SF 6 COMPARED WITH C 2 F 6 FOR INFERIOR RHEGMATOGENOUS RETINAL REPAIR : The Manchester Pseudophakic Retinal Detachment Study

PURPOSE

To compare SF 6 relative with C 2 F 6 in the anatomical and functional outcomes following pars plana vitrectomy for uncomplicated primary pseudophakic rhegmatogenous retinal detachment with inferior causative breaks.

METHODS

This is a retrospective, comparative study on eyes with pseudophakic rhegmatogenous retinal detachment with inferior causative breaks that had small-gauge pars plana vitrectomy repair using SF 6 and C 2 F 6 tamponade between 2011 and 2020 at a tertiary centre in the United Kingdom. Primary outcome was single surgery anatomical success, and the secondary outcome was best-corrected visual acuity. Propensity score matching, using preoperative findings as covariates to account for relevant confounders, was performed.

RESULTS

From 162 pseudophakic rhegmatogenous retinal detachment eyes with inferior causative breaks, the median (interquartile range) follow-up was 82 (52-182) days. The single surgery anatomical success was 156 (96.3%) overall: 47 of 47 (100.0%) and 109 of 115 (94.8%) in the SF 6 and C 2 F 6 groups, respectively ( P = 0.182). Relative to the SF 6 group, the C 2 F 6 group had a higher mean number of tears (SF 6 : 3.1[2.0], C 2 F 6 : 4.5[2.7], P = 0.002) and greater retinal detachment extent (SF 6 : 5.3[2.9], C 2 F 6 : 6.2[2.6] clock hours, P = 0.025). Following propensity score matching analysis, 80 eyes were matched with 40 in each group to homogenize preoperative factors. No significant difference was found in single surgery anatomical success and best-corrected visual acuity between the groups following propensity score matching.

CONCLUSION

Primary pars plana vitrectomy with gas tamponade leads to a high single surgery anatomical success rate in uncomplicated pseudophakic rhegmatogenous retinal detachment with inferior causative breaks with no additional benefit associated with long-acting tamponade when comparing C 2 F 6 with SF 6 .

PERSISTENT SUBRETINAL FLUID AFTER VITRECTOMY FOR MACULAR HOLE-ASSOCIATED RETINAL DETACHMENT

PURPOSE

To evaluate the incidence, associated factors, and outcome of persistent subretinal fluid (SRF) after vitrectomy for macular hole-associated retinal detachment (MHRD).

METHODS

A total of 158 eyes from 156 patients with MHRD who achieved macular hole closure after primary vitrectomy were included in the analysis; persistent SRF was defined as the presence of SRF for more than 1 month after first surgery. Preoperative and postoperative parameters were analyzed for their relationship with SRF development.

RESULTS

Persistent SRF was observed in 19 eyes (12.0% of 158) postoperatively. Seven eyes (36.8% of 19) with persistent SRF eventually displayed complete absorption during follow-up. Univariate analysis revealed that eyes with persistent SRF were statistically associated with internal limiting membrane inverted flap, duration of symptoms, tamponade (perfluoropropane/silicone oil: 14/5 vs. 35/104, P < 0.001), and MHRD subtype (Type 1/Type 2/Type 3: 15/4/0 vs. 60/40/39, P = 0.003). In multivariate analysis, only internal limiting membrane inverted flap (odds ratio, 15.778, 95% confidence interval, 3.170-78.523; P = 0.001) was positively associated with persistent SRF. There were no significant differences in best-corrected visual acuity improvement ( P = 0.425) between the SRF involved foveal and without involved foveal groups and no significant differences between the SRF complete absorption and incomplete absorption groups.

CONCLUSION

Absorption of persistent SRF may be more difficult in MHRD eyes than in ordinary rhegmatogenous retinal detachment eyes. The internal limiting membrane inverted flap in MHRD was associated with a greater likelihood of persistent SRF. The location and incomplete absorption of persistent SRF did not seem to be associated with the final visual outcome.

LONG-TERM VISUAL OUTCOMES AND THE TIMING OF SURGICAL REPAIR OF FOVEA-SPLITTING RHEGMATOGENOUS RETINAL DETACHMENTS

PURPOSE

To evaluate the visual outcomes and the affect of timing of surgical repair of fovea-splitting rhegmatogenous retinal detachments.

METHOD

A retrospective, consecutive cohort from multiple surgeons at a single center. Fovea status (fovea-on, fovea-splitting, or fovea-off) was classified by preoperative optical coherence tomography. The primary outcome measure was the visual acuity at the last follow-up that was further correlated with the timing of surgical repair.

RESULTS

One hundred and ninety-five eyes were included with 62 fovea-on, 65 fovea-splitting, and 68 fovea-off detachments. The mean preoperative logarithm of the minimum angle of resolution visual acuity for fovea-on, fovea-splitting, and fovea-off groups was 0.16 ± 0.21, 0.70 ± 0.56, and 1.67 ± 0.87, respectively (P = <0.001). Mean postoperative logarithm of the minimum angle of resolution visual acuity for fovea-on, fovea-splitting, and fovea-off groups were 0.07 ± 0.13, 0.10 ± 0.15, and 0.20 ± 0.22, respectively (P = <0.001). A statistically significant difference in mean postoperative logMAR visual acuity was found between fovea-off and fovea-on groups (P = 0.003) and between fovea-off and fovea-splitting groups (P = 0.013), however not between fovea-on and fovea-splitting groups (P = 0.827). Visual acuity improved when repair was performed earlier after presentation for fovea-on (R = 0.378, P = 0.002) and fovea-off groups (R = 0.277, P = 0.022), but not for the fovea-splitting group (R = 0.089, P = 0.481).

CONCLUSION

We described the favorable visual outcomes of surgery for fovea-splitting rhegmatogenous retinal detachment and correlated these with the timing of surgical repair, which may help guide the management of this urgent, vision-threatening condition.

Impact of Contrast Echocardiography on Outcomes in Critically Ill Patients

Limited data suggests ultrasound enhancing agent (UEA) use is associated with changes in clinical management and lower mortality in intensive care unit (ICU) patients. We conducted a retrospective observational study to determine if contrast echocardiography (vs non-contrast echocardiography) is associated with differences in length of stay (LOS) and subsequent resource utilization in the ICU setting. The Premier Healthcare Database (Charlotte, NC) was analyzed to identify patients receiving Definity vs. no use of contrast during the initial rest transthoracic echocardiogram (TTE) in an ICU setting. The primary outcomes of interest were subsequent TTE and transesophageal echocardiography (TEE) during the index hospitalization, and ICU LOS. Propensity scoring was used to statistically model treatment selection to minimize selection bias. A total of 1,538,864 patients from 773 hospitals were identified as undergoing resting TTE in the ICU with use of DEFINITY in 51,141 (3.3%) patients and no contrast agent use in 1,487,723 (96.7%) patients. After adjusting for patient, clinical, and hospital characteristics, patients in the Definity cohort were less likely to undergo a subsequent TTE or TEE as compared to those in the no contrast cohort (odds ratio = 0.704 for TTE, odds ratio = 0.841 for TEE; p < 0.0001 for both). Adjusted mean ICU LOS for the Definity cohort was shorter than that of the no contrast cohort (4.59 vs 4.15 days, p < 0.0001). In conclusion, Definity-enhanced echocardiography in the ICU setting (in comparison with non-contrast TTE) is associated with lower rates of subsequent TTE and TEE during the index hospitalization, and shorter ICU LOS.

LONG-TERM SURGICAL OUTCOMES OF LENS CAPSULAR FLAP TRANSPLANTATION IN THE MANAGEMENT OF REFRACTORY MACULAR HOLE

PURPOSE

To report long-term surgical outcomes of autologous and allogenic lens capsular flap transplantation (LCFT) in refractory macular hole (MH) treatment.

METHODS

Fifty consecutive eyes with refractory MH who received LCFT were reviewed retrospectively. Twelve eyes underwent autologous LCFT (LCF obtained from the same eye in 7 eyes and the fellow eye in 5 eyes) and 38 eyes with allogenic LCFT. All eyes underwent complete vitrectomy, internal limiting membrane peeling if not peeled, LCF transplantation, and 15% perfluoropropane tamponade. Simultaneous autologus whole-blood application was applied in 31 eyes to reduce LCF dislocation. The patients maintained a facedown position for 2 weeks postoperatively. Demographic information, functional results, and structural changes were evaluated.

RESULTS

The mean preoperative MH diameter was 1,102.00 µm ± 561.63 µm. The mean follow-up duration was 18.50 months ± 6.05 months (range, 12.0-38.9 months). The MH was completely closed in 48 eyes (96.00%) (18 eyes receiving autologous LCFT and 30 receiving allogenic LCFT). There are no differences of age, previous MH surgery times, MH diameter, preoperative and postoperative best-corrected visual acuity, and closure rate between the subgroups. The median visual acuity improved from 1.78 (interquartile range, 1.28-1.85) logarithm of the minimum angle of resolution (median Snellen acuity: 20/1,200) preoperatively to 1.00 (interquartile range, 0.90-1.70) logarithm of the minimum angle of resolution (median Snellen acuity: 20/200) (P < 0.01) in all patients.

