Initial Management of Indeterminate Renal Lesions in a Statewide Collaborative: A MUSIC-KIDNEY Analysis.

PURPOSE: Renal masses can be characterized as "indeterminate" due to lack of differentiating imaging characteristics. Optimal management of indeterminate renal lesions remains nebulous and poorly defined. We assess management of indeterminate renal lesions within the MUSIC-KIDNEY (Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY) collaborative. MATERIALS AND METHODS: Each renal mass is classified as suspicious, benign, or indeterminate based on radiologist and urologist assessment. Objectives were to assess initial management of indeterminate renal lesions and the impact of additional imaging and biopsy on characterization prior to treatment. RESULTS: Of 2,109 patients, 444 (21.1%) had indeterminate renal lesions on their initial imaging, which included CT without contrast (36.2%), CT with contrast (54.1%), and MRI (9.7%). Eighty-nine patients (20.0%) underwent additional imaging within 90 days, 8.3% (37/444) underwent renal mass biopsy, and 3.6% (16/444) had reimaging and renal mass biopsy. Additional imaging reclassified 58.1% (61/105) of indeterminate renal lesions as suspicious and 21.0% (22/105) as benign, with only 20.9% (22/105) remaining indeterminate. Renal mass biopsy yielded a definitive diagnosis for 87%. Treatment was performed for 149 indeterminate renal lesions (33.6%), including 117 without reimaging and 123 without renal mass biopsy. At surgery for indeterminate renal lesions, benign pathology was more common in patients who did not have repeat imaging (9.9%) than in those who did (6.7%); for ≤4 cm indeterminate renal lesions, these rates were 11.8% and 4.3%. CONCLUSIONS: About 33% of patients diagnosed with an indeterminate renal lesion underwent immediate treatment without subsequent imaging or renal mass biopsy, with a 10% rate of nonmalignant pathology. This highlights a quality improvement opportunity for patients with cT1 renal masses: confirmation that the lesion is suspicious for renal cell carcinoma based on high-quality, multiphase, cross-sectional imaging and/or histopathological features prior to surgery, even if obtaining subsequent follow-up imaging and/or renal mass biopsy is necessary. When performed, these steps lead to reclassification in 79% and 87% of indeterminate renal lesions, respectively.

Inhibition of GCK-IV kinases dissociates cell death and axon regeneration in CNS neurons.

Axon injury is a hallmark of many neurodegenerative diseases, often resulting in neuronal cell death and functional impairment. Dual leucine zipper kinase (DLK) has emerged as a key mediator of this process. However, while DLK inhibition is robustly protective in a wide range of neurodegenerative disease models, it also inhibits axonal regeneration. Indeed, there are no genetic perturbations that are known to both improve long-term survival and promote regeneration. To identify such a neuroprotective target, we conducted a set of complementary high-throughput screens using a protein kinase inhibitor library in human stem cell-derived retinal ganglion cells (hRGCs). Overlapping compounds that promoted both neuroprotection and neurite outgrowth were bioinformatically deconvoluted to identify specific kinases that regulated neuronal death and axon regeneration. This work identified the role of germinal cell kinase four (GCK-IV) kinases in cell death and additionally revealed their unexpected activity in suppressing axon regeneration. Using an adeno-associated virus (AAV) approach, coupled with genome editing, we validated that GCK-IV kinase knockout improves neuronal survival, comparable to that of DLK knockout, while simultaneously promoting axon regeneration. Finally, we also found that GCK-IV kinase inhibition also prevented the attrition of RGCs in developing retinal organoid cultures without compromising axon outgrowth, addressing a major issue in the field of stem cell-derived retinas. Together, these results demonstrate a role for the GCK-IV kinases in dissociating the cell death and axonal outgrowth in neurons and their druggability provides for therapeutic options for neurodegenerative diseases.

A novel protective role for the innate immunity Toll-Like Receptor 3 (TLR3) in the retina via Stat3.

