The modification of biomaterial surfaces has become increasingly relevant in the context of ongoing advancements in tissue engineering applications and the development of tissue-mimicking polymer materials. In this study, we investigated the layer-by-layer (LbL) deposition of polyelectrolyte multilayer protein reservoirs consisting of poly-l-lysine (PLL) and hyaluronic acid (HA) on the hydrophobic surface of poly(glycerol sebacate) (PGS) elastomer. Using the methods of isothermal titration calorimetry and surface plasmon resonance, we systematically investigated the interactions between the polyelectrolytes and evaluated the deposition process in real time, providing insight into the phenomena associated with film assembly. PLL/HA LbL films deposited on PGS showed an exceptional ability to incorporate bone morphogenetic protein-2 (BMP-2) compared to other growth factors tested, thus highlighting the potential of PLL/HA LbL films for osteoregenerative applications. The concentration of HA solution used for film assembly did not affect the thickness and topography of the (PLL/HA)10 films, but had a notable impact on the hydrophilicity of the PGS surface and the BMP-2 release kinetics. The release kinetics were successfully described using the Weibull model and hyperbolic tangent function, underscoring the potential of these less frequently used models to compare the protein release from LbL protein reservoirs.
- MeSH
- Hyaluronic Acid * chemistry MeSH
- Layer-by-Layer Nanoparticles MeSH
- Polyelectrolytes MeSH
- Polylysine * chemistry MeSH
- Polymers MeSH
- Publication type
- Journal Article MeSH
Cieľ: Cieľom práce bolo štatistické zhodnotenie hrúbky vrstvy nervových vlákien retiny (RNFL) meranej pomocou GDx analyzátora u stredných a vyšších stupňov myopie pred laser assisted in situ keratomileusis (LASIK) a v pooperačnom období 6 mesiacov. Materiál a metodika: Súbor tvorilo 35 očí 18 pacientov (8 mužov, 10 žien), priemerného veku 28,9 ± 5,08 roka. Refrakčná vada bola od -3,25 Dsf do -11,5 Dsf (Ņ -5,5 ± 1,4 Dpt). Pacienti podstúpili refrakčný zákrok technikou LASIK na korekciu myopie. Hrúbka RNFL bola meraná pomocou GDx analyzátora s variabilným rohovkovým kompenzátorom (Variable Corneal Compensator) pred refrakčným výkonom a v odstupe 3 a 6 mesiacov po zákroku. Pred každým meraním bola použitá nová kompenzácia rohovky vzhľadom k aktuálnej refrakcii. Hodnoty hrúbky RNFL v μm boli porovnané a štatisticky vyhodnotené pomocou Wilcoxonovho neparametrického párového testu v oblasti celej peripapilárnej elipsy (TSNIT) a v hornom a dolnom kvadrante tejto elipsy. Výsledky: Štatisticky významný rozdiel v hrúbke RNFL na 5% hladine významnosti sme zaznamenali v TSNIT oblasti po 3 mesiacoch od LASIK. Štatisticky významný rozdiel v hrúbke RNFL na 1% hladine významnosti sme zaznamenali v hornom kvadrante po 3 mesiacoch a v dolnom kvadrante po 3 a 6 mesiacoch od LASIK.
Purpose of this paper was to evaluate statistically the thickness of the retinal nerve fiber layer (RNFL) measured by means of the GDx analyzer in middle and high degrees of myopia before laser assisted in situ mileusis (LASIK) and in the postoperative period of 6 months. Material and methods: The group consisted of 35 eyes of 18 patients (8 men and 10 women), the average age was 28.9 ± 5.08 years of age. The refractive error was from -3.25 dioptres (D) to -11.5 D (average -5.5 ± 1.4 D). The patients underwent the corrective refractive procedure by means of LASIK to correct the myopia. The thickness of RNFL was measured by means of GDx analyzer with Variable Corneal Compensator before the refractive procedure and 3 and 6 months after this. Before each measurement, a new compensation of the cornea according to the actual refractive status was used. The RNFL thickness values (in μm) were compared and statistically evaluated using of the Wilcoxon’s nonparametric pair test in the whole peripapilary ellipse area (TSNIT) and in the superior and inferior quadrants of this ellipse. Results: Statistically significant difference of the RNFL thickness at the 5 % level of significance was found in the TSNIT area after 3 months and after LASIK. Statistically significant difference of the RNFL thickness at the 1 % level of significance was found in the superior quadrant after 3 months and in the inferior quadrant after 3 and 6 months after LASIK.
