177,030 research outputs found
The expression of LGR5 in healthy human stem cell niches and its modulation in inflamed conditions
No full textPurpose: The aims of this study are to investigate the expression of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) protein in the normal human cornea and limbus and to analyze modifications of this expression under inflammatory conditions. Methods: The expression of LGR5 was evaluated in seven limbal epithelial crypts (LECs), collected from healthy cadaver donors, and five inflamed LECs obtained from enucleated eyes. Central corneal buttons were used as controls. LGR5 protein distribution was determined by immunohistochemistry staining analysis. Results: The cytoplasmic expression of LGR5 protein was observed in 100% of healthy LECs. Three out of five inflamed tissues analyzed were completely negative, while in the two remaining cases, we observed a moderate positivity in the basal cells of LECs. No relation was found between the expression of LGR5 and the grade of inflammatory cells. Conclusions: These findings demonstrate the presence of LGR5-positive cells in human LECs and their decrease in inflamed conditions, which suggests a critical role of this protein during inflammation and its possible use as a marker in normal crypts
E-learning Tool nella misura dei processi di formazione
No full textIl presente lavoro mira a descrivere la progettazione di una classe virtuale che, basata sull’approccio di apprendimento collaborativo, possa attraverso l’integrazione di specifici strumenti di misurazione, permettere di valutare sia la qualità delle applicazioni che il livello di partecipazione degli studenti dell’ambiente e-learning proposto. I metodi di misurazione dell’ apprendimento degli studenti sembrano infatti essere gli unici autentici indicatori della qualità dell'insegnamento con la tecnologia. L’obiettivo di tale lavoro è, pertanto, definire un modello di valutazione della qualità della formazione on-line di facile applicazione e utilizzo basato essenzialmente sull’instaurazione di canali di feedback tra gli studenti ed il docente
Structural modifications and tissue response after standard epi-off and iontophoretic corneal crosslinking with different irradiation procedures
No full textPURPOSE: The aim of this study is to investigate modifications in human cadaver corneas after different crosslinking procedures, including standard epi-off treatment, iontophoresis imbibition, and different exposure to ultraviolet A (UVA) sources (30 minutes at 3 mW and 9 minutes at 10 mW).
METHODS:
A total of 12 human cadaver corneas was examined and divided as follows: 3 served as control (group 1), 3 were treated with a standard epi-off procedure (group 2), 6 underwent iontophoresis imbibition for 5 minutes, and then 3 were irradiated for 30 minutes with 3 mW UVA (group 3), and 3 for 9 minutes at 10 mW UVA (group 4). Deformation amplitude index was measured before and after the corneas underwent treatment. After treatment, corneas were prepared for hematoxylin-eosin and immunohistochemistry evaluation. The expression of TUNEL, matrix metalloproteinase-1 (MMP-1), collagen type I, and CD34 was investigate in all samples.
RESULTS:
The deformation amplitude index decreased in all groups, in particular in group 4, indicating an improvement of corneal biomechanical properties. Immunohistochemical staining showed a significant stromal alteration in group 2, mild damage in group 3, and no modifications in corneal morphology in group 4. The TUNEL (P < 0.001) and MMP-1 (P = 0.002) positivity was more evident in group 4. Collagen type I positivity significantly increased in groups 3 (P = 0.002) and 4 (P = 0.002). The CD34 expression was more evident in groups 2 (P = 0.003) and 3 (P = 0.003).
CONCLUSIONS:
Iontophoresis imbibition followed by UVA irradiation for 9 minutes at 10 mW determined less tissue damage and better stromal remodeling
S100 A and B expression in normal and inflamed human limbus
No full textPURPOSE: To study the expression of S100 A and B family proteins in normal human limbus and to analyze modification of the expression in inflammatory conditions.
METHODS:
The total expression of members of the S100 family and the expression of A4, A8, A9, and B individually were evaluated in nine normal human corneal limbi, collected from cadaver healthy donors, in particular in the limbal epithelial crypts (LECs), and in five inflamed limbi obtained from enucleated eyes. S100 protein distribution was determined with immunohistochemistry staining analysis.
RESULTS:
Cytoplasmic expression of total S100 proteins was observed in 100% of LECs; in contrast, the inflamed tissues were completely negative, and faint positivity was observed in only one case. Moreover, cytoplasmic expression of S100 A4 and A9 was uniformly found in the entire LECs in all samples analyzed, while S100 A8 positivity was observed in only 44.4% of cases and only in the cells localized in the central area of the LEC. Positivity for S100 B was not observed in all samples analyzed.
CONCLUSIONS:
As reported in the literature, normal limbal epithelial cells show strong expression of S100 proteins. A novel finding of this study was the expression for the limbal epithelial crypts. In particular, S100 A4 and A9, which are normally involved in regulating a wide range of biologic effects, including cell motility, survival, and differentiation, are the most expressed members in healthy limbal crypts. In inflamed tissues, expression of S100 proteins was dramatically decreased. S100 proteins, and in particular S100 A4 and S100 A9, can be useful as markers of early changes in stem cell niches due to inflammatio
In Vivo and Ex Vivo Evaluation of Inflammation and Apoptosis Induced after SMILE Procedures for Different Refractive Error Range
No full textAbstract
PURPOSE:
To detect corneal inflammation and apoptosis induced after small incision lenticule extraction (SMILE) at different refractive corrections for moderate to high values of myopia.
