Novel features of degenerative retinoschisis identified using ultra-widefield multicolor channels: A review of 139 eyes.

BACKGROUND/OBJECTIVE: To utilize ultra-widefield multimodal imaging (Optos PLC) to describe novel findings in degenerative retinoschisis. METHODS: This retrospective, non-comparative case series of degenerative retinoschisis received a waiver of consent from Advarra IRB, Protocol 00066379. Initial ultra-widefield pseudocolour, colour-separated, autofluorescence, and peripheral OCT imaging were analysed for characterizing features. RESULTS: In total, 139 eyes were included. A hyporeflective reticular pattern associated with retinoschisis was seen on pseudocolour images in 39% of cases, but visible in 53% on green-separated images. Fine hyper-reflective foci were observed in 49%. In 27%, retinoschisis was confirmed with OCT. CONCLUSIONS: Ultra-widefield pseudocolour and green-separated images are valuable for the diagnosis and characterization of degenerative retinoschisis. The findings described may prompt the evaluation of subtle retinoschisis with peripheral OCT.

Anti-VEGF and steroid combination therapy relative to anti-VEGF mono therapy for the treatment of refractory DME: A systematic review of efficacy and meta-analysis of safety.

The aim of the study was to determine the efficacy and safety of combined anti-VEGF and steroid therapy in treatment refractory DME patients. We conducted a systematic review and meta-analysis of peer-reviewed articles reporting on visual, anatomical and adverse outcomes to compare the efficacy and safety of combined intravitreal anti-VEGF/steroids versus anti-VEGF monotherapy for refractory DME. Seven studies (4 RCTs and 3 observational studies) reporting on 452 eyes were included. Our systematic review showed that combination therapy is significantly more effective for anatomical outcomes in the treatment of resistant DME compared to anti-VEGF monotherapy in six studies. Two studies found that addition of intravitreal steroids promoted faster visual improvement, but not significantly better final visual outcomes compared to anti-VEGF monotherapy. Combination therapy was associated with a higher incidence of IOP-related adverse events (RR = 0.10, 95% CI = [0.02, 0.42], p = 0.002) and cataract-related adverse events (RR = 0.10, 95% CI = [0.01, 0.71], p = 0.02). Our systematic review and meta-analysis of seven studies and 452 eyes revealed that combination therapy of anti-VEGF and steroid intravitreal drugs in the management of treatment refractory DME resulted in superior anatomical outcomes in all but one study. Combination therapy led to superior short-term visual outcomes in two studies, while others reported no difference between treatment groups. Meta-analysis revealed that combination therapy was associated with more adverse events. Future research should provide guidance on the standard definitions for treatment resistance and therapeutic alternatives for DME patients with sub-optimal response to anti-VEGF treatment.

Risk for Surgical Team Hearing Loss With Vitrectomy.

Purpose: To assess sound-level exposure during vitrectomy using 3 of the most common commercially available machines. Methods: This noninterventional cross-sectional study examined sound emission from the Constellation, Stellaris, and EVA vitrector systems. For each machine, a noise dosimeter was used to measure the sound-level exposure of the surgeon during 3 surgical cases in which vitrectomy was performed. Sound levels associated with progressively increasing cut rates and vacuum pressures were also measured. Finally, sound measurements were taken during the use of various additional functions of each machine, including diathermy, laser, and extrusion. Sound levels were compared with occupational health guidelines in Canada and the United States. Results: The maximum sound level recorded during vitrectomy surgery was 88.2 dBA. The mean sound level during vitrectomy surgical cases ranged from 58.5 to 66.8 dBA. A strong positive linear correlation was found between the cut rate and sound level (r = 0.88-0.98) and the vacuum pressure and sound level (r = 0.83-0.97). This relationship was consistent across the 3 vitrector systems (P < .001). Conclusions: Noise exposure during vitrectomy procedures was acceptable but may be sufficient for surgical team activity interference, as described by World Health Organization recommendations. A strong correlation was found between the cut rate and noise exposure. If cut rates continue to increase, attention should be given to ensure that the resulting noise exposure does not threaten the hearing of vitreoretinal surgeons and the operating room staff.

