Conjugations of unitary operators, II.

For a unitary operator U on a separable complex Hilbert space H, we describe the set Cc(U) of all conjugations C (antilinear, isometric, and involutive maps) on H for which CUC=U. As this set might be empty, we also show that Cc(U)≠∅ if and only if U is unitarily equivalent to U∗.

Conjugations of unitary operators, I.

If U is a unitary operator on a separable complex Hilbert space H, an application of the spectral theorem says there is a conjugation C on H (an antilinear, involutive, isometry on H) for which CUC=U∗. In this paper, we fix a unitary operator U and describe all of the conjugations C which satisfy this property. As a consequence of our results, we show that a subspace is hyperinvariant for U if and only if it is invariant for any conjugation C for which CUC=U∗.

Injectable ultrasound-powered bone-adhesive nanocomposite hydrogel for electrically accelerated irregular bone defect healing.

The treatment of critical-size bone defects with irregular shapes remains a major challenge in the field of orthopedics. Bone implants with adaptability to complex morphological bone defects, bone-adhesive properties, and potent osteogenic capacity are necessary. Here, a shape-adaptive, highly bone-adhesive, and ultrasound-powered injectable nanocomposite hydrogel is developed via dynamic covalent crosslinking of amine-modified piezoelectric nanoparticles and biopolymer hydrogel networks for electrically accelerated bone healing. Depending on the inorganic-organic interaction between the amino-modified piezoelectric nanoparticles and the bio-adhesive hydrogel network, the bone adhesive strength of the prepared hydrogel exhibited an approximately 3-fold increase. In response to ultrasound radiation, the nanocomposite hydrogel could generate a controllable electrical output (-41.16 to 61.82 mV) to enhance the osteogenic effect in vitro and in vivo significantly. Rat critical-size calvarial defect repair validates accelerated bone healing. In addition, bioinformatics analysis reveals that the ultrasound-responsive nanocomposite hydrogel enhanced the osteogenic differentiation of bone mesenchymal stem cells by increasing calcium ion influx and up-regulating the PI3K/AKT and MEK/ERK signaling pathways. Overall, the present work reveals a novel wireless ultrasound-powered bone-adhesive nanocomposite hydrogel that broadens the therapeutic horizons for irregular bone defects.

Spatial and temporal aspects of neuronal calcium and sodium signals measured with low-affinity fluorescent indicators.

Low-affinity fluorescent indicators for Ca2+ or Na+ allow measuring the dynamics of intracellular concentration of these ions with little perturbation from physiological conditions because they are weak buffers. When using synthetic indicators, which are small molecules with fast kinetics, it is also possible to extract spatial and temporal information on the sources of ion transients, their localization, and their disposition. This review examines these important aspects from the biophysical point of view, and how they have been recently exploited in neurophysiological studies. We first analyze the environment where Ca2+ and Na+ indicators are inserted, highlighting the interpretation of the two different signals. Then, we address the information that can be obtained by analyzing the rising phase and the falling phase of the Ca2+ and Na+ transients evoked by different stimuli, focusing on the kinetics of ionic currents and on the spatial interpretation of these measurements, especially on events in axons and dendritic spines. Finally, we suggest how Ca2+ or Na+ imaging using low-affinity synthetic fluorescent indicators can be exploited in future fundamental or applied research.

Biliary Drainage in Hilar and Perihilar Cholangiocarcinoma; 25-Year Experience at a Tertiary Cancer Center.

