Long-term rescue of cone photoreceptor degeneration in retinitis pigmentosa 2 (RP2)-knockout mice by gene replacement therapy.

Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR or RP2 gene. With a goal to develop gene therapy for the XLRP-RP2 disease, we first performed detailed characterization of the Rp2-knockout (Rp2-KO) mice and observed early-onset cone dysfunction, which was followed by progressive cone degeneration, mimicking cone vision impairment in XLRP patients. The mice also exhibited distinct and significantly delayed falling phase of photopic b-wave of electroretinogram (ERG). Concurrently, we generated a self-complementary adeno-associated viral (AAV) vector carrying human RP2-coding sequence and demonstrated its ability to mediate stable RP2 protein expression in mouse photoreceptors. A long-term efficacy study was then conducted in Rp2-KO mice following AAV-RP2 vector administration. Preservation of cone function was achieved with a wide dose range over 18-month duration, as evidenced by photopic ERG and optomotor tests. The slower b-wave kinetics was also completely restored. Morphologically, the treatment preserved cone viability, corrected mis-trafficking of M-cone opsin and restored cone PDE6 expression. The therapeutic effect was achieved even in mice that received treatment at an advanced disease stage. The highest AAV-RP2 dose group demonstrated retinal toxicity, highlighting the importance of careful vector dosing in designing future human trials. The wide range of effective dose, a broad treatment window and long-lasting therapeutic effects should make the RP2 gene therapy attractive for clinical development.

Perioperative blood ordering optimization process using information from an anesthesia information management system.

BACKGROUND: As part of ongoing perioperative surgical home implantation process, we applied a previously published algorithm for creation of a maximum surgical blood order schedule (MSBOS) to our operating rooms. We hypothesized that using the MSBOS we could show a reduction in unnecessary preoperative blood testing and associated costs. STUDY DESIGN AND METHODS: Data regarding all surgical cases done at UC Irvine Health's operating rooms from January 1, 2011, to January 1, 2014 were extracted from the anesthesia information management systems (AIMS). After the data were organized into surgical specialties and operative sites, blood order recommendations were generated based on five specific case characteristics of the group. Next, we assessed current ordering practices in comparison to actual blood utilization to identify potential areas of wastage and performed a cost analysis comparing the annual hospital costs from preoperative blood orders if the blood order schedule were to be followed to historical practices. RESULTS: Of the 19,138 patients who were categorized by the MSBOS as needing no blood sample, 2694 (14.0%) had a type and screen (T/S) ordered and 1116 (5.8%) had a type and crossmatch ordered. Of the 6073 procedures where MSBOS recommended only a T/S, 2355 (38.8%) had blood crossmatched. The cost analysis demonstrated an annual reduction in actual hospital costs of $57,335 with the MSBOS compared to historical blood ordering practices. CONCLUSION: We showed that the algorithm for development of a multispecialty blood order schedule is transferable and yielded reductions in preoperative blood product screening at our institution.

T1rho mapping of entire femoral cartilage using depth- and angle-dependent analysis.

OBJECTIVES: To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis. METHODS: T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4° over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created. RESULTS: T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur. CONCLUSIONS: Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications. KEY POINTS: • T1rho profiles are not homogeneous over the entire femur. • There is angle- and depth-dependent variation in T1rho profiles. • There is no influence of magic angle effect on T1rho profiles. • Maps/graphs might be useful if several difficulties are solved.

Normal T2 map profile of the entire femoral cartilage using an angle/layer-dependent approach.

PURPOSE: To create standard T2 map profiles from the entire femoral cartilage of healthy volunteers in order to assess regional variations using an angular and layer-dependent approach. MATERIALS AND METHODS: Twenty healthy knees were evaluated using 3T sagittal images of a T2 mapping sequence. Manual segmentation of the entire femoral cartilage was performed slice-by-slice by two raters using MatLab. Inter- and intrarater reliabilities were calculated using intraclass correlation coefficient (ICC) and Bland-Altman analysis. T2 values were analyzed with respect to specific locations (medial condyle, trochlea, and lateral condyle), angles to B0 , and layers of cartilage (whole, deep, and superficial). RESULTS: Inter- and intrarater reliability obtained from the entire femoral cartilage was excellent (ICC = 0.84, 0.86, respectively). The ICCs around the trochlea were lower than those of the medial and lateral condyle. Both the inter- and intrarater Bland-Altman plots indicated larger differences in pixel count are seen as the size of the angular segment becomes larger. T2 values were significantly higher in the superficial layer compared to the deep layer at each femoral compartment (P < 0.001). A magic angle effect was clearly observed, especially within the whole and deep layer over the medial and lateral femoral condyles, except for the superficial layer at the medial condyle. CONCLUSION: The normal T2 map profiles of the entire femoral cartilage showed variations in ICCs by location and in T2 values by angles and layers. These profiles can be useful for diagnosis of early cartilage degeneration in a specific angle and layer of each condyle and trochlea.

Comparison of T1rho imaging between spoiled gradient echo (SPGR) and balanced steady state free precession (b-FFE) sequence of knee cartilage at 3T MRI.

PURPOSE: To investigate the difference in T1rho profiles of the entire femoral cartilage between SPGR and b-FFE sequences at 3.0T. MATERIALS AND METHODS: 20 healthy volunteers were enrolled in this study. T1rho images of each subject were acquired with two types of pulse sequences: SPGR and b-FFE. Femoral cartilage segmentation was performed by two independent raters slice-by-slice using Matlab. Inter- and intra-observer reproducibility between the two imaging protocols was calculated. The relative signal intensity (SI) of cartilage, subchondral bone marrow, joint effusion, and the relative signal contrast between structures of the knee were quantitatively measured. The difference in T1rho values between SPGR and b-FFE sequences was statistically analyzed using the Wilcoxon signed-rank test. RESULTS: The average T1rho value of the entire femoral cartilage with b-FFE was significantly higher compared to SPGR (p<0.05). The reproducibility of the segmented area and T1rho values was superior with SPGR compared to b-FFE. The inter-class correlation coefficient was 0.846 on SPGR and 0.824 on b-FFE. The intra-class correlation coefficient of T1rho values was 0.878 on SPGR and 0.836 on b-FFE. The two imaging techniques demonstrated different signal and contrast characteristics. The relative SI of fluid was significantly higher on SPGR, while the relative SI of subchondral bone was significantly higher on b-FFE (p<0.001). There were also significant differences in the relative contrast between fluid-cartilage, fluid-subchondral bone, and cartilage-subchondral bone between the two sequences (all p<0.001). CONCLUSION: We need to pay attention to differences in T1rho values between SPGR and b-FFE in clinical applications.