Control of endothelial cell function and arteriogenesis by MEG3:EZH2 epigenetic regulation of integrin expression.

Epigenetic processes involving long non-coding RNAs regulate endothelial gene expression. However, the underlying regulatory mechanisms causing endothelial dysfunction remain to be elucidated. Enhancer of zeste homolog 2 (EZH2) is an important rheostat of histone H3K27 trimethylation (H3K27me3) that represses endothelial targets, but EZH2 RNA binding capacity and EZH2:RNA functional interactions have not been explored in post-ischemic angiogenesis. We used formaldehyde/UV-assisted crosslinking ligation and sequencing of hybrids and identified a new role for maternally expressed gene 3 (MEG3). MEG3 formed the predominant RNA:RNA hybrid structures in endothelial cells. Moreover, MEG3:EZH2 assists recruitment onto chromatin. By EZH2-chromatin immunoprecipitation, following MEG3 depletion, we demonstrated that MEG3 controls recruitment of EZH2/H3K27me3 onto integrin subunit alpha4 (ITGA4) promoter. Both MEG3 knockdown or EZH2 inhibition (A-395) promoted ITGA4 expression and improved endothelial cell migration and adhesion to fibronectin in vitro. The A-395 inhibitor re-directed MEG3-assisted chromatin remodeling, offering a direct therapeutic benefit by increasing endothelial function and resilience. This approach subsequently increased the expression of ITGA4 in arterioles following ischemic injury in mice, thus promoting arteriogenesis. Our findings show a context-specific role for MEG3 in guiding EZH2 to repress ITGA4. Novel therapeutic strategies could antagonize MEG3:EZH2 interaction for pre-clinical studies.

Medium term results of the cementless Oxford mobile bearing medial unicompartmental knee replacement.

BACKGROUND: Medial Unicompartmental Knee Replacement (UKR) has well-documented benefits over Total Knee Replacement in the treatment of anteromedial osteoarthritis of the knee. There has been an increasing move from cemented to cementless UKR over the last decade. This non-design centre study assesses the initial experience using the cementless Oxford medial partial knee replacement and provides medium term revision data, as well as Patient Reported Outcome Measures (PROMs). METHODS: A cohort of 200 consecutive patients undergoing medial UKR using the cementless Oxford were identified from our knee groups prospectively collected database. Cases were performed in a single centre under the care of one of four surgeons. All patients were beyond the 5-year minimum timepoint following UKR surgery in order to produce medium term results, at a mean of 7.9 years. Eligible patients completed a postal questionnaire to collect PROMs: Oxford Knee Score, WOMAC and modified American Knee Society Score questionnaires in January 2020 and had their clinical records reviewed. RESULTS: The survivorship in our cohort was 94.5% at a mean follow up of 7.9 years following surgery. There were 11 re-operations in total with a three percent risk of re-operation within the first 18 months following surgery. There was a sustained improvement in Oxford Knee Score with a near 20 points improvement on pre-operative scores. CONCLUSIONS: Our results provide further evidence that partial knee replacements using the cementless Oxford produce good clinical outcomes. Revision rates are similar to those published in the National Joint Registry. LEVEL OF EVIDENCE: III.

Single-stage repair of displaced bucket-handle meniscal tears with anterior cruciate ligament reconstruction leads to good meniscal survivorship : a retrospective cohort study.

AIMS: The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR. METHODS: We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks). RESULTS: Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived. CONCLUSION: These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J 2022;104-B(6):680-686.

Spatiotemporal droplet dispersion measurements demonstrate face masks reduce risks from singing.

COVID-19 has restricted singing in communal worship. We sought to understand variations in droplet transmission and the impact of wearing face masks. Using rapid laser planar imaging, we measured droplets while participants exhaled, said 'hello' or 'snake', sang a note or 'Happy Birthday', with and without surgical face masks. We measured mean velocity magnitude (MVM), time averaged droplet number (TADN) and maximum droplet number (MDN). Multilevel regression models were used. In 20 participants, sound intensity was 71 dB for speaking and 85 dB for singing (p < 0.001). MVM was similar for all tasks with no clear hierarchy between vocal tasks or people and > 85% reduction wearing face masks. Droplet transmission varied widely, particularly for singing. Masks decreased TADN by 99% (p < 0.001) and MDN by 98% (p < 0.001) for singing and 86-97% for other tasks. Masks reduced variance by up to 48%. When wearing a mask, neither singing task transmitted more droplets than exhaling. In conclusion, wide variation exists for droplet production. This significantly reduced when wearing face masks. Singing during religious worship wearing a face mask appears as safe as exhaling or talking. This has implications for UK public health guidance during the COVID-19 pandemic.