INTRODUCTION: This study analyzes the optimal biliary stenting strategy for palliation in cholangiocarcinoma (CCA). METHODS: This is a retrospective study of patients with CCA who underwent biliary drainage from 1997-2023. A per-patient analysis of percutaneous biliary drainage (PTBD) rates, the median number of ERCPs, overall survival (OS), and a per-procedure analysis of clinical success (CS), stent-specific Adverse Events (AEs), and mean time to reintervention by stent type and laterality (unilateral(u) & bilateral(b)) is presented. RESULTS: A total of 333 patients underwent 1,050 ERCPs; 85% with plastic stents (PS). PTBD was eventually done in 23% of PS patients, 35% of whom had PS removed prior to PTBD. ERCPs with SEMS/uniSEMS use had higher CS (89%/91%) vs PS/uPS (85% both) and PS within SEMS (PS-SEMS)/uPS-SEMS (71%/74%;p=0.013/p=0.054). Compared to PS, SEMS and PS-SEMS were associated with higher stent-specific AEs (OR SEMS 4.85; 3.23-7.27; PS-SEMS 9.99; 5.33-18.71;p<0.001). Straight PS were associated with more stent-specific AEs compared to double-pigtail stents (OR 6.74; 3.95-11.45;p<0.001). More 7 Fr stents were used in cases with balloon dilation (BD, 109 vs. 88 with no BD; p<0.001). BD had 79% CS rate vs 87% without BD (p<0.001). Cases with pus on ERCP and those with BD had a shorter mean time to reintervention. On regression analyses, higher Bismuth class, PS use, and PS-SEMS use were associated with a shorter mean time to repeat ERCP. 52% of patients in the bSEMS arm died from cholangitis (p=0.005). CONCLUSION: The relatively higher clinical success of SEMS is countered by the higher stent-specific complication rate. PS can be removed and may better facilitate PTBD. Within PS types, DPTs may have fewer stent-specific AEs. Cases requiring balloon dilation and with endoscopic evidence of pus may benefit from earlier reintervention.

Ultrasound-guided injection through the rotator cuff interval: a clinical perspective of one institution's results and description of technique.

CONTEXT: Fluoroscopic injection through the rotator cuff interval (RCI) is a common technique for diagnostic arthrography and therapeutic intervention. Ultrasound approaches through the RCI have been less commonly studied, but there is a growing body of literature. OBJECTIVES: The purpose of this study was to present a standardized technique of ultrasound-guided injection into the glenohumeral joint utilizing the RCI in magnetic resonance imaging (MRI) arthrography (MRA) and to report one medical group's experience with the technique. METHODS: A retrospective chart review of all ultrasound-guided injections into the glenohumeral joint utilizing the RCI was performed from July 1, 2014 through June 1, 2021. Data were compiled for age, gender, body mass index (BMI), and prior surgery on the shoulder. The primary endpoint was successful administration of intra-articular dilute gadolinium contrast adequate for radiologic interpretation. A total of 487 injections into the glenohumeral joint via the RCI were performed. One hundred and fifty-five patients had previous shoulder surgery, with the remainder naive to intervention. RESULTS: The success rate of injections into the glenohumeral joint was 99.4 %, with only three injections considered unsuccessful. The three unsuccessful injections did not succeed because of a lack of intra-articular contrast media present. This success rate is impressive and promising, particularly when considering that 155 of the patients had previous surgery, which could potentially cause complications, and because these injections were performed over a long period of 7 years. CONCLUSIONS: Accessing the RCI under ultrasound guidance is a very successful technique for injection within the glenohumeral joint.

Performance and attitudes toward real-time computer-aided polyp detection during colonoscopy in a large tertiary referral center in the United States.

BACKGROUND AND AIMS: Computer-aided detection (CADe) has been shown to improve polyp detection in clinical trials. Limited data exist on the impact, utilization, and attitudes toward artificial intelligence (AI)-assisted colonoscopy in daily clinical practice. We aimed to evaluate the effectiveness of the first U.S. Food and Drug Administration-approved CADe device for polyp detection in the United States and the attitudes toward its implementation. METHODS: We performed a retrospective analysis of a prospectively maintained database of patients undergoing colonoscopy at a tertiary center in the United States before and after a real-time CADe system was made available. The decision to activate the CADe system was at the discretion of the endoscopist. An anonymous survey was circulated among endoscopy physicians and staff at the beginning and conclusion of the study period regarding their attitudes toward AI-assisted colonoscopy. RESULTS: CADe was activated in 52.1% of cases. Compared with historical control subjects, there was no statistically significant difference in adenomas detected per colonoscopy (1.08 vs 1.04, P = .65), even after excluding diagnostic and therapeutic indications and cases where CADe was not activated (1.27 vs 1.17, P = .45). In addition, there was no statistically significant difference in adenoma detection rate (ADR), median procedure, and withdrawal times. Survey results demonstrated mixed attitudes toward AI-assisted colonoscopy, of which main concerns were high number of false-positive signals (82.4%), high level of distraction (58.8%), and impression it prolonged procedure time (47.1%). CONCLUSIONS: CADe did not improve adenoma detection in daily practice among endoscopists with high baseline ADRs. Despite its availability, AI-assisted colonoscopy was only activated in half of the cases, and multiple concerns were raised by staff and endoscopists. Future studies will help elucidate the patients and endoscopists that would benefit most from AI-assisted colonoscopy.

