Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 72
Filtrar
1.
Geriatr Gerontol Int ; 12(1): 16-22, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22188494

RESUMO

1. BACKGROUND: Recent medical advancements, and improvements in hygiene and food supply have led to Japan having the longest life expectancy in the world. Over the past 50 years, the percentage of the elderly population has increased fourfold from 5.7% in 1960 to 23.1% in 2010. This change has occurred at the fastest rate in the world. Compared with France, where the percentage of the elderly population has increased just twofold in the past 100 years, Japanese society is aging at an unprecedented rate. In addition, the percentage of the very elderly (aged 75 years and over), comprising more frail people, exceeded 10% of the nation's population in 2008. In such a situation, many elderly Japanese wish to spend their later years healthy, and wish to achieve great accomplishments in their lives. To achieve that, rather than considering an aging population as a negative social phenomenon, we should create a society where elderly people can enjoy a healthy, prosperous life through social participation and contribution. Factors that hamper the elderly from leading a healthy life include various psychological and social problems occurring in older age, as well as a high incidence of diseases. Therefore, gerontology, which focuses on health promotion of the elderly by encompassing the study of social welfare, psychology, environment and social systems; and geriatrics, which focuses on health care of elderly people and carried out research, education and practices to promote health in the elderly, are becoming more important. Furthermore, along with a need for multidisciplinary care to support geriatric medicine, the development of a comprehensive education system for aged-care professionals is awaited. Thus, we should now recognize the importance of gerontology and geriatrics, and a reform of medical-care services should be made in order to cope with the coming aged society. Population aging is a global phenomenon. The actions being taken by Japan, the world's most aged society, have been closely watched by the rest of the world. Japan's aged society has been posing not only medical, nursing and welfare problems, but also complex problems closely associated with economy, industry and culture. Therefore, to solve these problems, a macroscopic integration and cooperation among industries, education institutions, administration and community through an interdisciplinary approach including medical science, nursing science, nursing care, study of social welfare, social science, engineering, psychology, economics, religion and ethics should be made. Regarding the promotion of gerontology, the "Committee for Establishing a Scientific Community for Sustainable Aged Society" of the Science Council of Japan also prepared a proposal and this was announced on 20 April 2011. 2. CURRENT SITUATION AND PROBLEMS: (1) Promotion of social participation and contribution of elderly people In Japan, the overall labor force rate is expected to decrease in the near future as a result of the low birth rate and high life expectancy. In contrast, many elderly people, particularly the young-old, have sufficient physical strength to fulfil their job duties and make a social contribution. For these people, a social structure where elderly people can work should be developed through re-educating the elderly and providing various job types. Promotion of social participation and contribution of the elderly is expected to cause a substantial increase in the labor force. Furthermore, it is also expected to contribute to not only the upturn of national economic activity through an increase in total consumption, but also a decrease in the number of elderly people who are likely to be in need of care. Therefore, in order for elderly people to be engaged in various social activities, strategies for developing a social structure for re-education, various employment statuses and employment opportunities should be prepared. However, as the total number of jobs is fixed, consideration should also be given to young workers. (2) Fostering medical specialists for aging Older people often suffer from many diseases, together with geriatric syndromes with multiple etiologies. Signs and symptoms vary according to each individual, and are often atypical; therefore, the patients visit different hospitals and receive many screening tests and prescriptions at the same time. To solve this problem, an effective screening system carried out by a primary-care doctor, and privacy-preserving medical data sharing among hospitals and clinics are needed. In a geriatric clinical setting, health-care professionals should be aware of the physical traits of older people who often develop not only dementia, but also geriatric syndromes, such as depression, falls and urinary incontinence, so that a holistic approach with consideration of nursing care is required. However, the existing Japanese medical education system is not prepared for medical professionals enabled to respond to the aforementioned requirements. Thus, the fostering of medical professionals who can provide comprehensive care - especially for the oldest-old - such as geriatric specialists and medical professionals who understand the principles of elderly care, is urgently needed. (3) Diagnosis of elderly-specific diseases and reform of medical-care services In Japan, the diagnostic system for elderly-specific diseases, including dementia, and reform of medical care services are markedly delayed. The current status concerning diagnosis, care and nursing should be investigated to collect academic data. In order to accumulate evidence for providing safe elderly care and nursing, the promotion of clinical research and a marked expansion of geriatric medical centers with high-level medical services are eagerly awaited. (4) Promotion of home-based care and multidisciplinary care To reduce the length of stay in acute hospitals, to reduce the physical burden of health-care professionals working at acute hospitals and to meet the demand of older people who prefer to remain in their own homes, further promotion of home-based care is needed. In addition, "multidisciplinary care" is increasingly needed to meet various demands in the medical care and welfare of the elderly. It is considered important to share countermeasures against the problems of disease prevention, medicine, care and welfare among health-care professionals in medicine, care and welfare, and cooperate by making the best use of health-care professionals' specialties. 3. CONTENTS OF THE PROPOSAL: The subcommittee for aging, thus, provided the following proposal: 1 Development and promotion of systems that enable elderly people to participate socially and make a contribution using an interdisciplinary approach among the various areas, including nursing science, nursing care, study of social welfare, social science, psychology, economics, religion and ethics, as well as medical sciences; 2 Promotion of gerontology, reform and enhancement of geriatrics in undergraduate, postgraduate and lifelong education; 3 Building geriatric medical centers in each area, and accumulating large-scale evidence of geriatric diseases and geriatrics; and 4 Structural development and promotion of home-based care and multidisciplinary care. Through implementation of the above measures, Japan is expected to function as a successful example for the rest of the world.


