Consultant Oral & maxillofacial surgeon
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To evaluate the relationship between zone of retinal vascularization and refractive error in premature infants without retinopathy of prematurity (ROP) or with spontaneously regressed ROP. read more
Aflibercept (Eylea™, Regeneron) is supplied in single-use glass vials along with 1 cc polycarbonate syringes. We sought to determine if storage of aflibercept for sustained periods within these syringes would result in loss of antivascular endothelial growth factor (anti-VEGF) activity. Aflibercept samples were drawn from commercially available glass vials into manufacturer-supplied 1-mL syringes and stored at 4°C. Anti-VEGF activity was assessed using enzyme-linked immunosorbent assays at the following storage durations: 0, 4, 9, 14, and 28 days. Frozen samples stored at -20°C for 28 and 56 days were also assayed. Also, a subset of aflibercept samples was stored and then diluted to 1:10 and progressively smaller concentrations and the assays repeated. Aggregation of aflibercept was tested using a dynamic light scattering assay. There were no statistical differences in anti-VEGF activity among aflibercept samples of 1:1 or 1:10 dilution stored at either 4°C or -20°C at any of the storage intervals ( > 0.05). We also observed persistence of robust anti-VEGF activity for up to 14 days when diluted poststorage to 1:16,000, a concentration that would be expected after >7 vitreous half-lives within the eye (estimated at >50 days). No evidence of drug aggregation in specimens stored for 14 days was observed. Our findings support feasibility of prefilling and storage of aflibercept within manufacturer-supplied polycarbonate syringes for as long as 14 days before use under pharmacy-based sterile conditions, facilitating greater safety and efficiency in many clinics delivering anti-VEGF therapy. read more
Fabry disease is an X-linked lysosomal storage disease caused by deficiency of α-galactosidase A. Ocular findings, such as cornea verticillata, cataracts, and retinal vascular tortuosity, serve as important diagnostic markers. We aimed to evaluate ocular phenotypes in α-galactosidase A-deficient (Fabry) rats and hypothesized that these rats would manifest ocular signs similar to those observed in patients. Slit lamp biomicroscopy was used to evaluate the cornea and lens, and retinal vasculature was examined by fluorescein angiography in WT and Fabry rats. Mass spectrometry was used to characterize and quantify ocular glycosphingolipids, and histology and electron microscopy revealed the location of the glycosphingolipid storage. We found that Fabry rats developed corneal and lenticular opacities to a statistically greater degree than WT rats. Retinal vascular morphology did not appear grossly different, but there was vascular leakage in at least one Fabry rat. Fabry rat eyes accumulated substrates of α-galactosidase A, and these α-galactosyl glycoconjugates were found in corneal keratocytes, lens fibers, and retinal vascular endothelial cells. Electron-dense lamellar inclusions were observed in keratocytes. Because Fabry rats recapitulate many ocular phenotypes observed in patients, they can be used to study disease pathogenesis and determine whether ocular findings serve as noninvasive indicators of therapeutic efficacy. read more
Farber disease (FD) is a debilitating lysosomal storage disorder characterized by severe inflammation and neurodegeneration. FD is caused by mutations in the ASAH1 gene, resulting in deficient acid ceramidase (ACDase) activity. Patients with ACDase deficiency exhibit a broad clinical spectrum. In classic cases, patients develop hepatosplenomegaly, nervous system involvement, and childhood mortality. Ocular manifestations include decreased vision, a grayish appearance to the retina with a cherry red spot, and nystagmus. That said, the full effect of ACDase deficiency on the visual system has not been studied in detail. We previously developed a mouse model that is orthologous for a known patient mutation in Asah1 that recapitulates human FD. Herein, we report evidence of a severe ocular pathology in Asah1 mice. Asah1 mice exhibit progressive retinal and optic nerve pathology. Through noninvasive ocular imaging and histopathological analyses of these Asah1 animals, we revealed progressive inflammation, the presence of retinal dysplasia, and significant storage pathology in various cell types in both the retina and optic nerves. Lipidomic analyses of retinal tissues revealed an abnormal accumulation of ceramides and other sphingolipids. Electroretinograms and behavioral tests showed decreased retinal and visual responses. Taken together, these data suggest that ACDase deficiency leads to sphingolipid imbalance, inflammation, dysmorphic retinal and optic nerve pathology, and severe visual impairment. read more
We used the juvenile rabbit as a model for investigating therapeutic interventions for postoperative inflammation and fibrin formation following intraocular lens (IOL) insertion for management of pediatric cataracts. read more
