New roles of Rab GTPases on eye diseases: targeting VEGF secretion

RESUMO: A retina �� composta, entre outras estruturas, pelo epit��lio pigmentar da retina (EPR)e pela cor��ide. A regi��o central da retina denomina-se m��cula, e �� a zona mais afetada na degeneresc��ncia macular relacionada com a idade, a forma mais comum de degeneresc��ncia da retina. Nesta doen��a, a secre����o de fatores de crescimento pelo EPR �� afetada, nomeadamente a do fator de crescimento vascular endotelial (VEGF), e pouco se sabe ainda sobre os mecanismos moleculares conducentes a esta condi����o. A fam��lia de prote��nas Rab GTPases est�� envolvida nas vias intracelulares de sinaliza����o e tr��fego membranares, essenciais na transdu����o de sinais extracelulares em respostas biol��gicas. A sua crucial import��ncia nestes mecanismos levou-nos a considerar o seu potencial envolvimento nas vias de secre����o do VEGF, e a questionar-nos se teriam algum papel regulador sobre as mesmas. O principal objetivo deste trabalho �� identificar Rab GTPases importantes para as vias de secre����o e endocitose do VEGF no EPR. Essa identifica����o ajudar�� a esclarecer a patog��nese da degeneresc��ncia macular da retina, e poder�� servir para uma procura mais direcionada de novos agentes terap��uticos. A caracteriza����o de dois modelos in vitro do EPR, c��lulas prim��rias isoladas de murganho e a linha celular B6-RPE07,levou-nos a concluir que s��o ambos semelhantes. Contudo, a linha celular foi escolhida como prot��tipo do EPR por permitir o acesso a um n��mero ilimitado de c��lulas. No decurso deste trabalho, desenvolvemos e caracteriz��mos uma biblioteca de ferramentas moleculares que nos permitiram reduzir os n��veis proteicos das prote��nas Rab GTPases, com base na tecnologia de ��cido ribonucleico (ARN) de interfer��ncia. O papel das prote��nas Rab GTPases na secre����o do VEGF no EPR foi estudado com base no silenciamento de apenas uma prote��na, ou combinando v��rias, segundo a sua localiza����o e fun����es intracelulares descritas. Este trabalho permitiu-nos concluir que as prote��nas Rab GTPases s��o importantes intervenientes no processo de secre����o de VEGF pelo EPR, e confirmar dados anteriores que relatam o envolvimento de algumas Rab GTPases endoc��ticas no processo. Propomos ainda um novo modelo para a intera����o destas prote��nas no EPR, e sugerimos que a Rab10 e a Rab14 atuam negativamente sobre a Rab8, controlando o seu funcionamento. Os nossos resultados evidenciam a import��ncia das prote��nas Rab GTPases na secre����o do VEGF pelas c��lulas do EPR, e servem de base a futuros estudos que melhor procurem compreender este mecanismo e de que modo a sua altera����o se relaciona com a degeneresc��ncia da retina.--------ABSTRACT: Retinal pigment epithelium (RPE) and choroid are components of the mammalian retina, of which the central region is called macula. The most common form of retinaldegeneration, age-related macular degeneration (AMD), involves primarily deregulation of growth factors secretion by the RPE. Very little is known about the molecular mechanisms that lead to impairment of RPE���s homeostatic intracellular processes, namely the secretion of vascular endothelial growth factor (VEGF). Rab GTPases��� family regulates membrane targeting and traffic, being essential in the transduction of signal pathways. Given Rab proteins��� role in intracellular trafficking, we propose to identify key regulatory Rab proteins involved in either the secretory or the recycling pathways of VEGF in RPE. Understanding how Rab proteins��� function disruption could lead to retinal and choroidal pathology would ultimately contribute to find new therapeutic agents. Here, we characterized two mouse RPE in vitro cell models, primary cells and B6-RPE07 cell line, and concluded that both display important epithelial features as the RPE presents in vivo. Considering unlimited cell number and results reproducibility, we chose B6-RPE07 cells to further study Rab proteins��� function. To scrutinize the consequences of Rab proteins��� absence or diminished levels, we have developed novel molecular tools to achieve silencing of these key proteins using miRNA technology. We further addressed the effect of Rab proteins��� absence on VEGF secretion by performing an extensive screening where different Rab proteins were silenced, both individually and in multiple combinations considering their cellular/ compartment location. We conclude that Rab GTPases are important intervenients in VEGF secretion by RPE cells, confirming endocytic Rab proteins��� role in regulation of VEGF biology. We also propose a novel model for Rab proteins��� interaction in RPE. Our results suggest that Rab10 and Rab14 might influence Rab8 in a negative feedback mechanism, important for controlling VEGF secretion. Our achievements��� unravel Rab proteins��� role in VEGF secretion by RPE cells and are the basis for future studies to better understand RPE molecular secretory machinery.

