627 research outputs found
Structural and molecular tear film changes in glaucoma
No full textThe tear film (TF) is a trilaminar and dynamic fluid covering the entire ocular surface (OS), consisting of a mucus, aqueous, and lipid layer deeply interacting between them. Because of its structure and functions, TF plays a pivotal role in the preservation of the OS integrity and the quality of vision. Medical therapy for glaucoma is recognized to profoundly disturb the OS homeostasis by altering all components of the ocular surface unit, including TF. The presence of preservatives, the number of daily eye drops instillations, and the duration of therapy are the main contributors to TF changes. From the physio-pathological side, TF alterations are induced by toxic and allergic mechanisms, and result from goblet cell and Meibomian gland loss, dysfunction of accessory lacrimal glands, and epithelial disruption. In detail, TF changes are represented by mucus layer thinning, reduced mucin concentration, aqueous layer volume reduction, and lipid layer thinning with increased tear evaporation. Hyper-osmolarity and instability represent the main hallmarks of these changes and are expression of a iatrogenic form of dry eye. TF undergoes also molecular modifications that primarily reflect a therapy- or disease-induced inflammatory status of the OS. Over the last years, this field of research gained a progressively growing interest since molecular variations may be considered as potential candidate biomarkers of glaucoma. The aim of this review is to report the main TF changes occurring during glaucoma, exploring the relationship they may have with the glaucoma-related ocular surface disease and the patient quality of life, and their utility as potential biomarkers of disease
In vivo confocal microscopy of conjunctiva-associated lymphoid tissue in healthy humans
No full textPURPOSE: To investigate modifications with aging of the presence, distribution and morphologic features of conjunctiva-associated lymphoid tissue (CALT) in healthy human subjects using laser scanning in vivo confocal microscopy (IVCM).
METHODS:
A total of 108 (age range, 17-75 years) subjects were enrolled. In vivo confocal microscopy of the tarsal and bulbar conjunctiva, and impression cytology (IC) with CD3 (intra-epithelial T-lymphocytes) and CD20 (intra-epithelial B-lymphocytes) antibody immunofluorescence staining were performed. The main outcomes were subepithelial lymphocyte density (LyD), follicular density (FD), and follicular area (FA). The secondary outcomes were follicular reflectivity (FR), and lymphocyte density (FLyD), and CD3 and CD20 positivity.
RESULTS:
Conjunctiva-associated lymphoid tissue was observed in all subjects (97% only superior and 3% in both superior and inferior tarsum). Lymphocyte density ranged from 7.8 to 165.8 cells/mm(2) (46.42 [18.37]; mean [SD]), FD from 0.5 to 19.4 follicles/mm(2) (5.3 [3.6]), and FA from 1110 to 96,280 mm(2) (26,440 [26,280]). All three parameters showed a highly significant inverse cubic relationship with age (P < 0.001); that is, in the first and last parameters a steep decline up to 35 years and above 65 years of age, with a plateau phase between these ages, whereas FA had a gradually decreasing rate of loss over the studied age range. CD3 and CD20 IC were consistent with these results.
CONCLUSIONS:
In vivo confocal microscopy was effective in revealing CALT and modifications these structures undergo with aging. Aging correlated with an involution of all parameters defining lymphoid structures. These modifications may account for the decrease of mucosal immune response and increase of ocular surface diseases in the elderl
Meibomian Gland Features and Conjunctival Goblet Cell Density in Glaucomatous Patients Controlled With Prostaglandin/Timolol Fixed Combinations: A Case Control, Cross-sectional Study
No full textPURPOSE: To investigate, using in vivo confocal microscopy (IVCM), the Meibomian gland (MG) features and conjunctival goblet cell density (GCD) in glaucomatous patients controlled with prostaglandin/timolol fixed combinations (PTFCs).
MATERIALS AND METHODS:
In this cross-sectional study, 60 white patients were treated with PTFCs, 15 with latanoprost+timolol (L+T) unfixed combination, and 15 controls were enrolled. Patients underwent the Ocular Surface Disease Index questionnaire, tear film breakup time, corneal staining, Schirmer test I, and IVCM of MGs and goblet cells. The main outcome measures were: mean Meibomian acinar density (MMAD) and area (MMAA), inhomogeneity of glandular interstice (InI) and acinar wall (InAW), and GCD.