CONCLUSION

Both autologous and allogenic LCFT application may provide anatomical and visual improvements in refractory MH cases. Blood application can be applied in selected cases to reduce LCF dislocation. LCFT can be performed as first-line treatment for refractory MHs.

Cavitation Emissions Nucleated by Definity Infused through an EkoSonic Catheter in a Flow Phantom

The EkoSonic endovascular system has been cleared by the U.S. Food and Drug Administration for the controlled and selective infusion of physician specified fluids, including thrombolytics, into the peripheral vasculature and the pulmonary arteries. The objective of this study was to explore whether this catheter technology could sustain cavitation nucleated by infused Definity, to support subsequent studies of ultrasound-mediated drug delivery to diseased arteries. The concentration and attenuation spectroscopy of Definity were assayed before and after infusion at 0.3, 2.0 and 4.0 mL/min through the EkoSonic catheter. PCI was used to map and quantify stable and inertial cavitation as a function of Definity concentration in a flow phantom mimicking the porcine femoral artery. The 2.0 mL/min infusion rate yielded the highest surviving Definity concentration and acoustic attenuation. Cavitation was sustained throughout each 15 ms ultrasound pulse, as well as throughout the 3 min infusion. These results demonstrate a potential pathway to use cavitation nucleation to promote drug delivery with the EkoSonic endovascular system.

Reproducibility of 19 F-MR ventilation imaging in healthy volunteers

Purpose

To assess the reproducibility of percentage ventilated lung volume (%VV) measurements in healthy volunteers acquired by fluorine (¹⁹F)‐MRI of inhaled perfluoropropane, implemented at two research sites.

Methods

In this prospective, ethically approved study, 40 healthy participants were recruited (May 2018‐June 2019) to one of two research sites. Participants underwent a single MRI scan session on a 3T scanner, involving periodic inhalation of a 79% perfluoropropane/21% oxygen gas mixture. Each gas inhalation session lasted about 30 seconds, consisting of three deep breaths of gas followed by a breath‐hold. Four ¹⁹F‐MR ventilation images were acquired per participant, each separated by approximately 6 minutes. The value of %VV was determined by registering separately acquired ¹H images to ventilation images before semi‐automated image segmentation, performed independently by two observers. Reproducibility of %VV measurements was assessed by components of variance, intraclass correlation coefficients, coefficients of variation (CoV), and the Dice similarity coefficient.

Results

The MRI scans were well tolerated throughout, with no adverse events. There was a high degree of consistency in %VV measurements for each participant (CoV_observer1 = 0.43%; CoV_observer2 = 0.63%), with overall precision of %VV measurements determined to be within ± 1.7% (95% confidence interval). Interobserver agreement in %VV measurements revealed a high mean Dice similarity coefficient (SD) of 0.97 (0.02), with only minor discrepancies between observers.

Conclusion

We demonstrate good reproducibility of %VV measurements in a group of healthy participants using ¹⁹F‐MRI of inhaled perfluoropropane. Our methods have been successfully implemented across two different study sites, supporting the feasibility of performing larger multicenter clinical studies.

Biomimetic "Nanoplatelets" as a Targeted Drug Delivery Platform for Breast Cancer Theranostics

Breast cancer is a major threat to health and lives of females. Biomimetic nanotechnology brought brighter hope for early diagnosis and treatment of breast cancer. Here, we proposed a platelet (PLT) membrane-derived strategy for enhanced photoacoustic (PA)/ultrasonic (US)/fluorescence (FL) multimodal imaging and augmented synergistic photothermal/chemotherapeutic efficacy in tumor cells. A PA imaging contrast and photothermal agent, nanocarbons (CNs), a chemotherapeutic and FL material, doxorubicin (DOX), and perfluoropentane (PFP) were coencapsulated into the poly(lactic-co-glycolic) acid (PLGA) skeletons. Then, the PLT membranes were coated onto the PLGA NPs, which were named as "nanoplatelets" (DOX-PFP-CNs@PLGA/PM NPs). The "nanoplatelets", which conserved the structural advantages and inherent properties of PLTs, could not only escape from phagocytosis of macrophages but also actively targeted tumor cells by the way of antigen-antibody interactions between P-selectin on the PM and CD44 receptors of the tumor cells. With CNs and DOX loaded in, these "nanoplatelets" could serve as an excellent contrast agent for PA/FL imaging. Under laser irradiation, the "nanoplatelets" could turn light energy into heat energy. The laser-triggered photothermal effect, on the one hand, could ablate the tumor cells immediately, and on the other hand, could initiate the optical droplet vaporization of PFP, which subsequently enhanced US imaging and promoted the discharge of encapsulated DOX from the "nanoplatelets" for remarkably strengthening photothermal therapeutic power in turn. In this work, as compared with the bare drug-loaded nanoparticles, the "nanoplatelets" exhibited much more accumulation in the tumor cells, demonstrating superior multimodal imaging capability and preferable synergistic therapeutic performance. In conclusion, the "nanoplatelets" could serve as contrast agents for US imaging and PA imaging to guide the therapy. What is more, the bioinspired PLT-derived, targeted, and nontoxic "nanoplatelets", which were exploited for multimodal PA/US/FL imaging-guided synergistic photothermal/chemo therapy, will be of great value to breast cancer theranostics in the days to come.

The effect of the perfluorocarbon emulsion Oxycyte™ in an ovine model of severe decompression illness

BACKGROUND

The treatment of decompression sickness (DCS) with hyperbaric oxygen (HBO2) serves to decrease intravascular bubble size, increase oxygen (O2) delivery to tissue and enhance the elimination of inert gas. Emulsified perfluorocarbons (PFC) combined with breathing O2 have been shown to have similar effects animal models. We studied an ovine model of severe DCS treated with the intravenous PFC Oxycyte™ while breathing O2 compared to saline control also breathing O2.

METHODS

Juvenile male sheep (N=67; weight 24.4±2.10kg) were compressed to 257 feet of sea water (fsw) in our multiple large-animal chamber where they remained under pressure for 31 minutes. Animals then were decompressed to surface pressure and randomized to receive either Oxycyte at 5mL/kg intravenously (IV) or 5mL/kg saline IV (both receiving 100% O2) 10 minutes after reaching surface pressure. Mortality was recorded at two hours, four hours, and 24 hours after receiving the study drug. Surviving animals underwent perfusion fixation and harvesting of the spinal cord at 24 hours. Spinal cord sections were assessed for volume of lesion area and compared.

RESULTS

There was no significant difference in survival at two hours (p=0.2737), four hours (p=0.2101), or 24 hours (p=0.3171). Paralysis at 24 hours was not significantly different. However, spinal cord lesion area was significantly smaller in the Oxycyte group as compared to the saline group, with median spinal cord lesion areas 0.65% vs. 0.94% (p=0.0107).

CONCLUSION

In this ovine model of severe DCS the intravenous PFC Oxycyte did not reduce mortality but did ameliorate spinal cord injury when used after the onset of DCS.

Risk factors for breakthrough vitreous hemorrhage after intravitreal tissue plasminogen activator and gas injection for submacular hemorrhage associated with age related macular degeneration

Purpose

We investigated risk factors for breakthrough vitreous hemorrhage (VH) after an intravitreal tissue plasminogen activator (tPA) and gas injection in patients with submacular hemorrhage (SMH) associated with age-related macular degeneration (AMD).

Methods

The medical records of patients diagnosed with SMH associated with AMD who received an intravitreal tPA (50 μg/0.05 mL) and perfluoropropane gas (0.3 mL) injection were reviewed retrospectively. We analyzed the associations of breakthrough VH with age, sex, best-corrected visual acuity, intraocular pressure, AMD subtype, accompanying sub-retinal pigment epithelium (RPE) hemorrhage, history of cataract surgery, history of hypertension and diabetes mellitus, history of drinking and smoking, and history of antiplatelet or anticoagulant medication. We also examined the relationships between various parameters, including the area ratio of the SMH to the optic disc (AHD) and the height of the SMH obtained from optical coherence tomography.

Results

In total, 52 eyes from 52 patients were enrolled in this study; 16 eyes (30%) showed breakthrough VH. The proportions of patients with a current smoking history were 75.0% in the VH group and 22.2% in the non-VH group (p = 0.010). Other factors did not differ significantly between the two groups. The proportion of cases with accompanying sub-RPE hemorrhage was 50.0% and 58.3% in the VH and non-VH groups, respectively (p = 0.763). The AHD (p = 0.001) and SMH height (p < 0.001) were significantly greater in the VH group. In a receiver operating characteristic curve analysis, the cut-off values of AHD and SMH height were 20.1 and 1208 μm, respectively. According to logistic regression analysis, when the AHD and SMH height were greater than the individual cut-off values, the odds ratio of VH increased by 10.286 fold (95% confidence interval [CI], 2.452–43.148; p = 0.001) and 75.400 fold (95% CI, 7.991–711.441; p < 0.001), respectively, with respect to their respective reference groups (less than the cut-off value). Among the significant factors associated with VH occurrence, including current smoking, AHD, and SMH height, only current smoking and SMH height were found to be significant in multiple regression analysis (p = 0.040, 0.016).