The innate immune system and inflammatory pathways play key roles in numerous diseases of the central nervous system (CNS). Recent evidence indicates that innate immunity induces both pathogenesis and protection during neuronal injury. To test the possibility that the conflicting roles of innate immunity in the CNS depends on the cellular environment in which innate immunity is stimulated, we analyzed the effect of Toll-Like Receptor 3 (TLR3) activation on neuronal survival in the presence and absence of oxidative injury in a mouse model system. We demonstrated that activation of TLR3 by the double stranded RNA activator, Poly (I:C), during paraquat induced oxidative stress, significantly protected mouse photoreceptors, as measured by increased retinal structure, function, and improved visual acuity. In contrast, TLR3 activation without concurrent oxidative injury was neurotoxic. The neurotoxic and protective effects of Poly (I:C) stimulation were absent in TLR3 knockout animals, which indicates that protection by Poly (I:C) is dependent on the TLR3 signaling pathway. Furthermore, we identified the pro-survival transcription factor Stat3 as a necessary mechanism for protection. Knockdown of Stat3 using lentivirally delivered shRNA abolished the protective effects of TLR3 signaling in the retina during oxidative stress. Therefore, TLR3 activation in the context of oxidative stress triggers protective instead of pathogenic signaling, suggesting that TLR3 is a potential therapeutic target for neurodegeneration where oxidative stress is a significant contributor.

Antibiotic Stewardship and Treatment of Uncomplicated Urinary Tract Infection (UTI) in Children and Adolescents in the Emergency Department of a Community Hospital.

A retrospective, cross-sectional study of children with suspected urinary tract infections (UTIs) 3 months to 18 years of age who had a urinalysis and urine culture (UC) during an emergency department (ED) visit between 2019 and 2020 was performed. Chi-square, Fisher exact, and independent samples T tests were used as appropriate. Median age was 6.6 years (interquartile range = 3.3-12.4). Urinalysis positivity was 92.8%, of which 81.9% of children were prescribed a first-line antibiotic. First-line antibiotic use was 82.7%. Positive UC rate was 84.7%, with 84% receiving a first-line antibiotic (P = .025). The correlation between a positive urinalysis and a positive UC was 80.8% (P < .001). Change of antibiotics based on the uropathogen of positive UCs was 6.3% (P < .001). The urinalysis and UC guided the diagnosis and treatment of UTIs. First-line antibiotics can be safely administered in the ED and prescribed for positive urinalyses. Studies are needed to evaluate the discontinuation of antibiotics with negative UCs as part of antibiotic stewardship initiatives.

Osteopontin drives retinal ganglion cell resiliency in glaucomatous optic neuropathy.

Chronic neurodegeneration and acute injuries lead to neuron losses via diverse processes. We compared retinal ganglion cell (RGC) responses between chronic glaucomatous conditions and the acute injury model. Among major RGC subclasses, αRGCs and intrinsically photosensitive RGCs (ipRGCs) preferentially survive glaucomatous conditions, similar to findings in the retina subject to axotomy. Focusing on an αRGC intrinsic factor, Osteopontin (secreted phosphoprotein 1 [Spp1]), we found an ectopic neuronal expression of Osteopontin (Spp1) in other RGCs subject to glaucomatous conditions. This contrasted with the Spp1 downregulation subject to axotomy. αRGC-specific Spp1 elimination led to significant αRGC loss, diminishing their resiliency. Spp1 overexpression led to robust neuroprotection of susceptible RGC subclasses under glaucomatous conditions. In contrast, Spp1 overexpression did not significantly protect RGCs subject to axotomy. Additionally, SPP1 marked adult human RGC subsets with large somata and SPP1 expression in the aqueous humor correlated with glaucoma severity. Our study reveals Spp1's role in mediating neuronal resiliency in glaucoma.

Building a Roadmap for Surveillance of Renal Masses Using a Modified Delphi Method to Help Achieve Consensus.

