Mutational Analysis of (+)-Limonene Synthase.

The monoterpene limonene is produced by the enzyme limonene synthase in one of the simplest terpene cyclization reactions. The enzyme can use linalyl diphosphate (LPP) and neryl diphosphate (NPP) as substrates in addition to the naturally occurring substrate geranyl diphosphate (GPP), but the relationship among the three alternative substrates is not well understood. We explored the (+)-limonene synthase ((+)-LS) reaction using site-directed mutagenesis with the three different substrates (GPP, NPP, and LPP) to tease out details of the mechanism. In total, 23 amino acid positions in the active site of (+)-LS were targeted for mutation. In all cases, substitution with Ala resulted in a significant loss of enzyme activity using GPP or NPP as the substrate, but the mutations fell into two groups depending on the effect of using LPP as a substrate: group 1 mutations resulted in the loss of activity with all three substrates (GPP, NPP, and LPP); group 2 mutations resulted in loss of activity with GPP and NPP, but retained near-WT activity with LPP as a substrate. Importantly, mutations resulting in loss of activity with LPP but retention of activity with GPP and NPP were never observed. These data, in combination with the substrate order of reactivity for the WT enzyme (LPP > NPP > GPP), are consistent with a role for LPP as an intermediate in the (+)-LS reaction using either GPP or NPP as a substrate.

Chemistry and biology of enzymes in protein glutathionylation.

Protein S-glutathionylation is emerging as a central oxidation that regulates redox signaling and biological processes linked to diseases. In recent years, the field of protein S-glutathionylation has expanded by developing biochemical tools for the identification and functional analyses of S-glutathionylation, investigating knockout mouse models, and developing and evaluating chemical inhibitors for enzymes involved in glutathionylation. This review will highlight recent studies of two enzymes, glutathione transferase omega 1 (GSTO1) and glutaredoxin 1 (Grx1), especially introducing their glutathionylation substrates associated with inflammation, cancer, and neurodegeneration and showcasing the advancement of their chemical inhibitors. Lastly, we will feature protein substrates and chemical inducers of LanC-like protein (LanCL), the first enzyme in protein C-glutathionylation.

Hereditary cancer risk assessment and genetic testing in the community urology practice setting.

OBJECTIVES: To evaluate the feasibility of integrating a hereditary cancer risk assessment (HCRA) process in the community urology practice setting for patients with prostate cancer (PCa). METHODS: In this prospective intervention, an HCRA process was implemented across six different community urology clinics between May 2019 and April 2020. The intervention included a process integration during which the workflow at each site was refined, a post-integration period during which HCRA was conducted in all patients with PCa, and a follow-up period during which healthcare providers and patients reported their satisfaction with the HCRA and genetic testing process. RESULTS: Among patients who completed a family history assessment during the post-integration period, 23.6% met guideline criteria for genetic testing. Of all patients seen at the clinic during the post-integration period, 8.7% completed genetic testing; this was a twofold increase over the period immediately preceding process integration (4.2%), and a sevenfold increase over the same period 1 year prior (1.2%). The majority of providers reported that the HCRA was as important as other regularly performed assessments (61.0%) and planned to continue using the process in their practice (68.3%). Most patients believed that the genetic test results were important for their future cancer care (84.7%) and had already shared their test results with at least one family member (63.2%). CONCLUSIONS: This study demonstrated that implementing an HCRA process in the community urology practice setting was feasible, generally favored by providers and patients, and resulted in an increase in the number of patients with PCa who completed genetic testing.

Early patient experience following treatment with the UroLift prostatic urethral lift and Rezum steam injection.