Conclusions

The incidence of breakthrough VH was significantly higher in those with current smoking status and for SMH with a larger AHD and greater height. The height of the SMH was more predictable of the possibility of VH than AHD.

Alleviating tumor hypoxia with perfluorocarbon-based oxygen carriers

Hypoxia is a major impediment to many foremost cancer treatments that require O₂ for generation of tumoricidal reactive oxygen species. Liquid perfluorocarbons (PFCs) are inert gas solvents that help alleviate this oxygen deficit situation. PFC nanoemulsions have demonstrated oxygen delivery to tissues. The lifetime of ¹O₂ in PFCs is considerably expanded. PFC nanodroplets extravasate and accumulate in tumors. Alternatively, PFCs stabilize injectable O₂ microbubbles. On-demand local O₂ delivery is facilitated by ultrasound. Liquid PFC nanodroplets that convert into microbubbles upon activation provide another shuttle for O₂-delivery. PFC nanocarriers can also be enriched with fluorescent dyes, radiopaque materials, photo(sono)sensitizers, loaded with chemotherapeutics, and fitted with targeting devices, or stimuli-responsive functions for image-guided theranostics. We review recent literature on PFC-based O₂ carriers to enhance the efficacy of radiotherapy, photo(sono)dynamic therapy and chemotherapy. Of particular relevance to this series of reviews, PFC-based carriers may provide novel strategies to promote T-cell trafficking into tumors to improve immune responses.

Tissue distribution and bioaccumulation of 8:2 fluorotelomer alcohol and its metabolites in pigs after oral exposure

The tissue distribution and bioaccumulation of 8:2 fluorotelomer alcohol (8:2 FTOH) were evaluated in pigs after oral exposure of a dose of 5 mg/kg.b.w.d. for 7 d. The bioaccumulation of 8:2 FTOH and its metabolites showed significant differences among the various tissues. The parent compound was quickly depleted, and the main metabolites perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and 3-perfluoroheptyl propanoic acid (7:3 FTCA) were detected in all tissues examined. The relative elimination half-life (T_1/2re) calculated by compound concentration of 7:3 FTCA and PFOA was longest in kidney tissue (8.60 and 23.9 d, respectively), while their absolute elimination half-life (T_1/2ab) of 7:3 FTCA and PFOA calculated by compound amount was longest in kidney tissue (10.41 and 64.1 d, respectively). The T_1/2re and T_1/2ab for PFHpA was longest in heart tissue (19.3 d and 30.26 d, respectively).The accumulated PFOA in kidney and liver tissues was still above the detection limit (LOD) at 21 d postdosing. These results indicate that PFOA and the kidneys are the ideal biomonitoring marker and target tissue, respectively, for 8:2 FTOH pollution. The T_1/2 values of the main metabolites were of long duration compared to the growth cycle of farmed pigs (approximately 180 d) before slaughter; therefore, pigs contaminated with 8:2 FTOH present a potential risk to humans.

Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

BACKGROUND

Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery to restore normal anatomy and to stabilize or improve vision. PVR usually occurs in association with recurrent RD (that is, after initial retinal re-attachment surgery), but occasionally may be associated with primary RD. Either way, for both circumstances a tamponade agent (gas or silicone oil) is needed during surgery to reduce the rate of postoperative recurrent RD.

OBJECTIVES

The objective of this review was to assess the relative safety and effectiveness of various tamponade agents used with surgery for RD complicated by PVR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (the Cochrane Library 2019, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2019), Embase (January 1980 to January 2019), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2019), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 January 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) on participants undergoing surgery for RD associated with PVR that compared various tamponade agents.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results independently. We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified four RCTs (601 participants) that provided data for the primary and secondary outcomes. Three RCTs provided data on visual acuity, two reported on macular attachment, one on retinal reattachment and another two on adverse events such as RD, worsening visual acuity and intraocular pressure. Study Characteristics Participants' characteristics varied across studies and across intervention groups, with an age range between 21 to 89 years, and were predominantly men. The Silicone Study was conducted in the USA and consisted of two RCTs: (silicone oil versus sulfur hexafluoride (SF₆) gas tamponades; 151 participants) and (silicone oil versus perfluropropane (C₃F₈) gas tamponades; 271 participants). The third RCT compared heavy silicone oil (a mixture of perfluorohexyloctane (F₆H₈) and silicone oil) with standard silicone oil (either 1000 centistokes or 5000 centistokes; 94 participants). The fourth RCT compared 1000 centistokes with 5000 centistokes silicone oil in 85 participants. We assessed most RCTs at low or unclear risk of bias for most 'Risk of bias' domains. Findings Although SF₆ gas was reported to be associated with worse anatomic and visual outcomes than was silicone oil at one year (quantitative data not reported), at two years, silicone oil compared to SF₆ gas showed no evidence of a difference in visual acuity (33% versus 51%; risk ratio (RR) 1.57; 95% confidence interval (CI) 0.93 to 2.66; 1 RCT, 87 participants; low-certainty evidence). At one year, another RCT comparing silicone oil and C₃F₈ gas found no evidence of a difference in visual acuity between the two groups (41% versus 39%; RR 0.97; 95% CI 0.73 to 1.31; 1 RCT, 264 participants; low-certainty evidence). In a third RCT, participants treated with standard silicone oil compared to those receiving heavy silicone oil also showed no evidence of a difference in the change in visual acuity at one year, measured on logMAR scale ( mean difference -0.03 logMAR; 95% CI -0.35 to 0.29; 1 RCT; 93 participants; low-certainty evidence). The fourth RCT with 5000-centistoke and 1000-centistoke comparisons did not report data on visual acuity. For macular attachment, participants treated with silicone oil may probably experience more favorable outcomes than did participants who received SF₆ at both one year (quantitative data not reported) and two years (58% versus 79%; RR 1.37; 95% CI 1.01 to 1.86; 1 RCT; 87 participants; low-certainty evidence). In another RCT, silicone oil compared to C₃F₈ at one year found no evidence of difference in macular attachment (RR 1.00; 95% CI 0.86 to 1.15; 1 RCT, 264 participants; low-certainty evidence). One RCT that compared 5000 centistokes to 1000 centistoke reported that retinal reattachment was successful in 67 participants (78.8%) with first surgery and 79 participants (92.9%) with the second surgery, and no evidence of between-group difference (1 RCT; 85 participants; low-certainty evidence). The fourth RCT that compared standard silicone oil with heavy silicone oil did not report on macular attachment. Adverse events In one RCT (86 participants), those receiving standard 1000 centistoke silicone oil compared with those of the 5000 centistoke silicone oil showed no evidence of a difference in intraocular pressure elevation at 18 months (24% versus 22%; RR 0.90; 95% CI 0.41 to 1.94; low-certainty evidence), visually significant cataract (49% versus 64%; RR 1.30; 95% CI 0.89 to 1.89; low-certainty evidence), and incidence of retina detachment after the removal of silicone oil (RR 0.36 95% CI 0.08 to 1.67; low-certainty evidence). Another RCT that compared standard silicone oil with heavy silicone oil suggests no difference in retinal detachment at one year (25% versus 22%; RR 0.89; 95% CI 0.54 to 1.48; 1 RCT; 186 participants; low-certainty evidence). Retinal detachment was not reported in the RCTs that compared silicone oil versus SF₆ and silicone oil versus to C₃F₈.

AUTHORS' CONCLUSIONS

There do not appear to be any major differences in outcomes between C₃F₈ and silicone oil. Silicone oil may be better than SF₆ for macular attachment and other short-term outcomes. The choice of a tamponade agent should be individualized for each patient. The use of either C₃F₈ or standard silicone oil appears reasonable for most patients with RD associated with PVR. Heavy silicone oil, which is not available for routine clinical use in the USA, may not demonstrate evidence of superiority over standard silicone oil.

Comparison of Residual Subfoveal Fluid by Intraoperative OCT After Macula-Involving RRD Repair Using Direct Drainage, Drainage Retinotomy, or Perfluoro-n-Octane

BACKGROUND AND OBJECTIVE

This study evaluated the residual subfoveal fluid (SFF) immediately after rhegmatogenous retinal detachment (RRD) repair using intraoperative optical coherence tomography (iOCT).

PATIENTS AND METHODS

This retrospective cohort study assessed fovea-involving RRD repaired by pars plana vitrectomy (PPV) using different drainage techniques. iOCT images were acquired through the fovea at the start of the case prior to initiating vitrectomy and then again immediately prior to introduction of tamponade.

RESULTS

Ten eyes (32.3%) received perfluoro-n-octane (PFO), 12 (38.7%) underwent a posterior drainage retinotomy, and nine (29.0%) had drainage through the retinal break. There was no significant difference in the mean SFF thickness between eyes in either group (P = .85). There was no significant association between SFF thickness on iOCT and functional or anatomic outcomes (P > .05).