OBJECTIVE: To establish a consensus for initial evaluation and follow-up of patients on active surveillance (AS) for T1 renal masses (T1RM). METHODS: A modified Delphi method was used to gather information about AS of T1RM, with a focus on patient selection, timing/type of imaging modality, and triggers for intervention. A consensus panel of Michigan Urological Surgery Improvement Collaborative-affiliated urologists who routinely manage renal masses was formed. Areas of consensus (defined >80% agreement) about T1RM AS were established iteratively via 3 rounds of online questionnaires. RESULTS: Twenty-six Michigan Urological Surgery Improvement Collaborative urologists formed the panel. Consensus was achieved for 321/587 scenarios (54.7%) administered through 124 questions. Life expectancy, age, comorbidity, and renal function were most important for patient selection, with life expectancy ranking first. All tumors <3 cm and all patients with life expectancy <1 year were considered appropriate for AS. Appropriateness also increased with elevated perioperative risk, increasing tumor complexity, and/or declining renal function. Consensus was for multiphasic axial imaging initially (contrast CT for GFR >60 or MRI for GFR >30) with first repeat imaging at 3-6 months and subsequent imaging timing determined by tumor size. Consensus was for chest imaging for tumors >3 cm initially and >5 cm at follow up. Renal biopsy was not felt to be a requirement for entering AS, but useful in several scenarios. Consensus indicated rapid tumor growth as an appropriate trigger for intervention. CONCLUSION: Our consensus panel was able to achieve areas of consensus to help define a clinically useful and specific roadmap for AS of T1RM and areas for further discussion where consensus was not achieved.

Initial Observation of a Large Proportion of Patients Presenting with Clinical Stage T1 Renal Masses: Results from the MUSIC-KIDNEY Statewide Collaborative.

BACKGROUND: While surgical excision remains the principal management strategy for clinical T1 renal masses (cT1RMs), the rates of noninterventional approaches are not well known. Most single-institution and population-based series suggest rates below 10%. OBJECTIVE: To evaluate the use of observation for newly diagnosed cT1RM patients in academic and community-based practices across a statewide collaborative. DESIGN SETTING AND PARTICIPANTS: The Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) commenced data collection in September 2017 by recording clinical, radiographic, pathologic, and short-term follow-up data for cT1RM patients at 13 diverse practices. Patients with complete data were assessed at >90 d after initial evaluation as to whether observation or treatment was performed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Relationships with outcomes were analyzed using multivariable logistic regression, chi-square test, and Wilcoxon rank-sum test. RESULTS AND LIMITATIONS: Out of 965 patients, observation was employed in 48% (n = 459), with practice-level rates ranging from 0% to 68%. Patients managed with observation (vs treatment) were significantly older (71.2 vs 62.8 yr, p < 0.0001) and had smaller tumors (2.3 vs 3.4 cm, p < 0.0001). Observation was used for 53.5% of cT1a renal masses, for 29.9% of cT1b renal masses, and for 42.5%, 53.7%, and 63.9% of radiographically solid, Bosniak III-IV cystic, and indeterminate cT1RMs, respectively. Factors significantly associated with observation in multivariable analysis included lesion type (Bosniak III-IV vs solid, p = 0.017), tumor stage (cT1a vs cT1b, p < 0.001), and higher age (p < 0.001). A short duration of follow-up limits the assessment of longer-term patient management. CONCLUSIONS: Noninterventional management of cT1RMs is common across the MUSIC-KIDNEY collaborative, with wide variability across practices. Factors associated with observation were advanced age, smaller tumor size, and cystic tumor type. Durability of the initial decision for observation (delayed intervention vs active surveillance vs less active surveillance) will be a focus of subsequent study. PATIENT SUMMARY: The Michigan Urological Surgery Improvement Collaborative: Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) quality improvement collaborative assessed the current utilization of initial observation of a renal mass ≤7 cm across a diverse group of urology practices and found it to be used in 48% of patients. We found that the factors predicting observation were advanced age, smaller tumor size, and cystic tumor type.

Utilization of Renal Mass Biopsy for T1 Renal Lesions across Michigan: Results from MUSIC-KIDNEY, A Statewide Quality Improvement Collaborative.