INTRODUCTION: To report the early postoperative patient experience, including symptom response, catheterization, recovery and satisfaction, following treatment with two minimally invasive surgical therapies (MIST) for benign prostatic hyperplasia (BPH): mechanical disobstruction with UroLift prostatic urethral lift (PUL) and tissue ablation with steam injection (Rezum). MATERIALS AND METHODS: Patient reported outcomes of 53 non-retention patients from two U.S. sites patients who underwent PUL (n = 30) or Rezum (n = 23) were collected within 2 months post-treatment. There were no exclusion criteria for baseline symptoms, prostate size, or BPH medical therapy. Patients completed questionnaires which assessed postoperative BPH symptoms and characteristics. Outcomes were compared between treatment arms with unpaired t-tests and Fisher's exact tests. RESULTS: PUL and Rezum patients were similar in age and prostate volume; patients completed the questionnaire an average of 30 ± 11 days post-treatment. Absolute mean International Prostate Symptom Score and quality of life was significantly better for PUL patients. Seven percent of PUL patients were catheterized by postoperative day 3 compared to 55% of Rezum patients (p = 0.0003). PUL patients experienced a rate of 83% treatment satisfaction (versus 65% for Rezum, p = 0.2) and less interference with daily activities (sports interference, p = 0.007; entertainment interference, p = 0.01; community interference, p = 0.04). Both groups reported BPH medication use following treatment (37% PUL versus 91% Rezum), albeit significantly higher for Rezum (p < 0.0001). CONCLUSION: Preliminary data suggests UroLift PUL provides a superior patient experience with better sexual function, lower catheterization rates, less daily interference, and higher patient satisfaction in the recovery period compared to Rezum.

CONTRALATERAL ANESTHESIA IN TWO PATIENTS AFTER RETROBULBAR BLOCK.

PURPOSE: To report a case series of two patients with contralateral anesthesia after retrobulbar block. METHODS: Retrospective review of two cases and review of the literature. RESULTS: Two patients of one practitioner received contralateral anesthesia after retrobulbar block for posterior segment surgery. Patient 1 suffered from transient contralateral akinesia, whereas Patient 2 experienced transient contralateral amaurosis. CONCLUSION: Posterior spread of anesthetics is a rare but potentially serious complication of retrobulbar anesthesia caused by spread of anesthetics along the optic nerve sheath. Modification of injection technique can decrease the risk of this complication.

PROPHYLACTIC PREOPERATIVE LASER RETINOPEXY DOES NOT REDUCE THE OCCURRENCE OF RHEGMATOGENOUS RETINAL COMPLICATIONS IN MACULAR SURGERY.

PURPOSE: Knowledge on the utility of prophylactic 360° laser retinopexy before pars plana vitrectomy in the absence of peripheral retinal pathology is limited. This study compares the occurrence of rhegmatogenous events in the setting of small-gauge pars plana vitrectomy with and without prophylactic preoperative laser. METHODS: Our multicenter, retrospective case-control analysis reviewed patients who underwent epiretinal membrane removal or macular hole repair through 23- or 25-gauge pars plana vitrectomy: 205 controls who did not receive prophylactic laser and 176 cases who received preoperative prophylactic laser retinopexy anterior to the equator. Main outcome measures were the rate and characteristics of postoperative retinal tears and detachments. Patients with previous pars plana vitrectomy or significant retinal disease were excluded. RESULTS: Of those patients with prophylactic laser and those without, there was no significant difference in the number of retinal breaks (1.7% vs. 0.49%, respectively; P = 0.339) or retinal detachments (0% vs. 0.49%, respectively; P = 1.00). Of the lasered group, there was one sclerotomy-related retinal break and two non-sclerotomy-related retinal breaks. Of the nonlasered group, there was one non-sclerotomy-related retinal break and one sclerotomy-related retinal detachment. CONCLUSION: Preoperative prophylactic peripheral laser retinopexy does not seem to offer an added benefit in the prevention of intraoperative and postoperative rhegmatogenous events.

Sequential bilateral central retinal vein occlusions in a cystic fibrosis patient with hyperhomocysteinemia and hypergamma-globulinemia.

PURPOSE: To report a case of sequential bilateral central retinal vein occlusions in a cystic fibrosis patient with hyperhomocysteinemia and hypergamma-globulinemia over 6 years of follow up. METHODS: Observational case report of one patient. RESULTS: A 31 year-old male with a history of cystic fibrosis presented with a central retinal vein occlusion (CRVO) in his left eye, followed by a CRVO in his right eye 4 years later. His medical workup was significant for elevated levels of homocysteine and gamma-globulins, which coincided with initiation of intravenous immunoglobulin (IVIG) proceeding his second CRVO. CONCLUSIONS: We describe a case of sequential bilateral central retinal vein occlusions in a cystic fibrosis patient with hyperhomocysteinemia and hypergamma-globulinemia over 6 years of follow up and discuss the important role of these risk factors in retinal venous occlusive disease.

