RESUMO
Oscillatory gene expression is fundamental to development, but technologies for monitoring expression oscillations are limited. We have developed a statistical approach called Oscope to identify and characterize the transcriptional dynamics of oscillating genes in single-cell RNA-seq data from an unsynchronized cell population. Applying Oscope to a number of data sets, we demonstrated its utility and also identified a potential artifact in the Fluidigm C1 platform.
Assuntos
Interpretação Estatística de Dados , Modelos Genéticos , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Algoritmos , Análise de Variância , Células-Tronco Embrionárias/fisiologia , Perfilação da Expressão Gênica/métodos , Perfilação da Expressão Gênica/estatística & dados numéricos , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Análise de Sequência de RNA/estatística & dados numéricos , Análise de Célula Única/estatística & dados numéricos , SoftwareRESUMO
OBJECTIVES: To evaluate the biological effect of a paclitaxel-coated balloon (PCB) technology on vascular drug distribution and healing in drug eluting stent restenosis (DES-ISR) swine model. BACKGROUND: The mechanism of action and healing response via PCB technology in DES-ISR is not completely understood. METHODS: A total of 27 bare metal stents were implanted in coronary arteries and 30 days later the in-stent restenosis was treated with PCB. Treated segments were harvested at 1 hr, 14 days and 30 days post treatment for the pharmacokinetic analysis. In addition, 24 DES were implanted in coronary arteries for 30 days, then all DES-ISRs were treated with either PCB (n = 12) or uncoated balloon (n = 12). At day 60, vessels were harvested for histology following angiography and optical coherence tomography (OCT). RESULTS: The paclitaxel level in neointimal tissue was about 18 times higher (P = 0.0004) at 1 hr Cmax , and retained about five times higher (P = 0.008) at day 60 than that in vessel wall. A homogenous distribution of paclitaxel in ISR was demonstrated by using fluorescently labeled paclitaxel. Notably, in DES-ISR, both termination OCT and quantitative coronary angioplasty showed a significant neointimal reduction and less late lumen loss (P = 0.05 and P = 0.03, respectively) post PCB versus post uncoated balloon. The PES-ISR + PCB group displayed higher levels of peri-strut inflammation and fibrin scores compared to the -limus DES-ISR + PCB group. CONCLUSIONS: In ISR, paclitaxel is primarily deposited in neointimal tissue and effectively retained over time following PCB use. Despite the presence of metallic struts, a uniform distribution was characterized. PCB demonstrated an equivalent biological effect in DES-ISR without significantly increasing inflammation. © 2015 Wiley Periodicals, Inc.
Assuntos
Cateterismo Cardíaco/instrumentação , Cateteres Cardíacos , Fármacos Cardiovasculares/administração & dosagem , Materiais Revestidos Biocompatíveis , Reestenose Coronária/terapia , Vasos Coronários/efeitos dos fármacos , Paclitaxel/administração & dosagem , Intervenção Coronária Percutânea/instrumentação , Stents , Cicatrização/efeitos dos fármacos , Animais , Fármacos Cardiovasculares/farmacocinética , Angiografia Coronária , Reestenose Coronária/diagnóstico por imagem , Reestenose Coronária/etiologia , Reestenose Coronária/metabolismo , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/metabolismo , Modelos Animais de Doenças , Equipamentos e Provisões , Fibrina/metabolismo , Metais , Neointima , Paclitaxel/farmacocinética , Intervenção Coronária Percutânea/efeitos adversos , Suínos , Distribuição Tecidual , Tomografia de Coerência ÓpticaRESUMO
The salamander has the remarkable ability to regenerate its limb after amputation. Cells at the site of amputation form a blastema and then proliferate and differentiate to regrow the limb. To better understand this process, we performed deep RNA sequencing of the blastema over a time course in the axolotl, a species whose genome has not been sequenced. Using a novel comparative approach to analyzing RNA-seq data, we characterized the transcriptional dynamics of the regenerating axolotl limb with respect to the human gene set. This approach involved de novo assembly of axolotl transcripts, RNA-seq transcript quantification without a reference genome, and transformation of abundances from axolotl contigs to human genes. We found a prominent burst in oncogene expression during the first day and blastemal/limb bud genes peaking at 7 to 14 days. In addition, we found that limb patterning genes, SALL genes, and genes involved in angiogenesis, wound healing, defense/immunity, and bone development are enriched during blastema formation and development. Finally, we identified a category of genes with no prior literature support for limb regeneration that are candidates for further evaluation based on their expression pattern during the regenerative process.
