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BACKGROUND: To investigate the accuracy of preoperative biometry in eyes undergoing combined phacovitrectomy and to compare it with eyes having cataract surgery at a later point in time following vitrectomy. METHODS: Patients with epiretinal membrane or macular hole who underwent combined phacovitrectomy (group 1) or phacoemulsification following pars plana vitrectomy (PPV) (group 2) were included in this retrospective, comparative, interventional case series. The primary outcome measures were the intraocular lens power prediction error (PE) and the percentage of eyes with PE > ± 0.5D in the two groups. Secondary outcome measures included the correlation between epidemiological, clinical, or surgical factors and dioptric shift. In addition, the influence of optical coherence tomography characteristics to the PE was investigated. RESULTS: Group 1 and 2 consisted of 55 and 54 eyes, respectively, for a total of 109 eyes included in the study. The mean absolute PE was 0.59 D (range + 1.4 to - 2.5D) in group 1 and 0.35 (range + 1.0 to - 1.45D) in group 2 (p = 0.01). PE greater than 0.5D was observed in 47% of eyes in group 1 as opposed to 16.6% of eyes in group 2 (p = 0.027). The PE was associated with shallower anterior chamber depth (ACD), increased central macular thickness (> 300 µ), and worse baseline best-corrected visual acuity. Photoreceptor ellipsoid zone or external limiting membrane disruption was not associated with significantly greater postoperative refractive deviations. CONCLUSION: Combined phacovitrectomy may result in greater postoperative refractive prediction error compared to phacoemulsification alone following vitrectomy. Patients with worse vision, greater central macular thickness, and shallow anterior chambers require more caution since they are prone to inaccurate preoperative biometry.
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Membrana Epirretiniana/cirurgia , Facoemulsificação , Refração Ocular/fisiologia , Perfurações Retinianas/cirurgia , Acuidade Visual/fisiologia , Vitrectomia , Idoso , Biometria , Catarata/patologia , Membrana Epirretiniana/fisiopatologia , Feminino , Humanos , Pressão Intraocular , Implante de Lente Intraocular , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Pseudofacia/fisiopatologia , Reprodutibilidade dos Testes , Perfurações Retinianas/fisiopatologia , Estudos Retrospectivos , Microscopia com Lâmpada de Fenda , Tomografia de Coerência ÓpticaRESUMO
Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic 'microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.
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AIM: The hypothesis was tested that evoked pressure curves (EPCs) after transcranial magnetic stimulation (TMS) would provide additional neuropathophysiological information on the descending pathways to the external anal sphincter (EAS) in patients with faecal incontinence (FI). METHOD: Twenty-five healthy subjects and 69 patients with FI were investigated. TMS was applied to the vertex, and EPCs were recorded with a probe placed through the EAS. TMS was performed with the EAS at rest and during contraction (facilitated responses). At least three responses were recorded for each modality. Clinical data and anorectal manometric, electrophysiological perineal and transanal ultrasound recordings were compared with respect to the EPC results. RESULTS: There was no statistically significant difference between the EPCs of healthy subjects and FI patients. Twenty-three per cent of the FI patients had abnormal EPC latencies, with significantly lower voluntary contraction amplitudes (P = 0.03) and significantly higher rectal sensation (P = 0.04) than the other group. We found no significant difference between FI patients with and without abnormal EPC latencies in terms of clinical characteristics and electrophysiological and endoanal ultrasound parameters. There was no difference in the identified causes of the FI between the two groups. CONCLUSION: As abnormal EPC latencies were found in 23% of FI patients with no known central neurological disease, abnormal EPC latencies might reveal undetected lesions of descending pathways in patients with FI.
