Association of Occlusive Retinal Vasculitis With Intravitreal Faricimab.

This case report describes a patient with attenuation of retinal arterioles and veins associated with 2 blot hemorrhages and pallor of the inferotemporal retina without emboli.

Retrospective examination of pseudoprogression in IDH mutant gliomas.

Background: Tumor surveillance of isocitrate dehydrogenase (IDH) mutant gliomas is accomplished via serial contrast MRI. When new contrast enhancement (CEnew) is detected during postsurgical surveillance, clinicians must assess whether CEnew indicates pseudoprogression (PsP) or tumor progression (TP). PsP has been better studied in IDH wild-type glioblastoma but has not been well characterized in IDH mutant gliomas. We conducted a retrospective study evaluating the incidence, predictors, natural history, and survival of PsP patients in a large cohort of IDH mutant glioma patients treated at a single institution. Methods: We identified 587 IDH mutant glioma patients treated at UCLA. We directly inspected MRI images and radiology reports to identify CEnew and categorized CEnew into TP or PsP using MRI or histopathology. Results: Fifty-six percent of patients developed CEnew (326/587); of these, 92/326 patients (28% of CEnew; 16% of all) developed PsP and 179/326 (55%) developed TP. All PsP patients had prior radiation, chemotherapy, or chemoradiotherapy. PsP was associated with longer overall survival (OS) versus TP patients and similar OS versus no CEnew. PsP differs from TP based on earlier time of onset (median 5.8 vs 17.4 months from treatment, P < .0001) and MRI features that include punctate enhancement and enhancement location. Conclusion: PsP patients represented 28% of CEnew patients and 16% of all patients; PsP patients demonstrated superior outcomes to TP patients, and equivalent survival to patients without CEnew. PsP persists for <1 year, occurs after treatment, and differs from TP based on time of onset and radiographic features. Poor outcomes after CEnew are driven by TP.

A single-institution retrospective analysis of pathologically determined malignant transformation in IDH mutant glioma patients.

Background: Lower-grade IDH mutant glioma patients frequently undergo malignant transformation (MT), with apparent worse prognosis. Many studies examine MT in mixed IDH status cohorts and define MT using imaging, not histopathology. Our study examines the timing, predictors, and prognostic implications of pathologically determined MT in a large, exclusively IDH mutant cohort. Methods: We identified 193 IDH mutant lower-grade glioma patients at UCLA who received multiple surgeries. We examined the outcomes of pathologically determined MT patients. Results: Time to MT is longer in grade 2 oligodendroglioma (G2 Oligo) than in grade 2 astrocytoma (G2 Astro) (HR = 0.46, P = .0007). The grade 3 astrocytoma (G3 Astro) to grade 4 astrocytoma (G4 Astro) interval is shorter in stepwise MT (G2 to G3 to G4 Astro) patients than in initial G3 Astro patients (P = .03). Novel contrast enhancement had 65% positive predictivity, 67% negative predictivity, 75% sensitivity, and 55% specificity in indicating pathologically defined MT. In G2 Astro, initial gross total resection delayed MT (HR = 0.50, P = .02) and predicted better overall survival (OS) (HR = 0.34, P = .009). In G2 Oligo, spontaneous MT occurred earlier than treated MT (HR = 11.43, P = .0002), but treatment did not predict improved OS (P = .8). MT patients (n = 126) exhibited worse OS than non-MT patients (n = 67) in All (HR = 2.54, P = .0009) and G2 Astro (HR = 4.26, P = .02). Conclusion: Our study expands the understanding of MT to improve IDH mutant lower-grade glioma management.

A new FRET-based platform to track substrate ubiquitination by fluorescence.