Assuntos
Ambystoma mexicanum/fisiologia , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Oncogenes , Análise de Sequência de RNA/métodos , Ambystoma mexicanum/genética , Amputação Cirúrgica , Animais , Análise por Conglomerados , Extremidades/lesões , Extremidades/fisiologia , Regeneração/genética , Regeneração/fisiologia , Regulação para Cima , Cicatrização/genética , Cicatrização/fisiologiaRESUMO
BACKGROUND: Implementation science researchers often cite clinical champions as critical to overcoming organizational resistance and other barriers to the implementation of evidence-based health services, yet relatively little is known about who champions are or how they effect change. To inform future efforts to identify and engage champions to support HPV vaccination, we sought to describe the key characteristics and strategies of vaccine champions working in adolescent primary care. METHODS: In 2022, we conducted a national survey with a web-based panel of 2527 primary care professionals (PCPs) with a role in adolescent HPV vaccination (57% response rate). Our sample consisted of pediatricians (26%), family medicine physicians (22%), advanced practice providers (24%), and nursing staff (28%). Our survey assessed PCPs' experience with vaccine champions, defined as health care professionals "known for helping their colleagues improve vaccination rates." RESULTS: Overall, 85% of PCPs reported currently working with one or more vaccine champions. Among these 2144 PCPs, most identified the champion with whom they worked most closely as being a physician (40%) or nurse (40%). Almost all identified champions worked to improve vaccination rates for vaccines in general (45%) or HPV vaccine specifically (49%). PCPs commonly reported that champion implementation strategies included sharing information (79%), encouragement (62%), and vaccination data (59%) with colleagues, but less than half reported that champions led quality improvement projects (39%). Most PCPs perceived their closest champion as being moderately to extremely effective at improving vaccination rates (91%). PCPs who did versus did not work with champions more often recommended HPV vaccination at the earliest opportunity of ages 9-10 rather than later ages (44% vs. 33%, p < 0.001). CONCLUSIONS: Findings of our national study suggest that vaccine champions are common in adolescent primary care, but only a minority lead quality improvement projects. Interventionists seeking to identify champions to improve HPV vaccination rates can expect to find them among both physicians and nurses, but should be prepared to offer support to more fully engage them in implementing interventions.
RESUMO
Background: Advances in therapeutic drugs have increased life-expectancies for HIV-infected individuals, but the need for an effective vaccine remains. We assessed safety and immunogenicity of HIV-1 vaccine, Trimer 4571 (BG505 DS-SOSIP.664) adjuvanted with aluminum hydroxide (alum), in HIV-negative adults. Methods: We conducted a phase I, randomized, open-label, dose-escalation trial at the National Institutes of Health Clinical Center in Bethesda, MD, USA. Eligible participants were HIV-negative, healthy adults between 18-50 years. Participants were randomized 1:1 to receive Trimer 4571 adjuvanted with 500 mcg alum by either the subcutaneous (SC) or intramuscular (IM) route at weeks 0, 8, and 20 in escalating doses of 100 mcg or 500 mcg. The primary objectives were to evaluate the safety and tolerability of Trimer 4571 with a secondary objective of evaluating vaccine-induced antibody responses. The primary and safety endpoints were evaluated in all participants who received at least one dose of Trimer 4571. Trial results were summarized using descriptive statistics. This trial is registered at ClinicalTrials.gov, NCT03783130. Findings: Between March 7 and September 11, 2019, 16 HIV-negative participants were enrolled, including six (38%) males and ten (62%) females. All participants received three doses of Trimer 4571. Solicited reactogenicity was mild to moderate in severity, with one isolated instance of severe injection site redness (6%) following a third 500 mcg SC administration. The most commonly reported solicited symptoms included mild injection site tenderness in 14 (88%) and mild myalgia in six (38%) participants. The most frequent unsolicited adverse event attributed to vaccination was mild injection site pruritus in six (38%) participants. Vaccine-induced seropositivity occurred in seven (44%) participants and resolved in all but one (6%). No serious adverse events occurred. Trimer 4571-specific binding antibodies were detected in all groups two weeks after regimen completion, primarily focused on the glycan-free trimer base. Neutralizing antibody activity was limited to the 500 mcg dose groups. Interpretation: Trimer 4571 was safe, well tolerated, and immunogenic in this first-in-human trial. While this phase 1 trial is limited in size, our results inform and support further evaluation of prefusion-stabilized HIV-1 envelope trimers as a component of vaccine design strategies to generate broadly neutralizing antibodies against HIV-1. Funding: Intramural Research Program of the Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health.
