Hydrocyclones as cell retention devices for an N-1 perfusion bioreactor linked to a continuous-flow stirred tank production bioreactor.

A continuous Chinese hamster ovary (CHO) cell culture process comprised of a highly proliferative N-1 perfusion bioreactor utilizing a hydrocyclone as a cell retention device linked to a production continuous-flow stirred tank reactor (CSTR) is presented. The overflow stream from the hydrocyclone, which is only partially depleted of cells, provides a continuous source of high viability cells from the N-1 perfusion bioreactor to the 5-20 times larger CSTR. Under steady-state conditions, this linked-bioreactor system achieved a peak volumetric productivity of 0.96 g/L/day, twofold higher than the optimized fed-batch process. The linked bioreactor system using a hydrocyclone was also shown to be 1.8-3.1 times more productive than a dual, cascading CSTR system without cell retention.

Acute, Treatment-Naïve Branch Retinal Vein Occlusion in Younger Individuals: Risk Factors and Clinical Outcomes.

Purpose: To compare the risk factors and clinical outcomes in patients younger than 50 years with acute, treatment-naïve branch retinal vein occlusion (BRVO) with outcomes in patients 50 years or older. Methods: Patients diagnosed with acute, treatment-naïve BRVO at Duke Eye Center over a 9.5-year period who had BRVO with onset 3 months or less before presentation, BRVO with macular involvement, and 12 months or more of follow-up were included. Demographic data, presenting clinical features, risk factors, treatment patterns, and clinical outcomes were extracted during a retrospective review of medical records. Results: Of 302 patients identified, 23 were younger than 50 years (younger group) and 279 were 50 years or older (older group). Compared with older patients, younger patients had similar rates of hypertension (P = .275), diabetes mellitus (P = 1.000), smokers (P = .787), and open-angle glaucoma (P = .628). The younger group had a lower rate of hyperlipidemia than the older group (35% vs 59%) (P = .028). The 2 groups had similar presenting logMAR visual acuities (VAs) in the BRVO eye (P = .131). At the final follow-up, younger patients had significantly better logMAR VA in the BRVO-affected eye than older patients (mean 0.51 ± 0.65 vs 1.01 ± 1.20) (P = .016). The 2 groups had similar treatment burdens at 1 year (P = .516) and at the final follow-up (P = .782). Conclusions: Younger patients with acute, treatment-naïve BRVO have similar risk factors and treatment patterns as older patients, except for a lower rate of hyperlipidemia. Younger patients with BRVO may have similar presenting VA as older BRVO patients but better final VA, suggesting that age may be a potential prognostic factor.

Multimodal Retinal Imaging Classification for Parkinson's Disease Using a Convolutional Neural Network.

Purpose: Changes in retinal structure and microvasculature are connected to parallel changes in the brain. Two recent studies described machine learning algorithms trained on retinal images and quantitative data that identified Alzheimer's dementia and mild cognitive impairment with high accuracy. Prior studies also demonstrated retinal differences in individuals with PD. Herein, we developed a convolutional neural network (CNN) to classify multimodal retinal imaging from either a Parkinson's disease (PD) or control group. Methods: We trained a CNN to receive retinal image inputs of optical coherence tomography (OCT) ganglion cell-inner plexiform layer (GC-IPL) thickness color maps, OCT angiography 6 × 6-mm en face macular images of the superficial capillary plexus, and ultra-widefield (UWF) fundus color and autofluorescence photographs to classify the retinal imaging as PD or control. The model consists of a shared pretrained VGG19 feature extractor and image-specific feature transformations which converge to a single output. Model results were assessed using receiver operating characteristic (ROC) curves and bootstrapped 95% confidence intervals for area under the ROC curve (AUC) values. Results: In total, 371 eyes of 249 control subjects and 75 eyes of 52 PD subjects were used for training, validation, and testing. Our best CNN variant achieved an AUC of 0.918. UWF color photographs were the most effective imaging input, and GC-IPL thickness maps were the least contributory. Conclusions: Using retinal images, our pilot CNN was able to identify individuals with PD and serves as a proof of concept to spur the collection of larger imaging datasets needed for clinical-grade algorithms. Translational Relevance: Developing machine learning models for automated detection of Parkinson's disease from retinal imaging could lead to earlier and more widespread diagnoses.