Removal and dispersal of biofluid films by powered medical devices: Modeling infectious agent spreading in dentistry.

Medical procedures can disperse infectious agents and spread disease. Particularly, dental procedures may pose a high risk of disease transmission as they use high-powered instruments operating within the oral cavity that may contain infectious microbiota or viruses. Here we assess the ability of powered dental devices in removing the biofluid films and identified mechanical, hydrodynamic, and aerodynamic forces as the main underlying mechanisms of removal and dispersal processes. Our results indicate that potentially infectious agents can be removed and dispersed immediately after dental instrument engagement with the adherent biofluid film, while the degree of their dispersal is rapidly depleted owing to the removal of the source and dilution by the coolant water. We found that droplets created by high-speed drill interactions typically travel ballistically, while aerosol-laden air tends to flow as a current over surfaces. Our mechanistic investigation offers plausible routes for reducing the spread of infection during invasive medical procedures.

Does Partial Knee Replacement Allow Return to High-Demand Activities?

Purpose  The purpose of this study was to assess postoperative partial knee replacement (PKR) functional improvement using the postoperative Oxford Knee Score for Activity and Participation Questionnaire (OKS-APQ). PKR includes medial, lateral, and patellofemoral knee arthroplasty. Methods A search of a National Health Service hospital database was made to identify eligible candidates for a survey of Patient-Reported Outcome Measure (PROM). Database records were collected for patients who had medial, lateral, and patellofemoral knee arthroplasty. The first author, an orthopaedic surgery resident, retrospectively reviewed the data and selected 318 patient records for inclusion in a questionnaire survey. The inclusion criteria were: patients who had PKR within three years from the time of the study and patients who don't have medical problems that may affect their mobility; for example, balance problems. The survey used the postoperative Oxford Knee Score for Activity and Participation Questionnaire (OKS-APQ), Tegner Activity Score (TAS), and four questions were added to the present study, namely, three free-text questions and one visual analogue score (VAS). The survey was sent by post seeking the patients' responses. Results  Two-hundred five responded to the survey out of 318; a 64% response rate. The ceiling and floor effects were determined from patients' answers. Survey questions included: What is the most demanding activity you routinely do every month on your new knee? The patients' answers were divided into four groups. First, 29% were limited to low functional demand activities, for example, light walking for less than a mile. Second, 43% were involved in domestic work and sports activities, for example, golf, skittles, bowling, squatting, swimming, and gardening. Third, 21% had progressed to higher demand activities, for instance, dancing, racquet sports, cycling, and yoga. Fourth, 7% were performing higher demand activities involving impacts, for example, skiing, heavy gym workout, and marathon running. Conclusion The postoperative questionnaire demonstrated activities ranging from high-impact activities, for example, skiing, and from higher demand activities, for example, dancing to low function activities, for example, light walking.

Chronic Wear-Induced Bearing Dislocation in a Fixed-Bearing Unicompartmental Knee Arthroplasty: A Case Report.

Case: We present a case of late onset, bearing wear-induced failure of locking mechanism, resulting in bearing dislocation and rapidly progressive severe metallosis in a medial fixed-bearing (FB) unicompartmental knee arthroplasty (UKA). Conclusion: Bearing dislocation is a rare complication of chronic wear in FB UKA, and early recognition is essential to prevent metallic component articulation-induced metallosis and catastrophic failure.

The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime.

The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation.

Mapping targets for small nucleolar RNAs in yeast.