BACKGROUND: Renal mass biopsy (RMB) has had limited and varied utilization to guide management of renal masses (RM). OBJECTIVE: To evaluate utilization of RMB for newly diagnosed cT1 RMs across diverse practice types and assess associations of outcomes with RMB. DESIGN SETTING AND PARTICIPANTS: MUSIC-KIDNEY commenced data collection in September 2017 for all newly presenting patients with a cT1 RM at 14 diverse practices. Patients were assessed at ≥120 d after initial evaluation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Demographics and outcomes were compared for patients undergoing RMB versus no RMB. Clinical and demographic characteristics were summarized by RMB status using a χ2 test for categorical variables and Student t test for continuous variables. A mixed-effects logistic regression model was constructed to identify associations with RMB receipt. RESULTS AND LIMITATIONS: RMB was performed in 15.5% (n = 282) of 1808 patients with a cT1 RM. Practice level rates varied from 0% to 100% (p = 0.001), with only five of 14 practices using RMB in >20% of patients. On multivariate analysis, predictors of RMB included greater comorbidity (Charlson comorbidity index ≥2 vs 0: odds ratio [OR] 1.44; p = 0.025) and solid lesion type (cystic vs solid: OR 0.17; p = 0.001; indeterminate vs solid: OR 0.58; p = 0.01). RMB patients were less likely to have benign pathology at intervention (5.0% vs 13.5%; p = 0.01). No radical nephrectomies were performed for patients with benign histology at RMB. The limitations include short follow-up and inclusion of practices with low numbers of RMBs. CONCLUSIONS: Utilization of RMB varied widely across practices. Factors associated with RMB include comorbidities and lesion type. Patients undergoing RMB were less likely to have benign histology at intervention. PATIENT SUMMARY: Current use of biopsy for kidney tumors is low and varies across our collaborative. Biopsy was performed in patients with greater comorbidity (more additional medical conditions) and for solid kidney tumors. Pretreatment biopsy is associated with lower nonmalignant pathology detected at treatment.

Stromal support for Descemet's membrane endothelial keratoplasty.

PURPOSE: To evaluate the use of a peripheral stromal support to facilitate and improve the outcomes of Descemet's membrane endothelial keratoplasty (DMEK). DESIGN: Prospective case series. PARTICIPANTS: Ten patients with Fuchs' endothelial dystrophy. INTERVENTION: Pneumatic dissection was used to detach the central part of the Descemet's membrane and endothelium from the deep stroma. Endothelial grafts including a peripheral stromal support were obtained by eccentric punching of donor tissue and used to perform DMEK surgery in 10 patients. MAIN OUTCOME MEASURES: Operative time, graft attachment rate, best spectacle-corrected visual acuity (BSCVA), endothelial cell loss, refraction, and complications. RESULTS: In all cases the surgical time was ≤ 1 hour. The postoperative course was uneventful in all but 2 cases, which required rebubbling owing to early graft detachment. Final attachment rate was 100%. The average follow-up was 8.4 months (range, 6-12). Postoperative BSCVA was ≥ 20/40 in all cases and no substantial change in refraction was recorded. Postoperative endothelial cell loss averaged 24.1% (range, 8%-34.9%). CONCLUSIONS: Stromal support facilitates surgery, reduces complications, and appears to maintain the favorable outcomes of DMEK.

Pneumatic dissection and storage of donor endothelial tissue for Descemet's membrane endothelial keratoplasty: a novel technique.

PURPOSE: To investigate the feasibility of pneumatic dissection of donor endothelium and the effect of 7 days of storage in tissue culture medium on the endothelial cell count. DESIGN: Experimental study. PARTICIPANTS: We used 20 human donor corneoscleral tissues deemed unsuitable for transplantation. INTERVENTION: Donor corneas were mounted on an artificial anterior chamber and the anterior stroma removed with a 300-micron microkeratome head. Air was injected into the residual donor tissue with a 30-G needle from the endothelial side to detach Descemet's membrane. The "bubble" was expanded as far as possible into the periphery. A silicone weight was attached to the scleral ring and the prepared tissue was stored in tissue culture medium for 7 days. MAIN OUTCOME MEASURES: Complete detachment of Descemet's membrane, size of detachment, pre- and post-storage endothelial cell counts. RESULTS: Complete detachment of Descemet's membrane was achieved in 19 of 20 (95%) cases. In 12 (60%) cases, this was achieved with a single injection; 7 (35%) cases required repeat injections. In 1 case, Descemet's membrane could not be detached despite repeat air injections. The average size of detachment was 8.11+/-2.0 mm. Endothelial cell loss after 7 days of tissue culture medium storage was 4.44+/-4.3%. CONCLUSIONS: Descemet's membrane and endothelium can be separated from the overlying stroma with a simple technique using air dissection. An adequate size of graft tissue is obtained without the need to manually handle the tissue. The technique allows storage of the tissue in tissue culture medium with low endothelial cell loss.

Carotid Artery Flow Time Measured by Point-of-Care Ultrasound Correlates with Volume Changes in Pediatric Hemodialysis Patients.

