Effect of collagen cross-linking in stromal fibril organization in edematous human corneas.

PURPOSE: To assess structural stromal modifications after riboflavin and UV-A exposure in edematous human corneas. METHOD: Fourteen eyes with corneal edema were enrolled in the study. In the cross-linking (CXL) group, 7 corneal buttons were obtained from 6 patients who underwent penetrating keratoplasty (PK) 7-90 days after the CXL treatment. The control group was composed of 7 corneal buttons with bullous keratopathy. After the PK, stromal modifications were investigated using immunofluorescence in all corneal grafts. All patients had at least 3 months of corneal edema and were in the eye bank list waiting for keratoplasty. RESULTS: All corneas in the treated group showed a pronounced lamellar zone of collagen fibers highly organized in the anterior stroma, but there was not complete homogeneity between the samples. Corneas with advanced disease and stromal fibrosis were less compacted than ones with mild disease severity. Similarly, those ones that underwent PK 3 months after CXL also showed a decreased effect compared with those with a reduced time between the CXL and the PK. DAPI staining demonstrated a complete fragmentation of keratocytes nuclei in the anterior stroma in all treated corneas, which were absent in the control group. CONCLUSIONS: Our study showed an immediate effect of CXL with a limited long-term sustainability. Cross-linked corneas had a pronounced anterior zone of organized collagen fibers. Even the treated corneas with advanced bullous keratopathy and stromal fibrosis had histological evidence of collagen fibers organization, but this effect seems to be decreased compared with corneas in initial stages of the disease.

Effect of cross-linking on corneal thickness in patients with corneal edema.

PURPOSE: To investigate the pachymetric changes of collagen cross-linking in corneas with edema because of endothelial dysfunction. METHODS: Interventional case series included 25 eyes of 25 consecutive patients with corneal edema for at least 4 months related to Fuchs endothelial dystrophy, corneal graft failure, and postoperative bullous keratopathy. Central corneal thickness was measured preoperatively, 1, 3, and 6 months after the procedure by ultrasound pachymetry and optical coherence tomography. RESULTS: Mean central corneal thickness measured by ultrasound pachymetry decreased after corneal cross-linking (mean +/- SD): 712.0 +/- 99.7, 618.3 +/- 103.0, and 657.5 +/- 114.8 for preoperative, 1-, and 3-month follow-up, respectively. Differences between preoperative value and 1- and 3-month follow-up values were statistically significant (P < 0.01). Similar results were found with the optical coherence tomography (mean +/- SD): 777.3 +/- 131.0, 711.6 +/- 133.1, 746.4 +/- 142.4, and 830.6 +/- 198.7, for preoperative, 1-, 3-, and 6-month follow-up values, respectively. Fourteen patients (56%) developed new epithelial bullae after 3 months; 11 patients (44%) remained asymptomatic until their last visit. CONCLUSION: Corneal cross-linking showed to be a safe procedure and potential therapeutic alternative for the treatment of corneal edema.

Avaliação da microbiota ocular em pacientes com disfunção do filme lacrimal / Evaluation of conjunctival flora in patients with tear film dysfunction

OBJETIVO: Avaliar a microbiota conjuntival em olhos com disfunção do filme lacrimal, e a modificação desta microbiota após a colocação de plug de silicone no canalículo inferior. MÉTODOS: Série de casos intervencionais não comparativos para avaliar 68 olhos de 41 pacientes com disfunção do filme lacrimal, durante o período de 2002 a 2007, na Universidade Federal de São Paulo. Todos os pacientes foram submetidos à colheita de amostras de raspado conjuntival de fundo-de-saco inferior para cultivo em Brain heart infusion broth. Os vinte e dois pacientes submetidos à colocação de plug de silicone repetiram a colheita de raspado conjuntival um mês após o procedimento. RESULTADOS: Dos 68 olhos avaliados, 47 apresentaram crescimento bacteriano nas amostras colhidas. Nove diferentes espécies de bactérias foram identificadas: Staphylococcus coagulase negativa em 66,66 por cento, Staphylococcus aureus em 13,72 por cento, Corynebacterium sp em 5,86 por cento, Enterobacter aerogenes em 3,92 por cento, Streptococcus hemolítico do grupo viridans em 1,96 por cento, Serratia sp em 1,96 por cento, Alcaligenes xylosoxidans spp em 1,96 por cento, Corynebacterium xerosis em 1,96 por cento, e Proteus mirabilis em 1,96 por cento. Staphylococcus coagulase negativa (SCN) foi o microrganismo mais frequentemente isolado tanto antes quanto após o plug de silicone. A sensibilidade do SCN à Oxacilina antes da colocação do plug era de 87,50 por cento, e, após, de 73,68 por cento. CONCLUSÃO: A microbiota em olhos com disfunção do filme lacrimal é bastante semelhante à encontrada em olhos normais. A resistência de SCN à Oxacilina foi um pouco maior após o implante do plug de silicone.