Assuntos
Envelhecimento , Avaliação Geriátrica , Geriatria/normas , Promoção da Saúde , Necessidades e Demandas de Serviços de Saúde/tendências , Expectativa de Vida/tendências , Idoso , Humanos , Vigilância da População
2.
Nippon Ganka Gakkai Zasshi ; 114(9): 796-800, 2010 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-20865921

RESUMO

PURPOSE: To resolve the problems of visual acuity assessment in grading the vision of the physically handicapped as proposed by the Subcommittee for Promoting the Realization of a Cohesive Society with the Visually Disabled, Science Council of Japan, a method suitable for assessing visual disturbances, and the relationship between the degree of visual disturbances and the degree of difficulty in activities of daily life are clarified. SUBJECTS AND METHODS: 151 persons with age-related macular degeneration were studied. Examination methods for measuring visual acuity and reading performance were studied, and interviews using the daily living task dependent on vision (DLTV) questionnaire were performed. The correlations between total DLTV score and each examination method were analyzed. The median total DLTV score for each grade of visual acuity of the better eye was calculated. RESULTS: Spearman's correlation coefficient between distance corrected visual acuity of the better eye and total DLTV score was 0.76. Median DLTV scores for visual acuities (better eye) of 0.2, 0.3, 0.4, 0.5 were 65, 73.5, 62, 79 respectively. CONCLUSION: Visual acuity can be assessed by measuring distant corrected visual acuity of the better eye and setting the upper limit of visual disturbance at either 0.3 or 0.4.


Assuntos
Atividades Cotidianas , Degeneração Macular/fisiopatologia , Testes Visuais/métodos , Acuidade Visual , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto
4.
Hypertension ; 49(2): 347-54, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17159082

RESUMO

Hypertension is known to exacerbate diabetic complications, such as retinopathy and nephropathy. Apoptosis of retinal vascular pericytes has been well established as the earliest conceivable change in diabetic retinopathy. In this study, we investigated the contribution of cyclic stretch, which mimics a hypertensive state to pericyte apoptosis. A 48-hour cyclic stretch induced DNA fragmentation in porcine retinal pericytes and increased the number of TUNEL+ cells at a pathophysiologically relevant extension level (10%/60 cycles per minute). Stretch also increased intracellular reactive oxygen species generation and increased c-Jun NH(2)-terminal kinase phosphorylation in a time- and magnitude-dependent manner, which were reduced by the nicotinamide-adenine dinucleotide phosphate oxidase inhibitor diphenylene iodonium or dominant-negative protein kinase C-delta. Stretch activated protein kinase C-delta and increased its association with p47phox. Stretch induced cleavage of caspase-9 and -3 and increased caspase-3 activity. Protein kinase C-delta or c-Jun NH(2)-terminal kinase inhibition normalized stretch-induced caspase-3 activity and prevented stretch-induced apoptosis. These data indicate that cyclic stretch induces apoptosis in porcine retinal pericytes by activation of the reactive oxygen species-c-Jun NH(2)-terminal kinase-caspase cascades, suggesting a novel molecular mechanism to explain the exacerbation of early diabetic retinopathy by concomitant hypertension.


Assuntos
Apoptose/fisiologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Pericitos/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Retina/fisiologia , Animais , Caspases/metabolismo , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , NADPH Oxidases/metabolismo , Fosforilação , Proteína Quinase C-delta/metabolismo , Retina/citologia , Estresse Mecânico , Suínos , Fatores de Tempo
5.
J Biol Chem ; 282(9): 6677-84, 2007 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-17194706