Differences in Retinal and Choroidal Microvasculature and Structure in Dementia With Lewy Bodies Compared With Normal Cognition.

Purpose: To evaluate the retinal and choroidal microvasculature and structure in individuals with dementia with Lewy bodies (DLB) compared with controls with normal cognition using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: An institutional review board-approved cross-sectional comparison of patients with DLB and cognitively normal controls was performed. The Cirrus HD-OCT 5000 with AngioPlex (Carl Zeiss Meditec) was used to obtain OCT and OCTA images. Results: Thirty-four eyes of 18 patients with DLB and 85 eyes of 48 cognitively normal patients were analyzed. The average capillary perfusion density (CPD) was higher in the DLB group than in the control group (P = .005). The average capillary flux index (CFI) and ganglion cell inner-plexiform layer (GC-IPL) thickness were lower in the DLB group than in the control group (P = .016 and P = .040, respectively). Conclusions: Patients with DLB had an increased peripapillary CPD, decreased peripapillary CFI, and attenuated GC-IPL thickness compared with those with normal cognition.

Characterizing differences in retinal and choroidal microvasculature and structure in individuals with Huntington's Disease compared to healthy controls: A cross-sectional prospective study.

OBJECTIVE: To characterize retinal and choroidal microvascular and structural changes in patients who are gene positive for mutant huntingtin protein (mHtt) with symptoms of Huntington's Disease (HD). METHODS: This study is a cross-sectional comparison of patients who are gene positive for mHtt and exhibit symptoms of HD, either motor manifest or prodromal (HD group), and cognitively normal individuals without a family history of HD (control group). HD patients were diagnosed by Duke movement disorder neurologists based on the Unified Huntington's Disease Rating Scale (UHDRS). Fovea and optic nerve centered OCT and OCTA images were captured using Zeiss Cirrus HD-5000 with AngioPlex. Outcome metrics included central subfield thickness (CST), peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, and choroidal vascularity index (CVI) on OCT, and foveal avascular zone (FAZ) area, vessel density (VD), perfusion density (PD), capillary perfusion density (CPD), and capillary flux index (CFI) on OCTA. Generalized estimating equation (GEE) models were used to account for inter-eye correlation. RESULTS: Forty-four eyes of 23 patients in the HD group and 77 eyes of 39 patients in the control group were analyzed. Average GCIPL thickness and FAZ area were decreased in the HD group compared to controls (p = 0.001, p < 0.001). No other imaging metrics were significantly different between groups. CONCLUSIONS: Patients in the HD group had decreased GCIPL thickness and smaller FAZ area, highlighting the potential use of retinal biomarkers in detecting neurodegenerative changes in HD.

Longitudinal Assessment of the Choroidal Vascularity Index in Eyes with Branch Retinal Vein Occlusion-Associated Cystoid Macular Edema.