Ophtalmologie. Th��rapie g��nique des r��tinopathies h��r��ditaires: premiers r��sultats [Gene therapy for hereditary eye diseases: where are we?]

Les r��sultats pr��liminaires de trois essais cliniques de th��rapie g��nique d'une forme agressive de r��tinite pigmentaire (l'amaurose cong��nitale de Leber) ont prouv�� que le traitement des maladies d��g��n��ratives de la r��tine par transfert de g��ne peut ��tre s��r et efficace pour r��tablir une fonction visuelle. Il faudra encore attendre les r��sultats �� long terme de ces ��tudes pour que soit d��finitivement valid��e cette approche th��rapeutique. Dans l'intervalle, il importe de se pr��parer �� son introduction en ophtalmologie de fa��on �� la rendre accessible �� nos malades. Pratiquement cela revient �� promouvoir: 1) le recrutement; 2) la caract��risation du ph��notype et du g��notype des sujets atteints et 3) la constitution d'un registre des r��tinopathies h��r��ditaires. Recently, preliminary results of three clinical gene therapy trials for early onset retinitis pigmentosa--Leber congenital amaurosis--suggested that treating this degenerative retinal disease by gene transfection can be safe and efficient to restore a visual function. The definitive validation of this therapeutic approach depends on the long-term results. The forthcoming availability of gene therapy in ophthalmology prompts the implementation: of 1) recruitment, 2) phenotyping and genotyping of affected patients, 3) and creation of a hereditary retinopathy registry.

Estudo cl��nico da oncocercose na Guin��-Bissau

Em ��frica e no Sul da Ar��bia, a oncocercose est�� essencialmente associada ao complexo Simulium damnosum (Ovazza, 1967). A propaga����o da doen��a resulta essencialmente do tipo de actividade humana, e das altera����es do ambiente, espec��almente a desfloresta����o maci��a, transformando o habitat florestal em habitat de savana (Hocking, 1953, Dadzie, 1980, Amazigo, 1991, Amazigo, 2002 a, WHO, 1995 b). 2- Morfologia 2.1 - O ovo O ovo, t��m uma forma triangular, com os v��rtices arredondados, medindo de 0,1 a 0,5 mm de comprimento. A casca �� lisa, n��o apresentando qualquer adapta����o especial e o revestimento �� viscoso. S��o de cor branca aquando da oviposi����o, escurecendo com a embriog��nese, aparecendo ent��o com cores rosadas, amareladas e acinzentadas. 2.2 - A larva A larva dos simul��deos, apresenta um formato mais ou menos cil��ndrico, com duas dilata����es, uma no t��rax, ligeira e outra mais acentuada na parte terminal do abd��men. Pode atingir o comprimento de um cent��metro, e uma colora����o muito variada, dependendo do tipo de alimentos ingeridos, e apresentar-se de colora����o totalmente escura, a esbranqui��ada. O corpo da larva �� formado por tr��s partes distintas ��� a cabe��a, o t��rax e o abd��men. A cabe��a: A cabe��a de uma larva de simul��deo, �� observa����o dorsal, apresenta-se pigmentada, podendo com essa pigmenta����o expressar-se de duas formas, ou com manchas escuras em fundo claro (modelo positivo), ou manchas claras em fundo escuro (modelo negativo), e um par de finas antenas. �� observa����o ventral destacam-se dois caracteres de grande valor sistem��tico ��� a fenda p��sgenal e o hipostoma.