A decade's experience of managing suspected pancreatic adenocarcinoma at a tertiary cancer center.

Background: We present our experience and established management strategy for endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) in diagnosing suspected pancreatic neoplasms at a tertiary referral cancer hospital. Method: Relevant data were extracted from our database for patients who underwent EUS-FNA for suspected pancreatic neoplasms at our institution between 2007 and 2016. Results: Among the 309 patients, the median age was 67 years and 56% were men. The most common presenting symptoms were abdominal pain (37%) and jaundice (29%). Concordance between radiographic diagnosis and final pathology was 89%. The mean lesion size was 34.9 mm on computed tomography and 31.5 mm on EUS. There were 197 patients (64%) with localized disease, of whom 115 (58%) had resectable lesions, 61 (31%) had borderline resectable, and 21 (11%) had unresectable lesions (mean CA 19-9 levels 1705 U/mL, 2490 U/mL, and 479 U/mL, respectively). A median of 3 FNA passes were performed to establish a pathologic diagnosis. Two patients (1%) had postprocedural adverse events. Median overall survival was 47 months in those who underwent surgery after EUS and 12 months in those who did not (P<0.001). Conclusions: A multidisciplinary approach is employed for management of suspected pancreatic neoplasm at our tertiary cancer center. A combination of cross-sectional imaging and EUS-FNA serves as a highly effective duo in establishing a tissue diagnosis and staging with a low adverse event rate. Counterintuitively, CA 19-9 is not necessarily higher with resectable lesions than with unresectable lesions, indicating the limitation of CA 19-9 as a pancreatic tumor marker.

Fast Synaptically Activated Calcium and Sodium Kinetics in Hippocampal Pyramidal Neuron Dendritic Spines.

An accurate assessment of the time course, components, and magnitude of postsynaptic currents is important for a quantitative understanding of synaptic integration and signaling in dendritic spines. These parameters have been studied in some detail in previous experiments, primarily using two-photon imaging of [Ca2+]i changes and two-photon uncaging of glutamate. However, even with these revolutionary techniques, there are some missing pieces in our current understanding, particularly related to the time courses of synaptically evoked [Ca2+]i and [Na+]i changes. In new experiments, we used low-affinity, linear Na+ and Ca2+ indicators, laser fluorescence stimulation, and a sensitive camera-based detection system, combined with electrical stimulation and two-photon glutamate uncaging, to extend measurements of these spine parameters. We found that (1) almost all synaptically activated Na+ currents in CA1 hippocampal pyramidal neuron spines in slices from mice of either sex are through AMPA receptors with little Na+ entry through voltage-gated sodium channels (VGSCs) or NMDA receptor channels; (2) a spectrum of sodium transient decay times was observed, suggesting a spectrum of spine neck resistances, even on the same dendrite; (3) synaptically activated [Ca2+]i changes are very fast and are almost entirely because of Ca2+ entry through NMDA receptors at the time when the Mg2+ block is relieved by the fast AMPA-mediated EPSP; (4) the [Ca2+]i changes evoked by uncaging glutamate are slower than the changes evoked by synaptic release, suggesting that the relative contribution of Ca2+ entering through NMDA receptors at rest following uncaging is higher than following electrical stimulation.

Endoscopy for the diagnosis and treatment of gastrointestinal bleeding caused by malignancy.