Post-translational modification of protein by ubiquitin (Ub) alters the stability, subcellular location, or function of the target protein, thereby impacting numerous biological processes and directly contributing to myriad cellular defects or disease states, such as cancer. Tracking substrate ubiquitination by fluorescence provides opportunities for advanced reaction dynamics studies and for translational research including drug discovery. However, fluorescence-based techniques in ubiquitination studies remain underexplored at least partly because of challenges associated with Ub chain complexity and requirement for additional substrate modification. Here we describe a general strategy, FRET diubiquitination, to track substrate ubiquitination by fluorescence. This platform produces a uniform di-Ub product depending on specific interactions between a substrate and its cognate E3 Ub ligase. The diubiquitination creates proximity between the Ub-linked donor and acceptor fluorophores, respectively, enabling energy transfer to yield a distinct fluorescent signal. FRET diubiquitination relies on Ub-substrate fusion, which can be implemented using either one of the two validated strategies. Method 1 is the use of recombinant substrate-Ub fusion, applicable to all substrate peptides that can bind to E3. Method 2 is a chemoenzymatic ligation approach that employs synthetic chemistry to fuse Ub with a substrate peptide containing desired modification. Taken together, our new FRET-based diubiquitination system provides a timely technology of potential to advance both basic research and translation sciences.

MELAS: Monitoring treatment with magnetic resonance spectroscopy.

BACKGROUND: To assess the utility of Magnetic Resonance Spectroscopy (MRS) as a biomarker of response to L-arginine in mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). AIMS: To describe a case of MELAS treated with L-arginine that showed improvement clinically and on serial MRS METHODS: MRS was performed on a 1.5-Tesla scanner to evaluate a MELAS patient before, during, and after intravenous (IV) L-arginine therapy for the treatment of stroke-like episodes. L-arginine was infused at a dose of 500 mg/kg daily for 7 days followed by oral arginine therapy. RESULTS: The patient had clinical improvement after treatment with IV L-arginine. MRS performed before, during, and after treatment with IV L-arginine showed significant improvement in brain lactate and increase in the N-acetylaspartate/Choline (NAA/Cho) ratio compared to pre-treatment baseline. CONCLUSION: Serial MRS imaging showed significant improvement in lactate peaks and NAA/Cho ratios that corresponded with clinical improvement after L-arginine therapy. Given this correlation between radiologic and clinical improvement, MRS may be a useful biomarker assessing response to treatment in MELAS.

Extracellular LDLR repeats modulate Wnt signaling activity by promoting LRP6 receptor endocytosis mediated by the Itch E3 ubiquitin ligase.

The LOW-density lipoprotein related protein 6 (LRP6) receptor is an important effector of canonical Wnt signaling, a developmental pathway, whose dysregulation has been implicated in various diseases including cancer. The membrane proximal low-density lipoprotein (LDL) receptor repeats in LRP6 exhibit homology to ligand binding repeats in the LDL receptor (LDLR), but lack known function. We generated single amino acid substitutions of LRP6-LDLR repeat residues, which are highly conserved in the human LDLR and mutated in patients with Familial Hypercholesteremia (FH). These substitutions negatively impacted LRP6 internalization and activation of Wnt signaling. By mass spectrometry, we observed that the Itch E3 ubiquitin ligase associated with and ubiquitinated wild type LRP6 but not the LDLR repeat mutants. These findings establish the involvement of LRP6-LDLR repeats in the regulation of canonical Wnt signaling.

Optical coherence tomography imaging of optic disc cavernous haemangioma.

Optic disc cavernous haemangiomas are either found incidentally or after presentation with vitreous haemorrhage. They are characterised by a cluster of grapes appearance to the multiple vascular saccules that make up the tumour. They are more often found in the retinal periphery but rarely occur at the optic disc. Optical coherence tomography (OCT) imaging may be a useful non-invasive imaging modality to follow-up these lesions. We present the case of an asymptomatic 60-year-old lady referred from her optometrist with a lesion overlying the optic disc and the ensuing diagnosis of cavernous haemangioma using fundus fluorescein angiography and OCT.

Suramin inhibits cullin-RING E3 ubiquitin ligases.

Cullin-RING E3 ubiquitin ligases (CRL) control a myriad of biological processes by directing numerous protein substrates for proteasomal degradation. Key to CRL activity is the recruitment of the E2 ubiquitin-conjugating enzyme Cdc34 through electrostatic interactions between E3's cullin conserved basic canyon and the acidic C terminus of the E2 enzyme. This report demonstrates that a small-molecule compound, suramin, can inhibit CRL activity by disrupting its ability to recruit Cdc34. Suramin, an antitrypansomal drug that also possesses antitumor activity, was identified here through a fluorescence-based high-throughput screen as an inhibitor of ubiquitination. Suramin was shown to target cullin 1's conserved basic canyon and to block its binding to Cdc34. Suramin inhibits the activity of a variety of CRL complexes containing cullin 2, 3, and 4A. When introduced into cells, suramin induced accumulation of CRL substrates. These observations help develop a strategy of regulating ubiquitination by targeting an E2-E3 interface through small-molecule modulators.

