Fluorescence Angiography with Dual Fluorescence for the Early Detection and Longitudinal Quantitation of Vascular Leakage in Retinopathy.

BACKGROUND: Diabetic retinopathy (DR) afflicts more than 93 million people worldwide and is a leading cause of vision loss in working adults. While DR therapies are available, early DR development may go undetected without treatment due to the lack of sufficiently sensitive tools. Therefore, early detection is critically important to enable efficient treatment before progression to vision-threatening complications. A major clinical manifestation of early DR is retinal vascular leakage that may progress from diffuse to more localized focal leakage, leading to increased retinal thickness and diabetic macular edema (DME). In preclinical research, a hallmark of DR in mouse models is diffuse retinal leakage without increased thickness or DME, which limits the utility of optical coherence tomography and fluorescein angiography (FA) for early detection. The Evans blue assay detects diffuse leakage but requires euthanasia, which precludes longitudinal studies in the same animals. METHODS: We developed a new modality of ratiometric fluorescence angiography with dual fluorescence (FA-DF) to reliably detect and longitudinally quantify diffuse retinal vascular leakage in mouse models of induced and spontaneous DR. RESULTS: These studies demonstrated the feasibility and sensitivity of FA-DF in detecting and quantifying retinal vascular leakage in the same mice over time during DR progression in association with chronic hyperglycemia and age. CONCLUSIONS: These proof-of-concept studies demonstrated the promise of FA-DF as a minimally invasive method to quantify DR leakage in preclinical mouse models longitudinally.

Plasmid Diversity in Salmonella enteritidis of Animal, Poultry, and Human Origin.

One hundred thirty-eight isolates of Salmonella enteritidis from human, animal, and avian species were analyzed for the presence of plasmid DNA. Plasmid DNA from S. enteritidis isolates were extracted by a modification of a high alkaline extraction procedure. Comparisons were made between samples based on the number of plasmids present and their molecular weights. There were seven different profiles seen among the 15 human isolates from the Centers for Disease Control. These seven profiles were recognized with the animal isolates from the National Veterinary Services Laboratory, the chicken isolates from the northeastem (NE) region of the United States, and the turkey isolates from Minnesota (MN). There were no shared profdes between the human isolates and the chicken isolates from MN. The greatest relationship existed between the human isolates and the chicken isolates from the NE region of the United States, sharing four common profiles. Every Centers for Disease Control isolate shared a plasmid profile with chicken isolates from the NE region of the United States. The chicken isolates from MN had no profiles in common with any isolates from any other groups. The majority of animal isolates from National Veterinary Services Laboratory and the turkey isolates from MN possessed the virulence-associated 54 kb plasmid alone. This paper describes how plasmid profiles can be used as a tool in epidemiological investigations.