Carotid artery flow time corrected for heart rate (CFTc) correlates with intravascular volume changes in adults but has not been studied adequately in the pediatric population. We studied how fluid status changes correlate with CFTc in pediatric patients undergoing hemodialysis. This prospective observational study involved pediatric patients aged 5-18 y undergoing chronic hemodialysis at a tertiary care children's hospital in the United States. We measured CFTc by point-of-care ultrasound before and after each hemodialysis session, including passive leg raise. One hundred sixty-eight CFTc measurements were obtained from a total of 21 patient encounters. Post-dialysis CFTc decreased by 21.7 ms (95% confidence interval: 12.3-31.0) (p < 0.001). Pre- and post-dialysis ∆CFTc measurements were proportionally correlated with volume removed in dialysis adjusted for weight (mL/kg) (R2 = 0.224, p = 0.03). There was no significant change in mean CFTc with passive leg raise before or after hemodialysis. In children on hemodialysis, changes in CFTc were moderately correlated with decrease in intravascular volume after hemodialysis.

Improving Point-of-Care Ultrasound Documentation and Billing Accuracy in a Pediatric Emergency Department.

OBJECTIVE: The performance and interpretation of point-of-care ultrasound (POCUS) should be documented appropriately in the electronic medical record (EMR) with correct billing codes assigned. We aimed to improve complete POCUS documentation from 62% to 80% and improve correct POCUS billing codes to 95% or higher through the implementation of a quality improvement initiative. METHODS: We collected POCUS documentation and billing data from the EMR. Interventions included: (1) staff education and feedback, (2) standardization of documentation and billing, and (3) changes to the EMR to support standardization. We used P charts to analyze our outcome measures between January 2017 and June 2018. RESULTS: Six hundred medical records of billed POCUS examinations were included. Complete POCUS documentation rate rose from 62% to 91%, and correct CPT code selection for billing increased from 92% to 95% after our interventions. CONCLUSIONS: The creation of a standardized documentation template incorporated into the EMR improved complete documentation compliance.

Quality of Care for Renal Masses: The Michigan Urological Surgery Improvement Collaborative-Kidney Mass: Identifying & Defining Necessary Evaluation & Therapy (MUSIC-KIDNEY).

INTRODUCTION: We describe the establishment of the Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) to improve the quality of care that patients in Michigan receive for localized, 7 cm or smaller (T1) renal masses. METHODS: The MUSIC-KIDNEY collaborative is comprised of 45 urologists from 8 group practices. From June 2017 to November 2018 surgeons collected data for 821 patients with newly diagnosed T1 renal masses. Goals are to reduce the overall burden of treatment for T1 renal masses specifically by avoiding treatment when a noninterventional approach is appropriate, reducing the treatment of benign renal masses, preventing radical nephrectomy when a kidney sparing approach is appropriate, and decreasing length of hospitalization and readmission rates. RESULTS: Median age at diagnosis was 66 years, 56.8% of patients were male and 83.8% were Caucasian. The patient populations differed across practice sites for age (p <0.001), tumor size (p=0.002), race (p <0.001), Charlson comorbidity index and insurance type (p <0.001). Tumor complexity was infrequently reported (35.1%). Initial management included surveillance/repeat imaging (45.1%), biopsy (15.4%), intervention (39.1%) and second opinion (0.6%). No treatment at initial presentation (0% to 74.5%) and nephron sparing treatment (0% to 100%) varied significantly among practices (p <0.001). Of 133 patients with T1 renal masses who underwent radical nephrectomy (39.8%) 53 had tumors smaller than 4 cm and/or surgical findings without malignancy. Readmission or emergency department visit within 30 days after renal surgery occurred in 7.6%. CONCLUSIONS: Initial findings of MUSIC-KIDNEY indicate practice level variation and several quality improvement opportunities. Focusing on these goals may optimize practice patterns and surgical outcomes across Michigan.

Genetically Encodable Contrast Agents for Optical Coherence Tomography.