BACKGROUND AND AIM: The diagnosis and treatment of gastrointestinal (GI) bleeding secondary to malignancy can be challenging. Endoscopy is the gold standard to diagnose and treat gastrointestinal bleeding but clinical characteristics and outcomes of patients with malignancy-related bleeding are not well understood. This study aims to look at clinical characteristics, endoscopic findings, safety and clinical outcomes of endoscopic interventions for GI malignancy-related bleeding. METHODS: We retrospectively reviewed outcomes of patients with confirmed GI malignancies who underwent endoscopy for GI bleeding at MD Anderson Cancer Center between 2010 and 2019. Cox hazard analysis was conducted to identify factors associated with survival. RESULTS: A total of 313 patients were included, with median age of 59 years; 74.8% were male. The stomach (30.0%) was the most common tumor location. Active bleeding was evident endoscopically in 47.3% of patients. Most patients (77.3%) did not receive endoscopic treatment. Of the patients who received endoscopic treatment, 57.7% had hemostasis. No endoscopy-related adverse events were recorded. Endoscopic treatment was associated with hemostasis (P < 0.001), but not decreased recurrent bleeding or mortality. Absence of active bleeding on endoscopy, stable hemodynamic status at presentation, lower cancer stage, and surgical intervention were associated with improved survival. CONCLUSIONS: This study indicates that endoscopy is a safe diagnostic tool in this patient population; while endoscopic treatments may help achieve hemostasis, it may not decrease the risk of recurrent bleeding or improve survival.

Nth Dimensions Evolution, Impact, and Recommendations for Equity Practices in Orthopaedics.

Women and underrepresented medical students are frequently unable to see, identify, or interact with an orthopaedic surgeon who looks like them. Simultaneously, these students are repeatedly challenged about their aspirations and questioned about their ability to become an orthopaedic surgeon. Ultimately, students from marginalized groups are unable to envision any future role as an orthopaedic surgeon and are actively diverted to other medical specialties. Nth Dimensions has developed programming that provides relatable role models, consistent positive affirmation, hands-on surgical and research experiences, and exposure to a community that expects for the scholars to succeed. In addition, Nth Dimensions has developed a series of best practices, or "steps," designed to help orthopaedic surgery training programs successfully recruit and retain diverse residents and faculty and ensure their success by providing a safe, all-inclusive learning and working environment.

Evaluation of apical clips placed during axillary dissection demonstrates potential under-coverage of axillary radiation therapy target volumes during breast cancer regional nodal irradiation.

INTRODUCTION: Evidence-based Australian guidelines (eviQ) recommend adjuvant supraclavicular fossa irradiation after axillary lymph node dissection (ALND) in node-positive breast cancer patients. Disparity between surgically determined versus computed tomography (CT) determined nodal volumes may result in discontiguous nodal volumes and untreated nodal tissue. We examine the extent of untreated nodal tissue in women with breast cancer post-level II or III ALND and adjuvant radiation therapy (RT) using ESTRO contouring guidelines. METHODS: Female breast cancer patients who underwent level II and III ALND with apical clip placement from 2016 to 2020 and CT simulated in supine position were included. CT-defined axillary level II-IV volumes were contoured using ESTRO guidelines. The distance between the apical clip and RT nodal volumes was measured to indicate extent of untreated tissue. RESULTS: Of 34 eligible patients treated by 7 surgeons, 76% had level II ALND and 24% level III ALND. Only 5.9% of clips entirely encompassed the corresponding RT nodal volumes. 55.9% of clips fell within and 44.1% fell inferolaterally outside the corresponding RT nodal volumes. A median 3.6 cm (range 0-7.5 cm) of undissected nodal tissue would not be included within standard RT target volumes following eviQ recommendations. CONCLUSION: There is a disparity between surgically determined versus CT determined axillary nodal volumes, leading to discontiguous nodal volumes and untreated axillary nodal tissue, despite following standard radiation contouring guidelines. Intraoperatively placed apical axillary clips may assist radiation oncologists to accurately delineate undissected nodal tissues at risk.

Adequacy evaluation and use of pancreatic adenocarcinoma specimens for next-generation sequencing acquired by endoscopic ultrasound-guided FNA and FNB.

