Role of Protease-Inhibitors in Ocular Diseases.

It has been demonstrated that the balance between proteases and protease-inhibitors system plays a key role in maintaining cellular and tissue homeostasis. Indeed, its alteration has been involved in many ocular and systemic diseases. In particular, research has focused on keratoconus, corneal wounds and ulcers, keratitis, endophthalmitis, age-related macular degeneration, Sorsby fundus dystrophy, loss of nerve cells and photoreceptors during optic neuritis both in vivo and in vitro models. Protease-inhibitors have been extensively studied, rather than proteases, because they may represent a therapeutic approach for some ocular diseases. The protease-inhibitors mainly involved in the onset of the above-mentioned ocular pathologies are: α2-macroglobulin, α1-proteinase inhibitor (α1-PI), metalloproteinase inhibitor (TIMP), maspin, SERPINA3K, SERPINB13, secretory leukocyte protease inhibitor (SLPI), and calpeptin. This review is focused on the several characteristics of dysregulation of this system and, particularly, on a possible role of proteases and protease-inhibitors in molecular remodeling that may lead to some ocular diseases. Recently, researchers have even hypothesized a possible therapeutic effect of the protease-inhibitors in the treatment of injured eye in animal models.

Diabetic retinopathy and pregnancy.

Diabetes mellitus and pregnancy have reciprocal influences between them, therefore diabetes mellitus may complicate the course of pregnancy as well as pregnancy can worsen the performance of diabetes especially at the fundus oculi. Several factors seem to play a role in retinal neovascularization. Actually it's not possible to understand the mechanisms underlying this progression. Moreover chronic hyperglycemia leads to several events such as: the activation of aldose reductase metabolic pathway, the activation of the diacylglycerol-protein kinase C, the non-enzymatic glycation of proteins with formation of advanced glycation endproducts and the increase of hexosamines pathway. Although every structure of the eye can be affected by diabetes, retinal tissue, with all its vessels, is particularly susceptible. Pregnancy may promote the onset of diabetic retinopathy, in about 10 % of cases, as well as contribute to its worsening when already present. The proliferative retinopathy must always be treated; treatment should be earlier in pregnant women compared to non-pregnant women. Pregnancy can also cause macular edema; it spontaneously regresses during the postpartum and therefore does not require immediate treatment. In summary, collaboration between the various specialists is primary to ensure the best outcomes for both mother's health and sight, and fetus' health.

Age-related changes in the kinetics of human lenses: prevention of the cataract.

The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina and, by changing shape, it adjusts focal distance (accommodation). The three classes of structural proteins found in the lens are α, ß, and γ crystallins. These proteins make up more than 90% of the total dry mass of the eye lens. Other components which can be found are sugars, lipids, water, several antioxidants and low weight molecules. When ageing changes occur in the lens, it causes a gradual reduction in transparency, presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye. The main changes that occur with aging are: 1) reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2) crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3) production of advanced glycation end products (AGEs), lipid accumulation, reduction of reduced glutathione content and destruction of ascorbic acid. Even if effective strategies in preventing cataract onset are not already known, good results have been reached in some cases with oral administration of antioxidant substances such as caffeine, pyruvic acid, epigallocatechin gallate (EGCG), α-lipoic acid and ascorbic acid. Furthermore, methionine sulfoxide reductase A (MSRA) over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage. Nevertheless, promising results have been obtained by reducing ultraviolet-induced oxidative damage.

Hypobaric hypoxia: effects on contrast sensitivity in high altitude environments.

BACKGROUND: Effects of hypobarism and hypoxia on visual performance and mainly on contrast sensitivity (CS) are well known. The purpose of this study was to compare the adjustments of corneal thickness in hypobaric hypoxia conditions with changes in contrast sensitivity. METHODS: There were 12 healthy, emmetropic subjects assigned to the 14(th) Wing Aircrew based in Pratica di Mare AFB (Rome, Italy) who were evaluated for changes occurring in central corneal thickness (CCT), measured by portable ultrasonic pachymeter, and CS, assessed after reading the standard Pelli-Robson charts, during modification of atmospheric pressure and, therefore, of oxygen partial pressure. RESULTS: Hypobaric hypoxia conditions in pilots raised CCT (550 µm to 600 µm) and reduced CS (1.95 log to 1.05 log) in a statistically significant result. DISCUSSION: The study demonstrated that hypoxia and variations of atmospheric pressure may produce corneal edema, including changes of CCT and, correlatively, CS reduction.

Role of Electrophysiology in the Early Diagnosis and Follow-Up of Diabetic Retinopathy.

Retinopathy is a severe and common complication of diabetes, representing a leading cause of blindness among working-age people in developed countries. It is estimated that the number of people with diabetic retinopathy (DR) will increase from 126.6 million in 2011 to 191 million by 2030. The pathology seems to be characterized not only by the involvement of retinal microvessels but also by a real neuropathy of central nervous system, similar to what happens to the peripheral nerves, particularly affected by diabetes. The neurophysiological techniques help to assess retinal and nervous (optic tract) function. Electroretinography (ERG) and visual evoked potentials (VEP) allow a more detailed study of the visual function and of the possible effects that diabetes can have on the visual function. These techniques have an important role both in the clinic and in research: the central nervous system, in fact, has received much less attention than the peripheral one in the study of the complications of diabetes. These techniques are safe, repeatable, quick, and objective. In addition, both the ERG (especially the oscillatory potentials and the flicker-ERG) and VEP have proved to be successful tools for the early diagnosis of the disease and, potentially, for the ophthalmologic follow-up of diabetic patients.