RESUMO

Signal transduction in rod cells begins with photon absorption by rhodopsin and leads to the generation of an electrical response. The response profile is determined by the molecular properties of the phototransduction components. To examine how the molecular properties of rhodopsin correlate with the rod-response profile, we have generated a knock-in mouse with rhodopsin replaced by its E122Q mutant, which exhibits properties different from those of wild-type (WT) rhodopsin. Knock-in mouse rods with E122Q rhodopsin exhibited a photosensitivity about 70% of WT. Correspondingly, their single-photon response had an amplitude about 80% of WT, and a rate of decline from peak about 1.3 times of WT. The overall 30% lower photosensitivity of mutant rods can be explained by a lower pigment photosensitivity (0.9) and the smaller single-photon response (0.8). The slower decline of the response, however, did not correlate with the 10-fold shorter lifetime of the meta-II state of E122Q rhodopsin. This shorter lifetime became evident in the recovery phase of rod cells only when arrestin was absent. Simulation analysis of the photoresponse profile indicated that the slower decline and the smaller amplitude of the single-photon response can both be explained by the shift in the meta-I/meta-II equilibrium of E122Q rhodopsin toward meta-I. The difference in meta-III lifetime between WT and E122Q mutant became obvious in the recovery phase of the dark current after moderate photobleaching of rod cells. Thus, the present study clearly reveals how the molecular properties of rhodopsin affect the amplitude, shape, and kinetics of the rod response.


Assuntos
Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Visão Ocular , Animais , Arrestina , Meia-Vida , Cinética , Camundongos , Mutação de Sentido Incorreto , Fótons , Rodopsina/genética
6.
Am J Pathol ; 168(1): 331-9, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16400034

RESUMO

The Eph receptor/ephrin system is a recently discovered regulator of vascular development during embryogenesis. Activation of EphA2, one of the Eph receptors, reportedly suppresses cell proliferation and adhesion in a wide range of cell types, including vascular endothelial cells. Vascular endothelial growth factor (VEGF) plays a primary role in both pathological angiogenesis and abnormal vascular leakage in diabetic retinopathy. In the study described herein, we demonstrated that EphA2 stimulation by ephrinA1 in cultured bovine retinal endothelial cells inhibits VEGF-induced VEGFR2 receptor phosphorylation and its downstream signaling cascades, including PKC (protein kinase C)-ERK (extracellular signal-regulated kinase) 1/2 and Akt. This inhibition resulted in the reduction of VEGF-induced angiogenic cell activity, including migration, tube formation, and cellular proliferation. These inhibitory effects were further confirmed in animal models. Intraocular injection of ephrinA1 suppressed ischemic retinal neovascularization in a dose-dependent manner in a mouse model. At a dose of 125 ng/eye, the inhibition was 36.0 +/- 14.9% (P < 0.001). EphrinA1 also inhibited VEGF-induced retinal vascular permeability in a rat model by 46.0 +/- 10.0% (P < 0.05). These findings suggest a novel therapeutic potential for EphA2/ephrinA1 in the treatment of neovascularization and vasopermeability abnormalities in diabetic retinopathy.


Assuntos
Barreira Hematorretiniana/metabolismo , Efrina-A1/metabolismo , Neovascularização Retiniana/metabolismo , Transdução de Sinais/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Barreira Hematorretiniana/patologia , Northern Blotting , Western Blotting , Bovinos , Movimento Celular/fisiologia , Células Cultivadas , Células Endoteliais/metabolismo , Efrina-A2/metabolismo , Imuno-Histoquímica , Imunoprecipitação , Marcação In Situ das Extremidades Cortadas , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteína Oncogênica v-akt/metabolismo , Permeabilidade , Proteína Quinase C/metabolismo , Ratos , Vasos Retinianos/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
7.
Vision Res ; 46(10): 1655-64, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16243375

RESUMO

The purpose of this study was to compare the a-waves of mGluR6-deficient mice (KO) to that of wild-type mice (WT), and to determine whether the light-adapted electroretinogram of the KO mice originate exclusively from cones. Dark-adapted a-waves were recorded under the same conditions from both types of mice. With a 96-cd/m(2) background, the a-wave from both types of mice showed a rapid recovery over a 50-min period. The analysis of the a-waves in KO mice indicated that the recovery was determined mainly by the rod component. The light-adapted b-wave of WT mice showed no corresponding recovery. We conclude that rod contribution must be considered in the analyses of the light-adapted a-waves of KO mice.