CONCLUSION

There is no difference in the amount of residual SFF as measured on iOCT during RRD repair with pars plana vitrectomy using either direct drainage, drainage retinotomy, or PFO. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:497-503.].

Surgical outcomes of centripetal non-fovea-sparing internal limiting membrane peeling for myopic foveoschisis with and without foveal detachment: a follow-up of at least 3 years

BACKGROUND

We evaluated the surgical outcomes of vitrectomy with non-fovea-sparing internal limiting membrane (ILM) peeling for myopic foveoschisis with a follow-up of at least 3 years.

METHODS

In this retrospective study, 32 consecutive eyes with high myopia with or without foveal detachment underwent vitrectomy and centripetal, non-fovea-sparing ILM peeling with gas tamponade for myopic foveoschisis. Outcome measures were visual acuity (VA) and optical coherence tomography findings.

RESULTS

Mean axial length was 29.39±1.92 mm; mean follow-up was 42.66 (±8.29) months. Foveoschisis and foveal detachment completely resolved in all eyes postoperatively. Mean central foveal thickness (CFT) improved significantly from 631.88±191.72 to 232.65±69.67 µm, and mean best-corrected visual acuity improved significantly from 0.90 (Snellen equivalent (SE), 20/160)±0.43 logarithm of minimum angle of resolution (logMAR) to 0.43 (SE, 20/54)±0.29 logMAR (both p<0.001; two-tailed, paired t-test). Eyes with foveal detachment (n=10) at baseline had thicker preoperative CFT (737.8±239.83 vs 583.73±147.78 µm; p=0.033) but thinner postoperative CFT (188.20±31.52 vs 252.86±73.29 µm; p=0.012). Eyes without foveal detachment at baseline had significantly better postoperative VA (0.33 (SE, 20/43)±0.18 vs 0.65 (SE, 20/86)±0.37 logMAR; p=0.002). No macular hole or other complications occurred during follow-up.

CONCLUSION

Centripetal, non-fovea-sparing ILM peeling with gas tamponade may achieve myopic foveoschisis resolution and vision improvement without macular hole formation during at least 3-year follow-up.

Retinal Detachment: Patient Perspective and Electronic Health Records

PURPOSE

To provide a first-hand account of a retinal detachment suffered by one of the authors and how it relates to electronic health record (EHR) interoperability.

DESIGN

Single-patient, observational.

METHODS

1) Personal patient perspective - symptom, surgery, recovery and the worry about potential long lasting sequelae, and the need to reiterate detailed medical information several times during a stressful period. 2) U.S. National perspective regarding EHRs.

SETTING

Out-patient and community hospital. Patient or Study Population: Single patient. Intervention or Observation Procedure(s): Retinal surgery.

MAIN OUTCOME MEASURE(S)

Visual acuity.

RESULTS

Patient had a favorable outcome, but was required to provide medical history data multiple times to multiple providers. Only 41% of hospitals in the United States have EHR from outside providers or sources when treating a patient. Physicians in outpatient settings fare worse with only 14% of office-based physicians sharing data with providers outside of their organization.

CONCLUSIONS

While adoption and use of EHRs are incentivized by the federal government in the United States, the lack of interoperability between different physician and hospital systems means that we are far from achieving meaningful digitization of records. This case report provides a close look at how it may be difficult to receive care in a fragmented health care model in which physician and hospital do not share the same EHR. Information blocking, now prohibited by federal law, still remains an obstacle to interoperability. It will take continued effort and commitment from key stakeholders such as health care providers, patients, the federal government, and industry to bring this dream to fruition.

Acoustic Droplet Vaporization in Acoustically Responsive Scaffolds: Effects of Frequency of Excitation, Volume Fraction and Threshold Determination Method

Ultrasound-induced vaporization of liquid perfluorocarbon (PFC) droplets into microbubbles, termed acoustic droplet vaporization (ADV), has potential therapeutic and diagnostic applications. Recently, we demonstrated how ADV-a threshold-based phenomenon-can modulate the release of biomolecules from composite hydrogels, thereby stimulating regenerative processes, such as angiogenesis. These composite hydrogels, called acoustically responsive scaffolds (ARSs), consist of monodispersed, micron size PFC emulsions embedded within a fibrin matrix. This study investigated the effects of frequency of excitation (2.25, 5, 7.5 and 10 MHz) and volume fraction (0.05%, 0.2% and 1% [v/v]) of monodispersed, double emulsions in the ARSs on the ADV threshold. We determined and compared the ADV thresholds via acoustic methods, including active detection, passive detection and attenuation, as well as an echogenicity-based method using B-mode imaging. The ADV threshold determined via these four techniques showed an increasing trend with frequency of excitation. Further analysis of the wave propagation showed that the amplitudes of high frequency harmonics were diminished in ARSs with high volume fractions of emulsion. The ADV threshold inversely correlated with the volume fraction of emulsion at the lowest excitation frequency. However, at higher frequencies, possibly due to the high acoustic reflectivity of the PFC emulsions, the ADV threshold correlated directly with the volume fraction of the emulsion. Additionally, the ADV efficiency correlated with the supra-threshold acoustic pressure. Overall, these results elucidate fundamental acoustic properties of the ARSs, which can be used in future applications.

Acute exposure to perfluorononanoic acid in prepubertal mice: Effect on germ cell dynamics and an insight into the possible mechanisms of its inhibitory action on testicular functions

Perfluoroalkyl acids (PFAAs) are anthropogenic compounds used globally in a variety of commercial products. Perfluorononanoic acid (PFNA), a member of PFAAs, is detected in human blood and this has been reported to cause hepatotoxic, immunotoxic, and developmental and testicular toxic effects in laboratory animals. We have recently shown that the acute exposure to PFNA in prepubertal Parkes (P) mice impairs spermatogenesis by inducing oxidative stress and inhibiting testosterone biosynthesis in the testis. The present study was aimed to examine the effect of acute exposure to PFNA in prepubertal P mice on germ cell dynamics and to understand the possible mechanisms of action of this compound on testicular functions. PFNA (2 and 5 mg/kg body weight) was orally administered to male mice for 14 days from postnatal day 25-38. The treatment caused a decrease in overall germ cell transformation. The results also reveal that impairment in testicular functions in treated mice is associated with alterations in cholesterol and glucose homeostasis; further, an inhibition in expressions of growth hormone receptor (GHR), insulin-like growth factor-1 (IGF-1), insulin-like growth factor-1 receptor (IGF-1R), androgen receptor (AR), phosphorylated mammalian target of rapamycin (p-mTOR) and peroxisome proliferator activated receptor α (PPAR α) in the testis is also implicated in this action. The findings thus suggest involvement of multiple factors which altogether contribute to the alterations in spermatogenic process and testosterone production following acute exposure to PFNA in prepubertal mice.

Effect of catheter diameter and injection rate of flush solution on renal contrast-enhanced ultrasonography with perfluorobutane in dogs

OBJECTIVE

To assess effects of catheter diameter and injection rate of flush solution (saline [0.9% NaCl] solution) on renal contrast-enhanced ultrasonography (CEUS) with perfluorobutane in dogs.

ANIMALS

5 healthy Beagles.

PROCEDURES

CEUS of the kidneys was performed by IV injection of contrast medium (0.0125 mL/kg) followed by injection of 5 mL of saline solution at rates of 1, 3, and 5 mL/s through a 20-gauge or 24-gauge catheter; thus, CEUS was repeated 3 times for each catheter diameter. Time-intensity curves were created for regions of interest drawn in the renal cortex and medulla. Repeatability was determined by calculating the coefficient of variation (CV). Statistical analysis was used to assess whether perfusion variables or CV of the perfusion variables was associated with catheter diameter or injection rate.

RESULTS

Perfusion variables did not differ significantly between catheter diameters. Time to peak enhancement (TTP) in the renal cortex was affected by injection rate, and there were significantly lower values for TTP at higher injection rates. The CEUS variables with the lowest CVs among injection rates were TTP for the renal cortex; the CV for TTP of the renal cortex was the lowest at an injection rate of 5 mL/s.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of a 24-gauge catheter did not alter CEUS with perfluorobutane; therefore, such catheters could be used for CEUS of the kidneys of small dogs. Moreover, a rate of 5 mL/s is recommended for injection of flush solution to obtain greater accuracy for renal CEUS in Beagles.

Exposure to perfluorooctane sulfonate based on circadian rhythm changes the fecundity and expression of certain genes on the hypothalamic-pituitary-gonadal-liver axis of female zebrafish

Exposure of a variety of experimental animals to perfluorooctane sulfonate (PFOS) has shown that it is a potent endocrine-disrupting chemical. However, its interaction with the circadian rhythm on responses along the hypothalamic - pituitary - gonadal - liver (HPGL) axis should be of significant value but has not been adequately investigated. In present study, the effects of PFOS on fecundity, levels of estradiol (E₂) and expression of certain genes on the HPGL axis at two time points (8:00 AM and 7:00 PM) were compared after female zebrafish were exposed to 0, 2, 20 and 200 μg/L PFOS for 21 days. In brain, expressions of gonadotropin-releasing hormone (GnRH), gonadotropin-releasing hormone receptor (GnRHr), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were significantly different after the exposure when sampled at 8:00 AM and at 7:00 PM (P < .05). In liver, significant down-regulation of vitellogenin1 (VTG1) and estrogenic receptor α (ERα) were observed at 7:00 PM compared with 8:00 AM (P < .05). In ovary, the level of CYP19 was significantly different at the two time points (P < .05). The increase of E₂ after exposure to 20 μg/L PFOS at 8:00 AM caused compensatory down-regulation of GnRHr and up-regulation of VTG1 and ERα, but not at 7:00 PM. Profiles of concentrations of E₂ and several gene expressions alongside the HPGL axis were different between two times points. The change of E₂ and gene expressions were more perturbed by PFOS at 8:00 AM than at 7:00 PM with circadian rhythm.

