Estimated GFR and Incidence of Major Surgery: A Population-Based Cohort Study.

RATIONALE & OBJECTIVE: Kidney disease is associated with an increased risk for postoperative morbidity and mortality. However, the incidence of major surgery on a population level is unknown. We aimed to determine the incidence of major surgery by level of kidney function. STUDY DESIGN: Retrospective cohort study with entry from January 1, 2008, through December 31, 2009, and outcome surveillance from January 1, 2010, through December 31, 2016. SETTING & PARTICIPANTS: Population-based study using administrative health data from Alberta, Canada; adults with an outpatient serum creatinine measurement or receiving maintenance dialysis formed the study cohort. EXPOSURE: Participants were categorized into 6 estimated glomerular filtration rate (eGFR) categories: ≥60 (G1-G2), 45 to 59 (G3a), 30 to 44 (G3b), 15 to 29 (G4), and<15mL/min/1.73m2 with (G5D) and without (G5) dialysis. eGFR was examined as a time-varying exposure based on means of measurements within 3-month ascertainment periods throughout the study period. OUTCOME: Major surgery defined as surgery requiring admission to the hospital for at least 24 hours. ANALYTICAL APPROACH: Incidence rates (IRs) for overall major surgery were estimated using quasi-Poisson regression and adjusted for age, sex, income, location of residence, albuminuria, and Charlson comorbid conditions. Age- and sex-stratified IRs of 13 surgery subtypes were also estimated. RESULTS: 1,455,512 cohort participants were followed up for a median of 7.0 (IQR, 5.3) years, during which time 241,989 (16.6%) underwent a major surgery. Age and sex modified the relationship between eGFR and incidence of surgery. Men younger than 65 years receiving maintenance dialysis experienced the highest rates of major surgery, with an adjusted IR of 243.8 (95% CI, 179.8-330.6) per 1,000 person-years. There was a consistent trend of increasing surgery rates at lower eGFRs for most subtypes of surgery. LIMITATIONS: Outpatient preoperative serum creatinine measurement was necessary for inclusion and outpatient surgical procedures were not included. CONCLUSIONS: People with reduced eGFR have a significantly higher incidence of major surgery compared with those with normal eGFR, and age and sex modify this increased risk. This study informs our understanding of how surgical burden changes with differing levels of kidney function.

Hierarchically aligned fibrous hydrogel films through microfluidic self-assembly of graphene and polysaccharides.

Despite significant interest in developing extracellular matrix (ECM)-inspired biomaterials to recreate native cell-instructive microenvironments, the major challenge in the biomaterial field is to recapitulate the complex structural and biophysical features of native ECM. These biophysical features include multiscale hierarchy, electrical conductivity, optimum wettability, and mechanical properties. These features are critical to the design of cell-instructive biomaterials for bioengineering applications such as skeletal muscle tissue engineering. In this study, we used a custom-designed film fabrication assembly, which consists of a microfluidic chamber to allow electrostatic charge-based self-assembly of oppositely charged polymer solutions forming a hydrogel fiber and eventually, a nanocomposite fibrous hydrogel film. The film recapitulates unidirectional hierarchical fibrous structure along with the conductive properties to guide initial alignment and myotube formation from cultured myoblasts. We combined high conductivity, and charge carrier mobility of graphene with biocompatibility of polysaccharides to develop graphene-polysaccharide nanocomposite fibrous hydrogel films. The incorporation of graphene in fibrous hydrogel films enhanced their wettability, electrical conductivity, tensile strength, and toughness without significantly altering their elastic properties (Young's modulus). In a proof-of-concept study, the mouse myoblast cells (C2C12) seeded on these nanocomposite fibrous hydrogel films showed improved spreading and enhanced myogenesis as evident by the formation of multinucleated myotubes, an early indicator of myogenesis. Overall, graphene-polysaccharide nanocomposite fibrous hydrogel films provide a potential biomaterial to promote skeletal muscle tissue regeneration.

Compromised axon initial segment integrity in EAE is preceded by microglial reactivity and contact.

Axonal pathology is a key contributor to long-term disability in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS), but the mechanisms that underlie axonal pathology in MS remain elusive. Evidence suggests that axonal pathology is a direct consequence of demyelination, as we and others have shown that the node of Ranvier disassembles following loss of myelin. In contrast to the node of Ranvier, we now show that the axon initial segment (AIS), the axonal domain responsible for action potential initiation, remains intact following cuprizone-induced cortical demyelination. Instead, we find that the AIS is disrupted in the neocortex of mice that develop experimental autoimmune encephalomyelitis (EAE) independent of local demyelination. EAE-induced mice demonstrate profound compromise of AIS integrity with a progressive disruption that corresponds to EAE clinical disease severity and duration, in addition to cortical microglial reactivity. Furthermore, treatment with the drug didox results in attenuation of AIS pathology concomitantly with microglial reversion to a less reactive state. Together, our findings suggest that inflammation, but not demyelination, disrupts AIS integrity and that therapeutic intervention may protect and reverse this pathology. GLIA 2016;64:1190-1209.