Optical coherence tomography (OCT) has gained wide adoption in biological research and medical imaging due to its exceptional tissue penetration, 3D imaging speed, and rich contrast. However, OCT plays a relatively small role in molecular and cellular imaging due to the lack of suitable biomolecular contrast agents. In particular, while the green fluorescent protein has provided revolutionary capabilities to fluorescence microscopy by connecting it to cellular functions such as gene expression, no equivalent reporter gene is currently available for OCT. Here, we introduce gas vesicles, a class of naturally evolved gas-filled protein nanostructures, as genetically encodable OCT contrast agents. The differential refractive index of their gas compartments relative to surrounding aqueous tissue and their nanoscale motion enables gas vesicles to be detected by static and dynamic OCT. Furthermore, the OCT contrast of gas vesicles can be selectively erased in situ with ultrasound, allowing unambiguous assignment of their location. In addition, gas vesicle clustering modulates their temporal signal, enabling the design of dynamic biosensors. We demonstrate the use of gas vesicles as reporter genes in bacterial colonies and as purified contrast agents in vivo in the mouse retina. Our results expand the utility of OCT to image a wider variety of cellular and molecular processes.

Zwitterionic molecularly imprinted polymer-based solid-phase micro-extraction coupled with molecularly imprinted polymer sensor for ultra-trace sensing of L-histidine.

The proposed L-histidine sensing system composed of a molecularly imprinted solid-phase microextraction component combined with a molecularly imprinted polymer sensor was used to determine critical levels of test analyte in a complex matrix of highly diluted human blood serum without any non-specific sorption and false-positive contributions. The molecularly imprinted polymer was a zwitterionic polymer brush derived from the disodium salt of EDTA and chloranil, grafted to solid-phase microextraction material. The hyphenated approach was able to detect L-histidine quantitatively with a limit of detection as low as 0.0435 ng/mL (RSD = 0.2%, S/N = 3).

Targeted disruption of dual leucine zipper kinase and leucine zipper kinase promotes neuronal survival in a model of diffuse traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) is a major cause of CNS neurodegeneration and has no disease-altering therapies. It is commonly associated with a specific type of biomechanical disruption of the axon called traumatic axonal injury (TAI), which often leads to axonal and sometimes perikaryal degeneration of CNS neurons. We have previously used genome-scale, arrayed RNA interference-based screens in primary mouse retinal ganglion cells (RGCs) to identify a pair of related kinases, dual leucine zipper kinase (DLK) and leucine zipper kinase (LZK) that are key mediators of cell death in response to simple axotomy. Moreover, we showed that DLK and LZK are the major upstream triggers for JUN N-terminal kinase (JNK) signaling following total axonal transection. However, the degree to which DLK/LZK are involved in TAI/TBI is unknown. METHODS: Here we used the impact acceleration (IA) model of diffuse TBI, which produces TAI in the visual system, and complementary genetic and pharmacologic approaches to disrupt DLK and LZK, and explored whether DLK and LZK play a role in RGC perikaryal and axonal degeneration in response to TAI. RESULTS: Our findings show that the IA model activates DLK/JNK/JUN signaling but, in contrast to axotomy, many RGCs are able to recover from the injury and terminate the activation of the pathway. Moreover, while DLK disruption is sufficient to suppress JUN phosphorylation, combined DLK and LZK inhibition is required to prevent RGC cell death. Finally, we show that the FDA-approved protein kinase inhibitor, sunitinib, which has activity against DLK and LZK, is able to produce similar increases in RGC survival. CONCLUSION: The mitogen-activated kinase kinase kinases (MAP3Ks), DLK and LZK, participate in cell death signaling of CNS neurons in response to TBI. Moreover, sustained pharmacologic inhibition of DLK is neuroprotective, an effect creating an opportunity to potentially translate these findings to patients with TBI.

Combined panretinal photocoagulation and cataract surgery in a patient with diabetes mellitus.

A case is presented whereby a simple method of applying indirect laser during cataract surgery in the presence of retinal and iris neovascularization is described. The method involves placing an infusion cannula into the anterior chamber following standard phacoemulsification and soft lens matter removal. The main section is then sutured and indirect laser is delivered to the far retinal periphery with gentle manipulation of the eye. Successful delivery of indirect panretinal photocoagulation despite inadvertent vitreous loss in this case demonstrates the advantages of its use. Other advantages, including its use in previously vitrectomized eyes and allowing manipulation/indentation of the eye, control of bleeding, and better visualization, are discussed.

Wnt signaling promotes axonal regeneration following optic nerve injury in the mouse.