METHODS:
Fifty patients (50 eyes) suffering from medium to high myopia (spherical equivalent refraction from -3.75 to -10.00 diopters (D) with refractive astigmatism under -0.75 D) underwent SMILE in order to correct myopic error. In vivo evaluation was done by corneal confocal microscopy (IVCM) and ex vivo by immunohistochemistry. After surgery, all corneal lenticules were checked for regularity, entirety, and fixed in formalin for immunohistochemistry evaluation of apoptosis (TUNEL) and inflammation (CD11b) levels. Postoperative assessments took place during the first week and the first and third months after surgery. Patients returned for IVCM examination for analysis of the corneal stromal femtosecond laser treatment interfaces reflectivity.
RESULTS:
No correlation was observed between treated myopic refractive error and number of CD11b+ and TUNEL+ cell in all analyzed extracted lenticules. IVCM at 1 week and 1 month of follow-up showed numerous reflective particles at the laser treatment interface with a moderate light scattering. In semi-quantitative analysis of reflectivity intensity at the laser interfaces, a statistical difference was evident only between 1 week and 1 month (p = 0.0213).
CONCLUSIONS:
SMILE, as an innovative all-femto surgical procedure, results in a reduced tissue inflammation and apoptosis levels with a minimum tissue response, in terms of interface reflectivity, and there are no statistically significant differences among variable treated refractive error range
Morphological modification of the cornea after standard and transepithelial corneal cross-linking as imaged by anterior segment optical coherence tomography and laser scanning in vivo confocal microscopy
No full textPURPOSE: In vivo analysis of corneal modifications after traditional and transepithelial corneal cross-linking (CXL).
METHODS:
Forty eyes of 35 patients underwent traditional or transepithelial CXL; there was randomization of 20 eyes to each group. By means of in vivo confocal microscopy and anterior segment ocular coherence tomography, we evaluated corneal alterations at 1 week, 1 month, and 3, 6, and 12 months after the treatment.
RESULTS:
During follow-up, in vivo confocal microscopy showed a significant decrease in anterior keratocyte density (P = 0.001) and more evident stromal edema and keratocyte activation (P = 0.001) in the traditional group, whereas in the transepithelial group, no significant changes were observed (P > 0.05). Anterior segment ocular coherence tomography indicated the presence of hyperreflective stromal line significantly deeper and more persistent in the traditional group (P < 0.001).
CONCLUSIONS:
The preliminary results suggest that traditional CXL induced marked corneal modifications, which were poorly evident in the transepithelial group
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Missing data imputation in meteorological datasets with the GAIN method
No full textAim of this work is to present the preliminary results obtained using Generative Adversarial Imputation Networks (GAIN) to face the problem of incomplete time series in high frequency meteorological data. Meteorological data such as temperature, rain, wind etc., are being measured with many different techniques from many years. This fact has led to the creation of long time series that often are incomplete due to various reasons: temporary instrument faults, natural events, etc. Since these time series are used in many applications (from weather forecast to civil engineering design), their quality and completeness are becoming an even more critical question. In literature there are many studies aiming at meteorological time series completion using various approaches. In this context, authors show the results obtained using the GAIN method to complete high frequency temperature time series. The first obtained results seem to be very encouraging
Pathological changes of anatomical structure and markers of limbal stem cell niche due to inflammation
No full textPurpose: It’s known that severe inflammatory processes may cause limbal stem cell (SC) deficiency decreasing the number of SC niches and changing the microanatomy of these structures.Methods: The aim of this study was to evaluate the expression of different SC markers in normal human limbus and to study how an inflammatory conditions can modulate these antigens. To understand the pathological changes in limbal crypts structure due to severe inflammation, a case of corneal melting and perforation in advanced herpes simplex (HSV) disease, two cases of endophthalmitis and a case of fungal infection were analyzed.Samples were examined by immunohistochemistry or immunofluorescence for p63, vimentin, laminin5, integrin (Int) α6, int β1, int β4, ABCG2, desmoglein 3, connexin43, N-cadherin and cytokeratin (K) 12 positivity. We evaluated the anatomical structure of limbal crypts in each case and the positivity for SC marker used to identify SC.Results: In normal limbus, the investigated SC markers were positive. In the HSV we didn’t observe presence of crypts, whereas in both cases of endophthalmitis crypts were still present but they had an atypical structure: the basal cells in the crypts were “stretched” and endowed by inflammatory cells. In the pathological cases, we observed positivity for K12 while, among SC markers, p63, ABCG2 and connexin43 were still present; the others antigens were variably expressed.Conclusion: Different pathologies involving the limbus may result in marked chenges of expression of SC markers within the crypts
A new approach for the modelling of chestnut wood photo-degradation monitored by different spectroscopic techniques
No full textThe aim of this work is to study the colour and chemical modifications of the surfaces in chestnut wood samples as a consequence of irradiating in a controlled environment. The changes were investigated by a new analytical approach by combining traditional techniques such as reflectance spectrophotometry in the visible range and Fourier transform infrared spectroscopy with new hyperspectral imaging, in order to obtain forecast models to describe the phenomenon. The statistical elaboration of the experimental data allowed to validate the measurements and to obtain models enabling to relate the investigated parameters; the elaboration of the hyperspectral images by chemometric methods allowed for studying the changes in the reflectance spectra. A result of great importance is the possibility to correlate the oxidation of wood chemical components with the colour change in a totally non-invasive modality. This result is particularly relevant in the field of cultural heritage and in general in the control processes of wooden materials
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