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Canal Anal/fisiopatologia , Potencial Evocado Motor/fisiologia , Incontinência Fecal/fisiopatologia , Contração Muscular/fisiologia , Músculo Estriado/fisiopatologia , Pressão , Estimulação Magnética Transcraniana/métodos , Adulto , Idoso , Canal Anal/fisiologia , Estudos de Casos e Controles , Eletromiografia , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Manometria , Pessoa de Meia-Idade , Músculo Estriado/fisiologia , Adulto JovemRESUMO
Dysphagia is one of the most important complications encountered in amyotrophic lateral sclerosis (ALS). Our aim was to determine whether oropharyngeal dysphagia impacted the quality of life (QoL) of patients with ALS. Thirty consecutive patients were recruited (31-82 years, 18 men). Swallowing function was evaluated using a standardised videofluoroscopic barium swallow. All the patients completed a specific questionnaire on quality of life in dysphagia (SWAL-QoL) immediately after the videofluoroscopy. The results of dysphagia outcome severity scale separated 14 patients with oropharyngeal dysphagia and 16 with normal swallowing function. There was no difference in the average age, weight and body mass index of the two groups (dysphagic patients: 68 ± 11 kg versus non-dysphagic patients: 69 ± 14 kg). Most of the dysphagic patients had a bulbar affection based on their Norris scores which determine the importance of cranial nerves illness (20 ± 8), significantly lower than those of the non-dysphagic patients (35 ± 5) (P < 0·0001). There was no difference in the neurological peripheral symptoms evaluated by Amyotrophic Lateral Sclerosis Functional Rating Scale scores (dysphagic patients: 26 ± 7 versus non-dysphagic patients: 27 ± 8) (ns). The swallowing quality of life questionnaire revealed that the dysphagic patients had significant burden (P < 0·001). They were affected by the necessity to applied a food selection (P < 0·01), by the increase in eating duration (P < 0·05) and described a decrease in eating desire (P < 0·05). They complained of fear regarding the risk of dysphagia (P < 0·05). They also described difficulties with oral communication (P < 0·001). All of those complained about dysphagia which impacted directly mental health (P < 0·05) and social life (P < 0·05). In conclusion, oropharyngeal dysphagia is a common symptom accompanying ALS, which alters the patient's QoL, especially social health.
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Esclerose Lateral Amiotrófica/psicologia , Transtornos de Deglutição/psicologia , Qualidade de Vida , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Lateral Amiotrófica/complicações , Esclerose Lateral Amiotrófica/fisiopatologia , Transtornos de Deglutição/etiologia , Transtornos de Deglutição/fisiopatologia , Feminino , Fluoroscopia/métodos , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
PURPOSE: To determine the long-term functional and anatomical outcome of idiopathic uveitic cystoid macular edema (UCME). METHODS: A longitudinal retrospective study was undertaken of the medical records of patients with UCME. All individuals were examined in the uveitis Service at the Moorfields Eye Hospital. The main outcome measures were change in visual acuity and anatomical outcome of UCME at diverse time points. RESULTS: A total of 109 eyes (92 patients) with UCME were included in the analysis. Mean follow-up was 60 ± 45 months (median, 48 months). Mean logarithm of the minimum angle of resolution visual acuity 1 month after the intervention improved significantly (P < 0.001) by 0.21 ± 0.27 and maintained at similar levels throughout the follow-up period. Visual acuity at the final follow-up improved in 75 eyes (69%), was deteriorated in 21 eyes (19%), and remained unchanged in 13 eyes (12%). Younger age and better visual acuity at baseline were associated with more favorable visual outcome (P < 0.001). Optical coherence tomography documentation of improvement or total resolution of UCME was observed in 84 eyes (77%) at the final follow-up. CONCLUSION: Cystoid macular edema is a major complication in uveitis. Current management provides satisfactory long-term results for the majority of those individuals. Visual acuity 1 month after the intervention is usually indicative of the final functional outcome.
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Edema Macular/fisiopatologia , Uveíte Anterior/fisiopatologia , Uveíte Intermediária/fisiopatologia , Uveíte Posterior/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Angiofluoresceinografia , Seguimentos , Glucocorticoides/uso terapêutico , Humanos , Edema Macular/diagnóstico , Edema Macular/tratamento farmacológico , Masculino , Metilprednisolona/análogos & derivados , Metilprednisolona/uso terapêutico , Acetato de Metilprednisolona , Pessoa de Meia-Idade , Prednisolona/uso terapêutico , Estudos Retrospectivos , Tomografia de Coerência Óptica , Triancinolona Acetonida/uso terapêutico , Uveíte Anterior/diagnóstico , Uveíte Anterior/tratamento farmacológico , Uveíte Intermediária/diagnóstico , Uveíte Intermediária/tratamento farmacológico , Uveíte Posterior/diagnóstico , Uveíte Posterior/tratamento farmacológico , Acuidade Visual/fisiologia , Adulto JovemRESUMO