Quantum dot assisted tracking of the intracellular protein Cyclin E in Xenopus laevis embryos.

BACKGROUND: Luminescent semiconductor nanocrystals, also known as quantum dots (QD), possess highly desirable optical properties that account for development of a variety of exciting biomedical techniques. These properties include long-term stability, brightness, narrow emission spectra, size tunable properties and resistance to photobleaching. QD have many promising applications in biology and the list is constantly growing. These applications include DNA or protein tagging for in vitro assays, deep-tissue imaging, fluorescence resonance energy transfer (FRET), and studying dynamics of cell surface receptors, among others. Here we explored the potential of QD-mediated labeling for the purpose of tracking an intracellular protein inside live cells. RESULTS: We manufactured dihydrolipoic acid (DHLA)-capped CdSe-ZnS core-shell QD, not available commercially, and coupled them to the cell cycle regulatory protein Cyclin E. We then utilized the QD fluorescence capabilities for visualization of Cyclin E trafficking within cells of Xenopus laevis embryos in real time. CONCLUSIONS: These studies provide "proof-of-concept" for this approach by tracking QD-tagged Cyclin E within cells of developing embryos, before and during an important developmental period, the midblastula transition. Importantly, we show that the attachment of QD to Cyclin E did not disrupt its proper intracellular distribution prior to and during the midblastula transition. The fate of the QD after cyclin E degradation following the midblastula transition remains unknown.

MicroRNA-16 modulates HuR regulation of cyclin E1 in breast cancer cells.

RNA binding protein (RBPs) and microRNAs (miRNAs or miRs) are post-transcriptional regulators of gene expression that are implicated in development of cancers. Although their individual roles have been studied, the crosstalk between RBPs and miRNAs is under intense investigation. Here, we show that in breast cancer cells, cyclin E1 upregulation by the RBP HuR is through specific binding to regions in the cyclin E1 mRNA 3' untranslated region (3'UTR) containing U-rich elements. Similarly, miR-16 represses cyclin E1, dependent on its cognate binding sites in the cyclin E1 3'UTR. Evidence in the literature indicates that HuR can regulate miRNA expression and recruit or dissociate RNA-induced silencing complexes (RISC). Despite this, miR-16 and HuR do not affect the other's expression level or binding to the cyclin E1 3'UTR. While HuR overexpression partially blocks miR-16 repression of a reporter mRNA containing the cyclin E1 3'UTR, it does not block miR-16 repression of endogenous cyclin E1 mRNA. In contrast, miR-16 blocks HuR-mediated upregulation of cyclin E1. Overall our results suggest that miR-16 can override HuR upregulation of cyclin E1 without affecting HuR expression or association with the cyclin E1 mRNA.

Persistence of changed attitudes among students in an integrated anatomy curriculum.

Many medical schools in the United States have integrated anatomy into an organ-based preclinical curriculum with some schools using anatomy as the cornerstone of their reorganization efforts. Curricular change could affect one or more of the three domains of learning, with the cognitive domain often scrutinized exclusively. A previous study reported the impact of anatomy integration on the affective domain, specifically, student attitudes toward learning anatomy. This mixed methods follow-up study asked if the observed attitudinal changes and lack of effect on student knowledge and confidence persisted using knowledge and confidence surveys, focus groups, internal and national surveys, and United States Medical Licensing Examination® performance metrics. Results evidenced the persistence of specific attitudinal differences between cohorts with blocked versus integrated anatomy with no apparent short- or long-term differences in anatomy learning or confidence in this learning. Altered attitudes included lower value placed on working in teams and reflective practices, and less recognition of anatomy's contribution (or less contribution of anatomy learning) to professional identity formation. These attitudinal changes could result in a weaker foundation for building collaborative skills throughout the medical curriculum. A decreased sense of student engagement also followed curricular change, as assessed by data from the American Association of Medical Colleges Year 2 Questionnaire. Overall, results emphasized the necessity of anticipating, monitoring, and if necessary, addressing changes in the affective domain when undertaking curricular change.

