Renato Antunes Schiave Germano

Lipid bilayer pre-transition as the beginning of the melting process

We investigate the bilayer pre-transition exhibited by some lipids at temperatures below their main phase transition, and which is generally associated to the formation of periodic ripples in the membrane. Experimentally we focus on the anionic lipid dipalmytoylphosphatidylglycerol (DPPG) at different ionic strengths, and on the neutral lipid dipalmytoylphosphatidylcholine (DPPC). From the analysis of differential scanning calorimetry traces of the two lipids we find that both pre- and main transitions are part of the same melting process. Electron spin resonance of spin labels and excitation generalized polarization of Laurdan reveal the coexistence of gel and fluid domains at temperatures between the pre- and main transitions of both lipids, reinforcing the first finding. Also, the melting process of DPPG at low ionic strength is found to be less cooperative than that of DPPC. From the theoretical side, we introduce a statistical model in which a next-nearest-neighbor competing interaction is added to the usual two-state model. For the first time, modulated phases (ordered and disordered lipids periodically aligned) emerge between the gel and fluid phases as a natural consequence of the competition between lipid-lipid interactions.

Influência da correção cirúrgica da catarata na percepção laborativa

Objetivo: Analisar o beneficio gerado nas atividades profissionais apos a cirurgia de catarata. Metodos: Foi realizado um estudo prospectivo, randomizado, no Hospital das Clinicas da Universidade de Sao Paulo. Os pacientes foram submetidos a facoemulsificacao (FACO) e a extracao extracapsular (EECP). Resultados: A amostra foi composta de 205 pacientes, destes, 101 realizaram cirurgia pela tecnica de facoemulsificacao. A media de idade no grupo da facoemulsificacao foi de 68,3 anos ± 9 anos e de 69,1 anos ± 8,5 anos no grupo da extracao extracapsular (p=0,70). A porcentagem de pacientes empregados no grupo facoemulsificacao foi de 16,83%, e no outro grupo de 13,46%. A maioria dos pacientes que nao remunerados formalmente sentiu-se motivada a procurar trabalho. A maioria dos analisados relatou aumento da produtividade no trabalho apos a cirurgia, 82,50% no grupo facoemulsificacao e 78,60% no grupo extracao extracapsular (p=0,20). Conclusao: A cirurgia de catarata por ambas as tecnicas proporcionou melhora da produtividade no trabalho, e estimulou individuos economicamente inativos a procurar trabalho remunerado.

Rho kinase inhibitors for glaucoma treatment - Review.

Glaucoma is a progressive optic neuropathy characterized by the loss of ganglion cells and their axons. A major risk factor for glaucomatous visual field loss is elevated intraocular pressure (IOP), and several studies have shown that lowering IOP reduces the risk of glaucomatous progression. Currently, an increasing number of researches involve Rho kinase inhibitors, which are a new pharmacological class of hypotensive agents specifically targeting the diseased trabecular outflow pathway. Rho kinase inhibitors reduce IOP by increasing aqueous humor drainage through the primary outflow pathway in the eye, which is known as the trabecular meshwork. In addition to improving the outflow facility of the trabecular meshwork, Rho kinase inhibitors also enhance retinal ganglion cell survival after ischemic injury and increase ocular blood flow.