To evaluate the retinal nerve fibre layer (RNFL) thickness and choroidal thickness (CT) in Parkinson disease (PD) patients. A comparative cross-sectional, hospital-based study. 39 PD and 39 controls were recruited, who were gender and age matched. Subjects that fulfilled the inclusion criteria underwent optical coherence tomography for evaluation of RNFL thickness and choroidal thickness (CT). There was significant reduction of RNFL thickness in average (adjusted mean 88.87 μm vs. 94.82 μm, P=0.001), superior (adjusted mean 110.08 μm vs. 119.10 μm, P=0.002) and temporal (adjusted mean 63.77 μm vs. 70.36 μm, P=0.004) in PD compared to controls. The central subfoveal CT was significantly thinner in PD compared to controls (adjusted mean 271.13 μm vs. 285.10 μm, P=0.003). In PD group, there was significant weak negative correlation between the duration of PD with average RNFL thickness (r=-0.354, P=0.027), moderate negative correlation between the duration of PD with central subfoveal CT (r=-0.493, P=0.001), and weak negative correlation between the stage of PD with central subfoveal CT (r=-0.380, P=0.017). PD group had significant thinner average, superior and temporal RNFL thickness and CT compared to controls.
- MeSH
- Choroid MeSH
- Humans MeSH
- Nerve Fibers MeSH
- Parkinson Disease * complications MeSH
- Cross-Sectional Studies MeSH
- Retina MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
OBJECTIVES: The objective of this study was to observe and to measure the impact of corundum sandblasting on the thickness of the Immediate dentin sealing layer. METHODS: 20 recently extracted molars were collected and divided randomly into two groups. A standardized preparation was performed on each tooth and the Optibond FL dentin bonding agent (Kerr, Orange, USA) was applied on the prepared surface according to the manufacturer’s instructions. The surface was then partially sandblasted. RONDOflex plus 360 (KaVo, Bieberach an der Riss, Germany) and Airsonic Mini-Sandblaster (Hager et Werken, Duisburg, Germany) were used. Microscope observations were made. RESULTS: The arithmetic mean of the Optibond FL dentin bonding agent film thickness was 48.72 μm (Group 1=45.55 μm and Group 2=51.88 μm). The dentin bonding agent layer thickness was reduced to the average value of 17,12 μm by RONDOflex plus 360 sandblasting (Group 1). The zero value was recorded in 16 % of the locations. The Airsonic Mini-Sandblaster sandblasting changed the average thickness of the dentin bonding agent layer to 13.25 μm with 31 % of zero values (Group 2). CONCLUSION: The results of this research lead to a reflection on modifications of the immediate dentin sealing procedure (Tab. 4, Fig. 3, Ref. 28).
- MeSH
- Dentin-Bonding Agents * classification MeSH
- Humans MeSH
- Microscopy MeSH
- Molar drug effects MeSH
- Aluminum Oxide MeSH
- Air Abrasion, Dental * methods MeSH
- Statistics as Topic MeSH
- Dental Enamel diagnostic imaging drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Observational Study MeSH
- Research Support, Non-U.S. Gov't MeSH
This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A · dm(-2) and 3 A · dm(-2) for creating aluminium oxide layer.