Data derived Extrapolation Factors for developmental toxicity: A preliminary research case study with perfluorooctanoate (PFOA)

Guidelines of the United States Environmental Protection Agency (EPA, 1991) and the International Programme on Chemical Safety (IPCS, 2005) suggest two different default positions for dosimetric extrapolation from experimental animals to humans when the dosimetry of the critical effect is not known. The default position of EPA (1991) for developmental toxicity is to use peak concentration (or Cmax) for this dosimetric extrapolation. In contrast, IPCS (2005, page 39) states its default position for dosimetric choice in the absence of data is to use the area under the curve (or AUC). The choice of the appropriate dose metric is important in the development of either a Chemical Specific Adjustment Factor (CSAF) of IPCS (2005) or a Data Derived Extrapolation Factor (DDEF) of EPA (2014). This research shows the derivation of a DDEF for developmental toxicity for perfluorooctanoate (PFOA), a chemical of current interest. Here, identification of the appropriate dosimetric adjustment from a review of developmental effects identified by EPA (2016) is attempted. Although some of these effects appear to be related to Cmax, most appear to be related to the average concentration or its AUC, but only during the critical period of development for a particular effect. A comparison was made of kinetic data from PFOA exposure in mice with newly available and carefully monitored kinetic data in humans after up to 36 weeks of PFOA exposure in a phase 1 clinical trial by Elcombe et al. (2013). Using the average concentration during the various exposure windows of concern, the DDEF for PFOA was determined to be 1.3 or 14. These values are significantly different than comparable extrapolations by several other authorities based on differences in PFOA half-life among species. Although current population exposures to PFOA are generally much lower than both the experimental animal data and the clinical human study, the development of these DDEFs is consistent with current guidelines of both EPA (2014) and IPCS (2005).

Three-Dimensional Subharmonic Aided Pressure Estimation for Assessing Arterial Plaques in a Rabbit Model

OBJECTIVES

To investigate 3-dimensional subharmonic aided pressure estimation (SHAPE) for measuring intraplaque pressure and the pressure gradient across the plaque cap as novel biomarkers for potentially predicting plaque vulnerability.

METHODS

Twenty-seven rabbits received a high-cholesterol diet for 2 weeks before a balloon catheter injury to denude the endothelium of the aorta, followed by 8 to 10 weeks of the high-cholesterol diet to create arteriosclerotic plaques. SHAPE imagings of the resulting plaques were performed 12, 16, and 20 weeks after injury using a LOGIQ 9 scanner with a 4D10L probe (GE Healthcare, Milwaukee, WI) before and during an infusion of Definity (Lantheus Medical Imaging, North Billerica, MA) and Sonazoid (GE Healthcare, Oslo, Norway). The ratios of the maximum subharmonic magnitudes at baseline and during the infusion were correlated with the intraplaque pressure and pressure gradient across the plaque cap obtained from direct measurements.

RESULTS

Ten rabbits died prematurely after the balloon injury procedure or due to toxicity from the high-cholesterol diet, whereas 2 rabbits were excluded for other conditions. Five rabbits were scanned in the 12-, 16-, and 20-week groups, respectively. Even after 20 weeks, the plaques that developed were very small (mean ± SD, 0.9 ± 0.4 × 0.14 ± 0.05 cm). Definity performed better than Sonazoid in this application but still only achieved a moderate correlation with pressure across the plaque cap (Definity, r = -0.40; Sonazoid, r = 0.22) and intraplaque pressure (Definity, r = -0.19; Sonazoid, r = -0.11).

CONCLUSIONS

Initial findings from plaque pressure estimation using 3-dimensional SHAPE technique showed only moderate correlations with reference standards, but that may be have been due to weaknesses in the animal model studied.

Characterization and Imaging of Lipid-Shelled Microbubbles for Ultrasound-Triggered Release of Xenon

Xenon (Xe) is a bioactive gas capable of reducing and stabilizing neurologic injury in stroke. The goal of this work was to develop lipid-shelled microbubbles for xenon loading and ultrasound-triggered release. Microbubbles loaded with either xenon (Xe-MB) or xenon and octafluoropropane (Xe-OFP-MB) (9:1 v/v) were synthesized by high-shear mixing. The size distribution and the frequency-dependent attenuation coefficient of Xe-MB and Xe-OFP-MB were measured using a Coulter counter and a broadband acoustic attenuation spectroscopy system, respectively. The Xe dose was evaluated using gas chromatography/mass spectrometry. The total Xe doses in Xe-MB and Xe-OFP-MB were 113.1 ± 13.5 and 145.6 ± 25.5 μl per mg of lipid, respectively. Co-encapsulation of OFP increased the total xenon dose, attenuation coefficient, microbubble stability (in an undersaturated solution), and shelf life of the agent. Triggered release of gas payload was demonstrated with 6-MHz duplex Doppler and 220-kHz pulsed ultrasound. These results constitute the first step toward the use of lipid-shelled microbubbles for applications such as neuroprotection in stroke.

Evaluation of Single and Joint Toxicity of Perfluorinated Carboxylic Acids and Copper to Metal-Resistant Arthrobacter Strains

Perfluorocarboxylic acid compounds (PFCAs) and copper have been regarded as ubiquitous environmental contaminants in aquatic ecosystems worldwide. However, data on their possible joint toxic effects on microorganisms are still lacking. To study the combined effects of four PFCAs with different carbon chain lengths and copper, a series of experiments were conducted to explore the acute toxicity of these PFCAs in the absence and presence of copper on a metal-resistant Arthrobacter strain GQ-9 by microcalorimetry. The thermokinetic parameters, including growth rate constant (k), inhibitory ratio (I), and half inhibitory concentration (IC₅₀), were calculated and compared using the data obtained from the power-time curves. Our work revealed that GQ-9 is more resistant to perfluorooctanoic acid (PFOA) than Escherichia coli. The single and joint toxicity of PFCAs with copper are dose- and carbon chain length-dependent. The longer the carbon chain length of PFCAs, the higher the toxicity. In addition, PFCAs interacted synergistically with copper. This work could provide useful information for the risk assessment of co-exposure to perfluorinated compounds and heavy metals in natural environments.

Changes in hepato-renal gene expression in microminipigs following a single exposure to a mixture of perfluoroalkyl acids

It is evident that some perfluoroalkyl acids (PFAAs), a group of globally dispersed pollutants, have long biological half-lives in humans and farm animals. However, the effects of PFAAs in domestic animals have not been fully elucidated. The present study investigated how exposure to a single dose of a mixture of 10 PFAAs influenced hepatic and renal gene expression and histopathology, as well as plasma clinical biochemistry, in microminipigs (MMPigs) over 21 days. In animals treated with PFAAs, the mRNA expression of twelve genes related to fatty acid metabolism was upregulated in the kidney, while only few of these genes were induced in the liver. The expression of several kidney injury-associated genes such as, IGFBP1, IGFBP6, GCLC X2, GCLC X3, MSGT1, OLR1 was upregulated in the kidney. Interestingly, the expression of IGFBP-genes was differentially altered in the liver and kidney. Our findings thus identified hepato-renal gene expression changes in MMPigs that were associated with various molecular pathways including peroxisome proliferation, lipid metabolism, kidney injury, and apoptosis. Furthermore, serum HDL levels were significantly decreased following exposure to PFAAs, whereas no significant histopathological changes were detected, as compared to the vehicle group. Taken together, the present study provided the first indication that a single exposure to a mixture of PFAAs can produce changes in MMPig renal gene expression that were observed three weeks post exposure, suggesting that more attention should be paid to the kidney as a primary target organ of PFAAs.

Treatment of Vitreomacular Traction with Intravitreal Injection of Perfluoropropane

PURPOSE

To evaluate the effect of one intravitreal injection of expansile gas in the treatment of vitreomacular traction (VMT).

METHODS

A retrospective review of eyes with VMT treated with singl injection of 0,3 ml of 100% C3F8 gas was performed. The procedure was performed on an outpatient basis under topical anesthesia.

RESULTS

Twelve consecutive patient (14 eyes) with symptomatic VMT underwent pneumatic vitreolysis. Mean extend of vitreomacular adhesion was 490,5 µm (408-751). A posterior vitreous detachment developed in 13 eyes (92,9 %) after a single gas injection, in 11 eyes (84,6 %) during the first month of follow-up, in 2 eyes within two month of injection. Mean baseline and last BCVA were 0,5 (0,16-0,18) and 0,67 (0,2-1,0) respectively (p.