Assuntos
Adaptação Ocular , Receptores de Glutamato Metabotrópico/deficiência , Células Fotorreceptoras Retinianas Bastonetes/fisiopatologia , Animais , Adaptação à Escuridão , Eletrorretinografia , Iluminação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estimulação Luminosa/métodos , Receptores de Glutamato Metabotrópico/fisiologia , Retina/fisiopatologia , Células Fotorreceptoras Retinianas Cones/fisiopatologia
8.
Zoolog Sci ; 22(10): 1145-56, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16286727

RESUMO

Red-green color vision in primates is unique in the sense that it is mediated by two photoreceptor cells that are indistinguishable in all aspects except for their visual pigments. In order to generate an animal model for investigation of the interaction between red-green inputs at the molecular level, we applied knock-in technology and X-chromosome inactivation machinery to make a mouse model with cone cells possessing visual pigments with different spectral sensitivities. We introduced a S308A point mutation into the Green opsin gene allele on the X-chromosome. This manipulation generated a 24 nm red-shift of absorption maximum in the cone pigment with negligible functional differences in other molecular properties. Amplitudes of responses in ERG and ganglion cell recordings of homozygotes were similar to those of wild-types, although the spectral sensitivities differed. Heterozygotes showed variable spectral sensitivities of ganglion cell responses due to the different integration of the native and the S308A cone inputs on the dendritic fields. In situ hybridization experiments showed that cone cells with respective pigments formed patch-like clusters of specific L cone-types, approximately 30 mum in diameter, which were randomly distributed in the dorsal region of the retinas. Since the patch-like clustering was arranged by X-inactivation, such clustering could be present in the peripheral retinas of New World monkeys with polymorphic L pigments, indicating that our mice would be a suitable model to study evolution of the mammalian color vision system.


Assuntos
Camundongos/genética , Modelos Animais , Células Fotorreceptoras Retinianas Cones/fisiologia , Pigmentos da Retina/genética , Opsinas de Bastonetes/genética , Inativação do Cromossomo X/genética , Animais , Sequência de Bases , Linhagem Celular , Percepção de Cores/fisiologia , Eletrorretinografia , Éxons/genética , Proteínas de Ligação ao GTP/metabolismo , Humanos , Hibridização In Situ , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Células Fotorreceptoras Retinianas Cones/anatomia & histologia , Células Ganglionares da Retina/fisiologia , Análise de Sequência de DNA , Espectrofotometria Ultravioleta
9.
Retina ; 25(7): 911-8, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16205572

RESUMO

BACKGROUND: To determine the expression of connective tissue growth factor (CTGF) in choroidal neovascularization. METHODS: Surgically excised choroidal neovascular membranes (CNVMs) were obtained at vitrectomy from eight eyes with age-related macular degeneration, five eyes with high myopia, and two eyes with angioid streaks. Light microscopic immunohistochemical analysis was performed to detect CTGF, transforming growth factor beta 1 (TGF-beta1), vascular endothelial growth factor (VEGF), pancytokeratin, and smooth muscle actin (SMA). RESULTS: CNVMs were classified by fibrotic status as cellular CNVM, moderate fibrous CNVM, and extensive fibrous CNVM. CTGF expression was found in vascular cells, stromal cells, and retinal pigment epithelium (RPE) cells. For the stromal cells, fibroblastlike cells were most strongly positive for CTGF. CTGF immunoreactivity in the stroma was stronger in the fibrous CNVMs than in the cellular CNVMs. Immunohistochemical analysis of serial sections revealed colocalization of CTGF with TGF-beta1 and VEGF; colocalization of CTGF with pancytokeratin and SMA was also found. CONCLUSION: Our findings suggest that transdifferentiated RPE cells and vascular cells possess remarkable CTGF expression in CNVMs. This expression of CTGF may stimulate fibroblasts to produce extracellular matrix and may promote angiogenesis in vascular cells. Colocalized TGF-beta1 and VEGF may also contribute the upregulation of CTGF.


Assuntos
Neovascularização de Coroide/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Idoso , Fator de Crescimento do Tecido Conjuntivo , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , Membranas/metabolismo , Pessoa de Meia-Idade , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1 , Fator A de Crescimento do Endotélio Vascular/metabolismo , Vitrectomia
10.
Proc Natl Acad Sci U S A ; 102(32): 11331-6, 2005 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-16076961

RESUMO

We report directed differentiaion of retinal precursors in vitro from mouse ES cells. Six3+ rostral brain progenitors are generated by culturing ES cells under serum-free suspension conditions (SFEB culture) in the presence of Wnt and Nodal antagonists (Dkk1 and LeftyA), and subsequently steered to differentiate into Rx+ cells (16%) by treatment with activin and serum. Consistent with the characteristics of early neural retinal precursors, the induced Rx+ cells coexpress Pax6 and the mitotic marker Ki67, but not Nestin. The ES cell-derived precursors efficiently generate cells with the photoreceptor phenotype (rhodopsin+, recoverin+) when cocultured with embryonic retinal cells. Furthermore, organotypic culture studies demonstrate the selective integration and survival of ES cell-derived cells with the photoreceptor phenotype (marker expression and morphology) in the outer nuclear layer of the retina. Taken together, ES cells treated with SFEB/Dkk1/LeftyA/serum/activin generate neural retinal precursors, which have the competence of photoreceptor differentiation.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Proteínas do Olho/metabolismo , Proteínas de Homeodomínio/metabolismo , Fatores de Transcrição Box Pareados/metabolismo , Proteínas Repressoras/metabolismo , Retina/citologia , Células-Tronco/citologia , Ativinas/farmacologia , Animais , Células Cultivadas , Meios de Cultura Livres de Soro/farmacologia , Vetores Genéticos , Imuno-Histoquímica , Hibridização In Situ , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Fatores de Determinação Direita-Esquerda , Lentivirus , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Fator de Transcrição PAX6 , Retina/metabolismo , Rodopsina/metabolismo , Soro , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Proteína Homeobox SIX3
11.
Invest Ophthalmol Vis Sci ; 46(9): 3411-9, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16123446