BACKGROUND: Here we present our experience with the occurrence of neoplastic chondrocytes with target-like appearance surrounded with unusual hypertrophic thick eosinophilic perichondrocytic rings (baskets), sometimes containing two or several layers. METHODS AND RESULTS: Pericellular rings (baskets) were positive in APAS and Masson's staining method and showed immunoreactivity with antibody against type IV collagen. Such single cells or small groups of such cells were observed rarely in 3 osteochondromas, 2 skeletal chondromas, 2 extraskeletal chondromas and 2 skeletal and 1 laryngeal chondrosarcomas. Moreover, 1 unusual soft tissue chondrosarcoma was composed entirely of target-like chondrocytes with hypertrophic extremely thick perichondrocytic rings. Such cartilage-forming tumour with target-like cells, which, to the best of our knowledge, is the first such chondrosarcoma reported in the literature. Ultrastructural evidence is presented that perichondrocytic rings have complicated structure.They contained microfibrillar component with abundant admixture of irregular aggregates of dense amorphous non-fibrillar material localised in lacunar spaces. In outer part of the rings predominated microfibrillar structures corresponding to type VI collagen that produced a rather dense capsule-like demarcation line against surrounding intercellular spaces. CONCLUSIONS: The described unusual changes are probably the result of hyperproduction and remodelation of perichondrocytic matrix by abnormal neoplastic chondrocytes in response to unknown factors. Local vascular and molecular signals, may be supposed as probable causes of this phenomenon.
- MeSH
- Chondrocytes MeSH
- Chondroma * MeSH
- Chondrosarcoma * MeSH
- Cartilage MeSH
- Humans MeSH
- Bone Neoplasms * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Images of ocular fundus are routinely utilized in ophthalmology. Since an examination using fundus camera is relatively fast and cheap procedure, it can be used as a proper diagnostic tool for screening of retinal diseases such as the glaucoma. One of the glaucoma symptoms is progressive atrophy of the retinal nerve fiber layer (RNFL) resulting in variations of the RNFL thickness. Here, we introduce a novel approach to capture these variations using computer-aided analysis of the RNFL textural appearance in standard and easily available color fundus images. The proposed method uses the features based on Gaussian Markov random fields and local binary patterns, together with various regression models for prediction of the RNFL thickness. The approach allows description of the changes in RNFL texture, directly reflecting variations in the RNFL thickness. Evaluation of the method is carried out on 16 normal ("healthy") and 8 glaucomatous eyes. We achieved significant correlation (normals: ρ=0.72±0.14; p≪0.05, glaucomatous: ρ=0.58±0.10; p≪0.05) between values of the model predicted output and the RNFL thickness measured by optical coherence tomography, which is currently regarded as a standard glaucoma assessment device. The evaluation thus revealed good applicability of the proposed approach to measure possible RNFL thinning.
- MeSH
- Color * MeSH
- Optic Disk pathology MeSH
- Fundus Oculi MeSH
- Glaucoma pathology MeSH
- Humans MeSH
- Markov Chains * MeSH
- Nerve Fibers pathology MeSH
- Normal Distribution MeSH
- Tomography, Optical Coherence MeSH
- Retinal Ganglion Cells pathology MeSH
- Image Enhancement methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The paper presents a comparative study of the pulsatile attenuation amplitude (PAA) within the optic nerve head (ONH) at four different areas calculated from retinal video sequences and its relevance to the retinal nerve fiber layer thickness (RNFL) changes in normal subjects and patients with different stages of glaucoma. The proposed methodology utilizes processing of retinal video sequences acquired by a novel video ophthalmoscope. The PAA parameter measures the amplitude of heartbeat-modulated light attenuation in retinal tissue. Correlation analysis between PAA and RNFL is performed in vessel-free locations of the peripapillary region with the proposed evaluating patterns: 360° circular area, temporal semi-circle, nasal semi-circle. For comparison, the full ONH area is also included. Various positions and sizes of evaluating patterns in peripapillary region were tested which resulted in different outputs of correlation analysis. The results show significant correlation between PAA and RNFL thickness calculated in proposed areas. The highest correlation coefficient Rtemp = 0.557 (p<0.001) reflects the highest PAA-RNFL correspondence in the temporal semi-circular area, compared to the lowest value in the nasal semi-circular area (Rnasal = 0.332, p<0.001). Furthermore, the results indicate the most relevant approach to calculate PAA from the acquired video sequences is using a thin annulus near the ONH center. Finally, the paper shows the proposed photoplethysmographic principle based on innovative video ophthalmoscope can be used to analyze changes in retinal perfusion in peripapillary area and can be potentially used to assess progression of the RNFL deterioration.
