| 1. |
- Dombovari, Balazs, et al.
(författare)
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In vivo validation of the electronic depth control probes
- 2014
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Ingår i: Biomedizinische Technik (Berlin. Zeitschrift). - : Walter de Gruyter GmbH. - 1862-278X .- 0013-5585. ; 59:4, s. 283-289
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we evaluated the electrophysiological performance of a novel, high-complexity silicon probe array. This brain-implantable probe implements a dynamically reconfigurable voltage-recording device, coordinating large numbers of electronically switchable recording sites, referred to as electronic depth control (EDC). Our results show the potential of the EDC devices to record good-quality local field potentials, and single- and multiple-unit activities in cortical regions during pharmacologically induced cortical slow wave activity in an animal model.
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| 2. |
- Horváth, Attila, et al.
(författare)
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Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste
- 2013
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Ingår i: Clinical Oral Investigations. - : Springer. - 1432-6981 .- 1436-3771. ; 17:2, s. 423-430
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of the study was to clinically and histologically evaluate the healing of human intrabony defects treated with open flap surgery (OFD) and application of a new, resorbable, fully synthetic, unsintered, nanocrystalline, phase-pure hydroxyapatite (nano-HA). MATERIALS AND METHODS: Six patients, each of them displaying very advanced intrabony defects around teeth scheduled for extraction due to advanced chronic periodontitis and further prosthodontic considerations, were included in the study. Following local anaesthesia, mucoperiosteal flaps were reflected; the granulation tissue was removed, and the roots were meticulously debrided by hand and ultrasonic instruments. A notch was placed at the most apical extent of the calculus present on the root surface or at the most apical part of the defect (if no calculus was present) in order to serve as a reference for the histological evaluation. Following defect fill with nano-HA, the flaps were sutured by means of mattress sutures to allow primary intention healing. At 7 months after regenerative surgery, the teeth were extracted together with some of their surrounding soft and hard tissues and processed for histological analysis. RESULTS: The postoperative healing was uneventful in all cases. At 7 months following surgery, mean PPD reduction and mean CAL gain measured 4.0 ± 0.8 and 2.5 ± 0.8 mm, respectively. The histological analysis revealed a healing predominantly characterized by epithelial downgrowth. Limited formation of new cementum with inserting connective tissue fibers and bone regeneration occurred in three out of the six biopsies (i.e. 0-0.86 and 0-1.33 mm, respectively). Complete resorption of the nano-HA was found in four out of the six biopsies. A few remnants of the graft particles (either surrounded by newly formed mineralized tissue or encapsulated in connective tissue) were found in two out of the six biopsies. CONCLUSION: Within their limits, the present results indicate that nano-HA has limited potential to promote periodontal regeneration in human intrabony defects. CLINICAL RELEVANCE: The clinical outcomes obtained following surgery with OFD + nano-HA may not reflect true periodontal regeneration.
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| 3. |
- Horváth, Attila, et al.