Optic disk pit morphology and retinal detachment: optical coherence tomography with intraoperative correlation.

BACKGROUND: The pathogenesis of optic nerve head pits and associated retinal detachment, and the most effective surgical intervention when visual loss develops, remains unclear. METHODS: The morphology of the optic disk in patients with pits was investigated with optical coherence tomography. For those who underwent surgical treatment for pit-associated retinal detachment, the efficacy of treatment by vitrectomy and separation of the posterior hyaloid, with and without additional peeling of peripapillary tissue, was assessed. RESULTS: On optical coherence tomography imaging, 14 of 18 pits (78%) demonstrated a localized pit-like invagination, whereas 3 (17%) had disks with a generally excavated structure. For 16 of 18 pits (89%), there was evidence of condensed vitreous or glial tissue seen extending from the pit or inside the optic disk. Nine eyes with retinal detachment underwent vitrectomy, posterior hyaloid separation, and endolaser. The retinal detachment completely resolved in 6 of 6 cases where the surgeon additionally peeled the fibrous tissue from the pit and 2 of 3 cases where this was not performed. CONCLUSION: Spectral domain optical coherence tomography demonstrates the varying morphology of optic pit anatomy. Condensed vitreous strands or glial tissue in the optic nerve pit may also contribute to retinal detachment development.

Surgical outcomes after massive subretinal hemorrhage secondary to age-related macular degeneration.

PURPOSE: Massive subretinal hemorrhage (SRH), defined as a thick submacular bleed that extends past the equator in at least two quadrants, is a rare sequela of age-related macular degeneration. This report describes outcomes after surgical intervention for massive SRH. METHODS: The study design is a retrospective interventional case series. Records of consecutive patients who underwent surgical intervention for massive SRH were reviewed. Outcomes included change from baseline in postoperative acuity at Months 1, 3, 6, 9, and 12 and postoperative complications. RESULTS: Fifteen consecutive eyes of 13 patients who underwent surgery for massive SRH were included. Procedures performed on initial surgery included subretinal instillation of 25 µg/0.1 mL tissue plasminogen activator (15 of 15), gas tamponade (12 of 15), oil tamponade (3 of 15), 180° or greater retinotomy (4 of 15), and/or cataract extraction (2 of 15). Patients were followed for a median of 20 months (range, 3-66 months). The median visual acuity at baseline and postoperative Month 1 was hand motions but improved to counting fingers at postoperative Months 3 (P = 0.04), 6 (P = 0.04), 9 (P = 0.04), and 12 (P = 0.10). Of the 15 eyes, 9 required at least 1 additional procedure for an indication of hyphema and/or vitreous hemorrhage (n = 6), retinal detachment (n = 2), glaucoma (n = 1), cataract (n = 1), and aphakia (n = 1). At the time of the onset of SRH, 5 of 13 patients were anticoagulated with warfarin (4 patients) or clopidogrel (1 patient), and 1 was diagnosed with a coagulopathy, factor XI deficiency. CONCLUSION: Massive SRH related to age-related macular degeneration has a grave prognosis. Risk factors may include anticoagulation and coagulopathy. Limitations of the study include its retrospective nature, small sample size, imprecision in acuity measurements below 20/400, and lack of a control group. In this series, surgical intervention was associated with a modest improvement in median visual acuity up to 1 year postoperatively.

Simultaneous appearance of multiple evanescent white dot syndrome and multifocal choroiditis indicate a common causal relationship.

PURPOSE: To report simultaneous occurrence of multiple evanescent white dot syndrome (MEWDS) and multifocal choroiditis (MFC) in the same eye of a 33-year-old Caucasian woman. METHODS: Review of clinical and fluorescein angiographic features of a patient who presented with decreased visual acuity and was followed for 3 months. RESULTS: Patient presented with concurrent lesions of MEWDS and MFC occurring in the same eye. During the follow-up period MEWDS lesions resolved and MFC lesions evolved into chorioretinal scars. CONCLUSIONS: Simultaneous development of MEWDS and MFC may indicate a possible common causal entity.