RESUMO

PURPOSE: The purpose of this study was to investigate the effects of various genes related to photoreceptor development on rodent and primate iris cells and the potential of iris cells as donor cells for retinal transplantation. METHODS: Adult rat and monkey iris tissue were cultured in serum-free medium containing basic fibroblast growth factor. Gene deliveries of Crx, Nrl, NeuroD and some combinations (Crx-Nrl, Crx-NeuroD) were performed with recombinant retrovirus. Immunocytochemistry, Western blot analysis, RT-PCR, and intracellular recording were used to examine the expression of photoreceptor-specific phenotypes in the iris-derived cells after gene transfer, . Coculture of the iris-derived cells with embryonic retinal explant was conducted, to investigate the potential integration of these cells in coculture conditions. RESULTS: Misexpression of Crx induced adult rat iris cells to express several photoreceptor-specific antigens and transcripts, such as rhodopsin, recoverin, cGMP-gated channel, arrestin, interphotoreceptor retinal-binding protein, rhodopsin kinase, and NeuroD. In primates, a combination of Crx and NeuroD was needed to induce monkey iris-derived cells to adopt photoreceptor-specific phenotypes. Furthermore, the photoreceptor-like cells derived from both rat- and primate-iris tissues showed rod photoreceptor-specific electrophysiological response to light stimuli after Crx and Crx-NeuroD gene transfer, respectively. The results further showed that iris-derived cells integrated in the developing host retina in coculture conditions. CONCLUSIONS: Adult iris-derived cultured cells of both rodents and primates expressed photoreceptor-specific phenotypes by inductions of transcription factors. These iris-derived photoreceptor-like cells have electrophysiological characteristics of rod photoreceptors. Furthermore, they can integrate in the developing retina under coculture conditions.


Assuntos
Diferenciação Celular/fisiologia , Iris/citologia , Células Fotorreceptoras de Vertebrados/citologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Western Blotting , Técnicas de Cultura de Células , Técnicas de Cocultura , Meios de Cultura Livres de Soro , Eletrofisiologia , Proteínas do Olho/metabolismo , Feminino , Fator 2 de Crescimento de Fibroblastos/farmacologia , Expressão Gênica , Técnicas de Transferência de Genes , Proteínas de Homeodomínio/genética , Imuno-Histoquímica , Iris/efeitos dos fármacos , Iris/metabolismo , Lipocalina-2 , Lipocalinas , Macaca fascicularis , Proteínas de Neoplasias/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Fenótipo , Células Fotorreceptoras de Vertebrados/fisiologia , Gravidez , Ratos , Ratos Endogâmicos F344 , Retina/embriologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transativadores/genética
12.
J Biol Chem ; 280(36): 31841-9, 2005 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-16000309

RESUMO

Oxidative stress activates various signal transduction pathways, including Jun N-terminal kinase (JNK) and its substrates, that induce apoptosis. We reported here the role of angiopoietin-1 (Ang1), which is a prosurvival factor in endothelial cells, during endothelial cell damage induced by oxidative stress. Hydrogen peroxide (H2O2) increased apoptosis of endothelial cells through JNK activation, whereas Ang1 inhibited H2O2-induced apoptosis and concomitant JNK phosphorylation. The inhibition of H2O2-induced JNK phosphorylation was reversed by inhibitors of phosphatidylinositol (PI) 3-kinase and dominant-negative Akt, and constitutively active-Akt attenuated JNK phosphorylation without Ang1. These data suggested that Ang1-dependent Akt phosphorylation through PI 3-kinase leads to the inhibition of JNK phosphorylation. H2O2-induced phosphorylation of SAPK/Erk kinase (SEK1) at Thr261, which is an upstream regulator of JNK, was also attenuated by Ang1-dependent activation of the PI 3-kinase/Akt pathway. In addition, Ang1 induced SEK1 phosphorylation at Ser80, suggesting the existence of an additional signal transduction pathway through which Ang1 attenuates JNK phosphorylation. These results demonstrated that Ang1 attenuates H2O2-induced SEK1/JNK phosphorylation through the PI 3-kinase/Akt pathway and inhibits the apoptosis of endothelial cells to oxidative stress.