Generation of a proteolytic signal: E3/E2-mediated polyubiquitination of IκBα.

A key regulatory node in NF-κB signaling is the removal of the IκBα inhibitor, whose levels are tightly controlled by the ubiquitin-proteasome system. In response to signal activation and transmission, ubiquitin E1, E2, and E3 enzymes are employed to generate a lysine 48-linked ubiquitin chain that triggers degradation of IκBα by the proteasome. In this chapter we describe an in vitro biochemical approach to reconstitute the ubiquitination system. To do so, we detail methods for the preparation of the relevant enzymes and substrate, as well as for the execution of the reaction with high efficiency. This sensitive and highly reproducible readout can be applied to the study of proteins, small molecules, and other factors that modulate IκBα ubiquitination, thereby producing outcomes that impact NF-κB signaling to advance the course of improving human health.

Pivotal role for the ubiquitin Y59-E51 loop in lysine 48 polyubiquitination.

Lysine 48 (K48)-polyubiquitination is the predominant mechanism for mediating selective protein degradation, but the underlying molecular basis of selecting ubiquitin (Ub) K48 for linkage-specific chain synthesis remains elusive. Here, we present biochemical, structural, and cell-based evidence demonstrating a pivotal role for the Ub Y59-E51 loop in supporting K48-polyubiquitination. This loop is established by a hydrogen bond between Ub Y59's hydroxyl group and the backbone amide of Ub E51, as substantiated by NMR spectroscopic analysis. Loop residues Y59 and R54 are specifically required for the receptor activity enabling K48 to attack the donor Ub-E2 thiol ester in reconstituted ubiquitination catalyzed by Skp1-Cullin1-F-box (SCF)(ßTrCP) E3 ligase and Cdc34 E2-conjugating enzyme. When introduced into mammalian cells, loop-disruptive mutant Ub(R54A/Y59A) diminished the production of K48-polyubiquitin chains. Importantly, conditional replacement of human endogenous Ub by Ub(R54A/Y59A) or Ub(K48R) yielded profound apoptosis at a similar extent, underscoring the global impact of the Ub Y59-E51 loop in cellular K48-polyubiquitination. Finally, disulfide cross-linking revealed interactions between the donor Ub-bound Cdc34 acidic loop and the Ub K48 site, as well as residues within the Y59-E51 loop, suggesting a mechanism in which the Ub Y59-E51 loop helps recruit the E2 acidic loop that aligns the receptor Ub K48 to the donor Ub for catalysis.

A snapshot of ubiquitin chain elongation: lysine 48-tetra-ubiquitin slows down ubiquitination.

We have explored the mechanisms of polyubiquitin chain assembly with reconstituted ubiquitination of IκBα and ß-catenin by the Skp1-cullin 1-ßTrCP F-box protein (SCF(ßTrCP)) E3 ubiquitin (Ub) ligase complex. Competition experiments revealed that SCF(ßTrCP) formed a complex with IκBα and that the Nedd8 modified E3-substrate platform engaged in dynamic interactions with the Cdc34 E2 Ub conjugating enzyme for chain elongation. Using "elongation intermediates" containing ß-catenin linked with Ub chains of defined length, it was observed that a Lys-48-Ub chain of a length greater than four, but not its Lys-63 linkage counterparts, slowed the rate of additional Ub conjugation. Thus, the Ub chain length and linkage impact kinetic rates of chain elongation. Given that Lys-48-tetra-Ub is packed into compact conformations due to extensive intrachain interactions between Ub subunits, this topology may limit the accessibility of SCF(ßTrCP)/Cdc34 to the distal Ub Lys-48 and result in slowed elongation.

Transcriptional network analysis identifies BACH1 as a master regulator of breast cancer bone metastasis.