Nd: Yag laser iridotomy in Shaffer-Etienne grade 1 and 2: angle widening in our case studies.

AIM: To obtain widening of a potentially occludable angle, in according to Kanski's indications, through preventive Nd:Yag laser iridotomy. The observational study was performed by using gonioscopy for the selection and follow-up of 1165 treated eyes and exploiting Shaffer-Etienne gonioscopic classification as a quality/quantity test of the angle recession. METHODS: Between September 2000 and July 2012, 586 patients were selected at the Outpatients' Ophthalmological Clinic of the Policlinico Umberto I of Rome in order to undergo Nd: Yag laser iridotomy. A Goldmann type contact lens, Q-switched mode, 2-3 defocus, and 7-9 mJ intensity with 2-3 impulse discharges were used for surgery. RESULTS: From as early as the first week, a whole 360° angle widening were evident in the patients, thus showing the success of Nd:Yag laser iridotomy in solving relative pupil block. The angle remained narrow by 270° in 14 eyes only, despite repetitions of further treatment with laser iridotomy in a different part of the iris, twice in 10 eyes and three times in 4 eyes. CONCLUSION: Nd:Yag laser iridotomy revealed itself as being a safe and effective treatment in widening those critical Shaffer-Etienne grade 1 and 2 potentially occludable angles.

Scotopic microperimetry in the early diagnosis of age-related macular degeneration: preliminary study.

BACKGROUND: Recent clinical studies have shown that, in some degenerative retinal diseases, like age-related macular degeneration (AMD), the sensitivity of the rods decreases more rapidly than the sensitivity of the cones. The aim of this study was to evaluate if there is a correlation between the presence of hard drusen at the macular level and the rod damage responsible for the reduction in scotopic retinal sensitivity in subjects at risk for AMD. METHODS: The authors selected 24 subjects (14 men and 10 women) with an average age of 67.25 ± 5.7 years. Macular hard drusen were present in 50% of the subjects at the fundus oculi exam. The researchers evaluated the retinal sensitivity to light in mesopic and scotopic conditions of each subject with an MP-1 scotopic microperimeter (MP-1S). RESULTS: In subjects with hard drusen in the fundus oculi examination, there was a statistically significant reduction in scotopic retinal sensitivity, while the mesopic retinal sensitivity was not compromised. CONCLUSION: This study revealed how the presence of hard drusen at the macular level is associated with a reduction in scotopic retinal sensitivity compared to a control group of healthy subjects. Retinal functionality in a scotopic setting examined with MP-1S could be useful in early diagnosis of AMD.

Neuroeconomia e neuromarketing: imagens cerebrais explicando as decisões humanas de consumo / Neuroeconomics and neuromarketing: Brain imaging explaining human consumption decisions

Durante toda nossa vida somos impelidos a fazer escolhas, desde as mais simples até as mais complexas, que terão profundo impacto em nosso futuro. Dado a complexidade e importância de tais decisões, principalmente quando se referem ao consumo, fez-se necessário compreendê-las cada vez melhor. Dentro do arcabouço teórico da economia e administração, ramos como a microeconomia e o marketing foram os primeiros a se interessarem pelo tema. Entretanto, as simples modelagens matemáticas da microeconomia ou a observação empírica do marketing não garantem a compreensão absoluta de todas decisões. Pela carência de maiores detalhes sobre o real comportamento humano, novas áreas de estudos emergiram. Aliando conhecimentos de economia e marketing aos da psicologia, neurociência e outras ciências cognitivas, surgiram a neuroeconomia e o neuromarketing. Neste contexto, o objetivo deste estudo é apresentar estas novas correntes, evidenciando razões para seus surgimentos, bem como os progressos que já proporcionaram. Tal monta tem como pano de fundo estimular a discussão e reflexão acerca destas duas novas fronteiras de estudo no país que, na opinião dos autores, prometem revolucionar a compreensão acerca das preferências e escolhas dos indivíduos

Neuroeconomia e neuromarketing: imagens cerebrais explicando as decisões humanas de consumo / Neuroeconomics and neuromarketing: Brain imaging explaining human consumption decisions

Durante toda nossa vida somos impelidos a fazer escolhas, desde as mais simples até as mais complexas, que terão profundo impacto em nosso futuro. Dado a complexidade e importância de tais decisões, principalmente quando se referem ao consumo, fez-se necessário compreendê-las cada vez melhor. Dentro do arcabouço teórico da economia e administração, ramos como a microeconomia e o marketing foram os primeiros a se interessarem pelo tema. Entretanto, as simples modelagens matemáticas da microeconomia ou a observação empírica do marketing não garantem a compreensão absoluta de todas decisões. Pela carência de maiores detalhes sobre o real comportamento humano, novas áreas de estudos emergiram. Aliando conhecimentos de economia e marketing aos da psicologia, neurociência e outras ciências cognitivas, surgiram a neuroeconomia e o neuromarketing. Neste contexto, o objetivo deste estudo é apresentar estas novas correntes, evidenciando razões para seus surgimentos, bem como os progressos que já proporcionaram. Tal monta tem como pano de fundo estimular a discussão e reflexão acerca destas duas novas fronteiras de estudo no país que, na opinião dos autores, prometem revolucionar a compreensão acerca das preferências e escolhas dos indivíduos.