Prospective Validation of the Calgary Kids' Hand Rule: A Clinical Prediction Rule for Pediatric Hand Fracture Triage.

Introduction: Pediatric hand fractures are common and routinely referred to surgeons, yet most heal well without surgical intervention. This trend inspired the development of the Calgary Kids' Hand Rule (CKHR), a clinical prediction rule designed to predict "complex" fractures that require surgical referral. The CKHR was adapted into a checklist whereby the presence of any 1 of 6 clinically or radiologically identifiable fracture characteristics predicts a complex fracture. The aim of this study was to assess the accuracy of the CKHR in a prospective sample of children with hand fractures. Methods: Physicians were asked to complete the CKHR checklist when referring pediatric patients (< 18 years) to hand surgeons at a Canadian pediatric hospital (April 2019-September 2020). Completed checklists represented predicted outcomes and were compared to observed outcomes (determined via chart review). Predictive accuracy (primary outcome) was evaluated based on sensitivity and specificity. Secondary outcomes were interrater reliability between referring physicians and surgeons, and survey assessment of CKHR user satisfaction. Results: In total 365 fractures were included, with only 16 requiring surgical intervention. Overall performance of the CKHR was good with 84% sensitivity and 71% specificity. Percent agreement between referring physicians and surgeons ranged from 84.1% to 96.3% on individual predictors, with 78.1% agreement on the presence of any predictors. Survey results showed general user satisfaction but also identified areas for improvement. Conclusion: This study posits the CKHR as an accurate and clinically useful prediction rule and highlights the importance of education for its effective use and eventual scale and spread.

Introduction : Les fractures pédiatriques de la main sont fréquentes et régulièrement orientées vers les chirurgiens. Néanmoins, la plupart guérissent bien sans intervention chirurgicale. Cette tendance a inspiré l'élaboration de la Calgary Kids' Hand Rule (CKHR), un outil de prédiction clinique conçu pour prédire quelles fractures « complexes ¼ doivent être orientées vers un chirurgien. La CKHR a été adaptée sous forme de liste de contrôle où la présence de l'une quelconque de six caractéristiques cliniques ou radiologiques identifiables de fracture permet de conclure à une fracture complexe. Le but de cette étude était d'évaluer l'exactitude de la CKHR dans un échantillon prospectif d'enfants ayant une fracture de la main. Methodes : Les médecins ont été invités à remplir la liste de contrôle CKHR quand ils orientaient des patients pédiatriques (< 18 ans) à des chirurgiens de la main dans un hôpital pédiatrique canadien (avril 2019 à septembre 2020). Les listes de contrôle remplies représentaient les aboutissements prédits et elles ont été comparées aux aboutissements observés (établis par une revue des dossiers). La précision de la prédiction (critère d'évaluation principal) a été évaluée en termes de sensibilité et de spécificité. Les critères d'évaluation secondaires étaient la fiabilité inter-évaluateurs entre médecins référents et chirurgiens et l'évaluation de la satisfaction de l'utilisateur de la CKHR dans le cadre d'une enquête. Résultats : Au total, 365 fractures ont été incluses; seulement 16 d'entre elles ont nécessité une intervention chirurgicale. La performance globale de la CKHR a été bonne avec une sensibilité de 84% et une spécificité de 71%. Le pourcentage de concordance entre médecins référents et chirurgiens était compris entre 84,1% et 96,3% selon les éléments prédictifs individuels, avec une concordance de 78,1% sur la présence de l'un quelconque des éléments prédictifs. Les résultats de l'enquête ont montré une satisfaction globale des utilisateurs, mais ont aussi mis en évidence des domaines à améliorer. Conclusion : Cette étude assoit la CKHR comme règle de prédiction exacte et cliniquement utile; elle souligne aussi l'importance de l'éducation pour son utilisation efficace et une éventuelle plus grande diffusion.

Pediatric Hand Fracture Outcomes: How Often Do We Need to Operate?