BACKGROUND: Endoscopic ultrasound-guided tissue acquisition (EUS-TA), especially endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), is the mainstay of tissue acquisition for the diagnosis of pancreatic ductal adenocarcinoma (PDAC). Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using flexible biopsy needles has been used for patients with PDAC in an effort to increase diagnostic yields and biomarker testing. However, the role of EUS-TA in biomarker testing for personalized therapy or precise chemotherapy for PDAC is not well established. METHODS: PDAC cases with specimens acquired through concurrent EUS-FNA and EUS-FNB were identified retrospectively. Smears were prepared from EUS-FNA sampling, and cell blocks (CBs) were prepared from EUS-FNB sampling. Rapid onsite evaluation was conducted for all cases for diagnostic adequacy. The adequacy for biomarker testing, including next-generation sequencing (NGS) and immunohistochemistry (IHC) assays, was evaluated, and cases with smears and CBs adequate for NGS were processed for targeted NGS. RESULTS: There were 26 PDAC cases concurrently sampled by EUS-FNA and EUS-FNB. EUS-FNA smears for all 26 cases and EUS-FNB CBs for 20 cases (77%) were diagnostic for PDAC. Twenty-one smears (81%) and 11 CBs (42%) were adequate for NGS. Nine cases with both smears and CBs adequate for NGS underwent NGS, which identified clinically significant gene mutation variants, including KRAS, TP53, and SMAD4 mutations. CONCLUSIONS: Both EUS-FNA and EUS-FNB can provide optimal material for targeted NGS for PDACs. In PDAC cases subjected to concurrent EUS-FNA and EUS-FNB, EUS-FNA specimens had greater diagnostic yields and more adequate material for NGS than EUS-FNB specimens, whereas EUS-FNB was more suitable for IHC-based biomarker testing.

How much progress have we made?: a 20-year experience regarding esophageal stents for the palliation of malignant dysphagia.

Esophageal stents are widely used for the palliation of malignant esophageal obstruction. Advances in technology have made esophageal stenting technically feasible and widespread for such obstruction, but complications remain frequent. We present outcomes of a large cohort undergoing esophageal stent placement for malignant esophageal obstruction at a tertiary care cancer center. Patients who underwent placement of esophageal stents for malignancy-related esophageal obstruction between 1 January 2001 and 31 July 2020 were identified. Exclusion criteria included stents placed for benign stricture, fistulae, obstruction of proximal esophagus (proximal to 24 cm from incisors), or post-surgical indications. Patient charts were reviewed for demographics, procedure and stent characteristics, complications, and follow-up. A total of 242 patients underwent stent placement (median age: 64 years, 79.8% male). The majority, 204 (84.3%), had esophageal cancer. During the last two decades, there has been an increasing trend in the number of esophageal stents placed. Though plastic stents were previously used, these are no longer utilized. Complications are frequent and include early complications of pain in 68 (28.1%) and migration in 21 (8.7%) and delayed complications of recurrent symptoms of dysphagia in 46 (19.0%) and migration in 26 (10.7%). Over the study period, there has not been a significant improvement in the rate of complications. During follow-up, 92 (38%) patients required other enteral nutrition modalities after esophageal stent placement. No patient, treatment, or stent characteristics were significantly associated with stent complication or outcome. Esophageal stent placement is an increasingly popular method for palliation of malignant dysphagia. However, complications, particularly pain, migration, and recurrent symptoms of dysphagia are common. Almost 40% of patients may also require other methods of enteral access after esophageal stent placement. Given the high complication rates and suboptimal outcomes, removable stents should be considered as first-line in the case of poor palliative response.

Survival outcomes for breast cancer patients who decline recommended treatment: a propensity score-matched analysis.

