattunk egy Ășj, in vitro organotipikus retinatenyĂ©sztĂ©sen alapulĂł mĂłdszert, amely több fajon is lehetĆvĂ© teszi a transzdifferenciĂĄciĂł tanulmĂĄnyozĂĄsĂĄt. Az ĂĄltalunk hasznĂĄlt kontrol mĂ©diumban az M/L-csapok minden esetben kifejlĆdtek, a kiĂŒltetĂ©s idejĂ©tĆl fĂŒggetlenĂŒl. Az M/L-csapok elkötelezĆdĂ©se a 4. nap (P4) elĆtt vĂ©gbemegy, kĂŒlönbsĂ©get tĂĄpjaink között csak korĂĄbbi kiĂŒltetĂ©sek esetĂ©n talĂĄltunk. SzĂ©rum hozzĂĄadĂĄsa egyedĂŒl kĂ©pes volt biztosĂtani a differenciĂĄciĂłhoz szĂŒksĂ©ges összes faktort megfelelĆ koncentrĂĄciĂłban P1-P4 retinĂĄk esetĂ©ben. SzĂ©rummentes közegben a pajzsmirigyhormon egyedĂŒl elĂ©gsĂ©ges patkĂĄny M/L-csapjainak kifejlĆdĂ©sĂ©hez, de csak megfelelĆ mennyisĂ©gƱ E-vitamin hozzĂĄadĂĄsa mellett biztosĂtja a fejlĆdĂ©st szĂriai aranyhörcsögben. EredmĂ©nyeink bizonyĂtjĂĄk, hogy a technika hasznĂĄlhatĂł a csapfejlĆdĂ©sre hatĂł szolubilis faktorok szerepĂ©nek tanulmĂĄnyozĂĄsĂĄra. BizonyĂtottuk, hogy a pajzsmirigyhormon minden vizsgĂĄlt fajban szĂŒksĂ©ges az M/L-csapok elkötelezĆdĂ©sĂ©hez, de eredmĂ©nyeink szerint mĂĄs faktoroknak is fontos szerepe lehet, legalĂĄbbis a fajok egy rĂ©szĂ©ben. | The retina of most mammalian species contains two types of cones, one sensitive to shorter- (S-), and another to the middle- or long wavelengths (M/L-cones). These populations do not develop independently. All cones first express S-opsin only, but most of them switch to M/L-opsin production. Despite intensive studies, little is known about the factors influencing pigment switch. Hereby, we report a new model, in vitro organotypic retinal culture, to study these factors in tree species of mammals. All retinas fully differentiate in vitro, in control medium, independently of the time of explantation. Commitment for M/L-opsin expression is completed by P4: only in retinas explanted before, did we detect any difference in development. Serum supplementation alone, was sufficient to induce M/L-cone differentiation in cultures explanted prior to P4, indicating that it contains all the factors necessary. In serum free conditions, thyroid hormone was enough to induce transdifferentiation in the rat, whereas in the Syrian hamster, vitamin-E was also needed. These results prove that retinal culturing is a reliable tool to study the effect of soluble factors in retinal differentiation. In all species studied, thyroid hormone seems to be necessary for M/L-cone development, but other factors like vitamin-E could also play additional roles, indicating that development may be controlled by different mechanisms in different species
Az elĆagyi glukĂłz-monitorozĂł neuron-hĂĄlĂłzat mƱködĂ©si sajĂĄtsĂĄgainak vizsgĂĄlata egĂ©szsĂ©ges Ă©s kĂłros szervezetben: komplex neurofiziolĂłgiai kĂsĂ©rletek = Investigation of functional attributes of the forebrain glucose-monitoring neural network in healthy and pathological organism: complex neurophysiological experiments
A program a tĂĄplĂĄlkozĂĄs Ă©s az anyagcsere egymĂĄssal szorosan összefĂŒggĆ elĆagyi szabĂĄlyozĂĄsĂĄban alapvetĆ idegi Ă©s neurokĂ©miai mechanizmusok eddigieknĂ©l rĂ©szletesebb feltĂĄrĂĄsĂĄra irĂĄnyult. E többrĂ©tƱ cĂ©lok megvalĂłsĂtĂĄsĂĄra komplex, integratĂv szemlĂ©letƱ Ă©s metodikĂĄjĂș mikroelektrofiziolĂłgiai, neurokĂ©miai-biokĂ©miai Ă©s magatartĂĄsi vizsgĂĄlatokat folytattunk laboratĂłriumi patkĂĄnyokban Ă©s rhesus majomban. KutatĂĄsaink tengelyĂ©ben, a korĂĄbbiakhoz hasonlĂłan, a tĂĄplĂĄlkozĂĄs Ă©s az energiaforgalom központi szabĂĄlyozĂĄsĂĄban feltĂ©telezetten kiemelkedĆ jelentĆsĂ©gƱ elĆagyi glukĂłz-monitorozĂł (GM) idegsejt-hĂĄlĂłzat sokrĂ©tƱ, differenciĂĄlt jellemzĂ©se ĂĄllt. ĂsszessĂ©gĂ©ben közel 500 neuron extracellulĂĄris egysejttevĂ©kenysĂ©gĂ©t vezettĂŒk el laboratĂłriumi patkĂĄny Ă©s rhesus majom elĆagyban. Az irodalomban elsĆkĂ©nt azonosĂtottunk komplex, endogĂ©n Ă©s exogĂ©n kĂ©miai Ă©rzĂ©kenysĂ©gƱ GM idegsejteket a nukleusz akkumbenszben, a mediodorzĂĄlis prefrontĂĄlis Ă©s az orbitofrontĂĄlis kĂ©regben, s igazoltuk e kemoszenzoros neuronok jelentĆsĂ©gĂ©t a homeosztĂĄzis fenntartĂĄsĂĄban. A programban feltĂĄrt Ășj adatok tovĂĄbbi elmĂ©leti Ă©s preklinikai vizsgĂĄlatok kiindulĂł pontjaikĂ©nt tĂĄplĂĄlkozĂĄsi Ă©s metabolikus betegsĂ©gek terĂĄpiĂĄjĂĄt cĂ©lzĂł gyĂłgyszer-targetek feltĂĄrĂĄsĂĄhoz vihetnek közelebb. | The program aimed to reveal so far little known neural and neurochemical mechanisms of closely interrelated forebrain regulation of feeding and metabolism. To achieve these multiple goals, complex and integrative microelectrophysiological, neurochemical-biochemical, and behavioral studies were performed in the laboratory rat and rhesus monkey. Similar to the past, multiple, differential characterization of the forebrain glucose-monitoring (GM) neuronal network, supposedly with great significance in the central control of feeding and metabolism, was put in the center of our research efforts. The extracellular single neuron activity of altogether appx. 500 neurons was recorded in the rodent and macaque forebrain. Unprecedentedly in the literature, GM neurons with complex, endogenous and exogenous chemosensitivity were identified in the nucleus accumbens, mediodorsal prefrontal and orbitofrontal cortices. Evidence for the significance of these chemosensory units in the maintenance of homeostasis was also obtained. New data revealed in this program may serve as starting points of further theoretical and preclinical investigations that aim to establish pharmacological targets of the therapy of eating and metabolic disorders