Purpose: Pediatric hand fractures are frequent presentations to the emergency department. This study set out to evaluate the epidemiology, management, and outcomes, where care was imparted and by whom, and offer resource utilization suggestions regarding pediatric fractures presenting to a Canadian pediatric hospital. Methods: Records of patients from 0 to 18 years of age who presented to the British Columbia Children's Hospital Emergency Department between November 1, 2016, and January 31, 2021, with metacarpal or phalangeal fractures were analyzed. Results: A total of 524 hand fractures were identified in 499 patients. Over 60% of fractures occurred in boys. The number of fractures peaked at the age of 11 years for girls and 12 years for boys. Open fractures accounted for only 4.0% of all fractures. Approximately 40% of fractures were epiphyseal growth plate fractures, with Salter-Harris II fractures being the most common diagnosis overall. Management was primarily nonsurgical, with 75% of fractures managed with immobilization alone and 23% of fractures managed with bedside closed reduction and immobilization. Of the fractures requiring closed reduction, the majority were performed by the emergency physician with a success rate of 82%. Only 2.3% of all fractures required surgery. Conclusions: Hand fractures are common pediatric injuries and make up a large proportion of emergency room visits. The majority of fractures do not require formal surgery and are well managed with immobilization alone or closed reduction by an emergency room physician and immobilization. Nonsurgical treatment offers very encouraging outcomes. A certain percentage of these simple fractures would likely benefit from primary care management alone and not require specialist intervention.

Objectif : Les fractures de main de l'enfant sont des situations fréquemment rencontrées dans les services d'urgence. Cette étude a été menée pour évaluer l'épidémiologie, la gestion et les résultats, où les soins ont été transmis et par qui, et pour offrir des suggestions d'utilisation des ressources concernant les fractures pédiatriques arrivant dans un hôpital canadien pour enfants. Méthodes : Les dossiers des patients âgés de 0 à 18 ans arrivés au service des urgences de l'hôpital pour enfants de Colombie-Britannique avec une fracture métacarpienne ou phalangienne entre le 1er nov. 2016 et le 31 janvier 2021 ont été analysés. Résultats : Un total de 524 fractures de la main a été identifié chez 499 patients. Plus de 60 % des fractures concernaient des garçons. Le nombre de fractures était maximum à l'âge de 11 ans pour les filles et de 12 ans pour les garçons. Les fractures ouvertes représentaient seulement 4,0 % de toutes les fractures. Approximativement 40 % des fractures concernaient la plaque de croissance épiphysaire avec les fractures Salter-Harris II constituant globalement le diagnostic le plus fréquent. La gestion a été principalement non chirurgicale : 75 % des fractures ont été gérées par immobilisation seule et 23 % des fractures ont été gérées par réduction fermée au chevet des patients et immobilisation. La majorité des réductions fermées pour fracture a été réalisée par le médecin des urgences avec un taux de succès de 82 %. Seulement 2,3 % de toutes les fractures ont nécessité une intervention chirurgicale. Conclusions : Les fractures de la main sont des blessures pédiatriques fréquentes et constituent une proportion importante des visites aux urgences. La majorité des fractures ne nécessite pas de chirurgie et est bien gérée avec seulement une immobilisation ou une réduction fermée suivie d'une immobilisation par le médecin des urgences. Le traitement non chirurgical obtient des résultats très encourageants. Un certain pourcentage de ces fractures simples relèverait probablement d'une gestion en soins primaires uniquement et ne nécessitent pas l'intervention d'un spécialiste.

Cold-Inducible RNA Binding Protein Impedes Breast Tumor Growth in the PyMT Murine Model for Breast Cancer.

RNA binding proteins (RBPs) post-transcriptionally regulate gene expression by associating with regulatory sequences in the untranslated regions of mRNAs. Cold-inducible RBP (CIRP) is a stress-induced RBP that was recently shown to modulate inflammation in response to cellular stress, where it increases or decreases pro-tumorigenic (proinflammatory) cytokines in different contexts. CIRP expression is altered in several cancers, including breast cancer, but the effects of CIRP on inflammation in breast cancer is not known. Here, we investigate if CIRP alters growth and the inflammatory profile of breast tumors. Transgenic mice overexpressing CIRP in the mammary epithelium were crossed with the PyMT mouse model of breast cancer, and the effects on both early and late tumorigenesis and inflammation were assessed. The effects of CIRP knockdown were also assessed in Py2T cell grafts. Overexpression of CIRP led to decreased tumorigenesis in the PyMT mouse model. Conversely, the knockdown of CIRP in Py2T cell grafts led to increased tumor growth. Luminex cytokine assays assessed the effects on the inflammatory environment. CIRP/PyMT mammary glands/mammary tumors and serum had decreased cytokines that promote inflammation, angiogenesis, and metastasis compared to PyMT mammary glands and serum, documenting a shift towards an environment less supportive of tumorigenesis. CIRP overexpression also decreased CD4+ helper T cells and increased CD8+ cytotoxic T cells in mammary tumors. Overall, these data support a role for CIRP as a potent antitumor molecule that suppresses both local and systemic pro-tumorigenic inflammation.