RESUMO
The reovirus fusion-associated small transmembrane (FAST) proteins are virus-encoded membrane fusion proteins that function as dedicated cell-cell fusogens. The topology of these small, single-pass membrane proteins orients the majority of the protein on the distal side of the membrane (i.e., inside the cell). We now show that ectopic expression of the endodomains of the p10, p14, and p15 FAST proteins enhances syncytiogenesis induced by the full-length FAST proteins, both homotypically and heterotypically. Results further indicate that the 68-residue cytoplasmic endodomain of the p14 FAST protein (1) is endogenously generated from full-length p14 protein expressed in virus-infected or transfected cells; (2) enhances syncytiogenesis subsequent to stable pore formation; (3) increases the syncytiogenic activity of heterologous fusion proteins, including the differentiation-dependent fusion of murine myoblasts; (4) exerts its enhancing activity from the cytosol, independent of direct interactions with either the fusogen or the membranes being fused; and (5) contains several regions with protein-protein interaction motifs that influence enhancing activity. We propose that the unique evolution of the FAST proteins as virus-encoded cellular fusogens has allowed them to generate a trans-acting, soluble endodomain peptide to harness a cellular pathway or process involved in the poorly understood process that facilitates the transition from microfusion pores to macrofusion and syncytiogenesis.
Assuntos
Orthoreovirus de Mamíferos/metabolismo , Estrutura Terciária de Proteína/fisiologia , Proteínas Virais de Fusão/metabolismo , Animais , Linhagem Celular , Chlorocebus aethiops , Citoesqueleto/metabolismo , Citometria de Fluxo , Células Gigantes/metabolismo , Imuno-Histoquímica , Orthoreovirus de Mamíferos/genética , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Estrutura Terciária de Proteína/genética , Transdução de Sinais , Células Vero , Proteínas Virais de Fusão/genéticaRESUMO
As nonenveloped viruses, the aquareoviruses and orthoreoviruses are unusual in their ability to induce cell-cell fusion and syncytium formation. While an extraordinary family of fusion-associated small transmembrane (FAST) proteins is responsible for orthoreovirus syncytiogenesis, the basis for aquareovirus-induced syncytiogenesis is unknown. We now report that the S7 genome segment of an Atlantic salmon reovirus is polycistronic and uses a noncanonical CUG translation start codon to produce a 22-kDa integral membrane protein responsible for syncytiogenesis. The aquareovirus p22 protein represents a fourth distinct member of the FAST family with a unique repertoire and arrangement of structural motifs.
Assuntos
Células Gigantes/citologia , Células Gigantes/metabolismo , Proteínas de Membrana/metabolismo , Biossíntese de Proteínas/genética , Reoviridae/metabolismo , Proteínas Virais/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Chlorocebus aethiops , Genoma Viral/genética , Proteínas de Membrana/química , Proteínas de Membrana/classificação , Proteínas de Membrana/genética , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Reoviridae/genética , Salmo salar/virologia , Proteínas Virais/química , Proteínas Virais/classificação , Proteínas Virais/genética , Internalização do VírusRESUMO
In the present study, we presented picture-naming latencies along with ratings for a set of important characteristics of pictures and picture names: age of acquisition, frequency, picture-name agreement, name agreement, visual complexity, familiarity, and word length. The validity of these data was established by calculating correlations with previous studies. Regression analyses show that our ratings account for a larger amount of variance in RTs than do previous data. RTs were predicted by all variables except complexity and length. A complete database presenting details about all of these variables is available in the supplemental materials, downloadable from http://brm.psychonomic-journals.org/content/supplemental.