Influence of postoperative lens status on intraocular pressure in proliferative vitreoretinopathy.

PURPOSE: To determine the influence of lens status on postoperative intraocular pressure (IOP) in eyes undergoing vitrectomy for repair of recurrent retinal detachment (RD) resulting from proliferative vitreoretinopathy (PVR). DESIGN: Retrospective, consecutive, nonrandomized, single-center series. METHODS: One hundred and forty-five eyes with recurrent RD resulting from PVR were reviewed retrospectively. In all, 99 eyes underwent relaxing retinotomy at the time of surgery (68.4%). Perfluorocarbon gas (n = 60) or silicone oil (n = 85) were used as postoperative tamponades. For analysis, eyes were subdivided first based on tamponade and retinotomy status. The resultant groups then were divided further by lens status into 2 groups: aphakic eyes (aphakic group) and phakic and pseudophakic eyes (nonaphakic group). RESULTS: Surgical reattachment was achieved in all eyes except one. Eyes receiving both silicone oil and relaxing retinotomy had the worst baseline characteristics compared with those receiving other interventions. In this subset of eyes, a significantly lower proportion of hypotony was found in those eyes that were aphakic after surgery when compared with those eyes that were nonaphakic (P = .037). CONCLUSIONS: Surgical management of PVR often results in ultimate retinal reattachment. In eyes receiving both relaxing retinotomy and silicone oil, higher IOPs and a lower proportion of hypotony are found where a native lens or intraocular implant is absent. Removal of the lens or intraocular implant may be considered for those eyes at greatest risk of hypotony.

Pascal dynamic contour tonometry versus goldmann applanation tonometry in gas and air-filled eyes after vitrectomy surgery.

PURPOSE: To compare Pascal Dynamic Contour Tonometry with Goldmann Applanation Tonometry in eyes after vitrectomy surgery with intraocular tamponade of air, silicone oil or perfluorocarbon gas. METHODS: Prospective clinical comparative study. Eighty-two consecutive patients undergoing vitrectomy surgery with postoperative air, gas or oil tamponade were recruited. Intraocular pressure was measured with both devices. RESULTS: Mean Goldmann intraocular pressure was 16.6 mmHg (range, 1.0-46.0; SD = 8.80) and the mean Pascal intraocular pressure was 21.70 (range, 4.7-58.5; SD = 9.8) The mean difference between the Pascal and Goldmann readings was 5.09 mmHg (range, -14.7 to +12.9; 95% CI = 4.2-6.0; SD, 4.0; P < 0.001). Mean differences for the different tamponades were 5.09 mmHg for silicone oil, 4.02 mmHg for air, and 5.38 mmHg for perfluorocarbon gas. CONCLUSION: Pascal dynamic contour tonometry gives readings that are highly correlated with Goldmann applanation tonometry, but on average 5 mmHg higher in eyes after vitrectomy surgery with air, gas or silicone oil tamponades. The difference between Goldmann and Pascal readings does not appear to be altered by the presence of a scleral buckle, or the size of the intraocular gas bubble.

Nanophthalmos and acquired retinoschisis.

PURPOSE: To report three cases of nanophthalmos associated with acquired (senile) retinoschisis. DESIGN: Observational case series. METHODS: Complete ophthalmologic evaluation (including funduscopy with scleral indentation, total axial length measurement with A-scan, optical coherence tomography [Stratus 3 OCT; Carl Zeiss Meditec Inc, Dublin, California, USA], and fundus photography) of three consecutive patients presenting with nanophthalmos and acquired retinoschisis. RESULTS: Three patients with nanophthalmos presented with bilateral acquired retinoschisis. One patient underwent a course of systemic steroids to treat concurrent and bilateral uveal effusion with macular edema. In this patient, one eye responded to this course of therapy without recurrence, while the fellow eye required vortex vein decompression with scleral windows, with subsequent, successful resolution. The average follow-up period was 40 months (range, eight to 95 months). Retinoschisis cavities remained stationary in each case. CONCLUSIONS: Bilateral acquired retinoschisis may occur in patients with nanophthalmos, suggesting that there may be correlation in the mechanisms underlying these ocular disorders.