PURPOSE: To evaluate conjunctival microbiota in eyes with tear film dysfunction and its modification after punctal occlusion with silicone plug. METHODS: Non comparative interventional case series study to evaluate 68 eyes of 41 patients with tear film dysfunction, from 2002 to 2007, followed in Federal University of Sao Paulo. Samples for culture were all obtained from conjunctival swabs and inoculated in Brain heart infusion broth (BHI broth). Twenty two patients that undergone punctal plug occlusion repeated culture procedure one month after plug insertion. RESULTS: 47 of the 68 eyes evaluated had positive culture in their samples. Nine different types of bacteria were identified: Coagulase negative Staphylococcus in 66,66 percent, Staphylococcus aureus, in 13,72 percent, Corynebacterium sp, in 5,86 percent, Enterobacter aerogenes, in 3,92 percent, Streptococcus hemolítico do grupo viridans, in 1,96 percent, Serratia sp, in 1,96 percent, Alcaligenes xylosoxidans spp, in 1,96 percent, Corynebacterium xerosis, in 1,96 percent, and Proteus mirabilis in 1,96 percent. Coagulase negative Staphylococcus (CNS) was the most frequently isolated microorganism before and after punctal occlusion. CNS sensibility to Oxacilin before plug insertion was 87,50 percent, and after, 73,68 percent. CONCLUSION: Microbiota found in eyes with tear film dysfunction seems to be similar to that found in normal eyes. CNS resistance to oxacilin was slightly higher after silicone plug insertion.

Efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity.

PURPOSE: To report the efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity (ROP). METHODS: We reviewed the clinical records of the neonates who had undergone green laser photocoagulation for threshold ROP at the Federal University of Pernambuco in Brazil between January 2004 and January 2006. All procedures were conducted with local anesthetic drops. The neonates were monitored throughout the procedure by a neonatologist. A frequency-doubled solid state laser, diode-pumped, with 532 nm wavelength was used. The presence of tunica vasculosa lentis or cataract were excluded before laser treatment. The following preoperative data were obtained for each patient: age, birth weight and the grade of ROP. Postoperative data included complications associated with the laser treatment, grade of ROP and evaluation whether further surgery was necessary due to failure of laser photocoagulation. RESULTS: Twenty-two neonates underwent photocoagulation with green laser for threshold ROP. A total of 31 eyes were included in the study. The mean gestational age was 30 +/- 3 weeks and the mean birth weight was 1120 +/- 490 g. Regression of the disease after laser therapy was observed in 30 eyes (96.7%). Despite treatment one eye presented stage 4A. Only 7 eyes required repetitive laser therapy. No adverse effects such as burning anterior segment tissues or bleeding in the anterior chamber occurred. No posterior segment side-effects were observed. Cataract formation was not observed at the last follow-up examination. CONCLUSIONS: Green laser photocoagulation remains an effective and safe alternative to red laser photocoagulation and to cryotherapy in the treatment of threshold ROP.

Efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity

PURPOSE: To report the efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity (ROP). METHODS: We reviewed the clinical records of the neonates who had undergone green laser photocoagulation for threshold ROP at the Federal University of Pernambuco in Brazil between January 2004 and January 2006. All procedures were conducted with local anesthetic drops. The neonates were monitored throughout the procedure by a neonatologist. A frequency-doubled solid state laser, diode-pumped, with 532 nm wavelength was used. The presence of tunica vasculosa lentis or cataract were excluded before laser treatment. The following preoperative data were obtained for each patient: age, birth weight and the grade of ROP. Postoperative data included complications associated with the laser treatment, grade of ROP and evaluation whether further surgery was necessary due to failure of laser photocoagulation. RESULTS: Twenty-two neonates underwent photocoagulation with green laser for threshold ROP. A total of 31 eyes were included in the study. The mean gestational age was 30 ± 3 weeks and the mean birth weight was 1120 ± 490 g. Regression of the disease after laser therapy was observed in 30 eyes (96.7 percent). Despite treatment one eye presented stage 4A. Only 7 eyes required repetitive laser therapy. No adverse effects such as burning anterior segment tissues or bleeding in the anterior chamber occurred. No posterior segment side-effects were observed. Cataract formation was not observed at the last follow-up examination. CONCLUSIONS: Green laser photocoagulation remains an effective and safe alternative to red laser photocoagulation and to cryotherapy in the treatment of threshold ROP.

OBJETIVOS: Avaliar a eficácia e segurança da fotocoagulação com laser verde na retinopatia da prematuridade (ROP) limiar. MÉTODOS: Foram revisados prontuários dos neonatos submetidos à fotocoagulação com laser verde para ROP limiar, na Universidade Federal de Pernambuco, entre janeiro 2004 e janeiro 2006. Tratamento foi realizado com anestesia tópica, sob monitorização de neonatologistas. Foi utilizado laser verde de estado sólido com diodo de freqüência dobrada de 532 nm. Presença de túnica vasculosa lentis ou catarata foi excluída antes do tratamento. Foram obtidos os seguintes dados pré-operatórios: idade, peso ao nascer e estágio da ROP. Dados pós-operatórios incluíram complicações associadas com o tratamento, estágio da ROP e avaliação da necessidade de cirurgia por falha do tratamento com fotocoagulação. RESULTADOS: Vinte e dois neonatos foram submetidos à fotocoagulação com laser verde para ROP limiar. Um total de 31 olhos foi incluído no estudo. A idade gestacional média foi de 30 ± 3 semanas e a média do peso ao nascer foi de 1120 ± 490 g. Regressão da doença após terapia com laser foi observada em 30 olhos (96,7 por cento). Apesar do tratamento um olho evoluiu para estágio 4A. Apenas 7 olhos precisaram de mais uma sessão de laser. Não houve efeitos adversos na câmara anterior como queimaduras ou sangramentos. Também não foram observados efeitos colaterais no segmento posterior. Formação de catarata não foi observada até o final do acompanhamento. CONCLUSÕES: A fotocoagulação com laser verde é uma alternativa efetiva e segura à fotocoagulação com laser vermelho e à crioterapia para o tratamento da ROP limiar.

Avaliação da acidose metabólica em pacientes graves: método de Stewart-Fencl-Figge versus a abordagem tradicional de henderson-hasselbalch / Assessment of metabolic acidosis in critically ill patients: method of Stewart-Fencl-Figge versus the traditional henderson-hasselbalch approach

JUSTIFICATIVA E OBJETIVOS: Rever estratégias de avaliação da acidose metabólica dando ênfase ao método de Stewart-Fencl-Figge versus a abordagem tradicional de Henderson-Hasselbalch. CONTEÚDO: A acidose metabólica é um distúrbio comum em pacientes criticamente enfermos, sendo importante causa de depressão da função miocárdica e sensível indicador de má perfusão tissular. Tradicionalmente, é avaliada através do método de Henderson-Hasselbalch no qual a gasometria arterial fornece informações sobre a existência e o tipo de distúrbio ácido-básico. Porém, nem sempre, esse método é capaz de explicar os seus mecanismos causais e, por isso, muitos estudos têm sido feitos na tentativa de melhorar sua interpretação. O método de Stewart-Fencl-Figge, calculado através de fórmula matemática, em que além da gasometria arterial, são utilizados níveis séricos de vários eletrólitos, lactato e albumina, nos fornece informações mais fidedignas permitindo detectar anormalidades metabólicas mistas e estimar a magnitude de cada componente, principalmente na presença de múltiplas disfunções orgânicas. Nesses pacientes, a presença de ânions não mensurados no plasma é importante mecanismo de acidose metabólica e sua detecção precoce é fundamental para se evitar efeitos deletérios sobre o organismo. CONCLUSÕES: A abordagem tradicional de Henderson-Hasselbalch falha em analisar os mecanismos da acidose metabólica e possui muitas variáveis que interferem no seu resultado, principalmente no paciente criticamente enfermo. O método de Stewart-Fencl-Figge proporciona abordagem mais completa para avaliação da acidose metabólica, sugerindo seus mecanismos e orientando a terapêutica. Como alternativa, o anion gap corrigido pela albumina e lactato parece ser tão eficiente em identificar a presença de anions não mensurados quanto o método de Stewart.