INTRODUCTION: Cystoid macular edema (CME) is the most common cause of central vision loss in eyes with branch retinal vein occlusion (BRVO eyes). In recent literature, choroidal vascularity index (CVI) has been proposed to be an enhanced depth imaging optical coherence tomography (EDI-OCT) metric that may help characterize choroidal vascular changes in the setting of retinal ischemia, and potentially prognose visual outcomes and treatment patterns for patients with BRVO-related CME. This study sought to further characterize choroidal vascular changes in BRVO by comparing the CVI, subfoveal choroidal thickness (SFCT), and central subfield thickness (CST) in BRVO eyes with CME compared to unaffected fellow eyes. METHODS: This was a retrospective cohort study. Subjects included treatment-naïve BRVO eyes with CME diagnosed within 3 months of onset of symptoms and unaffected fellow eyes. EDI-OCT images were collected at baseline and at the 12-month follow-up visit. CVI, SFCT, and CST were measured. Demographics, treatment patterns, and best-corrected visual acuity (VA) were abstracted. Median CVI, SFCT, CST, and VA were compared between the two cohorts. Longitudinal relationships between these variables were analyzed. RESULTS: A total of 52 treatment-naïve eyes with BRVO and CME and 48 unaffected fellow eyes were identified. Baseline CVI was lower in eyes with BRVO than in fellow eyes (64.7% vs. 66.4%, P = 0.003). At 12 months, there was no difference in CVI between BRVO eyes and fellow eyes (65.7% vs 65.8%, P = 0.536). In BRVO eyes, there was a strong correlation between reduced CST and improved VA over the 12-month study period (r = 0.671, P < 0.001). CONCLUSION: There are differences in CVI in treatment-naïve BRVO eyes with CME at presentation compared to fellow eyes, but these differences resolve over time. Anatomic changes in macular thickness in BRVO eyes with CME may be correlated with VA outcomes.

Our study evaluated a novel ocular optical coherence tomography imaging metric, the choroidal vascularity index, in eyes that developed cystoid macular edema, a condition which can significantly impair acuity of central vision, after being diagnosed with branch retinal vein occlusion. In each patient, we compared the choroidal vascularity index in eyes that developed treatment-naïve, newly diagnosed branch retinal vein occlusion with cystoid macular edema to the non-diseased fellow eye. We made comparisons at the time of diagnosis (baseline) and at the 12-month follow up, and analyzed changes over time. We found that at the baseline visit, branch retinal vein occlusion eyes with cystoid macular edema had a significantly lower choroidal vascularity index than their unaffected fellow eyes, but that the differences between eyes resolved by the 12-month follow-up visit. Our findings suggest that choroidal vascularity may be compromised in the acute phase of branch retinal vein occlusion, but that this phenomenon resolves over time. Future research should further evaluate whether imaging characteristics of choroidal vascularity may be associated with changes in anatomic and visual outcomes in retinal diseases.

Convolutional Neural Network-Based Automated Quality Assessment of OCT and OCT Angiography Image Maps in Individuals With Neurodegenerative Disease.

Purpose: To train and test convolutional neural networks (CNNs) to automate quality assessment of optical coherence tomography (OCT) and OCT angiography (OCTA) images in patients with neurodegenerative disease. Methods: Patients with neurodegenerative disease were enrolled in the Duke Eye Multimodal Imaging in Neurodegenerative Disease Study. Image inputs were ganglion cell-inner plexiform layer (GC-IPL) thickness maps and fovea-centered 6-mm × 6-mm OCTA scans of the superficial capillary plexus (SCP). Two trained graders manually labeled all images for quality (good versus poor). Interrater reliability (IRR) of manual quality assessment was calculated for a subset of each image type. Images were split into train, validation, and test sets in a 70%/15%/15% split. An AlexNet-based CNN was trained using these labels and evaluated with area under the receiver operating characteristic (AUC) and summaries of the confusion matrix. Results: A total of 1465 GC-IPL thickness maps (1217 good and 248 poor quality) and 2689 OCTA scans of the SCP (1797 good and 892 poor quality) served as model inputs. The IRR of quality assessment agreement by two graders was 97% and 90% for the GC-IPL maps and OCTA scans, respectively. The AlexNet-based CNNs trained to assess quality of the GC-IPL images and OCTA scans achieved AUCs of 0.990 and 0.832, respectively. Conclusions: CNNs can be trained to accurately differentiate good- from poor-quality GC-IPL thickness maps and OCTA scans of the macular SCP. Translational Relevance: Since good-quality retinal images are critical for the accurate assessment of microvasculature and structure, incorporating an automated image quality sorter may obviate the need for manual image review.

Longitudinal Analysis of Retinal Microvascular and Choroidal Imaging Parameters in Parkinson's Disease Compared with Controls.