A practical treatise on the diseases of the eye /

"With one hundred and seventy-five illustrations."

Diseases of the eye, ear, throat, and nose, a manual for students and practitioners,

Mode of access: Internet.

May's manual of the diseases of the eye.

On spine, 1947- Mays�� diseases of the eye.

Cataract Remains an Important Cause of Blindness in Campinas, Brazil

Objective: To estimate the prevalence of blindness in the elderly population of Campinas, Brazil, and to describe the coverage and quality of cataract surgery services in the area. Methods: A brief assessment of cataract surgery services (using the RACSS (Rapid Assessment of Cataract Surgical Services Method) was conducted using random cluster sampling, with a sample composed of 60 clusters of 40 people aged 50 years or older. Visual acuity (VA) was measured and the lens status observed by direct visual ophthalmoscopy. From the selected sample of 2,400 subjects, 92.67% were examined. Results: Blindness (VA 3/60 with available correction) was found in 1.98 % (2.03 % among male subjects, and 1.94 % among female subjects). The prevalence of blindness varied with age, from 0.2%, in the group from 50 to 54 years, to 7.2% in those above 80. Cataract was the main cause of blindness (40.2%) followed by suspected posterior segment disorders (18.2%), diabetic retinopathy (15.9%), and glaucoma (11.4%). The cataract surgical coverage was of 93% (VA 3/60) and 82.18% when the criterion was VA 6/60 in the best eye. The main reasons the subjects did not receive surgical treatment were: fear of undergoing surgery, 11.1%; lack of awareness about the condition, 16.7%; waiting for maturity, 16.7%; and contraindication to surgery, 44.4%. Conclusion: Cataract is the major cause of blindness in Campinas. Education on eye diseases, their prevention and treatment must become part of the city`s public healthcare policies.

Assessment of a strategy for the control of respiratory diseases in children

A programme for the control of respiratory diseases in children was conceived for the State of S. Paulo, Brazil, in 1986. Its progress thereafter and the epidemiology of the diseases concerned are examined. Apart from an inquiry into the 64 existing State local health authorities, a sample of 18,255 cases of children assisted by the programme at different levels, including both in-patient and outpatient care, is analysed. Each case record included information about identification (child, doctor and health facility), reasons for calling, diagnoses made and outcome of treatment. Further data were also sought from hospitals and from State mortality records. The programme was found to be poorly implemented in the State but, where implemented, it showed itself capable of resolving problems (only 0.5% of the cases could not be handled) as also of changing ongoing trends (more than 50% reduction in hospital admission rates). Individual assessment of each item of the programme indicated its bottlenecks. Regarding the epidemiology of respiratory diseases, it is observed that the major burden to health services comes from children aged less than five, and that the most important diseases are wheezing illnesses and pneumonia. Morevoer, they were found to be significantly associated (p = 0.000) so that a child in the community presenting wheezing diseases is 5 times more likely to develop pneumonia than a child with any other respiratory diagnosis. Similarly, among the under five deaths it was found that the risk for pneumonia is 3 times greater for children who died presenting wheezing diseases than it is for children with any other sort of diagnosis. In conclusion, the programme is deemed to be efficient and effective but its efficacy is marred by administrative flaws. The successful control of respiratory problems in childhood is related to a proper appreciation of the importance of wheezing diseases.