RESULTS:
PTFCs were: latanoprost/timolol (LTFC, 15 eyes), travoprost/timolol (TTFC, 15), bimatoprost/timolol (BTFC, 15), and preservative-free bimatoprost/timolol (PF-BTFC, 15) fixed combinations. Mean time on therapy did not differ among treatments. IVCM documented lower GCD, MMAD, and MMAA (P<0.001), and greater InI and InAW (P<0.05) in glaucoma patients compared with controls. L+T showed worse values compared with PTFCs and PF-BTFC (P<0.05). Preserved PTFCs showed lower MMAD, MMAA, GCD, and greater InI and InAW compared with PF-BTFC (P<0.05) and controls (P<0.001). Differences were not found among PTFCs. InI and InAW significantly correlated with Ocular Surface Disease Index and breakup time (P<0.001), corneal staining (P<0.05), and GCD (P<0.001); GCD correlated with MMAD (P<0.05).
CONCLUSIONS:
PTFCs were less toxic towards MGs and goblet cells compared with the L+T unfixed combination, with PF-BTFC presenting the most tolerated profile. These findings should be carefully considered given the role of these structures in the induction of the glaucoma-related ocular surface disease
Conjunctival modifications induced by medical and surgical therapies in patients with glaucoma
No full textLowering intra-ocular pressure, either medically or surgically, is the proven strategy to control glaucoma, though profound changes to the ocular surface and conjunctiva are caused. Toxicity and allergy initiated by medical therapy induce modifications, which progressively worsen with the length of treatment and number of drugs. Conjunctival changes lead to symptoms of ocular surface disease, reduced quality of life, reduced therapeutic compliance and increased risk of surgical failure. Surgery modifies conjunctiva by inducing bleb formation in fistulizing techniques, and by activating secondary aqueous humour outflow pathways, such as trans-scleral routes, in both filtration and bleb-less approaches. The use of unpreserved medications, limitation of intra-operative conjunctival damage and development of bleb-less surgery are advisable
Femtosecond laser versus manual clear corneal incision in cataract surgery.
No full textPURPOSE:
To compare functional and morphological outcomes of femtosecond laser clear corneal incision (CCI) versus manual CCI during cataract surgery.
METHODS:
Sixty eyes of 60 patients who underwent CCI during cataract surgery were randomized into two groups: femtosecond laser CCI (30 eyes) and manual CCI (30 eyes).
RESULTS:
There were no significant between-group differences in uncorrected distance visual acuity, corrected distance visual acuity, surgically induced astigmatism, and corneal aberrations. Keratometric astigmatism was significantly lower in the femtosecond laser CCI group compared to the manual CCI group at 30 and 180 days (P < .05). Central endothelial cell count was significantly higher in the femtosecond laser CCI group compared to the manual CCI group at 7 and 30 days postoperatively (P < .05). A lower increase of corneal thickness at the incision site was observed at 30 and 180 days postoperatively in the femtosecond laser CCI group compared to the manual CCI group (P < .05). In addition, femtosecond laser CCI showed a better morphology (lower percentage of endothelial and epithelial gaping and endothelial misalignment) compared to manual CCI at different time points. Total phacoemulsification time was significantly lower in the femtosecond laser CCI group (P < .05).
CONCLUSIONS:
The femtosecond laser procedure was safe, efficient, and less damaging, as evidenced by lower central endothelial cell loss, lower increase of corneal thickness at the incision site, and better tunnel morphology compared to the manual technique
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
Anterior segment optical coherence tomography imaging of conjunctival filtering blebs after glaucoma surgery
No full textTime domain (TD) and spectral domain (SD) optical coherence tomography (OCT) are cross-sectional, noncontact, high-resolution diagnostic modalities for posterior and anterior segment (AS) imaging. The AS-OCT provides tomographic imaging of the cornea, iris, lens, and anterior chamber (AC) angle in several ophthalmic diseases. In glaucoma, AS-OCT is utilized to evaluate the morphology of AS structures involved in the pathogenesis of the disease, to obtain morphometric measures of the AC, to evaluate the suitability for laser or surgical approaches, and to assess modifications after treatment. In patients undergoing surgery, AS-OCT is crucial in the evaluation of the filtering bleb functionality, permitting a combined qualitative and quantitative analysis. In this field, AS-OCT may help clinicians in distinguishing between functioning and nonfunctioning blebs by classifying their macroscopic morphology, describing bleb-wall features, bleb cavity, and scleral opening. This information is critical in recognizing signs of filtration failure earlier than the clinical approach and in planning the appropriate timing for management procedures in failing blebs. In this review, we summarize the applications of AS-OCT in the conjunctival bleb assessment
The influence of hemodialysis on intraocular pressure: III. Aqueous humor dynamics and tissue hydration
No full textMetabolismo dei frutto-oligosaccaridi in piante tipiche del territorio pugliese
No full texti fruttani sono oligosaccaridi, prevalentemente costituiti
da fruttosio, che presentano un particolare interesse
dal punto di vista nutrizionale, in particolare
per la loro attività prebiotica, per l’effetto positivo
sull’assorbimento del calcio e sul mantenimento dell’integrità
della mucosa intestinale (RoBeRfRoid et
al., 1998; aBRamS et al., 2005; kleeSSen, Blaut,
2005).