Systematic review of efficacy and meta-analysis of safety of ranibizumab biosimilars relative to reference ranibizumab anti-VEGF therapy for nAMD treatment.

TOPIC: This systematic review and meta-analysis provides a summary of the efficacy and safety of ranibizumab biosimilars relative to reference ranibizumab anti-vascular endothelial growth factor (VEGF) therapy for the treatment of neovascular age-related macular degeneration (nAMD). METHODS: We conducted systematic searches from January 2003 to August 2022 on Ovid MEDLINE, EMBASE and the Cochrane Controlled Register of Trials. We included studies reporting changes in early treatment diabetic retinopathy study-measured best-corrected visual acuity (BCVA), number of patients who lost or gained more than 15 letters in BCVA from baseline, changes in retinal thickness and adverse events between treatment arms. The following studies were excluded: studies that did not report visual outcomes following biosimilar and reference ranibizumab intravitreal injections, study arms combining anti-VEGF agents with laser or steroid injections, sham injections as a control comparator, studies without English full texts and non-comparative, observational study design. RESULTS: Five studies reported on four randomised controlled trials (RCTs) and 1544 eyes at baseline were included in this systematic review and meta-analysis. The studies in our systematic review found no significant differences between reference ranibizumab and ranibizumab biosimilar medications (FYB201, SB11, RanizuRel and Lupin's ranibizumab) for visual and anatomical outcomes. No significant differences were detected between biosimilar and reference ranibizumab for treatment emergent adverse events (risk ratio, RR 1.06, 95% CI (0.91 to 1.23), p=0.45, I2=52%) or IOP-related adverse events with significant heterogeneity (RR 2.59, 95% CI (0.11 to 62.25), p=0.56, I2=76%). CONCLUSION: This systematic review of four RCTs demonstrated no significant difference in visual outcomes, retinal thickness outcomes, as well as meta-analysis of adverse events between biosimilar and reference ranibizumab therapies for nAMD treatment.

Factors contributing to the carbon footprint of cataract surgery.

The healthcare sector is a significant greenhouse gas emitter. Cataract surgery is a procedure that results in a large amount of carbon dioxide (CO2) emissions. We sought to review the literature for factors contributing to the carbon footprint of this procedure. The literature, although limited, varies greatly by region. The carbon footprint of cataract surgery ranged from approximately 6 kg CO2 equivalents in a center in India to 181.9 kg CO2 equivalents in a center in the United Kingdom. Factors contributing to the carbon footprint of cataract surgery included the procurement of materials, energy use, and the emissions associated with travel. Factors facilitating a lower carbon footprint include the reuse of surgical materials and more efficient autoclave settings. Potential areas for improvement to consider include the reduction in packaging material, the reuse of materials, and potentially reducing travel emissions by performing simultaneous bilateral cataract surgery.

Comparison of diabetic retinopathy severity grading on ETDRS 7-field versus ultrawide-field assessment.

OBJECTIVES: To compare the diabetic retinopathy (DR) severity level determined when considering only the ETDRS 7-field region versus the entire ultrawidefield (UWF) image. METHODS: In this retrospective, cross-sectional study, UWF pseudocolor images were graded on the Eyenuk image viewing, grading, and annotation platform for the severity of DR considering only the regions within the ETDRS 7-fields as well as the entire UWF image using two different protocols: 1) the simple International Classification of Diabetic Retinopathy (ICDR) scale and 2) the more complex DRCR.net Protocol AA grading scale. RESULTS: A total of 250 eyes from 157 patients were included in this analysis. Six eyes (2.4%) demonstrated a discrepancy in severity level between the ETDRS 7-field region and the entire UWF image when using the ICDR classification system. The discrepancies were due to the presence of lesions [intraretinal haemorrhage (n = 2), neovascular disease (n = 4)] in the peripheral fields which were not identified in the ETDRS 7-fields. Fourteen eyes (5.6%) had a discrepancy in severity level between the ETDRS 7-field region and the entire UWF image when using the ETDRS DRSS Protocol AA grading scale. The discrepancies were due to the presence of a higher level of disease [intraretinal haemorrhage (n = 4), neovascularization (n = 4), preretinal haemorrhage (n = 2), scatter laser scars (n = 4)] in the peripheral fields. CONCLUSION: Although considering regions outside of the ETDRS 7-fields altered the DR severity level assessment in <5% of cases in this cohort, significant and potentially vision-threatening lesions including neovascularization and preretinal haemorrhage were identified in these peripheral regions. This highlights the importance of evaluating the entire UWF region when assessing patients with diabetic retinopathy.