Assuntos
Testes de Linguagem/estatística & dados numéricos , Testes de Linguagem/normas , Nomes , Estimulação Luminosa/métodos , Tempo de Reação , Adulto , Fatores Etários , Inglaterra , Feminino , Humanos , Idioma , Masculino , Reconhecimento Visual de Modelos , Reconhecimento Psicológico , Percepção VisualRESUMO
Ophthalmic imaging has changed dramatically since the 1960s with increasingly complex technologies now available. Arguably, the greatest changes have been the development of the digital camera and the speed, processing power and storage of electronic data. Already, ophthalmic practices in many major institutions overseas have paperless medium storage and electronically generated reporting from all equipment that use a computer interface. It is hard to remember the widespread use of photographic film with its attendant costs, or even to remember the days before optical coherence tomography (OCT). These latest technical improvements in ophthalmic imaging are now standard in large Australian institutions and becoming more widespread in smaller private practices. The technicians that operate and maintain this ever-increasing plethora of gadgetry have seen their work practices change from the darkroom to the complexities of data-based imaging and storage. It is a fitting time to examine the contemporary state of ophthalmic imaging and what lies on the horizon as we move towards 2020.
Assuntos
Diagnóstico por Imagem/tendências , Olho/patologia , Olho/fisiopatologia , Corantes , Diagnóstico por Computador , Diagnóstico por Imagem/instrumentação , Angiofluoresceinografia , Fundo de Olho , Humanos , Imageamento Tridimensional , Verde de Indocianina , Microscopia Confocal , Oftalmoscopia , Fotografação/instrumentação , Fotografação/métodos , Retina/patologia , Tomografia de Coerência Óptica , Interface Usuário-ComputadorRESUMO
PURPOSE: To describe the use of intravitreal bevacizumab followed by sectorial retinal photocoagulation to treat the neovascular complications of laser-induced chorioretinal anastomosis (L-CRA) for nonischaemic central retinal vein occlusion (CRVO). METHODS: Prospective interventional case series of three patients with nonischaemic CRVO who were treated with L-CRA. Patients were followed up every 2 weeks after the laser treatment. If neovascularization occurred at the site of the anastomosis, intravitreal bevacizumab (1.25 mg) was injected followed by laser photocoagulation to areas of retinal ischaemia and the area of retina anterior to the L-CRA 1 week later. Fluorescein angiography was performed to confirm the presence of neovascularization. Best-corrected visual acuity measurements were performed at every visit. RESULTS: Three patients (one woman, two men) with a mean age of 76.3 years developed neovascularization at the L-CRA site and underwent treatment as described with a mean follow-up time of 7 months. The neovascularization developed within 1 month after the laser anastomosis in all three cases. All patients only required one intravitreal bevacizumab injection to control the neovascularization. No complications of the intravitreal injections were noted. CONCLUSIONS: Intravitreal bevacizumab appears to be an effective tool in the immediate control of neovascularization following L-CRA for nonischaemic CRVO. This appears to cause immediate regression of the neovascular frond and allows time for the laser, which is applied subsequently to have its effect.
Assuntos
Anastomose Cirúrgica , Inibidores da Angiogênese/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Fotocoagulação a Laser/efeitos adversos , Neovascularização Retiniana/tratamento farmacológico , Oclusão da Veia Retiniana/cirurgia , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados , Bevacizumab , Corioide/irrigação sanguínea , Feminino , Angiofluoresceinografia , Humanos , Injeções , Masculino , Pessoa de Meia-Idade , Neovascularização Retiniana/etiologia , Veia Retiniana/fisiologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Corpo VítreoRESUMO
BACKGROUND: Retinal vein pulsation is often absent in glaucoma, but can be induced by applying a graded ophthalmodynamometric force (ODF) to the eye, which is elevated in glaucoma. AIM: To assess whether ODF has a predictive value in determining glaucoma progression. METHODS: 75 patients with glaucoma and suspected glaucoma were examined prospectively in 1996, and then re-examined at a mean of 82 months later. All subjects had intraocular pressure, visual fields, stereo optic disc photography and ODF measured on their initial visit. When venous pulsation was spontaneous, the ODF was said to be 0 g. At re-examination, central corneal thickness and blood pressure were also measured. Initial and subsequent optic disc photographs were compared and graded into those that had increased excavation and those that had remained stable. The relationship between increased excavation (recorded as a binary response) and the measured variables was modelled using a multiple mixed effects logistic regression. RESULTS: ODF at the initial visit was strongly predictive of increased excavation (p = 0.004, odds ratio 1.16/g, range 0-60 g), with greater predictive value in women than in men (p = 0.004). Visual field mean deviation was predictive of increased excavation (p = 0.044), as was optic nerve haemorrhage in association with older age (p = 0.038). Central corneal thickness was not significantly predictive of increased excavation (p = 0.074) after having adjusted for other variables. CONCLUSION: ODF measurement seems to be strongly predictive of the patient's risk for increased optic disc excavation. This suggests that ODF measurement may have predictive value in assessing the likelihood of glaucoma progression.