The application of functional genomic analysis of breast cancer metastasis has led to the identification of a growing number of organ-specific metastasis genes, which often function in concert to facilitate different steps of the metastatic cascade. However, the gene regulatory network that controls the expression of these metastasis genes remains largely unknown. Here, we demonstrate a computational approach for the deconvolution of transcriptional networks to discover master regulators of breast cancer bone metastasis. Several known regulators of breast cancer bone metastasis such as Smad4 and HIF1 were identified in our analysis. Experimental validation of the networks revealed BACH1, a basic leucine zipper transcription factor, as the common regulator of several functional metastasis genes, including MMP1 and CXCR4. Ectopic expression of BACH1 enhanced the malignance of breast cancer cells, and conversely, BACH1 knockdown significantly reduced bone metastasis. The expression of BACH1 and its target genes was linked to the higher risk of breast cancer recurrence in patients. This study established BACH1 as the master regulator of breast cancer bone metastasis and provided a paradigm to identify molecular determinants in complex pathological processes.

Adenoid cystic carcinoma of the lacrimal gland: CT and MRI findings.

PURPOSE: To highlight the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of lacrimal gland adenoid cystic carcinoma. METHODS: We reviewed the clinical records and imaging findings of 17 patients who were histopathologically diagnosed with primary adenoid cystic carcinoma of the lacrimal gland between August 1998 and November 2010. Orbital CT scans were performed in 17 patients and MRI scans were obtained in 13 patients. RESULTS: On the CT scans, out of 4 cases of adenoid cystic carcinoma, 3 showed characteristic features of a soft tissue mass with poorly enhancing areas representing cystic changes, and 4 of 17 cases had contiguous bony erosion. On the MRI scans, all cases had mixed signal intensity on T2-weighted images, and 6 cases showed poorly enhancing areas. CONCLUSIONS: Enhanced CT and MRI (including T2-weighted) are helpful in the diagnosis of primary adenoid cystic carcinoma of the lacrimal gland.

Use of adjuvant hyperbaric oxygen therapy to support limbal conjunctival graft in the management of recurrent pterygium.

PURPOSE: To assess the role of hyperbaric oxygen therapy (HBOT) in the management of recurrent pterygium. METHODS: Thirty-nine eyes with recurrent pterygium were treated with surgical excision and limbal conjunctival autograft, followed by a course of HBOT. Patients were followed for development of recurrence. RESULTS: Of the 39 eyes, 18 had a known history of exposure to beta radiation or mitomycin C. The mean duration of follow-up in this group was 23.1 months. A single recurrence was noted in this group. For the remaining 21 eyes, the mean duration of follow-up was 19.4 months. No recurrences were recorded in this group. No significant complications from HBOT were recorded. CONCLUSIONS: The use of HBOT together with excision and limbal conjunctival autograft for recurrent pterygium is associated with a low recurrence rate. Adjuvant HBOT should be considered in the surgical management of recurrent pterygium.

MTDH activation by 8q22 genomic gain promotes chemoresistance and metastasis of poor-prognosis breast cancer.

Targeted therapy for metastatic diseases relies on the identification of functionally important metastasis genes from a large number of random genetic alterations. Here we use a computational algorithm to map minimal recurrent genomic alterations associated with poor-prognosis breast cancer. 8q22 genomic gain was identified by this approach and validated in an extensive collection of breast tumor samples. Regional gain of 8q22 elevates expression of the metastasis gene metadherin (MTDH), which is overexpressed in more than 40% of breast cancers and is associated with poor clinical outcomes. Functional characterization of MTDH revealed its dual role in promoting metastatic seeding and enhancing chemoresistance. These findings establish MTDH as an important therapeutic target for simultaneously enhancing chemotherapy efficacy and reducing metastasis risk.

Magnification-corrected photodynamic therapy.