Questioning the Utility of Temporal Artery Biopsy in Giant Cell Arteritis: A Negative Biopsy May Facilitate Decision-making.

Plastic surgeons are frequently consulted to perform temporal artery biopsy (TAB), even though patients meet the American College of Rheumatology diagnostic criteria for giant cell arteritis (GCA) and are already treated. This study aimed to analyze the impact of TAB on steroid duration in patients undergoing TAB. Methods: We undertook a prospective study of adult patients undergoing TAB for GCA in Calgary. Consecutive, multicenter recruitment was performed over 2 years. Primary outcomes included initiation or discontinuation and duration of corticosteroids. Results: Twenty-one TABs were performed in 20 patients. Nineteen percent of TABs were positive, and 71.4%, negative. In 9.5% of patients, accidental sampling of a vessel other than the superficial temporal artery occurred. Fifty-two percent of patients received steroids before TAB, of which the mean duration was 8.0 days for TAB+ (postive temporal artery biopsy result) patients and 8.4 days for TAB- (negative temporal artery biopsy result; P = 0.22) patients. Before TAB, the American College of Rheumatology score was 2.5 for TAB+ patients and 2.4 for TAB- (P = 0.74). Postbiopsy, the American College of Rheumatology score was 3.5 for TAB+ patients (therefore reaching diagnostic threshold of 3) but remained 2.4 for TAB- (P = 0.02). TAB+ patients were treated for 352.3 days, whereas TAB- patients for 16.7 days (P = 0.29). Complications were more likely with long-term (>6 weeks) steroids (P = 0.17). Conclusion: In patients with a low suspicion of GCA, a negative TAB helps bolster physician confidence and leads to a shorter steroid duration.

Applying holistic review practices to a Combined Baccalaureate/Medical Degree Program: Reflections on lessons learned.

PROBLEM: Despite the implementation of holistic review in the medical school application process, there is little information about how this can be utilized in Combined Baccalaureate/Medical Degree pipeline programs, especially since many programs offer reserved spots to their students in the medical school. Implementing holistic review in a Combined Baccalaureate/Medical Degree program and intentionally structuring it to align with the medical school mission and admissions practices and processes, can improve the diversification of the physician workforce, contribute to more primary care doctors, and promote in-state practice. INTERVENTION: Utilizing the medical school admissions by-laws, committee structure, shared training, and educational processes, we successfully engrained in our committee members the values and mission alignment to select the best applicants to fulfill the medical school mission using holistic review. To our knowledge, no other program has written about how holistic review is used in Combined Baccalaureate/Medical Degree programs and how it contributes to program outcomes. CONTEXT: The Combined Baccalaureate/Medical Degree Program is a partnership between the undergraduate College of Arts and Sciences and the School of Medicine. The Combined Baccalaureate/Medical Degree admissions committee is a subcommittee of the School of Medicine admissions committee but has a separate membership. Hence, the holistic admissions process for the program mirrors the School of Medicine admissions process. To determine the outcome of this process, we analyzed practice specialty, practice location, gender, race and ethnicity of program alumni. IMPACT: To date, the Combined Baccalaureate/Medical Degree holistic admissions processes have supported the medical school mission, "…To meet the physician workforce needs of the state by selection of students who are likely to train in specialty areas of need and to remain in or return to the areas of our state needing physicians." This implementation has resulted in 75% (37/49) of our practicing alumni selecting a primary care specialty, and 69% (34/49) practicing in the state. In addition, 55% (27/49) identify as Underrepresented in Medicine. LESSONS LEARNED: We observed that having an intentional structured alignment in place allowed for implementation of holistic practices in the Combined Baccalaureate/Medical Degree admissions process. The high retention rates and specialty of graduates from the Combined Baccalaureate/Medical Degree Program support our intentional efforts to diversify our admissions committees and align the Combined Baccalaureate/Medical Degree program's holistic review admissions process with our School of Medicine mission and admissions practices and processes, as key strategies to reach our diversity-related goals.

Strategies Addressing Barriers to the Implementation of a Pediatric Hand Fracture Care Pathway.