Assuntos
Glaucoma/diagnóstico , Disco Óptico/fisiopatologia , Veia Retiniana/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Progressão da Doença , Métodos Epidemiológicos , Feminino , Glaucoma/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Oftalmodinamometria , Fluxo Pulsátil , Resistência Vascular , Campos VisuaisRESUMO
Patients with controlled background pain associated with cancer frequently also experience episodes of moderate to severe intensity breakthrough pain. Opioid pharmacotherapy, particularly with oral morphine, remains the cornerstone for the management of cancer pain. Nasal administration of opioids provides a mechanism for more rapid drug absorption and more rapid onset of pain relief compared with oral dosing. This non-randomized, open-label, uncontrolled investigation evaluated the pharmacokinetics, safety and efficacy of a single 40 mg dose of nasal morphine gluconate, administered to cancer patients in response to an episode of breakthrough pain. Single dose nasal morphine gluconate administered to 11 patients was associated with effective plasma morphine concentrations (mean C(max) 64 ng/ml; range 33.8-121 ng/ml) and low plasma morphine metabolites (morphine-6-glucuronide mean C(max) 114 ng/ml; range 46-189 ng/ml; morphine-3-glucuronide mean C(max) 572 ng/ml; range 257-990 ng/ml). Side effects were minor and limited to nasal irritation. Patients reported rapid onset of pain relief (perceptible pain relief achieved in 10/11 patients, time to onset 2.4+/-2.1 min; and meaningful pain relief, achieved in five patients, 6.8+/-7.3 min to onset, mean t(max) 0.36 h). Pain intensity scores were significantly reduced at all times after dosing; pain relief scores were unchanged. Patient satisfaction ratings were high. These results show that nasal morphine has rapid absorption and apparent onset of effect. Additional multi-dose, dose-ranging and placebo-controlled studies of nasal morphine for cancer pain are warranted.
Assuntos
Morfina/administração & dosagem , Morfina/efeitos adversos , Neoplasias/complicações , Dor/tratamento farmacológico , Administração Intranasal , Adulto , Análise de Variância , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Morfina/sangue , Neoplasias/sangue , Dor/sangue , Dor/etiologia , Estatísticas não ParamétricasRESUMO
We report a case of a displaced laser in situ keratomileusis flap. The flap displacement was enhanced by using cross-polarized filters.
Assuntos
Migração de Corpo Estranho/diagnóstico , Ceratomileuse Assistida por Excimer Laser In Situ/efeitos adversos , Microscopia de Polarização , Retalhos Cirúrgicos/efeitos adversos , Adulto , Humanos , MasculinoRESUMO
Trafficking of integral membrane proteins between the ER and Golgi complex, and protein sorting and trafficking between the TGN and endosomal/lysosomal compartments or plasma membranes, are dependent on cis-acting, linear amino acid sorting signals. Numerous sorting signals of this type have been identified in the cytoplasmic domains of membrane proteins, several of which rely on basic residues. A novel Golgi export signal that relies on a membrane-proximal polybasic motif (PBM) was recently identified in the reptilian reovirus p14 protein, a representative of an unusual group of bitopic fusion-associated small transmembrane (FAST) proteins encoded by fusogenic orthoreoviruses and responsible for cell-cell fusion and syncytium formation. Using immunofluorescence microscopy, cell surface immunofluorescence, and endoglycosidase H assays, we now show the p14 PBM can mediate several distinct trafficking functions depending on its proximity to the transmembrane domain (TMD). When present within 4-residues of the TMD it serves as a Golgi export signal, but when located at the C-terminus of the 68-residue p14 cytoplasmic endodomain it functions as an ER retention signal. The PBM has no effect on protein trafficking when located at an internal position in the cytoplasmic domain. When present in both membrane-proximal and -distal locations, the PBMs promote export to, and efficient retrieval from, the Golgi complex. Interestingly, the conflicting trafficking signals provided by two PBMs induces extensive ER tubulation and segregation of ER components. These studies highlight how a single trafficking signal in a simple transmembrane protein can have remarkably diverse, position-dependent effects on protein trafficking and ER morphogenesis.