Purpose: To quantify rate of change of retinal microvascular and choroidal structural parameters in subjects with Parkinson's disease (PD) compared with controls using OCT and OCT angiography (OCTA). Design: Prospective longitudinal study. Participants: Seventy-four eyes of 40 participants with PD and 149 eyes of 78 control individuals from the Eye Multimodal Imaging in Neurodegenerative Disease database. Methods: Subjects underwent OCT and OCTA imaging at 2 time points approximately 12 months apart. Main Outcome Measures: Imaging parameters included central subfield thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness, peripapillary retinal nerve fiber layer thickness, choroidal vascularity index, superficial capillary plexus perfusion density (PFD), vessel density (VD), and foveal avascular zone area. Results: Participants with PD had greater rate of yearly decrease in GC-IPL (PD = -0.403µm, control = + 0.128 µm; P = 0.01), greater yearly decline in PFD in the 3 × 3 mm ETDRS circle (PD = -0.016, control = + 0.002; P < 0.001) and ring (PD = -0.016, control = + 0.002; P < 0.001); 6 × 6 mm ETDRS circle (PD = -0.021, control = 0.00; P = 0.001), and outer ring (PD = -0.022, control = 0.00; P = 0.001). Participants with PD had greater rate of yearly decline in VD in 3 × 3 mm circle (PD = -0.939/mm, control = + 0.006/mm; P < 0.001) and ring (PD = -0.942/mm, control = + 0.013/mm; P < 0.001); 6 × 6 mm circle (PD = -0.72/mm, control = -0.054/mm; P = 0.006), and outer ring (PD = -0.746/mm, control = -0.054/mm; P = 0.005). When stratified by PD severity based on Hoehn and Yahr stage, faster rates of decline were seen in Hoehn and Yahr stages 3 to 4 in the 3 × 3 mm circle PFD and VD as well as 3 × 3 mm ring VD. Conclusions: Individuals with PD experience more rapid loss of retinal microvasculature quantified on OCTA and more rapid thinning of the GC-IPL than controls. There may be more rapid loss in patients with greater disease severity. Financial Disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Rapid detection of Escherichia coli by using antibody-conjugated silver nanoshells.

Silver shells of 20 nm thickness have been deposited on silica particles of 200 nm diameter with narrow size distribution. Silver nanoshells dispersed in water exhibit a strong surface plasmon resonance band at 443 nm. This band was found to be very sensitive to rabbit immunoglobulin G antibodies, which were anchored on the nanoshells. These in turn could be utilized to detect the presence of small (approximately 5) to large numbers (approximately 10(9)) of Escherichia coli in water. The protocol presented here proves to be a specific, rapid, reliable, and inexpensive method to detect E. coli.

Cardiovascular health awareness and the effect of an educational intervention on school-aged children in a rural district of India.

BACKGROUND AND OBJECTIVES: India is the second most populous country in the world and two-thirds of its population is less than 35 years old. This survey was conducted to assess the level of health awareness of cardiovascular disease in adolescent school-aged children 14-16 years old, with the goal of establishing school-based health education and development of heart-healthy lifestyle practices. METHODS: A school-based survey was conducted in the rural district of West Midnapore, India between June and July of 2014. This involved a pre-evaluation of cardiovascular disease (CVD) health awareness, a short presentation on CVD, and a post-evaluation of CVD health awareness. RESULTS: A total of 2995 students (48% response rate) from 20 schools participated in the survey. The mean age of the students in the study sample was 14.7 years, 46% were male, 53% were in the 9th grade, and the rest were in the 10th grade. After assessing students' awareness in six domains with 20 multiple-choice questions with a maximum score of 100, the mean pre-test score was 41.1 (SD±10.5) and the mean post-test score was 48.1 (SD±16.9) (p<0.001). CONCLUSIONS: Awareness of CVD and its risk factors was far from optimal among the adolescent school-aged children in this study. A school-based educational program may help improve awareness of CVD and reduce the future disease burden in the community. The results of this study may be useful in formulating a nationwide school health program to deal with the emerging epidemic of CVD in countries such as India.