Hydrocarbon Soluble Alkali-Metal-Aluminium Hydride Surrog[ATES].

A series of group 1 hydrocarbon-soluble donor free aluminates [AM(t BuDHP)(TMP)Al(i Bu)2 ] (AM=Li, Na, K, Rb) have been synthesised by combining an alkali metal dihydropyridyl unit [(2-t BuC5 H5 N)AM)] containing a surrogate hydride (sp3 C-H) with [(i Bu)2 Al(TMP)]. These aluminates have been characterised by X-ray crystallography and NMR spectroscopy. While the lithium aluminate forms a monomer, the heavier alkali metal aluminates exist as polymeric chains propagated by non-covalent interactions between the alkali metal cations and the alkyldihydropyridyl units. Solvates [(THF)Li(t BuDHP)(TMP)Al(i Bu)2 ] and [(TMEDA)Na(t BuDHP)(TMP)Al(i Bu)2 ] have also been crystallographically characterised. Theoretical calculations show how the dispersion forces tend to increase on moving from Li to Rb, as opposed to the electrostatic forces of stabilization, which are orders of magnitude more significant. Having unique structural features, these bimetallic compounds can be considered as starting points for exploring unique reactivity trends as alkali-metal-aluminium hydride surrog[ATES].

Effects of High-Intensity Interval Training Protocols on Liver Enzymes and Wellness in Women.

BACKGROUND: Single-modality, high-intensity interval training (HIIT) using traditional cardiorespiratory exercise selection has been found to provide similar and sometimes superior cardiometabolic effects compared with moderate-intensity continuous training. However, little is known regarding the cardiometabolic and psychosocial effects of HIIT using resistance training modalities. Therefore, this study aims to compare the effects of HIIT using rowing (R-HIIT) and multimodal HIIT (MM-HIIT) using resistance training on liver enzymes, cardiometabolic risk factors, and psychosocial outcomes. METHOD: Recreationally active females with a body mass index <30 kg/m2 (N = 16, 23.0 ± 5.9 years) were randomized into a MM-HIIT or R-HIIT group and completed a 12-week HIIT intervention (ClinicalTrials.gov registration number: https://clinicaltrials.gov/ct2/show/NCT03093441) using principles of social cognitive theory (SCT). Participants completed pre- and postintervention measurements on anthropometrics, resting heart rate, blood pressure, blood measures (lipids, liver enzymes, and glucose), exercise self-efficacy, and perceived wellness. Analysis of covariance was used to examine differences in postintervention measures between groups after controlling for baseline values, waist circumference, and waist-to-height ratio. RESULTS: R-HIIT group had significantly decreased alanine aminotransferase (mean difference = 13.16, P=0.013, effect size (ES) = 0.44, confidence interval (CI) = 3.40 to 22.92) and aspartate aminotransferase (mean difference = 10.79, P=0.024, ES = 0.38, CI = 1.67 to 19.90) levels compared with the M-HIIT group, and the whole group had improved wellness scores (14.72 ± 2.6 to 16.89 ± 2.76, P=0.002). CONCLUSION: R-HIIT may be an effective preventative method for improving liver health in females without obesity. When using principles of SCT, HIIT may enhance overall well-being.

When Electrons Step in: Polarizing Effects Explored with Triisobutylaluminum.

High-resolution X-ray diffraction data of triisobutylaluminum were collected, and unexpected structural features were observed, hinting toward yet unnoticed polarization effects. To approach these, a multipole refinement using the Hansen and Coppens method, followed by a topological analysis using Bader's quantum theory of atoms in molecules, was employed. The electron localization function based on density functional theory calculations supported the experimental findings. Thereby, unobserved electron shifts within the isobutyl group become detectable. It is shown that the impact of this electron shift is dependent mainly on whether the iBu substituent of the homoleptic triisobutylaluminum dimer [AliBu3]2 (1) is connected by a directional (σ) or a multicenter (µ) bond to the metal. The effect found is assumed not only to be of paramount importance for organoaluminum compounds, widely used in synthesis and in the industrial value chain, but also to be present in organometallic chemistry in general.