Background: Lung cancer is the leading cause of cancer-related death globally and in South Africa. Historically, the majority of patients diagnosed with lung cancer are incurable at presentation. Objectives: To assess the tumour, nodes, metastasis (TNM) staging of lung cancer in a centre with access to both positron emission tomography-computed tomography (PET-CT) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) using a structured diagnostic approach and to compare results with a historical cohort from 2009 from the same hospital. Methods: A retrospective descriptive observational study was performed using the registry of a high-volume tertiary hospital's weekly multidisciplinary thoracic oncology meeting (MDT). A structured diagnostic approach was used for staging purposes. All patients with a tissue diagnosis of primary lung cancer and adequate imaging (chest CT and/or PET-CT) who presented at the MDT during the period from 1 January - 31 December 2019 were included. Final staging and tissue diagnoses were documented and compared with a historical cohort from 2009 from the same institution. Results: Adenocarcinoma was the most common subtype (38.8%; n=116). Less than a tenth of patients (6.3%; n=16/254) with non-small cell lung cancer had potentially curable lung cancer (stage IA to IIIA) at presentation, significantly less than the 2009 cohort (14.5%; n=25/173; p=0.007). The most common procedure administered on patients was transthoracic needle aspiration (37.54%; n=112), followed by conventional bronchoscopic needle aspiration or biopsy (20.4%; n=61), and EBUS-TBNA (17.1%; n=51/299). After PET-CT, 19/30 cases were upstaged including 9/18 from potentially resectable to unresectable. Two of these cases were down-staged to potentially resectable following EBUS-TBNA. Conclusion: There was a significant decline in resectable and potentially curable lung cancer at presentation over a 10-year period. PET-CT and EBUS-TBNA improved the accuracy of non-small cell lung cancer staging among patients with resectable and potentially curable lung cancer but have exposed a higher stage profile.
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Strong electric discharges associated with thunderstorms can produce terrestrial gamma-ray flashes (TGFs), i.e., intense bursts of x rays and γ rays lasting a few milliseconds or less. We present in this Letter new TGF timing and spectral data based on the observations of the Italian Space Agency AGILE satellite. We determine that the TGF emission above 10 MeV has a significant power-law spectral component reaching energies up to 100 MeV. These results challenge TGF theoretical models based on runaway electron acceleration. The TGF discharge electric field accelerates particles over the large distances for which maximal voltages of hundreds of megavolts can be established. The combination of huge potentials and large electric fields in TGFs can efficiently accelerate particles in large numbers, and we reconsider here the photon spectrum and the neutron production by photonuclear reactions in the atmosphere.
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PURPOSE: To investigate the correlation between outer and inner retina optical coherence tomography (OCT) biomarkers and visual acuity in patients with idiopathic epiretinal membrane (iERM) and identify which of them may be predictive of visual function. METHODS: A retrospective cross-sectional single-center study was conducted that included patients diagnosed with iERM. Spectral domain OCT images were obtained and assessed qualitatively and quantitatively. The association of OCT parameters with best corrected visual acuity was analyzed. RESULTS: Charts of 97 eyes of 97 patients were reviewed. Central foveal thickness, maximal retinal thickness (MRT), photoreceptor outer segment length, outer foveal thickness, ganglion cell-inner plexiform layer complex thickening, inner retinal thickness and inner retinal layer irregularity index were among the major outcome measures. OCT scans were also assessed for the presence of cotton ball sign, ellipsoid zone disruption, ectopic inner foveal layer, disorganization of retinal inner layers (DRIL), intraretinal fluid, subretinal fluid (SRF) and epimacular membrane rip. Univariate analysis showed statistically significant association between all the aforementioned parameters with worse vision, except for cotton ball sign and SRF. Multivariate analysis found that MRT and severe DRIL were strongly correlated with worse vision (p < 0.001). CONCLUSION: MRT and severe DRIL should be considered as negative prognostic factors for visual acuity.
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Membrana Epirretiniana , Tomografia de Coerência Óptica , Biomarcadores , Estudos Transversais , Membrana Epirretiniana/diagnóstico por imagem , Humanos , Retina , Estudos Retrospectivos , Acuidade VisualRESUMO
One of the restrictive measures of COVID-19 (coronavirus disease 2019) pandemic control is the prohibition of accompanied clinic visits. The specific features of ophthalmological patients imply different degrees of dependency that directly affect their response to such measures. This study aims to assess the effects of unaccompanied medical appointments on outpatients' stress levels and their retention of medical advice. A questionnaire-based survey was conducted at a large ophthalmic clinic in northern Greece during September 2020. Suitable subjects were asked to self-administer a 7-item questionnaire addressing their subjective perception of stress and their ability to fully understand and remember their doctor's instructions, given the fact that they would be alone during the consultation. The analysis was based on 200 patients who completed the survey. Sixty-three patients (31.5%) reported that unaccompanied clinic visits increased their stress, with a median value of 7.5 (mean 6.77 ± .2.7) on a scale from 1 to 10. A large number of the patients (30%) claimed it was difficult to remember the doctor's comments or instructions, and 24.6% indicated that they would not fully understand them if they were to attend the clinic unaccompanied. A marked impact on women and on the elderly (up to threefold) over 70 years of age was identified. This is the first study specifically addressing practical repercussions of unaccompanied clinic visits during the COVID-19 pandemic. A negative effect on patients' emotional status and on counseling effectiveness was demonstrated. Female gender and advanced age were found to be determinants of the highest vulnerability.