Assuntos
Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Proteínas de Membrana/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Aminoácidos Básicos , Animais , Linhagem Celular , Proteínas de Membrana/química , Dados de Sequência Molecular , Transporte Proteico , Alinhamento de SequênciaAssuntos
Encefalopatias/complicações , Doenças da Coroide/etiologia , Histiocitose de Células de Langerhans/etiologia , Adulto , Encefalopatias/diagnóstico , Encefalopatias/radioterapia , Encefalopatias/cirurgia , Doenças da Coroide/patologia , Histiocitose de Células de Langerhans/patologia , Humanos , Imageamento por Ressonância Magnética , MasculinoRESUMO
The reovirus fusion-associated small transmembrane (FAST) proteins evolved to induce cell-cell, rather than virus-cell, membrane fusion. It is unclear whether the FAST protein fusion reaction proceeds in the same manner as the enveloped virus fusion proteins. We now show that fluorescence-based cell-cell and cell-RBC hemifusion assays are unsuited for detecting lipid mixing in the absence of content mixing during FAST protein-mediated membrane fusion. Furthermore, membrane curvature agents that inhibit hemifusion or promote pore formation mediated by influenza hemagglutinin had no effect on p14-induced cell-cell fusion, even under conditions of limiting p14 concentrations. Standard assays used to detect fusion intermediates induced by enveloped virus fusion proteins are therefore not applicable to the FAST proteins. These results suggest the possibility that the nature of the fusion intermediates or the mechanisms used to transit through the various stages of the fusion reaction may differ between these distinct classes of viral fusogens.
Assuntos
Proteínas de Membrana/metabolismo , Reoviridae/fisiologia , Reoviridae/patogenicidade , Proteínas Virais/metabolismo , Internalização do Vírus , Fusão Celular , Membrana Celular/efeitos dos fármacos , HumanosRESUMO
Corneal neovascularization can be a difficult problem to treat. The authors describe a patient with lipid keratopathy secondary to corneal neovascularization treated with photodynamic therapy. Six months following treatment the neovascularization has not returned and the lipid keratopathy has not increased in size. No significant side effects from the treatment occurred. Photodynamic therapy with Verteporfin was a useful treatment modality in this case of corneal neovascularization with associated lipid keratopathy.
RESUMO
PURPOSE: To delineate morphometric and quantitative features of the capillary image derived from high-resolution fundus fluorescein angiography (FFA) and consequently determine the diagnostic value of FFA for studying the retinal capillary circulation. METHODS: Retinal capillary images obtained from healthy young subjects using high-resolution FFA were compared with confocal scanning laser microscopic capillary images derived from the retinas of age-matched human donors. Confocal microscopic images were acquired from retinal flatmount tissue after central retinal artery cannulation, perfusion fixation, and antibody labeling. Capillary images from equivalent retinal regions were morphologically and quantitatively analyzed in both groups. RESULTS: Ten human subjects (mean age, 27.4 years) were used for FFA studies, and five cadaveric eyes (mean donor age, 26.5 years) were used for histologic studies. In histologic specimens the density of the superficial capillary network was significantly greater than that of the deep capillary network. Despite use of a healthy young population, only 30% of high-resolution FFA studies provided clear capillary images. The configuration of the capillary network in FFA images was comparable to the superficial capillary network in confocal microscope images; however, the density of the capillary network in FFA images was consistently lower than that of histologic images. CONCLUSIONS: FFA provides incomplete morphologic information about the superficial capillary network and even less information about the deep capillary network. Caution should, therefore, be exercised when using FFA data to extrapolate information about microvascular histopathologic processes. The usefulness of newer technology for studying retinal capillary detail should be investigated.