Assessing the Effects of a Reformed System of Student Evaluation of Teaching
The importance of student evaluation of teaching (SET) in higher education has increased substantially in the past decades. Despite this increase, there is no consensus on the most efficient way of executing these surveys or about the questions. This study analyses the impact of an SET system reform on the distribution of the responses and the response rate. The reform impacted the questions, the scale used for evaluation, the anchor labels of the scale elements, and the incentives for students to fill out the survey. Our results show that the number of extreme responses increased after the reform, which can be due to the elimination of anchor labels of the middle scale points. Insufficient effort bias also increased; however, the new motivation system doubled the response rate, which helped to collect more representative sets of evaluations. Taking into consideration the relatively small increase in insufficient responses, we believe this incentive can be a valid choice for SET surveys
Porous Hydroxyapatite and Aluminium-Oxide Ceramic Orbital Implant Evaluation Using CBCT Scanning: A Method for In Vivo Porous Structure Evaluation and Monitoring
Objective. This study aimed to define CBCT as a technique for postimplantation in vivo examination of porous hydroxyapatite and aluminium-oxide orbital implant shape, volume and density changes. Methods and Materials. CBCT was used to evaluate 30 enucleated patients treated with spherical polyglactin 910 wrapped hydroxyapatite and aluminum-oxide orbital implants. The mean duration of patient
followup was 3.2 years or 1338 days with a range of 0.2 to 7.2 years or 79 to 2636 days in a population with an average age of 40.8 years. Results. The resolution of currently clinically used CBCT equipment allowed detailed structural observation of the orbital hydroxyapatite implants with some modifications. Volume and shape estimations were possible while density evaluation was more complicated compared to medical source computed tomography. The mean densities of the orbital implants were followed and a consistent gradual decrease identified from the beginning of implantation which was better defined after the applied correction procedure. Conclusion. CBCT with lower dosages of radiation exposure can be used to follow changes in implanted high-density porous structures. The density evaluation is possible with calibration modifications. Changes in orbital implant densities identified in this study may correspond to healing and maturation of soft tissues surrounding and penetrating the implants
Two Cases of Hallermann-Streiff Syndrome with Retinal Abnormalities
Hallermann-Streiff syndrome is a rare congenital disorder
that is characterized by malformations of the craniofacial
region with ocular abnormalities. Some ophthalmic signs can
be observed in early age and some in adulthood. The visual
functions are determined by a lot of factors including
microphthalmos, cataract and fundus abnormalities. We report
two cases of Hallermann-Streiff syndrome identified in our
department in the last decade
The Retinal TNAP
Accumulating evidence from recent literature underline the important roles of tissue non specific alkaline phosphatase (TNAP) in diverse functions as well as diseases of the nervous system. Exploration of TNAP in well characterized neural circuits such as the retina, might significantly advance our understanding regarding neural TNAPâs roles. This chapter reviews the scarce literature as well as our findings on retinal TNAP. We found that retinal TNAP activity was preserved and followed diverse patterns throughout vertebrate evolution. We have consistently observed TNAP activity (1) in retinal vessels, (2) in photoreceptors and (3) in the majority of the studied species in the outer (OPL) and inner plexiform layers (IPL), where synaptic transmission occurs. Importantly, in some species the IPL exhibits several TNAP positive strata. These strata exactly corresponded those seen after quadruple immunohistochemistry with four canonical IPL markers (tyrosine hydroxylase, choline acetyltransferase, calretinin, protein kinase C α). Diabetes results in diminishing retinal TNAP activity before changes in canonical markers
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