Preclinical Validation of the Therapeutic Potential of Glasgow Oxygen Level Dependent (GOLD) Technology: a Theranostic for Acute Stroke

In acute stroke patients, penumbral tissue is non-functioning but potentially salvageable within a time window of variable duration and represents target tissue for rescue. Reperfusion by thrombolysis and/or thrombectomy can rescue penumbra and improve stroke outcomes, but these treatments are currently available to a minority of patients. In addition to the utility of Glasgow Oxygen Level Dependent (GOLD) as an MRI contrast capable of detecting penumbra, its constituent perfluorocarbon (PFC) oxygen carrier, combined with normobaric hyperoxia, also represents a potential acute stroke treatment through improved oxygen delivery to penumbra. Preclinical studies were designed to test the efficacy of an intravenous oxygen carrier, the perfluorocarbon emulsion Oxycyte® (O-PFC), combined with normobaric hyperoxia (50% O₂) in both in vitro (neuronal cell culture) and in vivo rat models of ischaemic stroke. Outcome was assessed through the quantification of lipid peroxidation and oxidative stress levels, mortality, infarct volume, neurological scoring and sensorimotor tests of functional outcome in two in vivo models of stroke. Additionally, we investigated evidence for any positive or negative interactions with the thrombolytic recombinant tissue plasminogen activator (rt-PA) following embolus-induced stroke in rats. Treatment with intravenous O-PFC + normobaric hyperoxia (50% O₂) provided evidence of reduced infarct size and improved functional recovery. It did not exacerbate oxidative stress and showed no adverse interactions with rt-PA. The positive results and lack of adverse effects support human trials of O-PFC + 50% O₂ normobaric hyperoxia as a potential therapeutic approach. Combined with the diagnostic data presented in the preceding paper, O-PFC and normobaric hyperoxia is a potential theranostic for acute ischaemic stroke.

Two-stage oxygen delivery for enhanced radiotherapy by perfluorocarbon nanoparticles

Tumors are usually hypoxic, which limits the efficacy of current tumor therapies, especially radiotherapy in which oxygen is essential to promote radiation-induced cell damage. Herein, by taking advantage of the ability of perfluorocarbon (PFC) to promote red blood cell penetration, we developed a simple but effective two-stage oxygen delivery strategy to modulate the hypoxic tumor microenvironment using PFC nanoparticles. Methods: We first examined the two-stage oxygen delivery ability of PFC nanoparticles on relieving tumor hypoxia through platelet inhibition. To evaluate the effect of PFC nanoparticles on radiation sensitization, CT26 tumor and SUM49PT tumor model were used. Results: In this study, PFC was encapsulated into albumin and intravenously injected into tumor-bearing mice without hyperoxic breathing. After accumulation in the tumor, PFC nanoparticles rapidly released the oxygen that was physically dissolved in PFC as the first-stage of oxygen delivery. Then, PFC subsequently promoted red blood cell infiltration, which further released O2 as the second-stage of oxygen delivery. Conclusion: The hypoxic tumor microenvironment was rapidly relieved via two-stage oxygen delivery, effectively increasing radiotherapy efficacy. The safety of all substances used in this study has been clinically demonstrated, ensuring that this simple strategy could be rapidly and easily translated into clinical applications to solve the clinical problems associated with tumor hypoxia.

Autologous Neurosensory Retinal Free Flap Treatment for a Large Macular Hole

A patient presented with a large chronic macular hole (MH) of 700 μm. Best-corrected visual acuity (BCVA) was 20/200. Since the MHs edges were attached and stiff, an autologous neurosensory retinal flap was harvested and placed into the MH to close it. Perfluoro-n-octane heavy liquid (PFC) was instilled over the flap and exchanged with silicone oil (1,000 cs). Seven days postoperatively, the MH was closed, with a BCVA of 20/80 that improved to 20/60 at months 1 and 3. Optical coherence tomography and angiography showed patch incorporation with fovea formation and normal circulation. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e89-e92.].

Closure of Macular Hole Associated With Extreme High Myopia After Conventional Vitrectomy With ILM Peeling

Macular hole associated with high myopia (MH-HM) and macular hole-associated retinal detachment (MH-RD) are two conditions found in eyes with pathologic myopia that often have poor postoperative outcomes. A discrepancy in size between the stretched retina and the posteriorly expanded sclera is a major factor in the pathogenesis. The authors report a case comprising both types of maculopathy, one in each eye. The eye with the MH-HM (right eye) represents the longest axial length ever reported to have successful macular hole closure by any technique. The authors conclude that traditional surgery can be an adequate treatment for such a challenging condition. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e99-e101.].

Post-Traumatic Giant Retinal Tear Without Posterior Vitreous Detachment: A Case Series

BACKGROUND AND OBJECTIVE

To investigate the vitreal condition in retinal detachment (RD) related to giant retinal tears (GRT) after ocular blunt trauma.

PATIENTS AND METHODS

Retrospective, observational study conducted at Azienda Ospedaliera Universitaria Careggi, Florence, Italy. The institutional review board and ethics committee approved the study. Records of 23 eyes of 23 patients affected by traumatic RD associated with a GRT were evaluated. A total of four eyes had RD related to blunt trauma, in which the authors performed 25-gauge vitrectomy and silicone oil was used as a endotamponade.

RESULTS

Three out of four eyes did not display a posterior vitreous detachment at the B-scan, and this was confirmed during surgery. The three eyes had a mean visual acuity of 20/32 1 month after silicone oil removal.

CONCLUSIONS

Posterior vitreous detachment may not be present in RD associated with GRT after blunt trauma. This knowledge could result in modified intraoperative management to improve postoperative outcomes. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:686-690.].

Macrophages as Drug Delivery Carriers for Acoustic Phase-Change Droplets

The major challenges in treating malignant tumors are transport of therapeutic agents to hypoxic regions and real-time assessment of successful drug release via medical imaging modalities. In this study, we propose the use of macrophages (RAW 264.7 cells) as carriers of drug-loaded phase-change droplets to penetrate ischemic or hypoxic regions within tumors. The droplets consist of perfluoropentane, lipid and the chemotherapeutic drug doxorubicin (DOX, DOX-droplets). The efficiency of DOX-droplet uptake, migration mobility and viability of DOX-droplet-loaded macrophages (DLMs) were measured using a transmembrane cell migration assay, the alamarBlue assay and flow cytometric analysis, respectively. Our results indicate the feasibility of utilizing macrophages as DOX-droplet carriers (DOX payload of DOX-droplets: 459.3 ± 35.8 µg/mL, efficiency of cell uptake DOX-droplets: 88.8 ± 3.5%). The migration mobility (total number of migrated microphages) of DLMs decreased to 32.3% compared with that of healthy macrophages, but the DLMs provided contrast-enhanced ultrasound imaging (1.7-fold enhancement) and anti-tumor effect (70.9% cell viability) after acoustic droplet vaporization, suggesting the potential theranostic applications of DLMs. Future work will assess the tumor penetration ability of DLMs, mechanical effect of droplet vaporization on in vivo anti-tumor therapy and the release of the carried drug by ultrasound-triggered vaporization.

Management of Subfoveal Perfluorocarbon Liquid: A Review

Perfluorocarbon liquid (PFCL) has been widely used in vitreoretinal surgeries, especially in retinal detachment treatment. A prominent complication of intraoperative PFCL application is inadvertent subretinal PFCL retention. Subfoveal PFCL, even in small amounts, receives much attention due to its potential side effect on the macular structure and function. Whether to observe with follow-up or to deal with surgery is often an intractable problem in the management of subfoveal PFCL. Safety and necessity are the 2 key issues in considering surgical treatment, that is, can we avoid surgically induced macular injury and will surgery be beneficial for the recovery of vision? Herein, the authors review sub-foveal PFCL retention with its risk factors, morphological manifestations, pathological studies, clinical natural consequences, and different surgical methods with their outcomes. Analysis of the existing literature shows that visual acuity improved significantly after subfoveal PFCL removal or displacement and was positively correlated with visual acuity before the operation.

Primary Vitrectomy for Bullous Rhegmatogenous Retinal Detachments Due to Complex Breaks

Introduction

The role of vitrectomy for the treatment of uncomplicated retinal detachments has not been clearly defined. This study reports the results of a series of eyes with bullous rhegmatogenous retinal detachment (RRD) due to complex breaks that were managed by primary vitrectomy.

Methods

The study consisted of a consecutive series of 22 eyes (22 patients) with a bullous RRD not complicated by proliferative vitreoretinopathy (PVR) associated with large, multiple, or posterior breaks. All eyes underwent vitrectomy, injection of perfluorocarbon liquid (PFCL), cryopexy and gas tamponade as the primary procedure. Encircling scleral bands were placed in all cases. Follow-up ranged from 6 to 24 months (mean 10.9 ± 6.5 months).