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Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of â¼5-10° at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the subsatellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space.
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PURPOSE: To assess the value of ultrasound (US) imaging of the dorsal radiocarpal and intercarpal ligaments of the wrist, after characterization of their imaging features on cadaveric specimen. MATERIALS AND METHODS: Two wrist dissections of fresh cadaver were performed. The orientations and the osseous insertions of the ligaments were clarified, allowing development of an US examination protocol. Then, forty wrists of asymptomatic volunteers were analyzed prospectively with US. The visibility and thickness of both ligaments were estimated at their midpoint and at their osseous insertions. RESULTS: The dorsal radiocarpal and intercarpal ligaments were visualized as thin, hyperechoic and fibrillar structures, extending between their respective osseous insertions. The mid portions of the ligaments were visible at all volunteers. The osseous insertions were completely or partially visible in 90% of cases, except for the radial insertion of the dorsal radiocarpal ligament, visible in 77.5% of cases. CONCLUSION: US, based on good anatomical knowledge and a standardized protocol, which we describe in this work, enables evaluation of the dorsal radiocarpal and intercarpal ligaments of the wrist.
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Ligamentos Articulares/diagnóstico por imagem , Punho/diagnóstico por imagem , Adulto , Idoso de 80 Anos ou mais , Cadáver , Ossos do Carpo/diagnóstico por imagem , Feminino , Humanos , Ligamentos Articulares/anatomia & histologia , Masculino , Estudos Prospectivos , Rádio (Anatomia)/diagnóstico por imagem , Estatísticas não Paramétricas , Ultrassonografia , Punho/anatomia & histologiaRESUMO
Macular edema (ME) represents the most common cause for visual loss among uveitis patients. The management of uveitic macular edema (UME) may be challenging, due to its often recalcitrant nature. Corticosteroids remain the mainstay of treatment, through their capability of effectively controlling inflammation and the associated ME. Topical steroids may be effective in milder cases of UME, particularly in edema associated with anterior uveitis. Posterior sub-Tenon and orbital floor steroids, as well as intravitreal steroids often induce rapid regression of UME, although this may be followed by recurrence of the pathology. Intra-vitreal corticosteroid implants provide sustained release of steroids facilitating regression of ME with less frequent injections. Topical nonsteroidal anti-inflammatory drugs may provide a safe alternative or adjuvant therapy to topical steroids in mild UME, predominantly in cases with underlying anterior uveitis. Immunomodulators including methotrexate, mycophenolate mofetil, tacrolimus, azathioprine, and cyclosporine, as well as biologic agents, notably the anti-tumor necrosis factor-α monoclonal antibodies adalimumab and infliximab, may accomplish the control of inflammation and associated ME in refractory cases, or enable the tapering of steroids. Newer biotherapies have demonstrated promising outcomes and may be considered in persisting cases of UME.
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Corticosteroides/uso terapêutico , Imunossupressores/uso terapêutico , Edema Macular/tratamento farmacológico , Uveíte/tratamento farmacológico , Humanos , Inflamação/tratamento farmacológicoRESUMO
INTRODUCTION: The purpose of this report is to describe a case of Valsalva retinopathy in an intranasal cocaine user. CASE REPORT: A 49-year-old male presented with a history of sudden loss of vision and inferior visual field defect in his left eye. Clinical evaluation of the affected eye showed best corrected visual acuity of 20/25 and fundus examination revealed a preretinal hemorrhage superior to the disk with multiple intraretinal hemorrhages in and around the posterior pole. On further questioning, the patient revealed intranasal cocaine use the day before the onset of his visual symptoms. Blood tests were requested to exclude blood dyscrasias or predisposition to vascular occlusive disorders and no further treatment measures were taken. The patient was reviewed a month later when his hemorrhages had completely resolved and his visual acuity had improved to 20/20. His blood results were within normal limits. CONCLUSION: Although never been reported before, Valsalva retinopathy can be associated with intranasal cocaine abuse and should be considered in the differential diagnosis of visual reduction in such population.