Cirurgia de catarata realizada por residentes: avaliação dos riscos

OBJETIVO: Avaliar a frequencia de complicacoes nas cirurgias de catarata realizada por residentes de um hospital universitario (segundo e terceiro anos), comparado com as realizadas por cirurgioes experientes (assistentes). METODOS: Analise retrospectiva dos prontuarios de todos pacientes submetidos a cirurgia de catarata realizadas nas primeiras quinzenas de marco (epoca do inicio do aprendizado da tecnica cirurgica) e de novembro (meados do aprendizado da tecnica). Foram analisados a epoca da realizacao da cirurgia; graduacao do cirurgiao (residente ou medico assistente); tecnica cirurgica empregada (extracao extracapsular ou facoemulsificacao) e a ocorrencia de complicacoes per-operatorias e pos-operatorias. RESULTADOS: Foram analisadas 481 cirurgias, destas, 194 (40%) foram realizadas pelos residentes do terceiro ano, 165 (34%) pelos residentes do segundo ano e 116 (26%) pelos assistentes. A complicacao mais frequentemente encontrada em todas as cirurgias foi a rotura de capsula posterior (4,8%). Nao houve diferenca estatisticamente significativa de complicacoes entre as cirurgias realizadas em marco e novembro (p=0,97), bem como entre os residentes sob supervisao e os assistentes (p=0,08). CONCLUSAO: A rotura de capsula posterior continua sendo a complicacao mais frequentemente encontrada nas cirurgias de residentes em treinamento. Nao houve diferenca estatisticamente significativa entre as taxas de complicacao destes residentes e os assistentes, o que demonstra o importante papel de uma supervisao adequada.

Eyelid liquoric fistula secondary to orbital meningocele

Liquoric fistula (LF) is defined as the communication of the subarachnoid space with the external environment, which main complication is the development of infection in the central nervous system. We reported the case of a patient with non-traumatic eyelid liquoric fistula secondary to orbital meningocele (congenital lesion), which main clinical manifestation was unilateral eyelid edema. Her symptoms and clinical signs appeared in adulthood, which is uncommon. The patient received surgical treatment, with complete resolution of the eyelid swelling. In conclusion, eyelid cerebrospinal fluid (CSF) fistula is a rare condition but with great potential deleterious to the patient. It should be considered in the differential diagnosis of unilateral eyelid edema, and surgical treatment is almost always mandatory.

Lente intraocular multifocal refrativa: a performance visual e qualidade de vida em implantes bilaterais versus unilaterais

OBJETIVO: O objetivo desse estudo e comparar acuidade visual, sensibilidade ao contraste, velocidade de leitura e a qualidade de vida pos-operatoria de pacientes pseudofacicos unilaterais ou bilaterais com lentes intraoculares multifocais ReZoom. METODOS: Estudo comparativo, prospectivo, nao aleatorio incluindo 38 olhos de 24 pacientes, separados em um grupo com implante bilateral (14 pacientes) e outro com implante unilateral (10 pacientes). O exame oftalmologico completo incluiu acuidade visual nao corrigida pre-operatoria para perto, intermediario e para longe, acuidade visual com melhor correcao, topografia corneal, sensibilidade ao contraste, velocidade de leitura e escala de satisfacao realizado 60 dias apos a cirurgia. A analise estatistica foi realizada por meio dos testes de Kruskal-Wallis, Mann-Whitney e Qui-quadrado. RESULTADOS: Os resultados comparando funcao visual, sensibilidade ao contraste, velocidade de leitura e escala de satisfacao foram semelhante entre os grupos. CONCLUSAO: Nao houve diferenca estatistica entre os resultados comparando funcao visual, sensibilidade ao contraste, velocidade de leitura e escala de satisfacao entre os grupos.

Evaluation of a Novel Visual Field Analyzer Application for Automated Classification of Glaucoma Severity

Purpose: To describe the Glaucoma Staging Application (GSA), a new application for automated classification of visual field (VF) severity that can be used in any Humphrey perimeters. We also tested and validated its performance in staging glaucomatous VFs defects and assessed its reproducibility. Materials and Methods: The GSA is based upon the modified University of São Paulo Glaucoma Visual Field Staging System, and consists of 3 sections: severity based on the visual field index; defect location based on eccentricity; and extent of topographic damage by hemifields. We analyzed 612 VFs of 32 patients. VFs were analyzed by a glaucoma expert and then compared with the output of the GSA. To evaluate the repeatability, the same search criteria were repeated 1 week later using the same GSA. The classification given by the software was considered correct if it completely agreed in all variables (severity, location, and extent of topographic damage) with the classification performed manually by the glaucoma expert. Results: One hundred seventy-eight eyes were classified as early VF damage, 148 moderate, and 156 severe. One hundred thirty-one VFs were classified as normal. When repeated, 1 week later, the GSA showed excellent repeatability. The automated classification agreed with the expert’s grading in 100% of cases. Conclusions: The GSA allows an automated, fast, reproducible, and objective classification system for multiple 24-2 VFs of Humphrey perimetry. This study is a proof-of-concept that could translate into a useful tool to analyze and stage VFs more objectively and thus help detecting progression of different types of VFs defects.