We recently highlighted shortcomings in the care of pediatric hand fractures in our local context. The Calgary Kids' Hand Rule (CKHR) was developed to predict hand fractures that require referral to a hand surgeon. The aims of this study were to identify barriers to a new care pathway for pediatric hand fractures, based on the CKHR and to generate tailored strategies to support its implementation. Methods: We performed a conventional content analysis of transcripts from four focus groups (parents, emergency/urgent care physicians, plastic surgeons, and hand therapists) to identify relevant concepts (facilitators and barriers). These concepts were mapped to two frameworks. Generic strategies to address the barriers were identified, and further discussions with key stakeholders resulted in tailored strategies for implementation. Results: Five facilitators to implementation of a CKHR-based hand fracture care pathway included established rapport between hand therapists and surgeons, potential for more streamlined care, agreement on identifying another care provider, positive perceptions of hand therapist expertise, and opportunity for patient education. Two individual barriers were concern for poor outcomes and trust. Three systemic barriers were awareness and usability, referral process, and cost and resources. Strategies to address these barriers include pilot-testing of the new care pathway, ensuring closed loop communication, multiple knowledge translation activities, integration of CKHR into the clinical information system, coordinating care and development of parent handouts. Conclusion: Mapping barriers to established implementation frameworks has informed tailored implementation strategies, bringing us one step closer to successfully implementing a new pediatric hand fracture pathway.

Healthcare Providers and Parents Highlight Challenges of Pediatric Hand Fracture Care.

Pediatric hand fractures are common, and many are referred to hand surgeons despite less than 10% of referrals requiring surgical intervention. We explored healthcare provider and parent perspectives to inform a new care pathway. Methods: We conducted a qualitative descriptive study using virtual focus groups. Emergency physicians, hand therapists, plastic surgeons, and parents of children treated for hand fractures were asked to discuss their experiences with existing care for pediatric hand fractures, and perceptions surrounding the implementation of a new care pathway. Data were analyzed using directed content analysis with an inductive approach. Results: Four focus groups included 24 participants: 18 healthcare providers and six parents. Four themes were identified: educating parents throughout the hand fracture journey, streamlining the referral process for simple hand fractures, identifying the most appropriate care provider for simple hand fractures, and maintaining strong multidisciplinary connections to facilitate care. Participants described gaps in the current care, including a need to better inform parents, and elucidated the motivations behind emergency medicine physicians' existing referral practices. Participants also generally agreed on the need for more efficient management of simple hand fractures that do not require surgical care. Healthcare providers believed the strong preexisting relationship between surgeons and hand therapists would facilitate the changes brought forward by the new care pathway. Conclusion: These findings highlighted shortcomings of existing care for pediatric hand fractures and will inform the co-development and implementation of a new care pathway to enable more efficient management while preserving good patient outcomes.

Developmental downregulation of Xenopus cyclin E is phosphorylation and nuclear import dependent and is mediated by ubiquitination.

Cyclins are regulatory subunits that bind to and activate catalytic Cdks. Cyclin E associates with Cdk2 to mediate the G1/S transition of the cell cycle. Cyclin E is overexpressed in breast, lung, skin, gastrointestinal, cervical, and ovarian cancers. Its overexpression correlates with poor patient prognosis and is involved in the etiology of breast cancer. We have been studying how cyclin E is normally downregulated during development in order to determine if disruption of similar mechanisms could either contribute to its overexpression in cancer, or be exploited to decrease its expression. In Xenopus laevis embryos, cyclin E protein level is high and constant until its abrupt destabilization by an undefined mechanism after the 12th cell cycle, which corresponds to the midblastula transition (MBT) and remodeling of the embryonic to the adult cell cycle. Since degradation of mammalian cyclin E is regulated by the ubiquitin proteasome system and is phosphorylation dependent, we examined the role of phosphorylation in Xenopus cyclin E turnover. We show that similarly to human cyclin E, phosphorylation of serine 398 and threonine 394 plays a role in cyclin E turnover at the MBT. Immunofluorescence analysis shows that cyclin E relocalizes from the cytoplasm to the nucleus preceding its degradation. When nuclear import is inhibited, cyclin E stability is markedly increased after the MBT. To investigate whether degradation of Xenopus cyclin E is mediated by the proteasomal pathway, we used proteasome inhibitors and observed a progressive accumulation of cyclin E in the cytoplasm after the MBT. Ubiquitination of cyclin E precedes its proteasomal degradation at the MBT. These results show that cyclin E destruction at the MBT requires both phosphorylation and nuclear import, as well as proteasomal activity.

Necessity of Temporal Artery Biopsy for Giant Cell Arteritis: A Systematic Review.