Results

Anatomical retinal re-attachment was achieved in all eyes after one operation. Best-corrected final visual acuity was improved in all cases. Complications included progressive posterior subcapsular and nucleosclerotic cataract in four (22%) of the 18 phakic eyes and epiretinal membrane in one patient.

Conclusions

These results, together with the relatively low incidence of complications, lead us to conclude that this technique is an effective method for treatment of bullous RRD not complicated by PVR associated with technically difficult breaks. A controlled, prospective, randomized study would be necessary to thoroughly assess the advantages of vitrectomy over scleral buckling alone in these cases.

The Balloon-Gas Procedure: A Technique for Repair of Retinal Detachments Requiring Large Volumes of Gas

This report describes the balloon-gas procedure, a technique for obtaining large volumes of intraocular gas. With the balloon-gas procedure a kind of "external fluid-gas exchange" allows for the safe injection of up to 1.0 ml of gas without previous pars plana vitrectomy or surgical drainage of subretinal fluid. From April 1985 to October 1988, in Tübingen, this procedure was utilized in 36 retinal detachments with breaks not suited for scleral buckling: giant tears (nine eyes), large dialyses (seven eyes), posterior breaks (16 eyes), and multiple breaks at different latitudes (four eyes). Follow-up ranged from six to 28 months (average 16 months). Initial retinal reattachment was achieved in 28 eyes (77.8%). Reasons for initial failure were proliferative vitreoretinopathy in six eyes, and a missed break in two. Redetachment occurred in three eyes. All 11 failures were reoperated using segmental sponges (eight eyes) and gas injection (three eyes). Final reattachment was achieved in 29 of the 36 eyes (80.6%), and final failure was due to proliferative vitreoretinopathy in all seven detachments.

1-Octadecene as a Solvent for Ferrofluids for Intraocular use

Purpose.

1-Octadecene is a hydrocarbon with one double bond in its structure that could serve as a solvent for ferrofluids. The aim of this pilot study was to obtain preliminary information on intraocular tolerance to 1-octadecene.

Methods.

Vitreous compression with perfluoropropane gas was achieved in 20 eyes of albino rabbits. Four days after gas injection a fluid-gas exchange was undertaken. Sixteen eyes received 1-octadecene. Four eyes received balanced salt solution. Eyes were obtained at 3, 7, 14 and 30 days. The samples were fixed in 10% buffered formalin, processed in paraffin and sections were stained with hematoxylin and eosin.

Results.

Emulsification of the oil bubble was observed in 31.25% of the cases by the fifth day; light microscopy showed normal retinal architecture in all the eyes and epiretinal and vitreous macrophages in 50% of the eyes.

Conclusions.

1-Octadecene does not appear to have any retinal cytotoxic effect but elicits an inflammatory response in the vitreous activity.

Surgical Results for Proliferative Vitreoretinopathy

We reviewed 88 consecutive eyes that underwent vitrectomy for retinal detachment with proliferative vitreoretinopathy (PVR) and were followed a minimum of six months. A primary goal of the surgery was the meticulous trimming of the vitreous base in hopes of decreasing the incidence of post-operative reproliferation and anterior PVR. Those eyes with anterior PVR had aggressive release of vitreous base contraction (anteroposterior and circumferential) with intraocular scissors. All posterior tractional membranes were removed. All eyes received long-acting gas for postoperative retinal tamponade. Macular reattachment was achieved in 78 (88.6%) eyes. Forty-six (52.3%) obtained at least 5/200 vision. Seventeen (19%) eyes were re-operated at least once. We compared the importance of initial lens status (pseudophakic, aphakic, phakic), need for relaxing retinotomy, presence of anterior PVR, and history of previous vitrectomy on the anatomic and visual results. No single factor was responsible for a statistically significant effect on either vision or anatomic success, except for the need for a relaxing retinotomy, which carried with it a decreased chance of an eye obtaining 5/200 vision (Fisher's exact test, p = 0.03).

Hypertensive Gas Technique for Enucleation of Choroidal Melanomas: A Preliminary Report

The hypertensive gas technique induces avascularity within the eye during enucleation of a melanoma. Before touching the eye for enucleation, pressure is raised to maximum by an intravitreal injection of approximately 1.4 ml of gas (perfluorocarbon, air) resulting in a rock-hard eye. Avascularity persists for the duration of enucleation. From 9/1987 to 6/1989, 15 patients with choroidal melanomas were enrolled in a prospective study with the hypertensive gas technique instead of prior radiotherapy (the death rate in that series was five out of 26 melanoma patients at three years). Inclusion criteria for the hypertensive gas technique study were the same as for our previous irradiation series: (1) absence of detectable metastases and (2) a choroidal melanoma too large for a radioactive plaque. The average base diameter of melanomas measured 13.2 mm, height 8.4 mm. The cytology was: 11x spindle, 3x mixed, 1x epithelioid cells. At re-examination in 7/1991 (average follow-up 33 months) two diabetics had died with no detectable metastases prior to death, and one of the 15 melanoma patients had died with metastases 24 months after enucleation. So far the hypertensive gas technique for enucleation of a melanoma eye seems to have no adverse effect on survival. It seems to be a simple alternative to the precautions taken otherwise and it facilitates enucleation with pratically no bleeding from the globe.

Comparing the toxic potency in vivo of long-chain perfluoroalkyl acids and fluorinated alternatives

Since 2000, long-chain perfluoroalkyl acids (PFAAs) and their respective precursors have been replaced by numerous fluorinated alternatives. The main rationale for this industrial transition was that these alternatives were considered less bioaccumulative and toxic than their predecessors. In this study, we evaluated to what extent differences in toxicological effect thresholds for PFAAs and fluorinated alternatives, expressed as administered dose, were confounded by differences in their distribution and elimination kinetics. A dynamic one-compartment toxicokinetic (TK) model for male rats was constructed and evaluated using test data from toxicity studies for perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), perfluoroctanesulfonic acid (PFOS) and ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate (GenX). Dose-response curves of liver enlargement from sub-chronic oral toxicity studies in male rats were converted to internal dose in serum and in liver to examine the toxicity ranking of PFAAs and fluorinated alternatives. Converting administered doses into equivalent serum and liver concentrations reduced the variability in the dose-response curves for PFBA, PFHxA, PFOA and GenX. The toxicity ranking using modeled serum (GenX > PFOA > PFHxA > PFBA) and liver (GenX > PFOA ≈ PFHxA ≈ PFBA) concentrations indicated that some fluorinated alternatives have similar or higher toxic potency than their predecessors when correcting for differences in toxicokinetics. For PFOS and perfluorobutane sulfonic acid (PFBS) the conversion from administered dose to serum concentration equivalents did not change the toxicity ranking. In conclusion, hazard assessment based on internal exposure allows evaluation of toxic potency and bioaccumulation potential independent of kinetics and should be considered when comparing fluorinated alternatives with their predecessors.

Long-Term Results of Vitrectomy for Macular Holes after Failure of Vitreolysis

PURPOSE

Ocriplasmin injection may close some small-to-medium macular holes associated with vitreoretinal traction. If the treatment fails, does vitrectomy and gas injection yield the same results as primary surgery?

MATERIAL AND METHODS

We report a retrospective case series study of 3 eyes of 3 consecutive patients operated on a few months after initial intravitreal injection of ocriplasmin and enlargement of the macular hole. The minimal follow-up period after surgery was 18 months.

RESULTS

Surgery was uneventful in all cases. Vitrectomy, internal limiting membrane peeling, and gas injection allowed closing of the 3 macular holes with a progressive improvement in visual acuity over time. Before ocriplasmin injection, visual acuity ranged from 20/60 to 20/32, after failed ocriplasmin injection from 20/80 to 20/40, and at the final follow-up after 18 months from 20/32 to 20/25.

CONCLUSION

Vitrectomy with internal limiting membrane peeling leads to closure of macular holes even in cases of prior failure to close them by ocriplasmin injection.

Maternal Plasma per- and Polyfluoroalkyl Substance Concentrations in Early Pregnancy and Maternal and Neonatal Thyroid Function in a Prospective Birth Cohort: Project Viva (USA)

BACKGROUND

Prenatal exposure to some per- and polyfluoroalkyl substances (PFASs) may disrupt maternal and neonatal thyroid function, which is critical for normal growth and neurodevelopment.

OBJECTIVES

We examined associations of PFAS exposure during early pregnancy with maternal and neonatal thyroid hormone levels.

METHODS

We studied 732 mothers and 480 neonates in Project Viva, a longitudinal prebirth cohort in Boston, Massachusetts. We quantified six PFASs, including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and maternal thyroid hormones [thyroxine (T₄), Free T₄ Index (FT₄I), thyroid stimulating hormone (TSH)] in plasma samples collected at a median 9.6 wk gestation and neonatal T₄ levels from postpartum heel sticks. We estimated associations of PFAS concentrations with thyroid hormone levels using covariate-adjusted linear regression models and explored effect measure modification by maternal thyroid peroxidase antibody (TPOAb) status and infant sex.