Assuntos
Angiopoietina-1/fisiologia , Endotélio Vascular/enzimologia , Peróxido de Hidrogênio/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Estresse Oxidativo/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Animais , Apoptose/fisiologia , Células Cultivadas , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/fisiologia , Proteína Quinase 8 Ativada por Mitógeno/fisiologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais/fisiologia , Suínos
13.
Retina ; 25(1): 54-8, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15655441

RESUMO

PURPOSE: To determine the indications for internal limiting membrane (ILM) removal in stage 3 idiopathic macular holes (MHs). METHODS: Focal posterior vitreous detachments (PVDs) at MH rims were examined preoperatively by optical coherence tomography and binocular slit-lamp fundus examination in 19 patients retrospectively. All eyes underwent pars plana vitrectomy and creation of a PVD, and some eyes underwent a second surgery to remove the ILM. Indications of ILM removal for MH closure were discussed. RESULTS: Preoperatively, 9 eyes did not (non-PVD group) and 10 eyes did (PVD group) have complete focal PVDs. In all nine eyes in the non-PVD group, MHs were closed after the creation of a PVD without ILM peeling (P <0.05, chi test). In the PVD group, 5 eyes (50%) had MHs closed by making PVD complete without ILM removal, and 5 eyes (50%) required ILM removal in a second surgery. In the end, closure of MHs was achieved in all eyes. CONCLUSION: Anatomic closure of stage 3 idiopathic MHs without a PVD at the rim of the hole may be achieved only by creating a PVD without ILM removal.


Assuntos
Membrana Epirretiniana/cirurgia , Perfurações Retinianas/cirurgia , Adulto , Idoso , Membrana Basal/cirurgia , Técnicas de Diagnóstico Oftalmológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Perfurações Retinianas/classificação , Perfurações Retinianas/diagnóstico , Estudos Retrospectivos , Tomografia de Coerência Óptica , Acuidade Visual , Vitrectomia , Corpo Vítreo/cirurgia
15.
Mol Vis ; 10: 923-32, 2004 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-15616479

RESUMO

PURPOSE: Choroidal neovascularization (CNV) under the age of 50 is more often observed in women than in men. The effects of 17beta-estradiol (E2) on choroidal neovascularization development were investigated both in animal models and cultured cells to see if estrogen receptors (ERs) are involved in the process. METHODS: CNV was induced by fundus laser photocoagulation in adult male and female rats. The degree of CNV development was scored and compared between them. Gene expression levels of VEGF receptor 2 (VEGFR2) and ERs after photocoagulation were compared between genders using real time PCR. CNV formation and the gene expressions were also examined in ovariectomized females with and without E2 treatment. The roles of ERs were studied by overexpressing them in human umbilical vein endothelial cells (HUVECs). The localization of estrogen receptorbeta (ERbeta) and VEGFR2 in CNV were studied immunohistochemically. RESULTS: CNV scores were significantly higher in females than in males 14 and 21 days after photocoagulation (<0.05). VEGFR2 and ERbeta gene levels were increased more in females than in males on day 7 (3.4 fold compared to 1.8 fold) and on day 3 (5.8 fold compared to 2.3 fold) after photocoagulation, respectively. Both ERbeta and VEGFR2 gene expressions were additively enhanced by photocoagulation and E2 treatment in ovariectomized females. E2 significantly enhanced VEGFR2 gene expression and cell proliferation in HUVECs overexpressing ERbeta. ERbeta and VEGFR2 are well co-localized in CNV tissue. CONCLUSIONS: Estrogen may promote CNV development by increasing VEGFR2 gene expression via ERbeta.


Assuntos
Neovascularização de Coroide/fisiopatologia , Receptor beta de Estrogênio/fisiologia , Estrogênios/fisiologia , Animais , Técnicas de Cultura de Células , Proliferação de Células/efeitos dos fármacos , Neovascularização de Coroide/etiologia , Neovascularização de Coroide/metabolismo , Modelos Animais de Doenças , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Estradiol/farmacologia , Feminino , Angiofluoresceinografia , Técnica Indireta de Fluorescência para Anticorpo , Expressão Gênica/fisiologia , Vetores Genéticos , Fotocoagulação a Laser , Masculino , Ovariectomia , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos BN , Fatores Sexuais , Transfecção , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
16.
Invest Ophthalmol Vis Sci ; 45(11): 4197-201, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15505075