BACKGROUND AND OBJECTIVES: To review strategies of assessment of metabolic acidosis giving emphasis to the of Stewart-Fencl-Figge method versus the traditional method of Henderson-Hasselbalch. CONTENTS: Metabolic acidosis is a common issue in critically ill patients, an important cause of myocardial contractility depression and sensible marker of impaired tissue oxygenation. Traditionally, is evaluated by the Henderson-Hasselbalch approach in which an arterial blood sample provides information about the presence and type of acid base disturbance. However, this method is not always capable to explain the causes of the metabolic acidosis and, therefore, several studies have explored mechanisms to improve its interpretation. The Stewart-Fencl-Figge method calculated through a mathematical formula, where in addition to arterial blood gas levels, serum levels of electrolytes, lactate and albumin are used, supplies trustworthy information allowing detection of mixed metabolic abnormalities and quantification of the magnitude of each component, mainly in patients with multiple organic dysfunctions. In these individuals, the presence of unmeasured anions in the plasma is an important mechanism of metabolic acidosis and its early detection fundamental to avoid deleterious effect on the organism. CONCLUSIONS: The traditional Henderson-Hasselbalch approach fails in analyzing the underlying mechanisms of metabolic acidosis and possesses many variables that intervene with its result especially in the critically ill patient. The Stewart-Fencl-Figge method offers a broader analysis of metabolic acidosis, indicating its mechanisms and guiding a better therapeutically strategy. As an alternative, the albumin-corrected and lactate-corrected anion gap seems to be as useful as the Stewart approach in identifying the unmeasured anions.

[Assessment of metabolic acidosis in critically ill patients: method of Stewart-Fencl-Figge versus the traditional henderson-hasselbalch approach]. / Avaliação da acidose metabólica em pacientes graves: método de Stewart-Fencl-Figge versus a abordagem tradicional de henderson-hasselbalch.

BACKGROUND AND OBJECTIVES: To review strategies of assessment of metabolic acidosis giving emphasis to the of Stewart-Fencl-Figge method versus the traditional method of Henderson-Hasselbalch. CONTENTS: Metabolic acidosis is a common issue in critically ill patients, an important cause of myocardial contractility depression and sensible marker of impaired tissue oxygenation. Traditionally, is evaluated by the Henderson-Hasselbalch approach in which an arterial blood sample provides information about the presence and type of acid base disturbance. However, this method is not always capable to explain the causes of the metabolic acidosis and, therefore, several studies have explored mechanisms to improve its interpretation. The Stewart-Fencl-Figge method calculated through a mathematical formula, where in addition to arterial blood gas levels, serum levels of electrolytes, lactate and albumin are used, supplies trustworthy information allowing detection of mixed metabolic abnormalities and quantification of the magnitude of each component, mainly in patients with multiple organic dysfunctions. In these individuals, the presence of unmeasured anions in the plasma is an important mechanism of metabolic acidosis and its early detection fundamental to avoid deleterious effect on the organism. CONCLUSIONS: The traditional Henderson-Hasselbalch approach fails in analyzing the underlying mechanisms of metabolic acidosis and possesses many variables that intervene with its result especially in the critically ill patient. The Stewart-Fencl-Figge method offers a broader analysis of metabolic acidosis, indicating its mechanisms and guiding a better therapeutically strategy. As an alternative, the albumin-corrected and lactate-corrected anion gap seems to be as useful as the Stewart approach in identifying the unmeasured anions.