- MeSH
- Optic Disk * MeSH
- Glaucoma * diagnosis MeSH
- Humans MeSH
- Nerve Fibers MeSH
- Tomography, Optical Coherence methods MeSH
- Retinal Ganglion Cells MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Optic Disk anatomy & histology MeSH
- Evaluation Studies as Topic MeSH
- Humans MeSH
- Tomography, Optical Coherence utilization MeSH
- Retinal Ganglion Cells MeSH
- Check Tag
- Humans MeSH
- Publication type
- Book Review MeSH
Úvod: Alzheimerova choroba (ACH) je nejčastější příčina syndromu demence a mírné kognitivní poruchy (MCI). Současné diagnostické metody jsou nákladné, náročné a pro pacienta zatěžující. Proto se hledají alternativní přístupy pro časnou diagnostiku ACH. Jednou z možností může být zhodnocení tloušťky vrstvy nervových vláken sítnice (RNFL). Cíl: Cílem naší práce bylo stanovit tloušťku RNFL v jednotlivých kvadrantech sítnice cirkulárně kolem terče zrakového nervu u pacientů s ACH a MCI pomocí optické koherenční tomografie (OCT) a porovnat výsledky s kontrolním souborem. Soubor a metodika: Soubor obsahoval 24 pacientů s ACH, resp. 48 změřených očí a 10 pacientů s MCI, resp. 19 změřených očí. Kontrolní soubor čítal 26 osob, resp. 51 změřených očí. Všichni pacienti podstoupili komplexní oční vyšetření a byla u nich změřena tloušťka RNFL pomocí OCT. Výsledky: Mezi hodnotami tloušťky RNFL souborů studovaných a kontrolního jsme neprokázali statisticky signifikantní rozdíl. Závěry: Námi zvolená metodika a získané výsledky potvrzují výhody vyšetření sítnice jako použitelnou, časově přiměřenou a pro pacienta nezatěžující možnost. Výstupy z naší práce přispívají do diskuze o přínosu této metodiky v diagnostice ACH. Je třeba dalších studií, které by analyzovaly přínosnost OCT v diagnostice ACH s výhledem výhodnosti aplikace této metodiky v klinické praxi.
Introduction: Alzheimer's disease (AD) is the most common cause of dementia syndrome and mild cognitive impairment (MCI). Current diagnostic methods are expensive, challenging and burdening for patients. Therefore, alternative diagnostic methods suitable for early diagnosis are still being sought. Evaluation of retinal nerve fiber layer (RNFL) thickness, well accessible to examination through optical apparatus, could be one of the options. Aim: The aim of our research was to evaluate RNFL thickness in several peri-papillary quadrants of the retina by patients with AD and MCI measured with the optical coherence tomography (OCT) and to match the results with a control cohort. Patients and methods: 24 AD patients, precisely 48 measured eyes, and 10 MCI patients, precisely19 eyes, were included. The control cohort included 26 patients, precisely 51 eyes. All patients underwent detailed ophtalmological checkup and RNFL thickness in the area circular around the optic nerve head via OCT was measured. Results: We did not find any statistically significant difference of RNFL thickness between the studied and control cohort in any peri-papillary quadrant of the retina. Conclusions: The procedure we selected and our results have confirmed the advantages of retinal examination as a practical, timely and patient non-burdening method. Our results also contribute to the discussion on the benefits of this procedure in AD diagnostics. Previous research provided inconsistent results and they differed in used procedures and characteristics of selected cohorts. There is a need for further studies to assess utility of OCT in AD diagnostics with respect to convenience of application of this method into clinical practice.
- Keywords
- vrstva nervových vláken sítnice,
- MeSH
- Alzheimer Disease * diagnosis MeSH
- Nerve Degeneration MeSH
- Cognitive Dysfunction diagnosis MeSH
- Middle Aged MeSH
- Humans MeSH
- Nerve Fibers * pathology MeSH
- Tomography, Optical Coherence MeSH
- Retina * pathology MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