To determine whether retinopathy of prematurity (ROP) that persists beyond a postmenstrual age (PMA) of 45 weeks has abnormalities that can be documented by fundus photography or fluorescein angiography (FA). read more
We investigated the contribution of litter to the occurrence of Campylobacter on three broiler farms, which were known to have low (LO) and high (HI-A and HI-B) Campylobacter prevalence. For this purpose, we collected litter samples (n = 288) during and after two rearing cycles from each farm. We evaluated the occurrence of Campylobacter (using selective enrichment and quantitative real-time polymerase chain reaction [q-PCR] analysis) in the litter samples as well as the litter's pH and moisture content. Ceca from each flock (n = 144) were harvested at slaughter age and used to quantify Campylobacter colony-forming units (CFUs). Campylobacter was only retrieved from 7 litter samples that were collected from HI-A and HI-B during the growing period, but no Campylobacter was isolated from LO farms. The q-PCR analysis detected Campylobacter in pooled litter samples from all three farms. However, in litter collected during the same rotation, Campylobacter levels were significantly higher (p < 0.05) in HI-A and HI-B litter samples in comparison to those in LO. Cecal samples from HI-A and HI-B yielded relatively high numbers of Campylobacter CFUs, which were undetectable in LO samples. Litter's pH and moisture did not affect the overall occurrence of Campylobacter in litter and ceca on any of the farms. Our data suggest that Campylobacter was generally more abundant in litter that was collected from farms with highly colonized flocks. Therefore, better approaches for assessing the occurrence of Campylobacter in litter might be warranted in order to reduce the dissemination of these pathogens on and off poultry farms. read more
Salmonella is one of the most common causes of foodborne illnesses in humans in the United States, and domestic poultry is considered an important source of this pathogen. Salmonella enterica subsp. enterica serovar Heidelberg is the fourth most commonly reported Salmonella from retail meats and food animals in the United States. We assessed the genotypes and antimicrobial resistance phenotypes of Salmonella Heidelberg isolated from various chicken and turkey hatcheries and breeder farms in the Midwest. The genotypes of 33 S. Heidelberg isolates from chickens ( n = 19) and turkeys ( n = 14) were compared using pulsed-field gel electrophoresis analysis. Cluster analysis of the fingerprints showed that the majority of the chicken isolates grouped together with 87% similarity; those from turkeys clustered with 88% similarity. Similarity between chicken and turkey isolates was also high (86%). Isolates from turkeys were generally more genetically diverse than those from chickens. Antimicrobial susceptibility analysis detected resistance to sulfisoxazole (36% of the isolates), streptomycin (33%), gentamicin (27%), tetracycline (24%), ampicillin and amoxicillin-clavulanic acid (15%), cefoxitin (12%), ceftriaxone and ceftiofur (12%), and chloramphenicol (9%). None of the isolates was resistant to azithromycin, ciprofloxacin, or nalidixic acid. Although the number of the isolates was limited in our study, we conclude that S. Heidelberg isolates from the same host generally clustered together and that a considerable number of the isolates were resistant to a number of antimicrobial agents. read more
Colibacillosis caused by avian pathogenic E. coli (APEC), is an economically important bacterial disease of poultry. APEC are a subgroup of extra intestinal pathogenic E. coli (ExPEC) and poultry are considered potential sources of foodborne ExPEC to humans. Currently, APEC infections in poultry are controlled by antibiotics and/or vaccination; however, their effect is limited due to emergence of antibiotic resistant strains and infections with heterologous serotypes. Therefore, novel approaches are needed. Here, using the bioluminescent quorum sensing (QS) autoinducer 2 (AI-2) indicator Vibrio harveyi BB170, we screened the cell free culture supernatant of APEC O78 prepared from cultures grown in the presence of 4,182 small molecules (SMs; 100 μM). A total of 69 SMs inhibited > 75% of APEC O78 AI-2 activity in the indicator bacteria. Ten SMs that showed highest AI-2 inhibition were selected for further studies. Most of these SMs inhibited the AI-2 activity of other APEC serotypes and significantly reduced APEC O78 biofilm formation and motility. Most compounds showed minimal toxicity on human intestinal cells (Caco-2), chicken macrophage (HD-11), and chicken and sheep red blood cells, and reduced APEC survival in HD-11 and THP-1 macrophages. The SMs induced no or minimal toxicity and conferred protection against APEC in wax moth larval model. SMs affected the expression of APEC O78 QS, virulence, biofilm and motility associated genes providing insight on their potential mode(s) of action. Further testing in chickens will facilitate development of these SMs as novel therapeutics to control APEC in poultry and thereby also reduce zoonotic transmission. read more