(författare)
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Histologisk evaluering af humane intraossøse parodontale defekter behandlet med en usintret nanokrystallinsk hydroxyapatit pasta
- 2013
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Ingår i: Tandlægebladet. - : Dansk Tandlægeforening. - 0039-9353. ; 117:1, s. 12-13
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Formål Formålet med undersøgelsen var at evaluere den kliniske og histologiske heling af humane intraossøse defekter behandlet med konventionel flapkirurgi (OFD) og anvendelse af en ny, resorberbar, fuldsyntetisk, usintret, nanokrystallinsk, hydroxyapatit (nano-HA ). Materialer og metoder Seks patienter, som hver viste en meget avanceret intraossøs defekt omkring en tand planlagt til ekstraktion på grund af svær kronisk marginal parodontitis og yderligere restaurerende overvejelser, blev inkluderet i undersøgelsen. Efter lokalbedøvelse, mucoperiosteal lapløft, granulationsvævs fjernelse og omhyggelig roddepuration og afglatning med hånd- og ultralydsinstrumenter blev der på roden placeret et mindre boremærke ved den mest apikale tilstedeværelse af tandsten eller ved bunden af defekten (hvis ikke tandsten var til stede); boremærket tjente som reference ved den histologiske evaluering. Efter defektudfyldelse med nano-HA blev lapperne syet ved hjælp af madras-suturer mhp. primær heling. Syv måneder efter regenerativ kirurgi blev tænderne ekstraheret sammen med en mindre del af de omgivende bløde og hårde væv og præpareret til histologisk undersøgelse. Resultater Postoperativ heling var komplikationsfri i alle tilfælde. Syv måneder efter operationen sås der betydelig pochedybdereduktion og klinisk fæstegevinst på 4,0 mm ± 0,8 mm og 2,5 mm ± 0,8 mm, henholdsvis. Den histologiske analyse viste, at helingen hovedsageligt kendetegnede sig ved et lang epitelialt fæste. Begrænset dannelse af ny cement med indlejrede kollagenfibre og knogleregeneration sås hos tre ud af de seks biopsier på op til henholdsvis 0,86 mm og 1,33 mm. Komplet resorption af nano-HA-partikler blev fundet i fire ud af de seks biopsier. Nogle få rester af de implanterede partikler (enten omgivet af nydannet mineraliseret væv eller indkapslet i bindevæv) blev fundet i to ud af de seks biopsier. Konklusion De foreliggende resultater viser, at nano-HA har begrænset mulighed for at fremme parodontal regeneration i humane intraossøse defekter. Klinisk relevans: De kliniske resultater opnået efter kirurgi med OFD + nano-HA afspejler måske ikke ægte parodontal regeneration. Horváth A, Stavropoulos A, Windisch P et al. Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste. Clin Oral Investig 2012.
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| 4. |
- Horvath, Gabor, et al.
(författare)
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On the trail of Vikings with polarized skylight: experimental study of the atmospheric optical prerequisites allowing polarimetric navigation by Viking seafarers
- 2011
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Ingår i: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2970 .- 0962-8436. ; 366:1565, s. 772-782
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Tidskriftsartikel (refereegranskat)abstract
- Between AD 900 and AD 1200 Vikings, being able to navigate skillfully across the open sea, were the dominant seafarers of the North Atlantic. When the Sun was shining, geographical north could be determined with a special sundial. However, how the Vikings could have navigated in cloudy or foggy situations, when the Sun's disc was unusable, is still not fully known. A hypothesis was formulated in 1967, which suggested that under foggy or cloudy conditions, Vikings might have been able to determine the azimuth direction of the Sun with the help of skylight polarization, just like some insects. This hypothesis has been widely accepted and is regularly cited by researchers, even though an experimental basis, so far, has not been forthcoming. According to this theory, the Vikings could have determined the direction of the skylight polarization with the help of an enigmatic birefringent crystal, functioning as a linearly polarizing filter. Such a crystal is referred to as 'sunstone' in one of the Viking's sagas, but its exact nature is unknown. Although accepted by many, the hypothesis of polarimetric navigation by Vikings also has numerous sceptics. In this paper, we summarize the results of our own celestial polarization measurements and psychophysical laboratory experiments, in which we studied the atmospheric optical prerequisites of possible sky-polarimetric navigation in Tunisia, Finland, Hungary and the high Arctic.
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| 5. |
- Horvath, Istvan, et al.