Temporal artery biopsy (TAB) is currently the gold standard procedure to diagnose giant cell arteritis. Despite low sensitivity, TAB is routinely performed even if a clinical diagnosis has already been made. The objective of this study was to determine the usefulness of TAB for giant cell arteritis management. Methods: We performed a systematic review to identify studies that compared steroid treatment between TAB+ and TAB- patients. EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched from inception until April 4, 2020. Titles, abstracts, and full texts were reviewed by two independent reviewers and conflicts resolved by consensus. Studies reporting TAB result and steroid treatment were included. Information pertaining to steroid treatment was compared between TAB+ and TAB- groups. Steroid duration was compared by grouping patients in a less than 6 month group, a 6-24 month group, and a more than 24 month group. Results: An estimated 5288 abstracts were screened and 13 studies involving 1355 patients were included. Rate of prebiopsy steroid treatment was higher in TAB+ patients compared with TAB- patients [93% versus 63% (P < 0.001)]. The TAB+ group was more likely to be started on steroids prebiopsy [28% versus 8% (P < 0.001)]. TAB+ and TAB- patients had similar steroid duration for all groups [<6-month group 17% versus 19% (P-0.596), the 6-24-month group 16% versus 19% (P-0.596), and the >24-month group 66% versus 63% (P-0.642)]. Conclusion: TAB results have minimal impact on treatment, and the utility should be reconsidered when a clinical diagnosis of giant cell arteritis is possible.

Temporal Artery Biopsy Debate: Positive TAB Result Prolongs Steroid Use in Giant Cell Arteritis.

Temporal artery biopsy (TAB) in diagnosing giant cell arteritis has been criticized due to surgical risks, a high false negative rate, and redundant information when patients already met American College of Rheumatology criteria. The objective of this study was to investigate TAB's impact on steroid treatment duration. Methods: A retrospective chart review garnered patient demographics, symptoms, comorbidities, and steroid treatment duration in patients undergoing TAB at a single center. Steroid treatment was compared between TAB+ and TAB - patients. Results: One hundred seven patients undergoing TAB were included. Patients were predominantly women (70.1%) with a median age of 74 years (46 -91). Of 107 TAB results, 74 (69.2%) were negative, 23 (21.5%) were positive, and 10 (9.3%) were found to be indeterminate. In TAB+ patients, the mean erythrocyte sedimentation rate was not significantly different than TAB - patients (60.2 versus 43.7, P = 0.45), nor was the median C-reactive protein (38.8 versus 18.1, P = 0.17). Regarding steroid use, both TAB+ and TAB - patients had a similarly high rate of prebiopsy steroid initiation (82.6% versus 70.3%, P = 0.32). More TAB+ patients remained on steroids at 6 weeks (95.0% versus 57.4%, P = 0.004), 6 months (95% versus 37.7%, P < 0.001), 1 year (65.0% versus 31.1%, P = 0.024), and 18 months (50.0% versus 19.7%, P = 0.045). By 2 years, the difference no longer met significance (35.0% versus 14.8%, P = 0.12). P = 0.12). Conclusion: TAB positivity does seem to influence maintenance of steroids up to 18 months after biopsy.

Three-dimensional collagen represses cyclin E1 via ß1 integrin in invasive breast cancer cells.

The behavior of breast epithelial cells is influenced by their microenvironment which includes stromal cells and extracellular matrix (ECM). During cancer progression, the tissue microenvironment fails to control proliferation and differentiation, resulting in uncontrolled growth and invasion. Upon invasion, the ECM encountered by breast cancer cells changes from primarily laminin and collagen IV to primarily collagen I. We show here that culturing invasive breast cancer cells in 3-dimensional (3D) collagen I inhibits proliferation through direct regulation of cyclin E1, a G(1)/S regulator that is overexpressed in breast cancer. When the breast cancer cell line MDA-MB-231 was cultured within 3D collagen I gels, the G(1)/S transition was inhibited as compared to cells cultured on conventional 2D collagen or plastic dishes. Cells in 3D collagen downregulated cyclin E1 protein and mRNA, with no change in cyclin D1 level. Cyclin D1 was primarily cytoplasmic in 3D cultures, and this was accompanied by decreased phosphorylation of Rb, a nuclear target for both cyclin E1- and cyclin D1-associated kinases. Positive regulators of cyclin E1 expression, the transcription factor c-Myc and cold-inducible RNA binding protein (CIRP), were decreased in 3D collagen cultures, while the collagen I receptor ß1 integrin was greatly increased. Inhibition of ß1 integrin function rescued proliferation and cyclin E1 expression as well as c-Myc expression and Rb phosphorylation, but cyclin D1 remained cytoplasmic. We conclude that cyclin E1 is repressed independent of effects on cyclin D1 in a 3D collagen environment and dependent on ß1 integrin interaction with collagen I, reducing proliferation of invasive breast cancer cells.

Deadenylation of maternal mRNAs mediated by miR-427 in Xenopus laevis embryos.