i fruttani sono sintetizzati solo dal 15% delle
angiosperme, tra cui le Asteraceae, Campanulaceae e
Boraginaceae tra le dicotiledoni, Poaceae e Liliaceae
tra le monocotiledoni. È noto, inoltre, che le condizioni
ambientali, in particolare quelle relative allo
stato idrico e termico, influenzano notevolmente il
metabolismo dei fruttani, in quanto regolano l’attività
degli enzimi coinvolti nei processi di sintesi e idrolisi
(valluRu, van den ende, 2008).
nel nostro studio il contenuto dei fruttani è stato
analizzato in alcune piante tipiche del territorio
pugliese, scelte tra quelle appartenenti alle famiglie
notoriamente dotate del metabolismo dei fruttani.
alcune delle piante analizzate presentano livelli significativi
di fruttani anche nelle parti eduli: Muscari
comosum (25 mg/g peso fresco del bulbo)> Asparagus
officinalis (6 mg/g peso fresco del turione) > Borago
officinalis (4 mg/g peso fresco delle foglie). Questi
dati preliminari, se confrontati a quanto riportato in
letteratura (muiR et al., 2007), suggeriscono che le
condizioni ambientali del territorio pugliese possono
essere favorevoli all’accumulo di fruttani, anche in
piante di interesse agro-alimentare; tuttavia è necessario
ampliare l’indagine anche ad altre fasi di sviluppo
di queste piante e ad altri periodi di raccolta.
considerata la complessità degli studi sul metabolismo
in piante cresciute in campo, dovuta all’impossibilità
di analizzare un dato processo metabolico in
condizioni standardizzate, si è pensato di realizzare
uno studio sul metabolismo dei fruttani in un sistema
sperimentale altamente controllato, quale una
coltura in vitro. a tal scopo si è scelto di propagare
M. comosum, considerata l’elevata capacità di accumulo
di fruttani e il particolare carattere di tipicità di
questa pianta nel territorio pugliese. i bulbi di M.
comosum, infatti, sono impiegati da lungo tempo per
preparare piatti e conserve tipiche.
il prelievo degli espianti è stato effettuato da bulbi
preventivamente lavati in acqua corrente e privati
delle tuniche esterne. la fase di sterilizzazione è stata
completata con un lavaggio in ipoclorito di sodio
(1%) addizionato di tween 20 (2%) e con un lavaggio
in una soluzione biocida (PPm= Plant
Presevative mixture- micropoli). gli espianti, costituiti
dalle gemme apicali e da sezioni del girello, sono
stati impiantati su mezzo di coltura solido, del tipo
murashige e Skooge, addizionato di saccarosio (3%),
PPm (0.1%) e ormoni (iaa=acido indol acetico;
Ba=benzil adenina) in un range di concentrazione
compreso tra 0.8 mg/l e 1.2 mg/l per Ba; 0.2 mg/l e
1 mg/l per iaa.
le prove effettuate hanno permesso di identificare le
concentrazioni ormonali ottimali (Ba: 0.8 mg/l ;
iaa: 1 mg/l) utili per la propagazione in vitro di M.
comosum.
Sulle colture, attualmente in fase di stabilizzazione, è
stata fatta una verifica preliminare per valutare se,
anche in queste condizioni sperimentali, sia attivo il
metabolismo dei fruttani. le analisi effettuate evidenziano
un significativo accumulo di tali oligosaccaridi
nei tessuti ottenuti nella coltura in vitro (19
mg/g peso fresco), anche se i livelli riscontrati sono
leggermente inferiori a quelli dei bulbi commerciali.
i germogli ottenuti saranno sottoposti a condizioni
di crescita differenti variando l’apporto ormonale, la
quantità di saccarosio nel terreno e l’esposizione alla
luce, con l’obiettivo di poter ampliare le conoscenze
sul ruolo del metabolismo dei fruttani nella crescita e
nello sviluppo delle piante ed identificare le condizioni
colturali più idonee alla proliferazione e crescita
dei bulbi
- …