Background: Recent analyses implicate changes in the expression of the box C/D class of small nucleolar RNAs (snoRNAs) in several human diseases. Methods: Here we report the identification of potential novel RNA targets for box C/D snoRNAs in budding yeast, using the approach of UV crosslinking and sequencing of hybrids (CLASH) with the snoRNP proteins Nop1, Nop56 and Nop58. We also developed a bioinformatics approach to filter snoRNA-target interactions for bona fide methylation guide interactions. Results: We recovered 241,420 hybrids, out of which 190,597 were classed as reproducible, high energy hybrids. As expected, the majority of snoRNA interactions were with the ribosomal RNAs (rRNAs). Following filtering, 117,047 reproducible hybrids included 51 of the 55 reported rRNA methylation sites. The majority of interactions at methylation sites were predicted to guide methylation. However, competing, potentially regulatory, binding was also identified. In marked contrast, following CLASH performed with the RNA helicase Mtr4 only 7% of snoRNA-rRNA interactions recovered were predicted to guide methylation. We propose that Mtr4 functions in dissociating inappropriate snoRNA-target interactions. Numerous snoRNA-snoRNA interactions were recovered, indicating potential cross regulation. The snoRNAs snR4 and snR45 were recently implicated in site-directed rRNA acetylation, and hybrids were identified adjacent to the acetylation sites. We also identified 1,368 reproducible snoRNA-mRNA interactions, representing 448 sites of interaction involving 39 snoRNAs and 382 mRNAs. Depletion of the snoRNAs U3, U14 or snR4 each altered the levels of numerous mRNAs. Targets identified by CLASH were over-represented among these species, but causality has yet to be established. Conclusions: Systematic mapping of snoRNA-target binding provides a catalogue of high-confidence binding sites and indicates numerous potential regulatory interactions.

UtpA and UtpB chaperone nascent pre-ribosomal RNA and U3 snoRNA to initiate eukaryotic ribosome assembly.

Early eukaryotic ribosome biogenesis involves large multi-protein complexes, which co-transcriptionally associate with pre-ribosomal RNA to form the small subunit processome. The precise mechanisms by which two of the largest multi-protein complexes-UtpA and UtpB-interact with nascent pre-ribosomal RNA are poorly understood. Here, we combined biochemical and structural biology approaches with ensembles of RNA-protein cross-linking data to elucidate the essential functions of both complexes. We show that UtpA contains a large composite RNA-binding site and captures the 5' end of pre-ribosomal RNA. UtpB forms an extended structure that binds early pre-ribosomal intermediates in close proximity to architectural sites such as an RNA duplex formed by the 5' ETS and U3 snoRNA as well as the 3' boundary of the 18S rRNA. Both complexes therefore act as vital RNA chaperones to initiate eukaryotic ribosome assembly.

Polyoxometalate Complexes as Precursors to Vanadium-Doped Molybdenum or Tungsten Oxide Thin Films by Means of Aerosol-Assisted Chemical Vapour Deposition.

Aerosol-assisted chemical vapour deposition of substituted polyoxometalates H4 [PMo11 VO40 ], H7 [PMo8 V4 O40 ], [nBu4 N]4 [PVW11 O40 ] and [nBu4 N]5 [PV2 W10 O40 ] resulted in the formation of vanadium-doped metal oxide thin films. Depositions were carried out at 550 °C in methanol or acetonitrile for the POMs that contained molybdenum or tungsten, respectively. The as-deposited films were X-ray amorphous and relatively non-adherent. However, on annealing in air at 600 °C, decolourised translucent films that were more mechanically robust were obtained. Films deposited from H4 [PMo11 VO40 ] and H7 [PMo8 V4 O40 ] consisted of V-doped MoO3 in the orthorhombic phase and films from [nBu4 N]4 [PVW11 O40 ] and [nBu4 N]5 [PV2 W10 O40 ] comprised of monoclinic V-doped WO3 . All films were fully characterised by using X-ray photoelectron spectroscopy, energy-dispersive X-ray diffraction, scanning electron microscopy and UV/Vis spectroscopy.

Loss of the Yeast SR Protein Npl3 Alters Gene Expression Due to Transcription Readthrough.

Yeast Npl3 is a highly abundant, nuclear-cytoplasmic shuttling, RNA-binding protein, related to metazoan SR proteins. Reported functions of Npl3 include transcription elongation, splicing and RNA 3' end processing. We used UV crosslinking and analysis of cDNA (CRAC) to map precise RNA binding sites, and strand-specific tiling arrays to look at the effects of loss of Npl3 on all transcripts across the genome. We found that Npl3 binds diverse RNA species, both coding and non-coding, at sites indicative of roles in both early pre-mRNA processing and 3' end formation. Tiling arrays and RNAPII mapping data revealed 3' extended RNAPII-transcribed RNAs in the absence of Npl3, suggesting that defects in pre-mRNA packaging events result in termination readthrough. Transcription readthrough was widespread and frequently resulted in down-regulation of neighboring genes. We conclude that the absence of Npl3 results in widespread 3' extension of transcripts with pervasive effects on gene expression.