We show that microRNA-427 (miR-427) mediates the rapid deadenylation of maternal mRNAs after the midblastula transition (MBT) of Xenopus laevis embryogenesis. By MBT, the stage when the embryonic cell cycle is remodeled and zygotic transcription of mRNAs is initiated, each embryo has accumulated approximately 10(9) molecules of miR-427 processed from multimeric pri-miR-427 transcripts synthesized after fertilization. We demonstrate that the maternal mRNAs for cyclins A1 and B2 each contain a single miR-427 target sequence, spanning less than 30 nucleotides, that is both necessary and sufficient for deadenylation, and that inactivation of miR-427 leads to stabilization of the mRNAs. Although this deadenylation normally takes place after MBT, exogenous miRNAs produced prematurely in vivo can promote deadenylation prior to MBT, indicating that turnover of the maternal mRNAs is limited by the amount of accumulated miR-427. Injected transcripts comprised solely of the cyclin mRNA 3' untranslated regions or bearing a 5' ApppG cap undergo deadenylation, showing that translation of the targeted RNA is not required. miR-427 is not unique in promoting deadenylation, as an unrelated miRNA, let-7, can substitute for miR-427 if the reporter RNA contains an appropriate let-7 target site. We propose that miR-427, like the orthologous miR-430 of zebrafish, functions to down-regulate expression of maternal mRNAs early in development.

Attitudes of Canadian Plastic Surgeons on Temporal Artery Biopsy in Giant Cell Arteritis Management.

Temporal artery biopsies (TAB) rarely impact management of patients with suspected giant cell arteritis and carry complications. We sought plastic surgeons' perspectives on this procedure's risks and benefits. METHODS: An email survey was designed, piloted, and refined to elicit Canadian Society of Plastic Surgeons (CSPS) members about TAB's diagnostic contribution, complications, usefulness as a resident education tool, and surgeons' insight into emerging diagnostic modalities like ultrasound. Text comments were sought at each question. A reminder was emailed one week later. Data was compared and analyzed using the chi-squared test and student t-test. RESULTS: An estimated 83 responses were received from 435 surgeons (19%). Of the surgeons, 20% voiced uncertainty regarding TAB indications; 40% were unsure if TAB results changed steroid duration and dose; 83% did not see patients postoperatively. Surgeons recalled 29 cases of hematoma and three facial nerve injuries from TAB. In total, 80% felt TAB was a valuable learning opportunity for residents, although residents were involved in only 21% of cases; 65% of surgeons supported a changeover to ultrasound as primary diagnostic modality. Analysis of text comments revealed a sense of futility from TAB and disdain toward being mere technicians. Several participants wished for stakeholders to collaborate and potentially endorse noninvasive diagnostic modalities. CONCLUSIONS: This survey demonstrated varying attitudes to TAB. Generally, plastic surgeons were uncertain of TAB's contribution to treatment, tended not to follow-up on results or patients, and recognized a number of complications. Conversations are desired regarding switching from scalpel to probe to evaluate the temporal artery.

Derivation and Internal Validation of a Prediction Model for Pediatric Hand Fracture Triage.

BACKGROUND: Pediatric hand fractures are common, and most can be managed by a period of immobilization. However, it remains challenging to identify those more complex fractures requiring the expertise of a hand surgeon to ensure a good outcome. The purpose of this study was to develop a prediction model for identification of complex pediatric hand fractures requiring care by a hand surgeon. METHODS: A 2-year retrospective cohort study of consecutively referred pediatric (<18 years) hand fracture patients was used to derive and internally validate a prediction model for identification of complex fractures requiring the expertise of a hand surgeon. These complex fractures were defined as those that required surgery, closed reduction, or four or more appointments with a hand surgeon. The model, derived by multivariable logistic regression analysis, was internally validated using bootstrapping and then translated into a risk index. RESULTS: Of 1170 fractures, 416 (35.6%) met criteria for a complex fracture. Multivariable regression analysis identified six significant predictors of complex fracture: open fracture, rotational deformity, angulation, condylar involvement, dislocation or subluxation, and displacement. Internal validation demonstrated good performance of the model (C-statistic = 0.88, calibration curve p = 0.935). A threshold of ≥1 point (ie, any one of the predictors) resulted in a simple, easy-to-use tool with 96.4% sensitivity and 45.5% specificity. CONCLUSIONS: A high-performing and clinically useful decision support tool was developed for emergency and urgent care physicians providing initial assessment for children with hand fractures. This tool will provide the basis for development of a clinical care pathway for pediatric hand fractures.