Diabetic vitrectomy: the influence of lens status upon surgical outcomes.

PURPOSE OF REVIEW: Management of the lens in diabetic eyes undergoing vitrectomy has long been a source of controversy. Initially, the lens was removed during diabetic vitrectomy because of intraoperative changes. It was noted, however, that anterior segment neovascular complications were greater in aphakic eyes after diabetic vitrectomy, and subsequently the vitreoretinal surgeon attempted to spare the lens. Lens management in this regard continues to attract discussion. This report reviews recent trends in the management of the native lens in the diabetic eye undergoing vitrectomy. RECENT FINDINGS: The rate of cataract formation after diabetic vitrectomy is high in eyes left phakic. The rates of anterior segment neovascularization and retinal detachment after diabetic vitrectomy are similar in phakic and nonphakic eyes. The rate of subsequent reoperation after diabetic vitrectomy may be greater in eyes left phakic. SUMMARY: Although the management of the lens in an eye undergoing diabetic vitrectomy should be individualized, cataract extraction performed either before or in combination with vitrectomy may reduce the rate of subsequent reoperation. The vitreoretinal surgeon may consider rendering an eye nonphakic before or during diabetic vitrectomy to optimize outcomes.

Safety and efficacy assessment of chimeric ribozyme to proliferating cell nuclear antigen to prevent recurrence of proliferative vitreoretinopathy.

OBJECTIVE: To determine the safety and efficacy of VIT100 (Immusol, Inc, San Diego, California), a ribozyme to proliferating cell nuclear antigen, in preventing recurrent proliferative vitreoretinopathy (PVR) in patients with established PVR who undergo vitrectomy for retinal reattachment repair. METHODS: A multicenter, double-masked, placebo-controlled, randomized clinical trial. One hundred seventy-five eyes from 175 patients with grade C or worse PVR were randomly assigned to receive high-dose VIT100, low-dose VIT100, or placebo by intravitreal injection at the conclusion of retinal reattachment surgery. MAIN OUTCOME MEASURES: The primary efficacy end point was recurrent retinal detachment secondary to PVR. The secondary end point was recurrent retinal detachment due to any cause. RESULTS: One hundred fifty-four patients completed the study. Forty-one patients (27%) developed recurrent retinal detachment due to PVR by 24 weeks, including 18 patients (33%) in the group receiving 0.75 mg, 13 patients (24%) in the group receiving 0.15 mg, and 10 patients (22%) in the placebo group. There was no statistically significant difference in patients reaching this end point by 24 weeks (P = .37). Ancillary statistical analyses are reported. CONCLUSIONS: VIT100 was not effective in preventing PVR recurrence in patients with established grade C or worse PVR. APPLICATION TO CLINICAL PRACTICE: To our knowledge, this is the most recent, meticulously designed clinical trial in PVR.

Optic pit maculopathy after laser-assisted in situ keratomileusis.

CASE REPORT: Optic disc pit is an embryological malformation of the optic nerve that occurs in less than one in 10,000 people. It is 10%-15% bilateral, and 25% to 70% of patients develop a neurosensory macular detachment within the 2nd to 4th decade. COMMENTS: We report a case of unilateral optic disc pit maculopathy 2 months after laser-assisted in situ keratomileusis (LASIK) revision.

Ocular hypotony: a review.

The etiology, diagnosis, sequelae, and management of ocular hypotony are discussed in this review. Hypotony from decreased production of aqueous is often due to inflammation, medications, or proliferative vitreoretinopathy. Hypotony from aqueous loss may be external, such as following surgery or trauma, or internal, as in cyclodialysis cleft or retinal detachment. Treatment of hypotony is most effective if the underlying cause can be addressed, either surgically or medically. Marked improvement in vision may be achieved if hypotony is reversed.