Proteomics Links Ubiquitin Chain Topology Change to Transcription Factor Activation.

A surprising complexity of ubiquitin signaling has emerged with identification of different ubiquitin chain topologies. However, mechanisms of how the diverse ubiquitin codes control biological processes remain poorly understood. Here, we use quantitative whole-proteome mass spectrometry to identify yeast proteins that are regulated by lysine 11 (K11)-linked ubiquitin chains. The entire Met4 pathway, which links cell proliferation with sulfur amino acid metabolism, was significantly affected by K11 chains and selected for mechanistic studies. Previously, we demonstrated that a K48-linked ubiquitin chain represses the transcription factor Met4. Here, we show that efficient Met4 activation requires a K11-linked topology. Mechanistically, our results propose that the K48 chain binds to a topology-selective tandem ubiquitin binding region in Met4 and competes with binding of the basal transcription machinery to the same region. The change to K11-enriched chain architecture releases this competition and permits binding of the basal transcription complex to activate transcription.

Interaction of histone H4 with Cse4 facilitates conformational changes in Cse4 for its sumoylation and mislocalization.

Mislocalization of overexpressed CENP-A (Cse4 in budding yeast, Cnp1 in fission yeast, CID in flies) contributes to chromosomal instability (CIN) in yeasts, flies, and human cells. Mislocalization of CENP-A is observed in many cancers and this correlates with poor prognosis. Structural mechanisms that contribute to mislocalization of CENP-A are poorly defined. Here, we show that interaction of histone H4 with Cse4 facilitates an in vivo conformational change in Cse4 promoting its mislocalization in budding yeast. We determined that Cse4 Y193A mutant exhibits reduced sumoylation, mislocalization, interaction with histone H4, and lethality in psh1Δ and cdc48-3 strains; all these phenotypes are suppressed by increased gene dosage of histone H4. We developed a new in vivo approach, antibody accessibility (AA) assay, to examine the conformation of Cse4. AA assay showed that wild-type Cse4 with histone H4 is in an 'open' state, while Cse4 Y193A predominantly exhibits a 'closed' state. Increased gene dosage of histone H4 contributes to a shift of Cse4 Y193A to an 'open' state with enhanced sumoylation and mislocalization. We provide molecular insights into how Cse4-H4 interaction changes the conformational state of Cse4 in vivo. These studies advance our understanding for mechanisms that promote mislocalization of CENP-A in human cancers.

Efficacy and safety of avacincaptad pegol in patients with geographic atrophy (GATHER2): 12-month results from a randomised, double-masked, phase 3 trial.

BACKGROUND: Geographic atrophy is an advanced form of dry age-related macular degeneration that can lead to irreversible vision loss and high burden of disease. We aimed to assess efficacy and safety of avacincaptad pegol 2 mg in reducing geographic atrophy lesion growth. METHODS: GATHER2 is a randomised, double-masked, sham-controlled, 24-month, phase 3 trial across 205 retina clinics, research hospitals, and academic institutions globally. To be eligible, patients had to be aged 50 years or older with non-centrepoint-involving geographic atrophy and best corrected visual acuity between 20/25 and 20/320 in the study eye. Eligible patients were randomly assigned (1:1) to monthly avacincaptad pegol 2 mg administered as a 100 µL intravitreal injection or sham for the first 12 months. Randomisation was performed using an interactive response technology system with stratification by factors known to be of prognostic importance in age-related macular degeneration. Patients, investigators, study centre staff, sponsor personnel, and data analysts were masked to treatment allocation. The primary endpoint was geographic atrophy lesion size measured by fundus autofluorescence at baseline, month 6, and month 12. Efficacy and safety analyses were done in the modified intention-to-treat and safety populations, respectively. This trial is registered with ClinicalTrials.gov, NCT04435366. FINDINGS: Between June 22, 2020, and July 23, 2021, 1422 patients were screened for eligibility, of whom 448 were enrolled and randomly assigned to avacincaptad pegol 2 mg (n=225) or sham (n=223). One patient in the sham group did not receive study treatment and was excluded from analyses. There were 154 (68%) female patients and 71 (32%) male patients in the avacincaptad pegol 2 mg group, and 156 (70%) female patients and 66 (30%) male patients in the sham group. From baseline to month 12, the mean rate of square-root-transformed geographic atrophy area growth was 0·336 mm/year (SE 0·032) with avacincaptad pegol 2 mg and 0·392 mm/year (0·033) with sham, a difference in growth of 0·056 mm/year (95% CI 0·016-0·096; p=0·0064), representing a 14% difference between the avacincaptad pegol 2 mg group and the sham group. Ocular treatment-emergent adverse events in the study eye occurred in 110 (49%) patients in the avacincaptad pegol 2 mg group and 83 (37%) in the sham group. There were no endophthalmitis, intraocular inflammation, or ischaemic optic neuropathy events over 12 months. To month 12, macular neovascularisation in the study eye occurred in 15 (7%) patients in the avacincaptad pegol 2 mg group and nine (4%) in the sham group, with exudative macular neovascularisation occurring in 11 (5%) in the avacincaptad pegol 2 mg group and seven (3%) in the sham group. INTERPRETATION: Monthly avacincaptad pegol 2 mg was well tolerated and showed significantly slower geographic atrophy growth over 12 months than sham treatment, suggesting that avacincaptad pegol might slow disease progression and potentially change the trajectory of disease for patients with geographic atrophy. FUNDING: Iveric Bio, An Astellas Company.

International Classification System for Ocular Complications of Anti-Vascular Endothelial Growth Factor Agents in Clinical Trials.

OBJECTIVE: Complications associated with intravitreal anti-vascular endothelial growth factor (VEGF) therapies are inconsistently reported in the literature, thus limiting an accurate evaluation and comparison of safety between studies. This study aimed to develop a standardized classification system for anti-VEGF ocular complications using the Delphi consensus process. DESIGN: Systematic review and Delphi consensus process. PARTICIPANTS: 25 international retinal specialists participated in the Delphi consensus survey. METHODS: A systematic literature search was conducted to identify complications of intravitreal anti-VEGF agent administration based on randomized controlled trials (RCTs) of anti-VEGF therapy. A comprehensive list of complications was derived from these studies, and this list was subjected to iterative Delphi consensus surveys involving international retinal specialists that voted on inclusion, exclusion, rephrasing, and addition of complications. As well, surveys determined specifiers for the selected complications. This iterative process helped refine the final classification system. MAIN OUTCOME MEASURES: The proportion of retinal specialists who choose to include or exclude complications associated with anti-VEGF administration. RESULTS: After screening 18,229 articles, 130 complications were initially categorized from 145 included RCTs. Participant consensus via the Delphi method resulted in the inclusion of 91 (70%) complications after three rounds. After incorporating further modifications made based on participant suggestions, such as rewording certain phrases and combining similar terms, 24 redundant complications were removed, leaving a total of 67 (52%) complications in the final list. A total of 14 (11%) complications met exclusion thresholds and were eliminated by participants across both rounds. All other remaining complications not meeting inclusion or exclusion thresholds were also excluded from the final classification system after the Delphi process terminated. In addition, 47 out of 75 (63%) proposed complication specifiers were included based on participant agreement. CONCLUSION: Using the Delphi consensus process, a comprehensive, standardized classification system consisting of 67 ocular complications and 47 unique specifiers was established for intravitreal anti-VEGF agents in clinical trials. The adoption of this system in future trials could improve consistency and quality of adverse event reporting, potentially facilitating more accurate risk-benefit analyses.

The Ubiquitin Interacting Motif-Like Domain of Met4 Selectively Binds K48 Polyubiquitin Chains.

Protein ubiquitylation is an important posttranslational modification that governs most cellular processes. Signaling functions of ubiquitylation are very diverse and involve proteolytic as well as nonproteolytic events, such as localization, regulation of protein interactions, and control of protein activity. The intricacy of ubiquitin signaling is further complicated by several different polyubiquitin chain types that are likely recognized and interpreted by different protein readers. For example, K48-linked ubiquitin chains represent the most abundant chain topology and are the canonical degradation signals, but have been implicated in degradation-independent functions as well, likely requiring a variety of protein readers. Ubiquitin binding domains that interact with polyubiquitin chains are likely at the center of ubiquitin signal recognition and transmission, but their structure and selectivity are largely unexplored. Here we report identification and characterization of the ubiquitin interacting motif-like (UIML) domain of the yeast transcription factor Met4 as a strictly K48-polyubiquitin specific binding unit using methods such as biolayer interferometry (BLI), pull-down assays, and mass spectrometry. We further used the selective binding property to develop an affinity probe for purification of proteins modified with K48-linked polyubiquitin chains. The affinity probe has a Kd = 100 nM for K48 tetra-ubiquitin and shows no detectable interaction with either monoubiquitin or any other polyubiquitin chain configuration. Our results define a short strictly K48-linkage-dependent binding motif and present a new affinity reagent for the K48-polyubiquitin-modified proteome. Our findings benefit the ubiquitin field in analyses of the role of K48-linked polyubiquitylation and increase our understanding of chain topology selective ubiquitin chain recognition.

SUPRACHOROIDAL SPACE INJECTION TECHNIQUE: Expert Panel Guidance.

PURPOSE: To develop professional guidelines for best practices for suprachoroidal space (SCS) injection, an innovative technique for retinal therapeutic delivery, based on current published evidence and clinical experience. METHODS: A panel of expert ophthalmologists reviewed current published evidence and clinical experience during a live working group meeting to define points of consensus and key clinical considerations to inform the development of guidelines for in-office SCS injection. RESULTS: Core consensus guidelines for in-office SCS injection were reached and reported by the expert panel. Current clinical evidence and physician experience supported SCS injection as a safe and effective method for delivering retinal and choroidal therapeutics. The panel established consensus on the rationale for SCS injection, including potential benefits relative to other intraocular delivery methods and current best practices in patient preparation, pre- and peri-injection management, SCS-specific injection techniques, and postinjection management and follow-up. CONCLUSION: These expert panel guidelines may support and promote standardization of SCS injection technique, with the goal of optimizing patient safety and outcomes. Some aspects of the procedure may reasonably be modified based on the clinical setting and physician judgment, as well as additional study.

Cdc48Ufd1/Npl4 segregase removes mislocalized centromeric histone H3 variant CENP-A from non-centromeric chromatin.

Restricting the localization of CENP-A (Cse4 in Saccharomyces cerevisiae) to centromeres prevents chromosomal instability (CIN). Mislocalization of overexpressed CENP-A to non-centromeric chromatin contributes to CIN in budding and fission yeasts, flies, and humans. Overexpression and mislocalization of CENP-A is observed in cancers and is associated with increased invasiveness. Mechanisms that remove mislocalized CENP-A and target it for degradation have not been defined. Here, we report that Cdc48 and its cofactors Ufd1 and Npl4 facilitate the removal of mislocalized Cse4 from non-centromeric chromatin. Defects in removal of mislocalized Cse4 contribute to lethality of overexpressed Cse4 in cdc48,ufd1 andnpl4 mutants. High levels of polyubiquitinated Cse4 and mislocalization of Cse4 are observed in cdc48-3, ufd1-2 and npl4-1mutants even under normal physiological conditions, thereby defining polyubiquitinated Cse4 as the substrate of the ubiquitin directed segregase Cdc48Ufd1/Npl4. Accordingly, Npl4, the ubiquitin binding receptor, associates with mislocalized Cse4, and this interaction is dependent on Psh1-mediated polyubiquitination of Cse4. In summary, we provide the first evidence for a mechanism that facilitates the removal of polyubiquitinated and mislocalized Cse4 from non-centromeric chromatin. Given the conservation of Cdc48Ufd1/Npl4 in humans, it is likely that defects in such pathways may contribute to CIN in human cancers.

Factors That Can Prolong Ocular Treatment Duration in Age-Related Macular Degeneration.

Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are used to treat wet age-related macular degeneration (wAMD); however, they are associated with a considerable treatment burden and poor real-world outcomes. The molecular size and charge of anti-VEGF agents influence drug pharmacokinetics in the vitreous and peak drug efficacy. This article reviews the established and novel strategies to prolong drug action, in the vitreal cavity, and thus reduce dosing frequency. Increased ocular residency can be attained by increasing drug size as with large molecules, such as KSI-301; adding polyethylene glycol to pegcetacoplan (APL-2) or avacincaptad pegol to increase molecular size; or binding to other targets that increase molecular size, such as vitreal albumin in the case of BI-X. Faricimab is a bispecific antibody in which the fragment crystallizable portion is engineered to prolong ocular residency and reduce systemic exposure. Conversely, small VEGF-binding molecules, such as brolucizumab, can be administered at higher clinical doses, with the potential for prolonged clinical activity versus larger molecules. Other important considerations include sustained drug delivery routes, such as the ranibizumab port delivery system or subconjunctival or suprachoroidal injection. More effective and longer-lasting treatments are needed for wAMD to prolong drug action and reduce dosing frequency. Several strategies are under investigation and the prevention of vision loss in patients with AMD or other retinal diseases may be attainable in the near future.

Cdc48 cofactor Shp1 regulates signal-induced SCFMet30 disassembly.

Organisms can adapt to a broad spectrum of sudden and dramatic changes in their environment. These abrupt changes are often perceived as stress and trigger responses that facilitate survival and eventual adaptation. The ubiquitin-proteasome system (UPS) is involved in most cellular processes. Unsurprisingly, components of the UPS also play crucial roles during various stress response programs. The budding yeast SCFMet30 complex is an essential cullin-RING ubiquitin ligase that connects metabolic and heavy metal stress to cell cycle regulation. Cadmium exposure results in the active dissociation of the F-box protein Met30 from the core ligase, leading to SCFMet30 inactivation. Consequently, SCFMet30 substrate ubiquitylation is blocked and triggers a downstream cascade to activate a specific transcriptional stress response program. Signal-induced dissociation is initiated by autoubiquitylation of Met30 and serves as a recruitment signal for the AAA-ATPase Cdc48/p97, which actively disassembles the complex. Here we show that the UBX cofactor Shp1/p47 is an additional key element for SCFMet30 disassembly during heavy metal stress. Although the cofactor can directly interact with the ATPase, Cdc48 and Shp1 are recruited independently to SCFMet30 during cadmium stress. An intact UBX domain is crucial for effective SCFMet30 disassembly, and a concentration threshold of Shp1 recruited to SCFMet30 needs to be exceeded to initiate Met30 dissociation. The latter is likely related to Shp1-mediated control of Cdc48 ATPase activity. This study identifies Shp1 as the crucial Cdc48 cofactor for signal-induced selective disassembly of a multisubunit protein complex to modulate activity.

Skp, Cullin, F-box (SCF)-Met30 and SCF-Cdc4-Mediated Proteolysis of CENP-A Prevents Mislocalization of CENP-A for Chromosomal Stability in Budding Yeast.

Restricting the localization of the histone H3 variant CENP-A (Cse4 in yeast, CID in flies) to centromeres is essential for faithful chromosome segregation. Mislocalization of CENP-A leads to chromosomal instability (CIN) in yeast, fly and human cells. Overexpression and mislocalization of CENP-A has been observed in many cancers and this correlates with increased invasiveness and poor prognosis. Yet genes that regulate CENP-A levels and localization under physiological conditions have not been defined. In this study we used a genome-wide genetic screen to identify essential genes required for Cse4 homeostasis to prevent its mislocalization for chromosomal stability. We show that two Skp, Cullin, F-box (SCF) ubiquitin ligases with the evolutionarily conserved F-box proteins Met30 and Cdc4 interact and cooperatively regulate proteolysis of endogenous Cse4 and prevent its mislocalization for faithful chromosome segregation under physiological conditions. The interaction of Met30 with Cdc4 is independent of the D domain, which is essential for their homodimerization and ubiquitination of other substrates. The requirement for both Cdc4 and Met30 for ubiquitination is specifc for Cse4; and a common substrate for Cdc4 and Met30 has not previously been described. Met30 is necessary for the interaction between Cdc4 and Cse4, and defects in this interaction lead to stabilization and mislocalization of Cse4, which in turn contributes to CIN. We provide the first direct link between Cse4 mislocalization to defects in kinetochore structure and show that SCF-mediated proteolysis of Cse4 is a major mechanism that prevents stable maintenance of Cse4 at non-centromeric regions, thus ensuring faithful chromosome segregation. In summary, we have identified essential pathways that regulate cellular levels of endogenous Cse4 and shown that proteolysis of Cse4 by SCF-Met30/Cdc4 prevents mislocalization and CIN in unperturbed cells.

Sexual and nonsexual violence and mental health among male refugees from the Democratic Republic of Congo residing in Kampala, Uganda: a population-based survey.

We conducted a population-based survey in 2013 in Kampala, Uganda, to examine violence and mental health outcomes among self-settled male refugees from the Eastern Democratic Republic of Congo (DRC). Male DRC refugees aged 18+ years were sampled through respondent-driven sampling. Key interview domains included demographics, experiences of sexual and nonsexual violence, social support, PTSD, depression and suicide ideation. Data analysis was weighted to generate population-level estimates. We sampled 718 men (mean age: 33 years), most of whom had lived in North or South Kivu. Nonsexual violence, such as beatings (79.4%) and torture (63.8%), was frequent. A quarter (26.2%) had been raped; 49.9% of rape victims had been raped on multiple occasions, and 75.7% of rape victims had been gang raped. We estimated 52.8% had post-traumatic stress disorder (PTSD); 44.4% reported suicidal ideation. Numerous traumas were significantly (p < 0.05) associated with PTSD such as rape (adjusted odds ratio [aOR] = 1.82), war-related injuries (aOR = 2.90) or having been exposed to >15 traumas (compared to ≤10; aOR = 6.89). Traumata are frequent experiences in this self-settled male refugee population and are often accompanied by adverse mental health outcomes. Screening for trauma and adverse mental health outcomes and providing targeted services are paramount to improve these refugees' lives.

Efficacy and Safety of Biosimilar FYB201 Compared with Ranibizumab in Neovascular Age-Related Macular Degeneration.

PURPOSE: This trial was conducted to investigate the clinical equivalence of the proposed biosimilar FYB201 and reference ranibizumab in patients with treatment-naive, subfoveal choroidal neovascularization caused by neovascular age-related macular degeneration (nAMD). DESIGN: This was a prospective, multicenter, evaluation-masked, parallel-group, 48-week, phase III randomized study. PARTICIPANTS: A total of 477 patients were randomly assigned to receive FYB201 (n = 238) or reference ranibizumab (n = 239). METHODS: Patients received FYB201 or reference ranibizumab 0.5 mg by intravitreal (IVT) injection in the study eye every 4 weeks. MAIN OUTCOME MEASURES: The primary end point was change from baseline in best-corrected visual acuity (BCVA) by Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 8 weeks before the third monthly IVT injection. Biosimilarity of FYB201 to its originator was assessed via a 2-sided equivalence test, with an equivalence margin in BCVA of 3 ETDRS letters. RESULTS: The BCVA improved in both groups, with a mean improvement of +5.1 (FYB201) and +5.6 (reference ranibizumab) ETDRS letters at week 8. The analysis of covariance (ANCOVA) least squares mean difference for the change from baseline between FYB201 and reference ranibizumab was -0.4 ETDRS letters with a 90% confidence interval (CI) of -1.6 to 0.9. Primary end point was met as the 90% CI was within the predefined equivalence margin. Adverse events were comparable between treatment groups. CONCLUSIONS: FYB201 is biosimilar to reference ranibizumab in terms of clinical efficacy and ocular and systemic safety in the treatment of patients with nAMD.

The 12- and 24-Month Effects of Intravitreal Ranibizumab, Aflibercept, and Bevacizumab on Intraocular Pressure: A Network Meta-Analysis.

TOPIC: To investigate the effect of anti-vascular endothelial growth factor (VEGF) therapy on intraocular pressure (IOP) 12 and 24 months after initiation. CLINICAL RELEVANCE: It is unclear whether serial anti-VEGF injections result in sustained IOP increases. METHODS: Randomized controlled trials (RCTs) comparing anti-VEGF agents with each other or with controls for the treatment of neovascular age-related macular degeneration, retinal vein occlusions, or diabetic macular edema were included. Pairwise meta-analysis and Bayesian network meta-analysis examined the proportion of patients whose IOP (1) increased 5 mmHg or more from baseline on consecutive visits, (2) increased 10 mmHg or more from baseline at any visit, (3) was 21 mmHg or more on consecutive visits, (4) was 25 mmHg or more at any visit, (5) was 30 mmHg or more at any visit, (6) prompted initiation of IOP-lowering medications, or (7) increased as per the clinicians' discretion. Grading of Recommendations Assessments, Development, and Evaluations methodology informed the certainty of evidence. RESULTS: Twenty-six RCTs of 12 522 eyes were included. Aflibercept, bevacizumab, ranibizumab (0.3 mg and 0.5 mg), and noninjection controls were analyzed. Eighty-three of 84 network estimates for comparisons between anti-VEGF agents demonstrated no statistically significant difference (low to moderate certainty of evidence). Ranibizumab 0.5 mg showed higher rates than bevacizumab of IOP measurements of 30 mmHg or more at 12 months (low certainty of evidence). Fifty-three of 56 network estimates for comparisons between anti-VEGF agents and controls demonstrated no statistically significant difference (low to moderate certainty of evidence). Ranibizumab 0.5 mg showed higher rates of consecutive IOP increases of 5 mmHg or more at 24 months (low certainty of evidence) and higher rates of IOP increases as per the clinicians' discretion at 12 and 24 months (low and very low certainty of evidence, respectively). The 95% credible intervals in comparisons without statistically significant effects did not rule out important clinical effects. The certainty of evidence in these comparisons is limited by imprecision. CONCLUSION: This network meta-analysis does not show any clear difference in IOP increases 12 and 24 months after treatment initiation between anti-VEGF agents and controls. Imprecision precludes definitive conclusions.

ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR BIOSIMILARS IN OPHTHALMOLOGY.

BACKGROUND/PURPOSE: Anti-vascular endothelial growth factor therapies have proven effective in treating retinal diseases but come with a high financial burden to the patient and health care system. Biosimilar drugs present an opportunity to decrease the cost of these important ophthalmic medications, and several ophthalmic biosimilars are expected to be approved and enter the market in the coming years. The objectives of this review are to educate ophthalmologists on the safety and efficacy of biosimilars in ophthalmology in the United States and European Union, review the biosimilar manufacturing and approval process, and describe the upcoming ophthalmic biosimilars. RESULTS: Two ranibizumab biosimilars are currently approved in the United States and European Union. Additional ranibizumab biosimilars, as well as biosimilars for aflibercept and bevacizumab, are currently in clinical development. CONCLUSION: Biosimilar use in ophthalmology is expected to grow with the patent expiration of two major anti-vascular endothelial growth factor drugs, ranibizumab and aflibercept, and the development of an ophthalmology-specific bevacizumab biosimilar. Financial savings from biosimilar use in ophthalmology have the potential to reduce economic burden, increase treatment adherence, and ultimately improve health outcomes.

LONGITUDINAL ELLIPSOID ZONE AND OUTER RETINAL INTEGRITY DYNAMICS AFTER EPIRETINAL MEMBRANE SURGERY.

PURPOSE: To quantify ellipsoid zone (EZ) changes in integrity after epiretinal membrane (ERM) surgery, correlate findings to visual acuity, and determine predictors for prognosis. METHODS: A post hoc analysis of eyes undergoing ERM surgery pooled from the prospective DISCOVER intraoperative optical coherence tomography study and eyes undergoing conventional ERM surgery without intraoperative optical coherence tomography. Quantitative EZ features were extracted using a multilayer machine learning enabled automated segmentation platform after image analyst review/correction for segmentation accuracy. Visual acuity and EZ integrity were quantitatively assessed and correlated before and after ERM surgery. Multiple linear regression was performed to assess preoperative visual acuity and EZ features as predictors for improvement in visual acuity or EZ integrity. RESULTS: There were 177 eyes from 177 subjects that underwent ERM surgery from the DISCOVER and conventional arms. Improvement in visual acuity and multiple EZ integrity features was noted after ERM surgery, including EZ partial attenuation and EZ-retinal pigment epithelium (RPE) volume (P < 0.05). A reduction in EZ partial attenuation and increase in EZ-RPE central subfield thickness (EZ-RPE CST) was significantly correlated with improved visual acuity after ERM surgery (P < 0.05). More robust EZ-RPE CST at baseline predicted visual acuity improvement after ERM peel in regression modeling (ß = 0.005, P < 0.05). CONCLUSIONS: Longitudinal assessment of EZ features demonstrates significant postoperative improvement in multiple EZ integrity metrics after ERM surgery. Improving EZ integrity was correlated to improving the visual acuity. Ellipsoid zone integrity and visual acuity were significant predictors in regression modeling and may have value in clinical prognostication.

Lessons learned with the Cobra prosthesis in elderly patients with complex distal radius fractures-a retrospective follow-up study.

INTRODUCTION: Recently, the Cobra prostheses were introduced in the treatment of distal radius fractures (DRF) of elderly patients. Fracture prostheses provide an alternative treatment option for complex fractures where conservative therapy seems not acceptable and osteosynthesis seems not possible. Data reporting the feasibility of the Cobra prosthesis are sparse. Therefore, this retrospective follow-up study investigated the clinical and radiological mid-term outcome of the Cobra implant in complex DRFs of elderly patients. MATERIALS AND METHODS: Thirteen patients (mean age 73.5 years, range 65-87 years) were retrospectively evaluated with at least a 1-year follow-up after surgery. Objective and subjective clinical parameters as well as the radiological outcome and complications were analyzed. RESULTS: The mean follow-up period was 31.2 months. Seven cases required a cemented prosthesis. The mean relative range-of-motion compared to the healthy side was 72.3% and 51.8% for extension and flexion, respectively, and 87.9% and 85.7% for pronation and supination, respectively. The mean grip strength was 78.3% compared to the non-operated side. Eight patients were very satisfied, five patients were partly satisfied with the result. The DASH, PRWE, MHQ and Lyon-Scores averaged 39.1, 36.2, 64.9 and 63.3 points, respectively. The mean VAS-Score for pain was 1.1 at rest and 3.2 during activities. Perioperative complications included one dissection of the extensor pollicis longus tendon, one heterotopic ossification, one radiocarpal dislocation and two cases of an ulnar impaction syndrome due to implant subsidence. CONCLUSION: The prosthetic treatment of complex DRFs in elderly patients with the Cobra implant led to clinically and radiologically satisfactory mid-term results. The Cobra prosthesis still does not represent a gold standard but can be regarded as a feasible salvage option for complex DRFs when osteosyntheses may not be possible and non-operative treatment will lead to further functional restrictions and wrist pain during performing activities of daily life in high functional demand patients.

Retrospective comparison of conservative treatment and surgery for widely displaced olecranon fractures in low-demanding geriatric patients.

INTRODUCTION: The aim of this study was to evaluate the difference of the clinical outcome of elderly patients who were treated surgically or conservatively for a displaced olecranon fracture (Mayo type IIA or IIB). PATIENTS AND METHODS: Patients above the age of 70 years who were treated surgically (n = 11) for a displaced Mayo type IIA and IIB olecranon fracture between July 2015 and February 2019 were retrospectively compared with patients who were treated conservatively (n = 6). The range of motion, elbow strength, grip strength, VAS, DASH, OES, MEPI and Broberg and Morrey scores were evaluated. RESULTS: The conservative group showed a non-union with a persistent fracture gap of 17 mm (SD 12 mm) at the articular rim and 31 mm (15 mm) at the dorsal rim while there was no case of non-union in the surgical group. The arch of motion was 120° in the conservative group and 136° in the surgical group. There was no obvious difference in elbow extension strength in comparison to the healthy contralateral side (p = 0.20; 88% group I/87% group II). There was no difference in the OES (p = 0.30; 42 (SD 7) vs. 45 (SD 5)) and MEPI score (p = 0.46; (SD 8) vs. 96 (SD 19)). The conservative group presented a slightly worse DASH [p = 0.10; 26 (SD 25) vs 7 (SD 14)] and a significantly worse Broberg and Morrey score (p = 0.02; 84(SD 9) vs. 95 (SD 7)). The conservative group presented one complication (ulnar nerve palsy), while the surgical group presented two cases (prolonged lymphedema; blocked forearm rotation due to screw length with consecutive revision surgery). CONCLUSION: Widely displaced olecranon fractures can successfully be treated conservatively in low-demanding geriatric patients with a satisfactory outcome. Patient selection is essential as patients that are more active might benefit from surgical treatment. Yet, treatment risks and benefits need to be balanced carefully in regard to the patient`s demands and requests.

Arthroscopic debridement of the dorsal capsule in intraarticular distal radius fractures: does it provide superior outcomes?