BACKGROUND: For patients with breast cancer who decline recommended treatments, available data examining survival outcomes are sparse. We compared overall survival and relapse-free survival outcomes between patients with breast cancer who declined recommended primary treatments and those who received recommended primary treatments. METHODS: Using data from the BreastSurgANZ Quality Audit database, a retrospective cohort study was performed for patients diagnosed with breast carcinoma (stage 0-IV) between 2001 and 2014 who were treated in our integrated cancer centre. A propensity score-matched analysis was performed to compare overall survival and relapse-free survival between patients who either declined or received the standard recommended treatment. RESULTS: A total of 56/912 (6.1%) patients declined one or more recommended therapies. Five-year overall survival for those who declined or received treatment as recommended was 81.8% versus 88.9% (P = 0.17), respectively. Ten-year survival was 61.3% versus 67.8% (P = 0.22), respectively. For patients who declined treatments, 5-year relapse-free survival was 72.4%, compared to 87.4% for those who received them (P = 0.005). Ten-year relapse-free survival was 61.0% versus 80.6% (P = 0.002), respectively. On adjusted Cox regression analysis, treatment refusal was associated with poorer relapse-free survival (adjusted hazard ratio 2.76 (95% confidence interval 1.52-5.00), P < 0.001). CONCLUSION: In conclusion, patients who declined recommended treatment for breast cancer had poorer relapse-free survival compared to those who received them. These data may help clinicians assist patients with breast cancer in their decision-making.

Mechanism of ArcLight derived GEVIs involves electrostatic interactions that can affect proton wires.

The genetically encoded voltage indicators ArcLight and its derivatives mediate voltage-dependent optical signals by intermolecular, electrostatic interactions between neighboring fluorescent proteins (FPs). A random mutagenesis event placed a negative charge on the exterior of the FP, resulting in a greater than 10-fold improvement of the voltage-dependent optical signal. Repositioning this negative charge on the exterior of the FP reversed the polarity of voltage-dependent optical signals, suggesting the presence of "hot spots" capable of interacting with the negative charge on a neighboring FP, thereby changing the fluorescent output. To explore the potential effect on the chromophore state, voltage-clamp fluorometry was performed with alternating excitation at 390 nm followed by excitation at 470 nm, resulting in several mutants exhibiting voltage-dependent, ratiometric optical signals of opposing polarities. However, the kinetics, voltage ranges, and optimal FP fusion sites were different depending on the wavelength of excitation. These results suggest that the FP has external, electrostatic pathways capable of quenching fluorescence that are wavelength specific. One mutation to the FP (E222H) showed a voltage-dependent increase in fluorescence when excited at 390 nm, indicating the ability to affect the proton wire from the protonated chromophore to the H222 position. ArcLight-derived sensors may therefore offer a novel way to map how conditions external to the ß-can structure can affect the fluorescence of the chromophore and transiently affect those pathways via conformational changes mediated by manipulating membrane potential.

Assessment of genetic referrals and outcomes for women with triple negative breast cancer in regional cancer centres in Australia.

BACKGROUND: Guidelines for referral to cancer genetics service for women diagnosed with triple negative breast cancer have changed over time. This study was conducted to assess the changing referral patterns and outcomes for women diagnosed with triple negative breast cancer across three regional cancer centres during the years 2014-2018. METHODS: Following ethical approval, a retrospective electronic medical record review was performed to identify those women diagnosed with triple negative breast cancer, and whether they were referred to a genetics service and if so, the outcome of that genetics assessment and/or genetic testing. RESULTS: There were 2441 women with newly diagnosed breast cancer seen at our cancer services during the years 2014-2018, of whom 237 women were diagnosed with triple negative breast cancer. Based on age of diagnosis criteria alone, 13% (31/237) of our cohort fulfilled criteria for genetic testing, with 81% (25/31) being referred to a cancer genetics service. Of this group 68% (21/31) were referred to genetics services within our regions and went on to have genetic testing with 10 pathogenic variants identified; 5x BRCA1, 4x BRCA2 and × 1 ATM:c.7271 T > G. CONCLUSIONS: Referral pathways for women diagnosed with TNBC to cancer genetics services are performing well across our cancer centres. We identified a group of women who did not meet eligibility criteria for referral at their time of diagnosis, but would now be eligible, as guidelines have changed. The use of cross-discipline retrospective data reviews is a useful tool to identify patients who could benefit from being re-contacted over time for an updated cancer genetics assessment.