BACKGROUND: To present a method for performing photodynamic therapy (PDT) with a constant predictable light fluence based on actual laser spot magnification. METHODS: A calibrated Gullstrand-type model eye with a scale of half circles in the centre of the artificial fundus was used for this study. The axial length of the model eye was set to different values ranging from 20 to 31 mm, and the actual laser spot magnification of four indirect condensing laser lenses were determined using a PDT laser unit. RESULTS: Equations for determining the actual laser spot magnification were calculated for each laser lens. The total change in laser spot magnification from hyperopia (axial length 20 mm) to myopia (axial length 31 mm) was -20% to +24.8% for Mainster Standard lens (Ocular Instruments Inc, Bellevue, Washington, USA), -15.7% to +27.7% for Mainster Wide Field lens (Ocular Instruments Inc), -16.3% to +33.1% for Volk Transequator lens (Volk Optical Inc, Mentor, Ohio, USA), and -19.2% to +24.4% for Volk PDT Laser lens (Volk Optical Inc). CONCLUSIONS: Axial length of the eye has a considerable effect on PDT laser spot magnification when an indirect laser lens is used. By calculating the actual laser spot magnification in conjunction with knowledge of the true greatest linear dimension of the neovascular lesion, the clinician may be able to deliver a constant predictable amount of light fluence to the fundus independent of the axial length of the PDT treating eye.

Spectrum of clear corneal incision cataract wound infection.

PURPOSE: To describe the presentation, management, and outcome of 5 patients who presented with main-port or side-port wound infection after uneventful clear corneal cataract surgery. SETTING: Ophthalmic Surgery Centre, Chatswood, and Department of Ophthalmology, Prince of Wales Hospital, Randwick, Australia, and Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. METHODS: This retrospective case series comprised 5 patients who had uneventful clear corneal phacoemulsification surgery and developed either a main-port or side-port wound infection. The clinical features, microbiologic studies, management, and results are reported. RESULTS: The median age of the patients was 79 years. Infection of the main-port incision occurred in 3 cases and of the side port in 2 cases. The patients presented from a few days to several weeks after uneventful phacoemulsification. In 2 cases, the bacteria Pseudomonas aeruginosa and Staphylococcus aureus were isolated. In 1 case, the fungus Aspergillus was isolated and required extensive medical and surgical treatment. In the other 2 cases; empiric antimicrobial therapy was given because no organism was isolated in 1 case, and in the other milder case, microbiological investigations were not performed. Final visual acuity was 6/4 in 2 cases and 6/5, 6/12, and 6/18 in 1 case each. CONCLUSIONS: Bacterial or fungal wound infection can present within days or even several weeks following clear corneal cataract surgery. Patients with ocular discomfort or blurred vision after such surgery should be advised to report promptly. Rapid identification and appropriate management of patients with clear corneal wound infection can result in good visual outcomes.

Survey of major chronic iIlnesses and hospital admissions via the emergency department in a randomized older population in Randwick, Australia.

OBJECTIVE: To find out if patients with chronic illnesses living in the community are at risk of unplanned hospital admissions through emergency departments; what types of chronic illnesses may be putative risk factors; and if an increase in the number of chronic illnesses may be associated with increased risk. METHODS: The survey included the completion of a standardized questionnaire for medical illnesses in a random sample of older people dwelling in the community and analysis of admission records to our hospital. The principal diagnoses for admissions were recorded. The risk factors for admissions were analysed. RESULTS: Five hundred and twenty-six (239 men and 287 women) people aged 55 years and over were interviewed. Musculoskeletal disorders, hypertension, gastrointestinal disorders and ischaemic heart disease were the most frequently reported of the chronic illnesses surveyed. A total number of 70 people from the survey group with a total of 115 admissions through emergency departments were recorded. Using logistic regression model, hypertension, ischaemic heart disease and age were found to be risk factors for emergency admissions amongst this group of community-dwelling residents. The ratios were 2.03 (95% confidence interval (CI): 1.2-3.44), 2.02 (95% CI: 1.16-3.49) and 1.05 (95% CI: 1.02-1.09), respectively. Furthermore, multiple (three or more) chronic illnesses were found to be a strong predictor of hospital admission via emergency department (chi-square = 16.647, DF = 1, P-value < 0.001). CONCLUSION: We conclude that there was significant association between multiple chronic diseases and emergency admissions for older people. Of these, hypertension and ischaemic heart disease were found to be significant predictors. Age per se was found to be of borderline significance.