Choroidal thickness variation in highly myopic eyes during the water drinking test

PURPOSE To evaluate variations in choroidal thickness (CT) during the water drinking test (WDT) in emmetropic eyes (EE) and highly myopic eyes (ME) using spectral-domain optical coherence tomography (SD-OCT). METHODS Clinical trial performed at a tertiary care hospital comprising 30 randomly selected eyes. The WDT and SD-OCT macular scans were performed 10 and 45 min after water ingestion in 15 myopic and 15 EE of 15 healthy patients in each group. Primary study outcomes were average macular CT measured by SD-OCT and intraocular pressure (IOP) during the WDT. RESULTS The mean spherical equivalent refraction was 0.15 ± 0.24 D in emmetropic and -7.1 ± 1.75 D in ME (p<0.001). No statistical differences between EE and ME were observed during the WDT response. EE had higher CT compared with ME at the fovea (361.4 ± 55.4 vs 257.9 ± 95.3; p<0.001), 3 mm nasal to the fovea (158.0 ± 71.8 vs 122.5 ± 54.5; p =0.047), and 3 mm temporally to the fovea (310.6 ± 52.4 vs 247.6 ± 90.1; p=0.05). Regarding CT variation, significant differences in foveal CT at 10 min after water ingestion were observed in both EE and ME, with no statistically significant difference observed between groups. A moderate correlation between IOP peak during the WDT and CT was demonstrated in ME (r=0.52; p=0.04). CONCLUSIONS No statistically significant differences in CT variation during the WDT were observed between EE and ME, indicating similar behavior of the choroidal bed during the WDT in both groups. Further, CT was thinner in highly ME, with CT variation unable to explain elevations in IOP observed during the WDT.

Adie-Holmes Syndrome

A Sindrome de Holmes-Adie E caracterizada pela presenca de pupila tonica associada a diminuicao ou ausencia dos reflexos tendineos profundos. Em alguns casos pode haver disfuncao nervosa autonoma. O mecanismo que causa a desordem nao e totalmente conhecido, mas acredita-se que seja causada pela desnervacao do suprimento pos-ganglionar para o esfincter da pupila e para o musculo ciliar, que pode ocorrer apos doenca viral. Tipicamente afeta adultos jovens e e unilateral em 80% dos casos, embora possa se desenvolver no olho contralateral em meses ou anos. Nos relatamos o caso de uma mulher apresentando sinais tipicos desta sindrome, em que o teste farmacologico foi fundamental para o diagnostico.

Recurrent myopic foveoschisis: resolution after internal limiting membrane removal

We report a case of a 66-year-old man with a history of high myopia and who was referred for acute decreased visual acuity of the right eye. Fundus examination and optical coherence tomography (OCT) showed a mild epiretinal membrane (ERM) and splitting of retinal layers. Pars plana vitrectomy was performed with intravitreous triamcinolone injection, posterior hyaloid and ERM peeling, and 12% perfluoropropane (C3F8) gas tamponade. After remaining asymptomatic for 17 months, the patient reported a new episode of sudden decreased visual acuity in his right eye, and OCT showed recurrent myopic foveoschisis (MF). He underwent vitrectomy and internal limiting membrane (ILM) peeling. Six months later, the patients best corrected visual acuity had improved to 20/25. Optical coherence tomography showed a remarkably improved macular anatomy, with residual traction along the inferotemporal arcade, which was attributed to the vessel stiffness itself. We conclude that removing the internal limiting membrane is a challenging maneuver in myopic foveoschisis, even with staining approaches. Although myopic foveoschisis may be resolved without peeling the internal limiting membrane, its removal should be considered if the condition recurs.