RESULTS

PFAS concentrations were not associated with maternal T₄, but PFOA, perfluorohexane sulfonate (PFHxS), and 2-(N-methyl-perfluorooctane sulfonamido) acetate (MeFOSAA) were inversely associated with maternal FT₄I [e.g., -1.87% (95% confidence interval (CI): -3.40, -0.31) per interquartile (IQR) increase in PFOA]. PFAS concentrations [PFOA, PFOS, and perfluorononanoate (PFNA)] were inversely associated with TSH levels in TPOAb-positive women only. Prenatal PFOS, PFOA, and PFHxS concentrations were inversely associated with T₄ levels in male [e.g., PFHxS, quartile 4 vs.1: -2.51μg/dL (95% CI: -3.99, -1.04 )], but not female neonates [0.40μg/dL (95% CI: -0.98, 1.79)].

CONCLUSIONS

In this study, prenatal exposure to some PFASs during early pregnancy was inversely associated with maternal FT₄I and neonatal T₄ in male infants. These results support the hypothesis that prenatal exposure to PFASs influences thyroid function in both mothers and infants. https://doi.org/10.1289/EHP2534.

Outcomes of Vitreoretinal Surgery for Retinal Detachment after LASIK for Myopia

PURPOSE

To report and compare outcomes of vitreoretinal surgery for repair of retinal detachment in myopic patients with and without previous laser-assisted in situ keratomileusis (LASIK).

METHODS

This is a descriptive retrospective observational study with a control group for comparison that consisted of the analysis of clinical and surgical charts of patients who underwent vitreoretinal procedures for retinal detachment at the Fundación Oftalmologica Nacional between January 1995 and December 2002. The authors identified those myopic patients who had previous history of LASIK and an age- and myopia-matched control group without refractive surgery.

RESULTS

The sample contains 24 myopic eyes of 22 patients with previous LASIK and 23 myopic eyes without previous LASIK in the control group, matched by age and myopia. Mean refractive error was -9.4 D before LASIK for the cases group and -11.2 for the control group. Poor preoperative best-corrected visual acuity was present in 71% of cases and 61% of controls (p=0.489). Macula off retinal detachment was found in 17 eyes in both groups. Five eyes required at least two procedures, achieving 91% (20 eyes) reattachments at the end of follow-up in each group. Final best-corrected visual acuity was better than 20/100 in 15 eyes (62.5%) in the LASIK group and 17 eyes (74 %) in the control group (p=0.659).

CONCLUSIONS

Retinal detachment in patients with previous myopic LASIK has similar characteristics as in myopic patients without refractive surgery. Current vitreoretinal surgery is of good prognosis as the retina was successfully reattached in most cases in both groups.

A Simple way to Prevent Indocyanine Green from Entering the Subretinal Space during Vitrectomy for Retinal Detachment Due to Myopic Macular Hole

Purpose

To present a safe and simple method of preventing indocyanine green (ICG) from entering the subretinal space in patients undergoing vitrectomy for retinal detachment caused by myopic macular hole.

PATIENTS AND METHODS

Four consecutive highly myopic eyes (three phakic, one Pseudophakic) with retinal detachment due to myopic macular hole were operated on by pars plana vitrectomy. The ICG-assisted peeling of the internal limiting membrane was performed after temporarily closing the macular hole by means of a small bubble of perfluorocarbon liquid (PFCL) in order to prevent ICG from entering the subretinal space.

Results

Retinal reattachment was successful in all patients, and anatomic closure of the macular hole occurred during the follow-up period (range 3 to 10 months).

CONCLUSIONS

A small bubble of PFCL prevents ICG dye from entering the subretinal space during vitrectomy for retinal detachment due to macular hole in highly myopic eyes.

Phacoemulsification in the Vitreous Cavity for Retained Nuclear Lens Fragments

Purpose

To evaluate anatomic and functional results after surgery of retained lens fragments in the vitreous cavity after previous phacoemulsification.

Methods

The authors studied retrospectively 18 patients who underwent pars plana vitrectomy (PPV) for retained nuclear lens fragments. Patients having only cortical material in the vitreous cavity were excluded. In all cases the nucleus or nuclear fragments were removed after a complete vitrectomy using perfluorocarbon injection in the vitreous cavity, associated with phacoemulsification in the vitreous cavity. The authors used a conventional phaco probe devoid of the silicone sleeve. Time lapse between cataract surgery and vitrectomy varied between 0 and 24 days (mean 8.2 ± 7.4). Follow-up was 33.9 ± 20.6 months (range 4 to 53).

Results

The mean final best-corrected visual acuity (BCVA) was 20/45 (range 20/400 to 20/20). It was 20/40 or better in 33% of patients, reaching 40% when patients with pevious macular disease were excluded. A total of 61% of patients reached a final BCVA ranging from 20/50 to 20/200. Retinal detachment occurred in one eye and topical medications were necessary to manage intraocular pressure in four cases.

Conclusions

PPV with intravitreous phacoemulsification is the technique of choice for dislocated nuclei or nuclear fragments in the vitreous cavity.

Vitreoretinal Surgery of Retinal Detachment and Macular Hole Associated with Optic Nerve Pit: An Optical Coherence Tomography Study

PURPOSE

To describe the course of a case of macular elevation and a full-thickness macular hole associated with optic nerve pit.

METHODS

Case report. A 28-year-old woman who had laser-assisted in situ keratomileusis surgery 2.5 years ago presented with decreased vision, full-thickness macular hole, and macular detachment in association with optic nerve pit. Complete ophthalmic examination was done and optical coherence tomography (OCT) was performed before and after vitreoretinal surgery.

RESULTS

OCT showed that the macular elevation consisted of both separation of the inner and outer retinal layers with neurosensory retinal detachment. There was a full-thickness macular hole. After vitreous surgery and intraocular gas tamponade, the macular elevation completely resolved, and OCT showed the flattening of the outer and inner retinal layers but the macular hole was not closed.

CONCLUSIONS

OCT is a reliable technique to study macular elevation with a hole associated with optic nerve pit before and after vitrectomy and gas tamponade.

Perfluorocarbons Prevent Lung Injury and Promote Development during Artificial Placenta Support in Extremely Premature Lambs

BACKGROUND

Extremely premature neonates suffer high morbidity and mortality. An artificial placenta (AP) using extracorporeal life support (ECLS) is a promising therapy.

OBJECTIVES

We hypothesized that intratracheal perfluorocarbon (PFC) instillation during AP support would reduce lung injury and promote lung development relative to intratracheal amniotic fluid or crystalloid.

METHODS

Lambs at an estimated gestational age (EGA) 116-121 days (term 145 days) were placed on venovenous ECLS with jugular drainage and umbilical vein reinfusion and intubated. Airways were managed by the instillation of amniotic fluid and tracheal occlusion (TO; n = 4), or lactated Ringer's (LR; n = 4) or perfluorodecalin (a PFC) without occlusion (n = 4). After 7 days, the animals were sacrificed. Early (EGA 116-121 days) and late (EGA 125-131 days) tissue control lambs were delivered and sacrificed. Lungs were formalin-inflated to 30 cm H2O and sectioned for histology. Injury was scored by an unbiased pathologist. Slides were immunostained for PDGFR-α and α-actin; development was quantified by the area fraction of double-positive tips. Surfactant protein-C (SP-C) concentration in bronchoalveolar lavage fluid was quantified using ELISA.

RESULTS

Total injury scores were lower in PFC lungs (1.8 ± 1.7) than in TO (6.5 ± 2.1; p = 0.01) and LR lungs (5.5 ± 2.4; p = 0.01). The area fraction of double-positive alveolar tips appeared higher in PFC lungs than in TO lungs (0.18 ± 0.007 vs. 0.008 ± 0.004; p = 0.07). SP-C concentration was higher in PFC lungs than in TO lungs (37.9 ± 7.6 vs. 20.0 ± 5.4 pg/mL; p = 0.005), and both early (12.4 ± 1.7 g/mL; p = 0.007) and late tissue control lungs (15.1 ± 5.0 pg/mL; p = 0.0008).

CONCLUSION

During AP support, intratracheal PFC prevents lung injury and promotes normal lung development better than crystalloid or amniotic fluid with TO.

High concentrations of perfluorooctane sulfonate in mucus of tiger puffer fish Takifugu rubripes: a laboratory exposure study

Distribution of perfluorooctane sulfonate (PFOS) was investigated in tissues (plasma, blood clot, mucus, skin, liver, muscle, and gonad) of tiger puffer fish Takifugu rubripes. A single dose of PFOS was intraperitoneally injected at 0.1 mg/kg body weight with samples taken over a 14-day period. The highest concentration of PFOS was found in the plasma, 861 ng/mL at 14 days, followed by the mucus, liver, blood clot, gonads, muscles, and skin of fish. A gradual upward trend in PFOS concentration was observed in the mucus and liver whereas there was no change in the plasma, blood clot, gonad, muscle, and skin after the initial increase in PFOS concentrations following injection. No significant trend for estimated total PFOS content in whole body was observed during the experimental period. Relatively high concentrations of PFOS (690 ng/g ww after 14 days) were detected in body surface mucus that continuously oozes from the skin. These results may suggest that mucus is one of the elimination pathways of PFOS in tiger puffer fish.