The many faces of ocular syphilis: case-based update on recognition, diagnosis, and treatment.

In recent years, syphilis (Treponema pallidum) has become increasingly prevalent in Canada, and as a result, rates of ocular syphilis are also rising. Classically, syphilis was seen primarily in men who have sex with men; now, it is increasingly seen in people of all age groups, sexes, and sexual orientations. We present a series of 26 cases of ocular syphilis from London, Ontario, 5 of which are discussed in detail to illustrate the varied presentations and diagnostic challenges of ocular syphilis. The presentations include uveitis, iris granuloma (gumma), retinitis (acute syphilitic posterior placoid chorioretinitis), vasculitis, optic neuritis, and serous retinal detachment. The 5 cases are mostly middle-aged heterosexual men and women without the typical risk factors that would alert the examiner to suspect syphilis. We emphasize the importance of testing for syphilis when assessing and treating inflammatory eye disease, regardless of demographics and known risk factors, given the increasing prevalence of this disease. Diagnosis of syphilis relies on serologic testing, which is complex and has undergone significant changes from historical reliance on the Venereal Disease Research Laboratory test. We provide an overview of the strategy and rationale for modern serologic testing. The mainstay of treatment remains intravenous penicillin G, with alternative antibiotics (e.g., ceftriaxone) being less effective.

Main Group Metal-Mediated Transformations of Imines.

Main-group-metal-mediated transformations of imines have earned a valued place in the synthetic chemist's toolbox. Their versatility allows the simple preparation of various nitrogen containing compounds. This review will outline the early discoveries including metallation, addition/cyclisation and metathesis pathways, followed by the modern-day use of imines in synthetic methodology. Recent advances in imine C-F activation protocols are discussed, alongside revisiting "classic" imine reactivity from a sustainable perspective. Developments in catalytic methods for hydroelementation of imines have been reviewed, highlighting the importance of s-block metals in the catalytic arena. Whilst stoichiometric transformations in alternative reaction media such as deep eutectic solvents or water have been summarised. The incorporation of imines into flow chemistry has received recent attention and is summarised within.

Structural Elucidation of Silver(I) Amides and Their Application as Catalysts in the Hydrosilylation and Hydroboration of Carbonyls.

This study details the isolation and characterisation of three novel silver(I) amides in solution and solid-state, [Ag(Cy3 P)(HMDS)] 2, [Ag(Cy3 P){N(TMS)(Dipp)}] 3 and [Ag(Cy3 P)2 (NPh2 )] 4. Their catalytic abilities have proved successful in hydroboration and hydrosilylation reactions with a full investigation performed with complex 2. Both protocols proceed under mild conditions, displaying exceptional functional-group tolerance and chemoselectivity, in excellent conversions at competitive reaction times. This work reveals the first catalytic hydroboration of aldehydes and ketones performed by a silver(I) catalyst.

A regioselectively 1,1',3,3'-tetrazincated ferrocene complex displaying core and peripheral reactivity.