RESUMO

PURPOSE: To evaluate new physiologic and three-dimensional methods for monitoring leukocyte behavior in mouse retina. METHODS: Endotoxin-induced uveitis (EIU) was produced in mice by footpad injection of lipopolysaccharide (LPS). Leukocytes were labeled with acridine orange (AO). Leukocyte rolling in the retinal microcirculation was evaluated in vivo with AO digital fluorography. The number of migrated leukocytes was counted in flatmounted retina. The behavior of leukocyte migration was observed three-dimensionally at the time of peak migration. After leukocytes were labeled with AO, the mice were perfused with rhodamine-labeled concanavalin A lectin to stain the vascular endothelium. Leukocyte migration into the retina was then monitored three-dimensionally with confocal microscopy, and the velocity of the migration was measured. RESULTS: Both leukocyte rolling and migration peaked at 48 hours after LPS injection. Leukocytes were seen to extravasate from the deeper capillary layers and to migrate toward the outer layer of the retina. The traveling velocity of extravasated leukocytes in retinal tissue was 2.0 +/- 0.1 microm/h. CONCLUSIONS: New methods have been demonstrated for the three-dimensional and quantitative evaluation of leukocyte behavior in mouse retina.


Assuntos
Leucócitos/fisiologia , Vasos Retinianos/fisiologia , Salmonella typhimurium , Uveíte/fisiopatologia , Laranja de Acridina , Animais , Modelos Animais de Doenças , Endotélio Vascular/metabolismo , Corantes Fluorescentes , Fluorofotometria , Contagem de Leucócitos , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microcirculação , Microscopia Confocal , Uveíte/induzido quimicamente
17.
J Neurosci ; 24(37): 8124-34, 2004 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-15371513

RESUMO

Tlx belongs to a class of orphan nuclear receptors that underlies many aspects of neural development in the CNS. However, the fundamental roles played by Tlx in the control of eye developmental programs remain elusive. By using Tlx knock-out (KO) mice, we show here that Tlx is expressed by retinal progenitor cells in the neuroblastic layer during the period of retinal layer formation, and it is critical for controlling the generation of appropriate numbers of retinal progenies through the activities of cell cycle-related molecules, cyclin D1 and p27Kip1. Tlx expression is restricted to Müller cells in the mature retina and appears to control their proper development. Furthermore, we show that Tlx is expressed by immature astrocytes that migrate from the optic nerve onto the inner surface of the retina and is required for their generation and maturation, as assessed by honeycomb network formation and expression of R-cadherin, a critical component for vasculogenesis. The impaired astrocyte network formation on the inner retinal surface is accompanied by the loss of vasculogenesis in Tlx KO retinas. Our studies thus indicate that Tlx underlies a fundamental developmental program of retinal organization and controls the generation of the proper numbers of retinal progenies and development of glial cells during the protracted period of retinogenesis.


Assuntos
Astrócitos/citologia , Proteínas do Olho/fisiologia , Neuroglia/citologia , Receptores Citoplasmáticos e Nucleares/fisiologia , Retina/citologia , Animais , Apoptose , Astrócitos/metabolismo , Caderinas/biossíntese , Caderinas/genética , Contagem de Células , Ciclo Celular , Proteínas de Ciclo Celular/fisiologia , Diferenciação Celular , Movimento Celular , Ciclina D1/fisiologia , Inibidor de Quinase Dependente de Ciclina p27 , Anormalidades do Olho/genética , Proteínas do Olho/biossíntese , Proteínas do Olho/genética , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Camundongos Knockout , Neovascularização Fisiológica/genética , Neuroglia/metabolismo , Receptores Citoplasmáticos e Nucleares/biossíntese , Receptores Citoplasmáticos e Nucleares/deficiência , Receptores Citoplasmáticos e Nucleares/genética , Retina/embriologia , Retina/crescimento & desenvolvimento , Vasos Retinianos/embriologia , Vasos Retinianos/crescimento & desenvolvimento , Proteínas Supressoras de Tumor/fisiologia
18.
Mol Vis ; 10: 608-17, 2004 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-15354084

RESUMO

PURPOSE: The angiopoietin (Ang)/Tie-2 system may play a role in vascular integrity and angiogenesis. In this study, we investigated alterations of the gene expression of Ang-1 and Ang-2 in the retinas of streptozotocin (STZ) induced diabetic rats. METHODS: In situ hybridization, reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analyses were performed to determine the mRNA and protein content for Ang-1 and Ang-2 and the Tie2 receptor in the retinas of STZ diabetic and age matched control rats. RESULTS: Using in situ hybridization analysis, Ang-1, Ang-2, and Tie2 mRNA expression was observed in the ganglion cell layer (GCL) and the inner nuclear layer (INL). While Ang-2 mRNA expression did not changed after 2 weeks, 1 month, or 3 months of STZ induced diabetes, it was increased in the GCL and slightly elevated in the INL after 6 months of diabetes. In contrast, Ang-1 and Tie2 mRNA expression was stable at every timepoint during 6 months of STZ induced diabetes. RT-PCR and western blot analyses confirmed the increase of Ang-2 expression after 6 months of diabetes. Furthermore, double staining of alpha-smooth muscle actin (alphaSMA) and Ang-2 mRNA demonstrated that the SMA positive cells surrounding Ang-2-expressing cells were decreased in the GCL. CONCLUSIONS: Diabetes increases Ang-2 expression in the GCL accompanied by a reduction of alphaSMA positive perivascular cells. These changes may suggest a role for Ang-2 in the mechanism of pericyte loss in diabetic retinopathy.