Cost-Effectiveness of High, Moderate and Low-Dose Statins in the Prevention of Vascular Events in the Brazilian Public Health System

Background:Statins have proven efficacy in the reduction of cardiovascular events, but the financial impact of its widespread use can be substantial.Objective:To conduct a cost-effectiveness analysis of three statin dosing schemes in the Brazilian Unified National Health System (SUS) perspective.Methods:We developed a Markov model to evaluate the incremental cost-effectiveness ratios (ICERs) of low, intermediate and high intensity dose regimens in secondary and four primary scenarios (5%, 10%, 15% and 20% ten-year risk) of prevention of cardiovascular events. Regimens with expected low-density lipoprotein cholesterol reduction below 30% (e.g. simvastatin 10mg) were considered as low dose; between 30-40%, (atorvastatin 10mg, simvastatin 40mg), intermediate dose; and above 40% (atorvastatin 20-80mg, rosuvastatin 20mg), high-dose statins. Effectiveness data were obtained from a systematic review with 136,000 patients. National data were used to estimate utilities and costs (expressed as International Dollars - Int$). A willingness-to-pay (WTP) threshold equal to the Brazilian gross domestic product per capita (circa Int$11,770) was applied.Results:Low dose was dominated by extension in the primary prevention scenarios. In the five scenarios, the ICER of intermediate dose was below Int$10,000 per QALY. The ICER of the high versus intermediate dose comparison was above Int$27,000 per QALY in all scenarios. In the cost-effectiveness acceptability curves, intermediate dose had a probability above 50% of being cost-effective with ICERs between Int$ 9,000-20,000 per QALY in all scenarios.Conclusions:Considering a reasonable WTP threshold, intermediate dose statin therapy is economically attractive, and should be a priority intervention in prevention of cardiovascular events in Brazil.

Epidemiology and prevention of cardiovascular disease in the Seychelles Islands (Indian Ocean)

This article presents selected findings and lessons from a cardiovascular research and prevention program initiated in 1989 in the Republic of Seychelles, a country in demographic and epidemiological transition. Rapid and sustained aging of the population (e.g., two-fold increase of people aged 30-39 from 1979 to 1995) implies, over the next few decades, further dramatic increase of the burden of chronic diseases, particularly cardiovascular disease (CVD). Epidemiological surveillance shows high age-specific rates of CVD (particularly stroke), high prevalence of peripheral atherosclerosis (plaques in carotid and femoral arteries), high prevalence of classical modifiable risk factors in the adult population (particularly hypertension), and substantial proportions of children with overweight. Stagnant life expectancy in men and an increase in women have been observed over the last two decades; this occurred despite largely improved health services and reduced infant mortality rates, and may reflect the large CVD burden found in middle-aged men (less so in middle-aged women). A national program of prevention of CVD has been initiated since 1991, which includes a mix of interventions to reduce risk factors in the general population and in high-risk individuals. Substantial research to back the prevention program indeed shows, at the moment, epidemiological patterns in Seychelles similar to those observed in Western countries (e.g., an association between peripheral atherosclerosis [as a proxy of CVD] and low density lipoprotein-cholesterol, smoking, diabetes, and [inversely] walking). This clearly supports the view that promotion of healthy lifestyles and control of conventional risk factors should be the main targets for CVD prevention and control.

Colloidal systems for the delivery of cyclosporin A to the anterior segment of the eye.

Due to the eye's specific anatomical and physiological conformation, the treatment of eye diseases is a real challenge for pharmaceutical therapy. The presence of efficient protective barriers (i.e., the conjunctival and corneal membranes) and protective mechanisms (i.e., blinking and nasolachrymal drainage) makes this organ particularly impervious to local drug therapy. To overcome these issues, numerous strategies have been envisioned using pharmaceutical technology. Many formulations currently on the market or still under development are emulsions or colloidal systems intended to enhance precorneal residence time and corneal penetration, causing a consequent increase in drug bioavailability after instillation. After a review of some recent developments in the field of cyclosporin A formulations for the eye, a novel micellar formulation of cyclosporine A based on a diblock methoxy-poly(ethylene glycol)-hexysubstituted poly(lactides) (MPEG-hexPLA) is described.

Pr��vention primaire et d��pistage chez l'adulte: mise �� jour 2010. [Prevention and screening in adults: trends in 2010].

This article proposes an update on the recommendations for the check-up and the primary and secondary prevention of cancers and cardio-vascular diseases. Indeed, new clinical data led the adaptation and clarification of some of them. The novelties for cancer screening concern mainly colorectal, breast and prostate cancers. Screening for low ankle brachial index is not recommended.