Regioselective 1,1',3,3'-tetrazincation [C-H to C-Zn(tBu)] of ferrocene has been achieved by reaction of a fourfold excess of di-t-butylzinc (tBu2Zn) with sodium 2,2,6,6-tetramethylpiperidide (NaTMP) in hexane solution manifested in the trimetallic iron-sodium-zinc complex [Na4(TMP)4Zn4(tBu)4{(C5H3)2Fe}], 1. X-ray crystallographic studies supported by DFT modelling reveal the structure to be an open inverse crown in which two [Na(TMP)Zn(tBu)Na(TMP)Zn(tBu)]2+ cationic units surround a {(C5H3)2Fe}4- tetraanion. Detailed C6D6 NMR studies have assigned the plethora of 1H and 13C chemical shifts of this complex. It exists in a major form in which capping and bridging TMP groups interchange, as well as a minor form that appears to be an intermediate in this complicated exchange phenomenon. Investigation of 1 has uncovered two distinct reactivities. Two of its peripheral t-butyl carbanions formally deprotonate toluene at the lateral methyl group to generate benzyl ligands that replace these carbanions in [Na4(TMP)4Zn4(tBu)2(CH2Ph)2{(C5H3)2Fe}], 2, which retains its tetrazincated ferrocenyl core. Benzyl-Na π-arene interactions are a notable feature of 2. In contrast, reaction with pyridine affords the crystalline product {[Na·4py][Zn(py*)2(tBu)·py]}∞, 3, where py is neutral pyridine (C5H5N) and py* is the anion (4-C5H4N), a rare example of pyridine deprotonated/metallated at the 4-position. This ferrocene-free complex appears to be a product of core reactivity in that the core-positioned ferrocenyl anions of 1, in company with TMP anions, have formally deprotonated the heterocycle.

Lithium-Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways.

By exploring lithium-bromide exchange reactivity of aromatic Schiff's bases with tert-butyllithium (tBuLi), we have revealed unprecedented competitive intermolecular and intramolecular cascade annulation pathways, leading to valuable compounds, such as iso-indolinones and N-substituted anthracene derivatives. A series of reaction parameters were probed, including solvent, stoichiometry, sterics and organolithium reagent choice, in order to understand the influences that limit such ring-closing pathways. With two viable reactivity options for the organolithium on the imine; namely, nucleophilic addition or lithium-bromide exchange, a surprising competitive nature was observed, where nucleophilic addition dominated, even under cryogenic conditions. Considering the most commonly used solvents for lithium-bromide exchange, tetrahydrofuran (THF) and diethyl ether (Et2 O), contrasting reactivity outcomes were revealed with nucleophilic addition promoted in THF, while Et2 O yielded almost double the conversion of cyclic products than in THF.

Exploiting Synergistic Effects in Organozinc Chemistry for Direct Stereoselective C-Glycosylation Reactions at Room Temperature.

Pairing a range of bis(aryl) zinc reagents ZnAr2 with the stronger Lewis acidic [(ZnArF2 )] (ArF =C6 F5 ), enables highly stereoselective cross-coupling between glycosyl bromides and ZnAr2 without the use of a transition metal. Reactions occur at room temperature with excellent levels of stereoselectivity, where ZnArF2 acts as a non-coupling partner although its presence is crucial for the execution of the C(sp2 )-C(sp3 ) bond formation process. Mechanistic studies have uncovered a unique synergistic partnership between the two zinc reagents, which circumvents the need for transition-metal catalysis or forcing reaction conditions. Key to the success of the coupling is the avoidance of solvents that act as Lewis bases versus diarylzinc compounds (e.g. THF).

Donor-influenced Structure-Activity Correlations in Stoichiometric and Catalytic Reactions of Lithium Monoamido-Monohydrido-Dialkylaluminates.

A series of heteroleptic monoamido-monohydrido-dialkylaluminate complexes of general formula [iBu2 AlTMPHLi⋅donor] were synthesized and characterised in solution and in the solid state. Applying these complexes in catalytic hydroboration reactions with representative aldehydes and ketones reveals that all are competent, however a definite donor substituent effect is discernible. The bifunctional nature of the complexes is also probed by assessing their performance in metallation of a triazole and phenylacetylene and addition across pyrazine. These results lead to an example of phenylacetylene hydroboration, which likely proceeds via deprotonation, rather than insertion as observed with the aldehydes and ketones. Collectively, the results emphasise that reactivity is strongly influenced by both the mixed-metal constitution and mixed-ligand constitution of the new aluminates.

Lithium diamidodihydridoaluminates: bimetallic cooperativity in catalytic hydroboration and metallation applications.

Cooperativity between the Li and Al centres is implicated in catalytic hydroboration reactions of aldehydes and ketones with pinacolborane via heteroleptic lithium diamidodihydridoaluminates. In addition to implementing hydroalumination, these versatile heteroleptic ates can also perform as amido bases as illustrated with an acidic triazole.