Assuntos
Angiopoietina-1/genética , Angiopoietina-2/genética , Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/metabolismo , Regulação da Expressão Gênica , Receptor TIE-2/genética , Retina/metabolismo , Angiopoietina-1/metabolismo , Angiopoietina-2/metabolismo , Animais , Western Blotting , Técnicas Imunoenzimáticas , Hibridização In Situ , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor TIE-2/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
19.
Proc Natl Acad Sci U S A ; 101(37): 13654-9, 2004 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-15353594

RESUMO

It has long been believed that the retina of mature mammals is incapable of regeneration. In this study, using the N-methyl-D-aspartate neurotoxicity model of adult rat retina, we observed that some Müller glial cells were stimulated to proliferate in response to a toxic injury and produce bipolar cells and rod photoreceptors. Although these newly produced neurons were limited in number, retinoic acid treatment promoted the number of regenerated bipolar cells. Moreover, misexpression of basic helix-loop-helix and homeobox genes promoted the induction of amacrine, horizontal, and rod photoreceptor specific phenotypes. These findings demonstrated that retinal neurons regenerated even in adult mammalian retina after toxic injury. Furthermore, we could partially control the fate of the regenerated neurons with extrinsic factors or intrinsic genes. The Müller glial cells constitute a potential source for the regeneration of adult mammalian retina and can be a target for drug delivery and gene therapy in retinal degenerative diseases.


Assuntos
N-Metilaspartato/toxicidade , Regeneração Nervosa , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Retina/efeitos dos fármacos , Retina/patologia , Envelhecimento/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Proteínas do Olho , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Imuno-Histoquímica , Masculino , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/citologia , Neurônios/patologia , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados , Ratos , Ratos Sprague-Dawley , Proteínas Repressoras , Retina/metabolismo , Rodopsina/metabolismo , Transativadores/genética , Transativadores/metabolismo , Tretinoína/farmacologia
20.
Ocul Immunol Inflamm ; 12(1): 35-43, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15209462

RESUMO

OBJECTIVE: To examine the results of pars plana vitrectomy for nonclearing vitreous opacities associated with ocular sarcoidosis that is resistant to corticosteroid treatment. METHODS: Eight consecutive patients (11 eyes) with vitreous opacities and uveitis associated with sarcoidosis were studied. All patients were resistant to or intolerant of corticosteroid therapy. All eyes underwent pars plana vitrectomy, followed by evaluation of visual acuity and recording of the grade of inflammation and complications. RESULTS: Seven eyes had gained two or more lines of Snellen visual acuity six months postoperatively; visual acuity remained unchanged in the other four eyes. Vitreous inflammation was reduced in all cases. Severe postoperative inflammation did not recur in any eyes. Five eyes developed visually significant cataracts and underwent cataract extraction and intraocular lens insertion within 8-30 months. Based on slit-lamp biomicroscopy and fluorescein angiography, preoperative cystoid macular edema in five eyes resolved or improved within six months after vitrectomy. Postoperative complications included elevated intraocular pressure in three eyes, cataract formation in six eyes, epiretinal membrane formation in one eye, and choroidal neovascularization in one eye. None of the patients developed cystoid macular edema postoperatively. Only three patients received systemic corticosteroids after surgery. At the final visit, only one patient required systemic corticosteroid therapy. CONCLUSIONS: Pars plana vitrectomy appears to have beneficial effects on restoring vision, stabilizing vitreous inflammation, and reducing systemic corticosteroid requirements in eyes with thick vitreous opacities associated with sarcoidosis that is resistant to medical treatment.


Assuntos
Oftalmopatias/cirurgia , Sarcoidose/cirurgia , Uveíte/cirurgia , Vitrectomia , Corpo Vítreo/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Resistência a Medicamentos , Oftalmopatias/etiologia , Feminino , Glucocorticoides/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Sarcoidose/complicações , Sarcoidose/tratamento farmacológico , Uveíte/complicações , Uveíte/tratamento farmacológico , Acuidade Visual , Corpo Vítreo/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA