Biochemical and cellular insights into the Baz2B protein, a non-catalytic subunit of the chromatin remodeling complex.

Baz2B is a regulatory subunit of the ATP-dependent chromatin remodeling complexes BRF1 and BRF5, which control access to DNA during DNA-templated processes. Baz2B has been implicated in several diseases and also in unhealthy ageing, however limited information is available on the domains and cellular roles of Baz2B. To gain more insight into the Baz2B function, we biochemically characterized the TAM (Tip5/ARBP/MBD) domain with the auxiliary AT-hook motifs and the bromodomain (BRD). We observed alterations in histone code recognition in bromodomains carrying cancer-associated point mutations, suggesting their potential involvement in disease. Furthermore, the depletion of Baz2B in the Hap1 cell line resulted in altered cell morphology, reduced colony formation and perturbed transcriptional profiles. Despite that, super-resolution microscopy images revealed no changes in the overall chromatin structure in the absence of Baz2B. These findings provide insights into the biological function of Baz2B.

Impact of NaOH based perfusion-decellularization protocol on mechanical resistance of structural bone allografts.

INTRODUCTION: To mitigate the post-operative complication rates associated with massive bone allografts, tissue engineering techniques have been employed to decellularize entire bones through perfusion with a sequence of solvents. Mechanical assessment was performed in order to compare conventional massive bone allografts and perfusion/decellularized massive bone allografts. MATERIAL AND METHODS: Ten porcine femurs were included. Five were decellularized by perfusion. The remaining 5 were left untreated as the "control" group. Biomechanical testing was conducted on each bone, encompassing five different assessments: screw pull-out, 3-points bending, torsion, compression and Vickers indentation. RESULTS: Under the experimental conditions of this study, all five destructive tested variables (maximum force until screw pull-out, maximum elongation until screw pull-out, energy to pull out the screw, fracture resistance in flexion and maximum constrain of compression) were statistically significantly superior in the control group. All seven nondestructive variables (Young's modulus in flexion, Young's modulus in shear stress, Young's modulus in compression, Elastic conventional limit in compression, lengthening to rupture in compression, resilience in compression and Vickers Hardness) showed no significant difference. DISCUSSION: Descriptive statistical results suggest a tendency for the biomechanical characteristics of decellularized bone to decrease compared with the control group. However, statistical inferences demonstrated a slight significant superiority of the control group with destructive mechanical stresses. Nondestructive mechanical tests (within the elastic phase of Young's modulus) were not significantly different.

QTY code designed thermostable and water-soluble chimeric chemokine receptors with tunable ligand affinity.

Chemokine receptors are of great interest as they play a critical role in many immunological and pathological processes. The ability to study chemokine receptors in aqueous solution without detergent would be significant because natural receptors require detergents to become soluble. We previously reported using the QTY code to design detergent-free chemokine receptors. We here report the design of 2 detergent-free chimeric chemokine receptors that were experimentally unattainable in detergent solution. We designed chimeric receptors by switching the N terminus and 3 extracellular (EC) loops between different receptors. Specifically, we replaced the N terminus and 3 EC loops of CCR5QTY with the N terminus and 3 EC loops of CXCR4. The ligand for CXCR4; namely CXCL12, binds to the chimeric receptor CCR5QTY (7TM)-CXCR4 (N terminus+3 EC loops), but with lower affinity compared to CXCR4; the CCL5 ligand of CCR5 binds the chimeric receptor with ∼20× lower affinity. The chimeric design helps to elucidate the mechanism of native receptor-ligand interaction. We also show that all detergent-free QTY-designed chemokine receptors, expressed in Escherichia coli, bind to their respective chemokines with affinities in the nanomolar (nM) range, similar to the affinities of native receptors and SF9-produced QTY variants. These QTY-designed receptors exhibit remarkable thermostability in the presence of arginine and retain ligand-binding activity after heat treatment at 60 °C for 4 h and 24 h, and at 100 °C for 10 min. Our design approach enables affordable scale-up production of detergent-free QTY variant chemokine receptors with tunable functionality for various uses.

Valence, sensations and appraisals co-occurring with feeling moved: evidence on kama muta theory from intra-individually cross-correlated time series.

Emotional experiences typically labelled "being moved" or "feeling touched" may belong to one universal emotion. This emotion, which has been labelled "kama muta", is hypothesised to have a positive valence, be elicited by sudden intensifications of social closeness, and be accompanied by warmth, goosebumps and tears. Initial evidence on correlations among the kama muta components has been collected with self-reports after or during the emotion. Continuous measures during the emotion seem particularly informative, but previous work allows only restricted inferences on intra-individual processes because time series were cross-correlated across samples. In the current studies, we instead use a within-subject design to replicate and extend prior work. We compute intra-individual cross-correlations between continuous self-reports on feeling moved and (1) positive and negative affect; (2) goosebumps and subjective warmth and (3) appraisals of closeness and morality. Results confirm the predictions of kama muta theory that feeling moved by intensified communal sharing cross-correlates with appraised closeness, positive affect, warmth and (less so) goosebumps, but not with negative affect. Contrary to predictions, appraised morality cross-correlated with feeling moved as much as appraised closeness did. We conclude that strong inferences on emotional processes are possible using continuous measures, replace earlier findings, and are largely in line with theorising.

The NHL domain of BRAT is an RNA-binding domain that directly contacts the hunchback mRNA for regulation.

The Drosophila protein brain tumor (Brat) forms a complex with Pumilio (Pum) and Nanos (Nos) to repress hunchback (hb) mRNA translation at the posterior pole during early embryonic development. It is currently thought that complex formation is initiated by Pum, which directly binds the hb mRNA and subsequently recruits Nos and Brat. Here we report that, in addition to Pum, Brat also directly interacts with the hb mRNA. We identify Brat-binding sites distinct from the Pum consensus motif and show that RNA binding and translational repression by Brat do not require Pum, suggesting so far unrecognized Pum-independent Brat functions. Using various biochemical and biophysical methods, we also demonstrate that the NHL (NCL-1, HT2A, and LIN-41) domain of Brat, a domain previously believed to mediate protein-protein interactions, is a novel, sequence-specific ssRNA-binding domain. The Brat-NHL domain folds into a six-bladed ß propeller, and we identify its positively charged top surface as the RNA-binding site. Brat belongs to the functional diverse TRIM (tripartite motif)-NHL protein family. Using structural homology modeling, we predict that the NHL domains of all TRIM-NHL proteins have the potential to bind RNA, indicating that Brat is part of a conserved family of RNA-binding proteins.

Conversion of RNA Aptamer into Modified DNA Aptamers Provides for Prolonged Stability and Enhanced Antitumor Activity.

Aptamers, synthetic single-strand oligonucleotides that are similar in function to antibodies, are promising as therapeutics because of their minimal side effects. However, the stability and bioavailability of the aptamers pose a challenge. We developed aptamers converted from RNA aptamer to modified DNA aptamers that target phospho-AXL with improved stability and bioavailability. On the basis of the comparative analysis of a library of 17 converted modified DNA aptamers, we selected aptamer candidates, GLB-G25 and GLB-A04, that exhibited the highest bioavailability, stability, and robust antitumor effect in in vitro experiments. Backbone modifications such as thiophosphate or dithiophosphate and a covalent modification of the 5'-end of the aptamer with polyethylene glycol optimized the pharmacokinetic properties, improved the stability of the aptamers in vivo by reducing nuclease hydrolysis and renal clearance, and achieved high and sustained inhibition of AXL at a very low dose. Treatment with these modified aptamers in ovarian cancer orthotopic mouse models significantly reduced tumor growth and the number of metastases. This effective silencing of the phospho-AXL target thus demonstrated that aptamer specificity and bioavailability can be improved by the chemical modification of existing aptamers for phospho-AXL. These results lay the foundation for the translation of these aptamer candidates and companion biomarkers to the clinic.

QTY code enables design of detergent-free chemokine receptors that retain ligand-binding activities.

Structure and function studies of membrane proteins, particularly G protein-coupled receptors and multipass transmembrane proteins, require detergents. We have devised a simple tool, the QTY code (glutamine, threonine, and tyrosine), for designing hydrophobic domains to become water soluble without detergents. Here we report using the QTY code to systematically replace the hydrophobic amino acids leucine, valine, isoleucine, and phenylalanine in the seven transmembrane α-helices of CCR5, CXCR4, CCR10, and CXCR7. We show that QTY code-designed chemokine receptor variants retain their thermostabilities, α-helical structures, and ligand-binding activities in buffer and 50% human serum. CCR5QTY, CXCR4QTY, and CXCR7QTY also bind to HIV coat protein gp41-120. Despite substantial transmembrane domain changes, the detergent-free QTY variants maintain stable structures and retain their ligand-binding activities. We believe the QTY code will be useful for designing water-soluble variants of membrane proteins and other water-insoluble aggregated proteins.

Compound A Increases Cell Infiltration in Target Organs of Acute Graft-versus-Host Disease (aGVHD) in a Mouse Model.

Systemic steroids are used to treat acute graft-versus-host disease (aGVHD) caused by allogenic bone marrow transplantation (allo-BMT); however, their prolonged use results in complications. Hence, new agents for treating aGVHD are required. Recently, a new compound A (CpdA), with anti-inflammatory activity and reduced side effects compared to steroids, has been identified. Here, we aimed to determine whether CpdA can improve the outcome of aGVHD when administered after transplantation in a mouse model (C57BL/6 in B6D2F1). After conditioning with 9Gy total body irradiation, mice were infused with bone marrow (BM) cells and splenocytes from either syngeneic (B6D2F1) or allogeneic (C57BL/6) donors. The animals were subsequently treated (3 days/week) with 7.5 mg/kg CpdA from day +15 to day +28; the controls received 0.9% NaCl. Thereafter, the incidence and severity of aGVHD in aGVHD target organs were analyzed. Survival and clinical scores did not differ significantly; however, CpdA-treated animals showed high cell infiltration in the target organs. In bulk mixed lymphocyte reactions, CpdA treatment reduced the cell proliferation and expression of inflammatory cytokines and chemokines compared to controls, whereas levels of TNF, IL-23, chemokines, and chemokine receptors increased. CpdA significantly reduced proliferation in vitro but increased T cell infiltration in target organs.

Proper understanding of grounded procedures of separation needs a dual inheritance approach.

Grounded procedures of separation are conceptualized as a learned concept. The simultaneous cultural universality of the general idea and immense diversity of its implementations might be better understood through the lens of dual inheritance theories. By drawing on examples from developmental psychology and emotion theorizing, we argue that an innate blueprint might underlie learned implementations of cleansing that vary widely.

GUV-AP: multifunctional FIJI-based tool for quantitative image analysis of Giant Unilamellar Vesicles.

MOTIVATION: Giant Unilamellar Vesicles (GUVs) are widely used synthetic membrane systems that mimic native membranes and cellular processes. Various fluorescence imaging techniques can be employed for their characterization. In order to guarantee a fast and unbiased analysis of imaging data, the development of automated recognition and processing steps is required. RESULTS: We developed a fast and versatile Fiji-based macro for the analysis of digital microscopy images of GUVs. This macro was designed to investigate membrane dye incorporation and protein binding to membranes. Moreover, we propose a fluorescence intensity-based method to quantitatively assess protein binding. AVAILABILITY AND IMPLEMENTATION: The ImageJ distribution package FIJI is freely available online: https://imagej.net/Fiji. The macro file GUV-AP.ijm is available at https://github.com/AG-Roemer/GUV-AP. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The Composition of the Arabidopsis RNA Polymerase II Transcript Elongation Complex Reveals the Interplay between Elongation and mRNA Processing Factors.

Transcript elongation factors (TEFs) are a heterogeneous group of proteins that control the efficiency of transcript elongation of subsets of genes by RNA polymerase II (RNAPII) in the chromatin context. Using reciprocal tagging in combination with affinity purification and mass spectrometry, we demonstrate that in Arabidopsis thaliana, the TEFs SPT4/SPT5, SPT6, FACT, PAF1-C, and TFIIS copurified with each other and with elongating RNAPII, while P-TEFb was not among the interactors. Additionally, NAP1 histone chaperones, ATP-dependent chromatin remodeling factors, and some histone-modifying enzymes including Elongator were repeatedly found associated with TEFs. Analysis of double mutant plants defective in different combinations of TEFs revealed genetic interactions between genes encoding subunits of PAF1-C, FACT, and TFIIS, resulting in synergistic/epistatic effects on plant growth/development. Analysis of subnuclear localization, gene expression, and chromatin association did not provide evidence for an involvement of the TEFs in transcription by RNAPI (or RNAPIII). Proteomics analyses also revealed multiple interactions between the transcript elongation complex and factors involved in mRNA splicing and polyadenylation, including an association of PAF1-C with the polyadenylation factor CstF. Therefore, the RNAPII transcript elongation complex represents a platform for interactions among different TEFs, as well as for coordinating ongoing transcription with mRNA processing.

Expandable distal femur megaprosthesis: A European Musculoskeletal Oncology Society study on 299 cases.

BACKGROUND AND OBJECTIVES: Expandable distal femur prostheses have become more popular over the last decades, but scientific data is limited. METHODS: A retrospective study was performed, including cases treated between 1986 and 2019 in 15 European referral centers for bone sarcomas. RESULTS: A total of 299 cases were included. Average follow-up was 80 months (range, 8-287 months). Mean patient age was 10 years. Most (80%) of the implants were noninvasive growers and a fixed hinge knee was used more often (64%) than a rotating hinge. Most prosthetic designs showed good (>80%) implant survival at 10 years, but repeat surgery was required for 63% of the patients. The most frequent reason for revision procedure was the completion of lengthening potential. Noninvasive expandable implants showed less risk of infection compared to invasive growers (11.8% vs 22.9% at 10 years). No difference in aseptic loosening was found between cemented and uncemented stems. CONCLUSIONS: This study shows the increasing popularity of expandable distal femur prostheses, with overall good results for function and implant survival. However, repeat surgery is frequently required, especially in patients under the age of 10 years old. Infection is less frequent in noninvasive growers compared to implants that require invasive lengthening procedures.

Df31 protein and snoRNAs maintain accessible higher-order structures of chromatin.

Packaging of DNA into nucleosomes and the formation of higher-order chromatin structures determine DNA accessibility and activity of genome domains. We identified an RNA-dependent mechanism maintaining the open chromatin structure within euchromatic regions in Drosophila cells. The mechanism of reversible chromatin opening, reconstituted in vitro, depends on the Drosophila decondensation factor 31 (Df31) that specifically binds to RNA and localizes to euchromatic regions. Df31 is capable to tether a heterogeneous pool of short, single-stranded RNAs to chromatin. This class of chromatin-associated RNA (caRNA) is stably linked to chromatin and is largely composed of snoRNAs, which are preferentially bound by Df31. We suggest that the Df31-mediated linkage of snoRNAs and chromatin, forms a RNA-chromatin network resulting in the establishment of open chromatin domains. Analysis of caRNAs in human cells also reveals a strong enrichment of snoRNAs, implying a conserved role for these molecules in higher-order structures of chromatin.

ALY RNA-Binding Proteins Are Required for Nucleocytosolic mRNA Transport and Modulate Plant Growth and Development.

The regulated transport of mRNAs from the cell nucleus to the cytosol is a critical step linking transcript synthesis and processing with translation. However, in plants, only a few of the factors that act in the mRNA export pathway have been functionally characterized. Flowering plant genomes encode several members of the ALY protein family, which function as mRNA export factors in other organisms. Arabidopsis (Arabidopsis thaliana) ALY1 to ALY4 are commonly detected in root and leaf cells, but they are differentially expressed in reproductive tissue. Moreover, the subnuclear distribution of ALY1/2 differs from that of ALY3/4. ALY1 binds with higher affinity to single-stranded RNA than double-stranded RNA and single-stranded DNA and interacts preferentially with 5-methylcytosine-modified single-stranded RNA. Compared with the full-length protein, the individual RNA recognition motif of ALY1 binds RNA only weakly. ALY proteins interact with the RNA helicase UAP56, indicating a link to the mRNA export machinery. Consistently, ALY1 complements the lethal phenotype of yeast cells lacking the ALY1 ortholog Yra1. Whereas individual aly mutants have a wild-type appearance, disruption of ALY1 to ALY4 in 4xaly plants causes vegetative and reproductive defects, including strongly reduced growth, altered flower morphology, as well as abnormal ovules and female gametophytes, causing reduced seed production. Moreover, polyadenylated mRNAs accumulate in the nuclei of 4xaly cells. Our results highlight the requirement of efficient mRNA nucleocytosolic transport for proper plant growth and development and indicate that ALY1 to ALY4 act partly redundantly in this process; however, differences in expression and subnuclear localization suggest distinct functions.

Next generation sequencing for GNAS uncovers CD34 as a sensitive marker for intramuscular myxoma.

BACKGROUND: Intramuscular myxoma is a soft tissue myxoid tumor with a broad morphological differential diagnosis and recent developments have led to the identification of markers that can exclude some, but not all, differential diagnostic entities. However, a sensitive confirmatory marker for intramuscular myxoma has not been clearly identified. Since there is some evidence that mutations in the GNAS gene could be such a marker, we evaluated our results of next-generation sequencing testing for GNAS mutations performed in recent years on our series of intramuscular myxoma. MATERIALS AND METHODS: Next-generation sequencing was performed on 10 cases of intramuscular myxoma diagnosed between 2015 and 2019, using either the TruSight Tumor 26 panel or an in-house developed 97 cancer gene panel. Additionally, immunohistochemistry for CD34 was performed on all cases. RESULTS: All intramuscular myxomas showed a diffuse and strong expression of CD34 and a GNAS mutation was found in 88% of cases, making this a very sensitive positive test for the diagnosis of intramuscular myxoma. CONCLUSIONS: Under the condition that contemporary next-generation sequencing is applied as testing method, searching for GNAS mutations is a very sensitive confirmatory test for the diagnosis of intramuscular myxoma, obviating the necessity to perform tests that exclude other entities by the virtue of their negative result. The molecular tests results also identified strong and diffuse CD34 expression as a sensitive, albeit non-specific, marker for intramuscular myxoma.

Touching the base: heart-warming ads from the 2016 U.S. election moved viewers to partisan tears.

Some political ads used in the 2016 U.S. election evoked feelings colloquially known as being moved to tears. We conceptualise this phenomenon as a positive social emotion that appraises and motivates communal relations, is accompanied by physical sensations (including lachrymation, piloerection, chest warmth), and often labelled metaphorically. We surveyed U.S. voters in the fortnight before the 2016 U.S. election. Selected ads evoked the emotion completely and reliably, but in a partisan fashion: Clinton voters were moved to tears by three selected Clinton ads, and Trump voters were moved to tears by two Trump ads. Viewers were much less moved by ads of the candidate they did not support. Being moved to tears predicted intention to vote for the candidate depicted. We conclude that some contemporary political advertising is able to move its audience to tears, and thereby motivates support.

Enhanced vascular regeneration with chemically/physically treated bovine/human pericardium in rodents.

BACKGROUND: Glutaraldehyde-treated pericardia for cardiovascular applications have poor long-term clinical results. The efficacy of a combined physical/chemical treatment to improve pericardium biocompatibility and vascular regeneration was assessed and compared with detergent treatment and two commercial bovine pericardia: PeriGuard (DGBP) and Edwards pericardium (nDGBP). The physical and chemical process was applied to bovine and human pericardia (DBP-DHP), and the detergent process was applied to bovine (DDBP). MATERIAL AND METHODS: Native (NBP) and treated bovine tissues were assessed for decellularization (HE/DAPI/DNA/α-Gal and MHC-1 staining) and mechanical integrity ex vivo. Twenty Wistar rats received subcutaneous patches of each bovine tissue to assess immunogenic response up to 4 months (flow cytometry). Ten additional rats received four subcutaneous bovine-treated patches (one/condition) to evaluate the inflammatory reaction (CD3/CD68 immunostaining), calcification (von Kossa staining/calcium quantification), and integration assessment (Hematoxylin and eosin staining). Finally, 15 rodents received a patch on the aorta (DBP n = 5, DHP n = 5, and DGBP n = 5), and vascular biocompatibility and arterial wall regeneration were assessed after 4 months (CD3/CD68/CD31/ASMA and Miller staining). RESULTS: DBP reached the higher level of decellularization, no immunogenic response whereas maintaining mechanical properties. DBP induced the lowest level grade of inflammation after 2 months (P < 0.05) concomitantly for better remodeling. No complications occurred with DBP and DHP where vascular regeneration was confirmed. Moreover, they induced a low level of CD3/CD68 infiltrations. CONCLUSIONS: This process significantly reduces immunogenicity and improves biocompatibility of bovine and human pericardia for better vascular regeneration.

Decellularized and Secured Porcine Arteries with NaOH-based Process: Proof of Concept.

BACKGROUND: There is a need for small caliber vascular prosthesis. Synthetic grafts are hindered by thrombogenicity and rapid occlusion. Decellularized matrices could be an alternative. We assessed in vitro and in vivo the biocompatibility of porcine artery treated with a chemical/physical process for decellularization and graft securitization with non/conventional pathogens inactivation. METHODS: Porcine carotid arteries (PCA) were treated. First, biopsies (n = 4/tissue) were performed before/after treatment to assess decellularization (hematoxylin and eosin/-4',6-diamidino-2-phenylindole/DNA/Miller). Second, 5 rats received an abdominal aortic patch of decellularized PCA (DPCA). Four pigs received subcutaneous DPCA implants (n = 2/pig). Half were explanted at day 15 and half at day 30. Finally, 2 pigs received DPCA (n = 2) and polytetrafluoroethylene prosthesis (n = 1), respectively, as carotid interposition. Implants were removed at day 30. Inflammation (CD3 and CD68 immunostaining) calcifications (von Kossa staining), remodeling (hematoxylin and eosin), and vascular characterization (CD31 and alpha-smooth muscle actin immunofluorescent staining) were investigated. RESULTS: Ninety-five percentage of decellularization was obtained without structural deterioration. No death occurred. Low inflammatory reaction was found in the 2 models for DPCA. Acquisition of vascular identity was confirmed in the rodent and porcine models. Similarity between native PCA and DPCA was observed after 30 days. In contrast, polytetrafluoroethylene graft showed severe calcifications, higher CD3 reaction, and higher intimal hyperplasia (P < 0.05). CONCLUSIONS: The physical and chemical process ensures decellularization of carotid porcine arteries and their in vivo remodeling with the presence of an endothelium and smooth-muscle-like cells as well as a low level of inflammatory cells.

Enhanced Vascular Biocompatibility and Remodeling of Decellularized and Secured Xenogeneic/Allogeneic Matrices in a Porcine Model.

BACKGROUND/PURPOSE: Calcifications and absence of growth potential are the major drawbacks of glutaraldehyde-treated prosthesis. Decellularized and secured xeno-/allogeneic matrices were assessed in a preclinical porcine model for biocompatibility and vascular remodeling in comparison to glutaraldehyde-fixed bovine pericardium (GBP; control). METHODS: Native human (fascia lata, pericardium) and porcine tissues (peritoneum) were used and treated. In vitro, biopsies were performed before and after treatment to assess decellularization (hematoxylin and eosin/DAPI). In vivo, each decellularized and control tissue sample was implanted subcutaneously in 4 mini-pigs. In addition, 9 mini-pigs received a patch or a tubularized prosthesis interposition on the carotid artery or abdominal aorta of decellularized (D) human fascia lata (DHFL; n = 4), human pericardium (DHP; n = 9), porcine peritoneum (DPPt; n = 7), and control tissue (GBP: n = 3). Arteries were harvested after 1 month and subcutaneous samples after 15-30 days. Tissues were processed for hematoxylin and eosin/von Kossa staining and immunohistochemistry for CD31, alpha-smooth muscle actin, CD3, and CD68. Histomorphometry was achieved by point counting. RESULTS: A 95% decellularization was confirmed for DHP and DPPt, and to a lower degree for DHFL. In the subcutaneous protocol, CD3 infiltration was significantly higher at day 30 in GBP and DHFL, and CD68 infiltration was significantly higher for GBP (p < 0.05). In intravascular study, no deaths, aneurysms, or pseudoaneurysms were observed. Inflammatory reaction was significantly higher for DHFL and GBP (p < 0.05), while it was lower and comparable for DHP/DPPt. DHP and DPPt showed deeper recellularization, and a new arterial wall was characterized. CONCLUSIONS: In a preclinical model, DPPt and DHP offered better results than conventional commercialized GBP for biocompatibility and vascular remodeling.

Arthroscopic Double-Layer Lasso Loop Technique to Repair Delaminated Rotator Cuff Tears.

PURPOSE: To evaluate the arthroscopic double-layer lasso loop repair technique for delaminated posterosuperior rotator cuff tears. METHODS: Forty-one patients underwent arthroscopic rotator cuff repair of a delaminated posterosuperior rotator cuff tear by the double-layer lasso loop technique. Their preoperative and postoperative clinical and functional scores were compared to evaluate surgical outcomes. The prerequisite for inclusion was a minimum follow-up period of 2 years. We excluded patients with a history of shoulder surgery before the double-layer lasso loop repair. RESULTS: Statistically significant improvements (P < .001) were found in the Constant score (54 vs 83) and University of California, Los Angeles functional score (6.4 vs 9.5). Pain and strength improved according to the Jobe test, bear-hug test, belly-press test, Gerber lift-off test, and external rotation test (P < .001). No significant difference in strength was noted between the operated and nonoperated sides. There was only 1 complete rerupture (3.1%), whereas 5 patients (15.6%) had partial ruptures. CONCLUSIONS: The arthroscopic double-layer lasso loop repair technique for delaminated posterosuperior rotator cuff tears is an effective procedure. Our series showed a low rerupture rate. At a mean follow-up of 44 months, postoperative recovery with resultant functional, pain, and patient satisfaction scores was good to excellent and was comparable with the nonoperated side. LEVEL OF EVIDENCE: Level IV, case series.