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Transtornos Relacionados ao Uso de Cocaína/complicações , Hemorragia Retiniana/etiologia , Manobra de Valsalva , Administração Intranasal , Diagnóstico Diferencial , Angiofluoresceinografia , Fundo de Olho , Humanos , Masculino , Pessoa de Meia-Idade , Hemorragia Retiniana/diagnóstico , Tomografia de Coerência Óptica , Transtornos da Visão/diagnóstico , Acuidade VisualRESUMO
Emerging anti-vascular endothelial growth factor (anti-VEGF) therapies for neovascular age-related macular degeneration (nAMD) have revolutionised medical retina practice and the management and eventual outcome of nAMD. Recent research has focused on evaluating and comparing the efficacy of the two most widely employed anti-VEGF agents, bevacizumab and ranibizumab; however, a subgroup of patients with nAMD demonstrates a suboptimal response to standard therapy. We have therefore conducted a review of pertinent studies published until August 2018 which have documented the clinical efficacy when switching to a different anti-VEGF. Evidence on baseline disease characteristics, injection frequency and disease outcome has been obtained for patients treated with ranibizumab 0.5 mg and/or bevacizumab 1.25 mg and were switched to aflibercept 2 mg. Our review identified 45 studies investigating switching to aflibercept. Our review showed a clear anatomical benefit after the switch in terms of central retinal thickness and pigment epithelium detachment characteristics, whereas the functional outcomes were variable. Remarkable heterogeneity was documented among the relevant studies with regard to several factors including the baseline characteristics of the cohorts, the non-response definition and previous treatment protocols. Larger prospective trials with appropriate control arms are therefore required to elucidate the potential benefit when switching between anti-VEGF agents in refractory nAMD.
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Bevacizumab/farmacologia , Substituição de Medicamentos , Degeneração Macular/tratamento farmacológico , Ranibizumab/farmacologia , Proteínas Recombinantes de Fusão/farmacologia , Idoso , Inibidores da Angiogênese/farmacologia , Substituição de Medicamentos/efeitos adversos , Substituição de Medicamentos/métodos , Humanos , Receptores de Fatores de Crescimento do Endotélio Vascular , Resultado do TratamentoRESUMO
Advances in the technology and processing of flexible optical materials have paved the way toward the integration of semiconductor emitters and polymers into functional light emitting fabrics. Lead halide perovskite nanocrystals appear as highly suitable optical sensitizers for such polymer fiber emitters due to their ease of fabrication, versatile solution-processing and highly efficient, tunable, and narrow emission across the visible spectrum. A beneficial byproduct of the nanocrystal incorporation into the polymer matrix is that it provides a facile and low-cost method to chemically and structurally stabilize the perovskite nanocrystals under ambient conditions. Herein, we demonstrate two types of robust fiber composites based on electrospun hydrophobic poly(methyl methacrylate) (PMMA) or hydrophilic polyvinylpyrrolidone (PVP) fibrous membranes sensitized by green-emitting all-inorganic CsPbBr3 or hybrid organic-inorganic FAPbBr3 nanocrystals. We perform a systematic investigation on the influence of the nanocrystal-polymer relative content on the structural and optical properties of the fiber nanocomposites and we find that within a wide content range, the nanocrystals retain their narrow and high quantum yield emission upon incorporation into the polymer fibers. Quenching of the radiative recombination at the higher/lower bound of the nanocrystal:polymer mass ratio probed is discussed in terms of nanocrystal clustering/ligand desorption due to dilution effects, respectively. The nanocomposite's optical stability over an extended exposure in air and upon immersion in water is also discussed. The studies confirm the demonstration of robust and bright polymer-fiber emitters with promising applications in backlighting for LCD displays and textile-based light emitting devices.
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Coriorretinite/virologia , Infecções Oculares Virais/fisiopatologia , Transtornos da Visão/virologia , Acuidade Visual/fisiologia , Campos Visuais/fisiologia , Adolescente , Coriorretinite/fisiopatologia , Diagnóstico Diferencial , Infecções Oculares Virais/tratamento farmacológico , Humanos , Masculino , Transtornos da Visão/tratamento farmacológico , Transtornos da Visão/fisiopatologia , Acuidade Visual/efeitos dos fármacos , Campos Visuais/efeitos dos fármacosRESUMO
Minimally invasive surgery is rapidly becoming the norm in medicine, as it often leads to better outcomes and earlier rehabilitation. This article reviews the principles and different techniques employed to perform minimally invasive strabismus surgery (MISS). In these techniques, strabismus surgery is performed through keyhole openings, thus reducing the risk of postoperative corneal complications, minimizing postoperative discomfort, and better preserving muscle function. MISS can be used to perform all types of strabismus surgery, namely rectus muscle recessions, resections, plications, reoperations, retroequatorial myopexy, transpositions, oblique muscle recessions, or plications even in the presence of limited motility. Of note, ocular alignment outcomes with MISS versus more traditional techniques have not been compared in randomized trials. Consequently, more controlled evidence is still needed to better delineate the future role and value of MISS in clinical management.