Adult mammalian CNS axons generally do not regenerate, creating an obstacle to effective repair and recovery after neuronal injury. The canonical Wnt/ß-catenin signaling pathway is an essential signal transduction cascade that regulates axon growth and neurite extension in the developing mammalian embryo. In this study, we investigated whether a Wnt/ß-catenin signaling activator could be repurposed to induce regeneration in the adult CNS after axonal injury. We used a retinal ganglion cell (RGC) axon crush injury model in a transgenic Wnt reporter mouse, and intravitreal injections were used to deliver Wnt3a or saline to the RGC cell bodies within the retina. Our findings demonstrated that Wnt3a induced Wnt signaling in RGCs and resulted in significant axonal regrowth past the lesion site when measured at two and four weeks post-injury. Furthermore, Wnt3a-injected eyes showed increased survival of RGCs and significantly higher pattern electroretinography (PERG) amplitudes compared to the control. Additionally, Wnt3a-induced axonal regeneration and RGC survival were associated with elevated activation of the transcription factor Stat3, and reducing expression of Stat3 using a conditional Stat3 knock-out mouse line led to diminished Wnt3a-dependent axonal regeneration and RGC survival. Therefore, these findings reveal a novel role for retinal Wnt signaling in axonal regrowth and RGC survival following axonal injury, which may lead to the development of novel therapies for axonal regeneration.

Defining the Relationships Among Retinal Function, Layer Thickness and Visual Behavior During Oxidative Stress-Induced Retinal Degeneration.

PURPOSE: The purpose of this study was to identify how changes in retinal structure and function correlate with visual deficits during increasing amounts of retinal degeneration. MATERIALS AND METHODS: Retinal degeneration was induced in adult mice by subretinal injections of paraquat (PQ) (0.2-1 mM). Retinal anatomy and photoreceptor layer thickness were quantified by histology and optical coherence tomography (OCT), retinal function was measured using electroretinography (ERG), and visual behavior were measured by optokinetic tracking, at 1 to 3 week post-injury. RESULTS: Photoreceptor layer structure, function and visual behavior declined at a linear rate over time following PQ-induced degeneration, with the correlations between outcome measures being lowest at mild injury levels and increasing with injury severity. Overall reductions in visual acuity were highly correlated with declines in retinal thickness (r(2) = 0.78) and function (r(2) = 0.67) and retinal thickness correlated with photoreceptor function (r(2) = 0.72). ERG a-wave scotopic amplitudes showed a stronger correspondence to retinal structure and visual behavior than b-waves. CONCLUSIONS: Measurements of photoreceptor loss at the structural and functional levels showed good correspondence with degeneration-associated changes in visual behavior after oxidative stress injury. The results provide new insight about the relative kinetics of measurements of retinal degeneration induced by oxidative stress, which could guide the choice of optimal outcome measurements for other retinal diseases.

Protective effects of a grape-supplemented diet in a mouse model of retinal degeneration.

OBJECTIVE: Retinal degenerations are a class of devastating blinding diseases that are characterized by photoreceptor dysfunction and death. In this study, we tested whether grape consumption, in the form of freeze-dried grape powder (FDGP), improves photoreceptor survival in a mouse model of retinal degeneration. METHODS: Retinal degeneration was induced in mice by acute oxidative stress using subretinal injection of paraquat. The grape-supplemented diet was made by formulating base mouse chow with FDGP, corresponding to three daily human servings of grapes, and a control diet was formulated with equivalent sugar composition as FDGP (0.68% glucose-0.68% fructose mixture). Mice were placed on the diets at weaning for 5 wk before oxidative stress injury until analysis at 2 wk post-injection. Retinal function was measured using electroretinography, thickness of the photoreceptor layer was measured using optical coherence tomography, and rows of photoreceptor nuclei were counted on histologic sections. RESULTS: In mice fed the control diet, oxidative stress significantly reduced photoreceptor layer thickness and photoreceptor numbers. In contrast, retinal thickness and photoreceptor numbers were not reduced by oxidative stress in mice on the grape-supplemented diet, indicating significantly higher photoreceptor survival after injury than mice on the control diet. Furthermore, mice on the grape diet showed preservation of retinal function after oxidative stress injury compared with mice on the control diet. CONCLUSIONS: A diet supplemented with grapes rescued retinal structure and function in an oxidative stress-induced mouse model of retinal degeneration, which demonstrates the beneficial effect of grapes on photoreceptors.