Implant-related complications following hip hemiarthroplasty: a comparison of modern cemented and uncemented prostheses.

Fractured neck of femurs is a very common presentation to hospital, especially in an elderly population and in almost all cases requires an operation, usually a cemented or uncemented hemiarthroplasty. Current evidence and multiple guidance issued in UK suggest the use of cemented hemiarthroplasty above uncemented prostheses. This retrospective case series performed in District General Hospital in Wales, UK. Notes and radiographs of 80 consecutive patients who had hemiarthroplasty for the fracture of neck of femur were examined by independent observer. All patients received modern prosthesis-collarless, polished tapered cemented stem or fully HA-coated uncemented stem-based on the choice of treating consultant. There were 47 uncemented prostheses and 33 cemented hemiarthroplasties used. We identified 12 significant complications in the uncemented group (26 %) as compared to three in the cemented group (6 %). The most significant difference was periprosthetic fracture rate, with five in the uncemented group (10.7 %) as compared to none in the cemented group. There were a total of six reoperations in four patients all of whom had initially undergone uncemented operations. In both groups, 24-h mortality rate was similar. Our study supports the use of modern cemented prosthesis as opposed to modern uncemented hemiarthroplasty. Post-operative complication rate after uncemented prosthesis is unacceptably high, especially periprosthetic fracture rate.

Formation of microporous NiTi by transient liquid phase sintering of elemental powders.

Porous metallic structures are attractive for biomedical implant applications as their open porosity simultaneously improves the degree of fixation and decreases the mismatch in stiffness between bone and implant, improving bonding and reducing stress-shielding effects respectively. NiTi alloys exhibit both the shape memory effect and pseudoelasticity, and are of particular interest, though they pose substantial problems in their processing. This is because the shape memory and pseudoelastic behaviours are exceptionally sensitive to the presence of oxygen, and other minor changes in alloy chemistry. Thus in processing careful control of composition and contamination is vital. In this communication, we investigate these issues in a novel technique for producing porous NiTi parts via transient liquid phase sintering following metal injection moulding (MIM) of elemental Ni and Ti powders, and report a new mechanism for pore formation in the powder processing of metallic materials from elemental powders.

Ce(IV) complexes with donor-functionalized alkoxide ligands: improved precursors for chemical vapor deposition of CeO2.

Thin films of ceria (CeO(2)) have many applications, and their synthesis by liquid-injection MOCVD (metal-organic chemical vapor deposition) or ALD (atomic layer deposition) requires volatile precursor compounds. Here we report the synthesis of a series of homoleptic and heteroleptic Ce(IV) complexes with donor-functionalized alkoxide ligands mmp (1-methoxy-2-methylpropan-2-olate), dmap (1-(dimethylamino)propan-2-olate), and dmop (2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)propan-2-olate) and their potential as precursors for MOCVD and ALD of CeO(2). New complexes were synthesized by alcohol exchange reactions with [Ce(OBu(t))(4)]. [Ce(mmp)(4)] and [Ce(dmap)(4)] were both found to be excellent precursors for liquid-injection MOCVD of CeO(2), depositing high purity thin films with very low carbon contamination, and both have a large temperature window for diffusion controlled growth (350-600 °C for [Ce(mmp)(4)]; 300-600 °C for [Ce(dmap)(4)]). [Ce(mmp)(4)] is also an excellent precursor for liquid-injection ALD of CeO(2) using H(2)O as oxygen source and demonstrates self-limiting growth from 150 to 350 °C. [Ce(dmap)(4)] has lower thermal stability than [Ce(mmp)(4)] and does not show self-limiting growth in ALD. Heteroleptic complexes show a tendency to undergo ligand redistribution reactions to form mixtures in solution and are unsuitable as precursors for liquid-injection CVD.

Surgical repair of chronic tears of the hip abductor mechanism.