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Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Procedimentos Cirúrgicos Oftalmológicos/métodos , Estrabismo/cirurgia , Humanos , Músculos OculomotoresRESUMO
Mitochondria and synaptosomes from adult rat forebrain can easily be separated by counter-current distribution in an aqueous two phase system composed of Dextran T500 and poly(ethylene glycol) 4000. Both particles may also be separated by a batch procedure in which the same phase system is used. Electron micrographs and enzymatic activities show a high purity of the mitochondria obtained from the dextran-rich lower phase. Electron micrographs and enzymatic activities also show that intact synaptosomes can be obtained from the poly(ethylene glycol)-rich upper phase. The mitochondria purified by this method show good ADP/O ratios, respiratory control ratios, and state 3 rates. Synaptosomes showed a state 2-state 3 transition with no recuperation to state 4.
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Encéfalo/ultraestrutura , Mitocôndrias/ultraestrutura , Acetilcolinesterase/análise , Animais , Encéfalo/metabolismo , Fracionamento Celular/métodos , Distribuição Contracorrente , L-Lactato Desidrogenase/análise , Masculino , Microscopia Eletrônica , Consumo de Oxigênio , Ratos , Sinaptossomos/ultraestruturaRESUMO
The possible formation of a multienzyme complex between sucrose (Suc)-phosphate synthase (SPS) and Suc-phosphate phosphatase (SPP) was examined by measuring the rates of Suc-6-phosphate (Suc-6-P) synthesis and hydrolysis in mixing experiments with partially purified enzymes from spinach (Spinacia oleracea) and rice (Oryza sativa) leaves. The addition of SPP to SPS stimulated the rate of Suc-6-P synthesis. SPS inhibited the hydrolysis of exogenous Suc-6-P by SPP when added in the absence of its substrate (i.e. UDP-glucose) but stimulated SPP activity when the SPS substrates were present and used to generate Suc-6-P directly in the reaction. Results from isotope-dilution experiments suggest that Suc-6-P was channeled between SPS and SPP. A portion of the SPS activity comigrated with SPP during native polyacrylamide gel electrophoresis, providing physical evidence for an enzyme-enzyme interaction. Taken together, these results strongly suggest that SPS and SPP associate to form a multienzyme complex.
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INTRODUCTION: The present study aimed to identify preoperative factors that predispose the development of subretinal fluid (SRF) following successful macular hole (MH) surgery. METHODS: Thirty-four eyes of 33 consecutive patients that underwent pars plana vitrectomy for idiopathic full-thickness MH surgery were included in this retrospective study. Best corrected visual acuity (BCVA), and spectral domain-optical coherence tomography (OCT) images were evaluated pre- and postoperatively in all cases. Patient's demographic characteristics, stage of MH, measurements of base diameter and minimum aperture diameter of the MH, preoperative foveal vitreomacular traction and selected intra-operative parameters were correlated with the development of postoperative SRF. RESULTS: Postoperative SRF was observed in 15 cases (48%). Total absorption of SRF was observed in 73% of affected eyes and was most commonly seen between the third and the fifth postoperative month. One patient developed lamellar hole leading to full-thickness MH. Postoperative BCVA was similar between the eyes that did and the eyes that did not develop postoperative SRF (0.31 ± 0.2 vs 0.35 ± 0.2; p ≥ 0.05). Development of postoperative SRF was significantly associated with the presence of preoperative foveal vitreomacular traction (p = 0.048), stage II MH (p = 0.017) and smaller size of the closest distance between the MH edges (p = 0.046). CONCLUSIONS: Postoperative SRF is a common occurrence following successful MH surgery. Meticulous evaluation of preoperative clinical and OCT findings may disclose risk factors associated with this condition. Based on our observations, idiopathic holes of early stage appear to be at a higher risk of developing postoperative SRF. This could be a point of interest with the advancing use of enzymatic proteolysis.