INTRODUCTION: Distal radius fractures (DRFs) are very common. One of the most significant complications after intraarticular DRF is arthrofibrosis with loss of wrist motion and pain. Wrist arthroscopy has become increasingly popular in the treatment of DRF with the advantage of good visualization of the joint surface and soft tissue injuries. In intraarticular DRFs injuries of the dorsal capsule are a characteristic finding which potentially cause loss of wrist motion. In this study, we investigated if arthroscopic debridement of dorsal capsule injuries at time of surgical fixation provides superior outcomes compared to the same treatment without debridement. MATERIALS AND METHODS: Between 2013 and 2017, we included 42 patients who underwent arthroscopy-assisted palmar plating for intraarticular DRFs in a prospective randomized controlled study. In group A (intervention group), the dorsal capsule tears were debrided during primary surgery, while in group B these were left in place. Active range of motion (AROM), grip strength, subjective outcomes and radiographic results were assessed 3, 6 and 12 months after primary surgery. A subgroup analysis was performed for patient age, fracture severity and duration of immobilization. RESULTS: Arthroscopic debridement of the dorsal capsule improved AROM in patients over 60 years of age, more severe fractures (AO 23 C2/C3) and prolonged postoperative immobilization for more than two weeks, while it was not relevant for younger patients with simple fractures and short immobilization. CONCLUSIONS: Debridement of the injured dorsal capsule in arthroscopic-assisted surgical treatment of intraarticular DRFs can improve surgical performance and optimize patient outcomes in a specific subgroup of patients.

Surgical treatment of the bony mallet thumb: a case series and literature review.

INTRODUCTION: The aim of this study was to provide a more precise statement on the outcome after surgical treatment of a bony mallet thumb and possibly give a treatment recommendation regarding the surgical fixation method. PATIENTS AND METHODS: All patients (n = 16) who underwent a surgical treatment for an acute bony mallet thumb fracture between January 2006 and July 2019 were enrolled. The surgical method, complications, the range of motion, tip pinch, lateral key pinch, overall grip strength, visual analog score, Disability of the Arm, Shoulder and Hand Score, Mayo Wrist Score, Patient-Rated Wrist Evaluation Score, Buck-Gramcko Score and radiologic parameters were evaluated. Further, a comprehensive literature search on PubMed was conducted covering a period from 1956 to 2021 to include all possible matching articles on the treatment of the bony mallet thumb (n = 21 articles). RESULTS: Surgical treatment was very inhomogenous including indirect and direct K-wire fixation, screw fixation, plate fixation and anchor fixation methods. The IP joint range of motion and thumb strength ranged from 66 to 94% in comparison to the contralateral side. An open reduction led to worse functional scores compared to a closed reduction. Treatment methods in the literature were also very inhomogenous with a very low patient count, often even pooling data of bony mallet thumb fractures with bony mallet finger fractures. The risk for infection was higher in K-wire fixation methods than in open reduction and internal fixation methods. CONCLUSION: The evidence for the best treatment of a bony mallet thumb fracture is low. On one hand the functional outcome can be inferior using an open reduction approach, but on the other hand, K-wire fixation methods with a closed reduction approach showed a higher risk for infection. Future multi-center research must be conducted to find the best treatment procedure for the best outcome of the patient.

Lipid remodeling in response to methionine stress in MDA-MBA-468 triple-negative breast cancer cells.

Methionine (Met) is an essential amino acid and critical precursor to the cellular methyl donor S-adenosylmethionine. Unlike nontransformed cells, cancer cells have a unique metabolic requirement for Met and are unable to proliferate in growth media where Met is replaced with its metabolic precursor, homocysteine. This metabolic vulnerability is common among cancer cells regardless of tissue origin and is known as "methionine dependence", "methionine stress sensitivity", or the Hoffman effect. The response of lipids to Met stress, however, is not well-understood. Using mass spectroscopy, label-free vibrational microscopy, and next-generation sequencing, we characterize the response of lipids to Met stress in the triple-negative breast cancer cell line MDA-MB-468 and its Met stress insensitive derivative, MDA-MB-468res-R8. Lipidome analysis identified an immediate, global decrease in lipid abundances with the exception of triglycerides and an increase in lipid droplets in response to Met stress specifically in MDA-MB-468 cells. Furthermore, specific gene expression changes were observed as a secondary response to Met stress in MDA-MB-468, resulting in a downregulation of fatty acid metabolic genes and an upregulation of genes in the unfolded protein response pathway. We conclude that the extensive changes in lipid abundance during Met stress is a direct consequence of the modified metabolic profile previously described in Met stress-sensitive cells. The changes in lipid abundance likely results in changes in membrane composition inducing the unfolded protein response we observe.