(författare)
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Mechanisms of Protein Oligomerization : Inhibitor of Functional Amyloids Templates α-Synuclein Fibrillation
- 2012
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 134:7, s. 3439-3444
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Tidskriftsartikel (refereegranskat)abstract
- Small organic molecules that inhibit functional bacterial amyloid fibers, curli, are promising new antibiotics. Here we investigated the mechanism by which the ring-fused 2-pyridone FN075 inhibits fibrillation of the curli protein CsgA. Using a variety of biophysical techniques, we found that FN075 promotes CsgA to form off-pathway, non-amyloidogenic oligomeric species. In light of the generic properties of amyloids, we tested whether FN075 would also affect the fibrillation reaction of human α-synuclein, an amyloid-forming protein involved in Parkinson's disease. Surprisingly, FN075 stimulates α-synuclein amyloid fiber formation as measured by thioflavin T emission, electron microscopy (EM), and atomic force microscopy (AFM). NMR data on (15)N-labeled α-synuclein show that upon FN075 addition, α-synuclein oligomers with 7 nm radius form in which the C-terminal 40 residues remain disordered and solvent exposed. The polypeptides in these oligomers contain β-like secondary structure, and the oligomers are detectable by AFM, EM, and size-exclusion chromatography (SEC). Taken together, FN075 triggers oligomer formation of both proteins: in the case of CsgA, the oligomers do not proceed to fibers, whereas for α-synuclein, the oligomers are poised to rapidly form fibers. We conclude that there is a fine balance between small-molecule inhibition and templation that depends on protein chemistry.
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| 6. |
- Horvath, Istvan, et al.
(författare)
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Modulation of α-synuclein fibrillization by ring-fused 2-pyridones : templation and inhibition involve oligomers with different structure
- 2013
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Ingår i: Archives of Biochemistry and Biophysics. - : Elsevier. - 0003-9861 .- 1096-0384. ; 532:2, s. 84-90
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Tidskriftsartikel (refereegranskat)abstract
- In a recent study we discovered that a ring-fused 2-pyridone compound triggered fibrillization of a key protein in Parkinson's disease, α-synuclein. To reveal how variations in compound structure affect protein aggregation, we now prepared a number of strategic analogs and tested their effects on α-synuclein amyloid fiber formation in vitro. We find that, in contrast to the earlier templating effect, some analogs inhibit α-synuclein fibrillization. For both templating and inhibiting compounds, the key species formed in the reactions are α-synuclein oligomers that contain compound. Despite similar macroscopic appearance, the templating and inhibiting oligomers are distinctly different in secondary structure content. When the inhibitory oligomers are added in seed amounts, they inhibit fresh α-synuclein aggregation reactions. Our study demonstrates that small chemical changes to the same central fragment can result in opposite effects on protein aggregation.
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| 7. |
- Rozsas, Anita, et al.
(författare)
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Erythropoietin Receptor Expression Is a Potential Prognostic Factor in Human Lung Adenocarcinoma
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Recombinant human erythropoietins (rHuEPOs) are used to treat cancer-related anemia. Recent preclinical studies and clinical trials, however, have raised concerns about the potential tumor-promoting effects of these drugs. Because the clinical significance of erythropoietin receptor (EPOR) signaling in human non-small cell lung cancer (NSCLC) also remains controversial, our aim was to study whether EPO treatment modifies tumor growth and if EPOR expression has an impact on the clinical behavior of this malignancy. A total of 43 patients with stage III-IV adenocarcinoma (ADC) and complete clinicopathological data were included. EPOR expression in human ADC samples and cell lines was measured by quantitative real-time polymerase chain reaction. Effects of exogenous rHuEPO alpha were studied on human lung ADC cell lines in vitro. In vivo growth of human ADC xenografts treated with rHuEPO alpha with or without chemotherapy was also assessed. In vivo tumor and endothelial cell (EC) proliferation was determined by 5-bromo-2'-deoxy-uridine (BrdU) incorporation and immunofluorescent labeling. Although EPOR mRNA was expressed in all of the three investigated ADC cell lines, rHuEPO alpha treatment (either alone or in combination with gemcitabine) did not alter ADC cell proliferation in vitro. However, rHuEPO alpha significantly decreased tumor cell proliferation and growth of human H1975 lung ADC xenografts. At the same time, rHuEPO alpha treatment of H1975 tumors resulted in accelerated tumor endothelial cell proliferation. Moreover, in patients with advanced stage lung ADC, high intratumoral EPOR mRNA levels were associated with significantly increased overall survival. This study reveals high EPOR level as a potential novel positive prognostic marker in human lung ADC.
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