Lateral sided hip pain frequently presents to the orthopaedic clinic. The most common cause of this pain is trochanteric bursitis. This usually improves with conservative treatment. In a few cases it doesn't settle and warrants further investigation and treatment. We present a series of 28 patients who underwent MRI scanning for such pain, 16 were found to have a tear of their abductors. All 16 underwent surgical repair using multiple soft tissue anchors inserted into the greater trochanter of the hip to reattach the abductors. There were 15 females and 1 male. All patients completed a self-administered questionnaire pre-operatively and 1 year post-operatively. Data collected included: A visual analogue score for hip pain, Charnley modification of the Merle D'Aubigne and Postel hip score, Oxford hip score, Kuhfuss score of Trendelenburg and SF36 scores.Of the 16 patients who underwent surgery 5 had a failure of surgical treatment. There were 4 re ruptures, 3 of which were revised and 1 deep infection which required debridement. In the remaining 11 patients there were statistically significant improvements in hip symptoms. The mean change in visual analogue score was 5 out of 10 (p=0.0024) The mean change of Oxford hip score was 20.5 (p=0.00085). The mean improvement in SF-36 PCS was 8.5 (P=0.0020) and MCS 13.7 (P=0.134). 6 patients who had a Trendelenburg gait pre-surgery had normal gait 1 year following surgery.We conclude that hip abductor mechanism tear is a frequent cause of recalcitrant trochanteric pain that should be further investigated with MRI scanning. Surgical repair is a successful operation for reduction of pain and improvement of function. However there is a relatively high failure rate.

Anterior cruciate ligament injuries in snowboarders: a quadriceps-induced injury.

Anterior cruciate ligament (ACL) injuries in snowboarders are rare. However, in expert boarders landing big jumps, ACL injuries are occurring more frequently. We identified 35 snowboarders with an identical injury mechanism. All these patients were landing from a jump. All described a flat landing on a flexed knee with significant knee compression. In 31 of 35 boarders, it was the front knee that was injured. Only two riders felt there was any twisting component to their injury. We postulate that the ACL rupture is due to maximal eccentric quadriceps contraction, as the boarder resists a compressive landing. Internal tibial rotation of the front knee in the snowboarding stance results in preloading of the ACL predisposing to injury.

Tungsten imido complexes as precursors to tungsten carbonitride thin films.

Thin films of tungsten carbonitride have been formed on glass by low-pressure chemical vapour deposition (LP)CVD at 550 degrees C from four closely related precursors: [W(mu-N(t)Bu)(N(t)Bu)Cl(2)(H(2)N(t)Bu)](2), [W(N(t)Bu)(2)Cl(2)(TMEDA)] (TMEDA = N,N,N',N'-tetramethylethylenediamine), [W(N(t)Bu)(2)Cl(2)(py)(2)] (py = pyridine) and [W(N(t)Bu)(2)Cl(N{SiMe(3)}(2))]. The grey mirror-like films were grown with a nitrogen or ammonia bleed gas. In all cases the chlorine content of the deposited films was less than 1 at% and the oxygen content of the films was lower for those grown using ammonia. Surprisingly, the use of ammonia did not significantly change the carbon content of the resulting films. Despite the coordination environment around the metal being essentially the same and the materials having a comparable volatility, some differences in film quality were observed. The films were uniform, adhesive, abrasion resistant, conformal and hard, being resistant to scratching with a steel scalpel. X-Ray powder diffraction patterns of all the films showed the formation of beta-WN(x)C(y). As a comparison the aerosol-assisted chemical vapour deposition (AA)CVD of [W(mu-N(t)Bu)(N(t)Bu)Cl(2)(H(2)N(t)Bu)](2) was investigated and amorphous tungsten carbonitride films were deposited.

Aerosol assisted chemical vapor deposition of In2O3 films from Me3In and donor functionalized alcohols.

The reaction of Me3In and ROH (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH2CH2OMe) in toluene under aerosol assisted chemical vapor deposition (AACVD) conditions leads to the production of indium oxide thin films on glass. The indium oxide films were deposited at 550 degrees C and analyzed by scanning electron microscopy (SEM), X-ray powder diffraction, wavelength dispersive analysis of X-rays (WDX), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. This CVD technique offers a rapid, convenient route to In2O3, which presumably involves the in situ formation of dimethylindium alkoxides, of the type [Me2InOR]2. In order to identify compounds present in the aerosol mist, the solution-phase reaction between Me3In and ROH (R = CH2CH2NMe2, C(CH3)2CH2OMe, CH(CH3)CH2NMe2, CH(CH2NMe2)2) at room temperature in toluene was carried out. Dimeric indium alkoxides, of the type [Me2In(OR)]2, were isolated, and their structures were determined by X-ray crystallography.