Transgender Women Exhibit a Distinct Stress Echocardiography Profile Compared to Age-Matched Cisgender Counterparts: The Mayo Clinic Women's Heart Clinic Experience

BACKGROUND

Stress echocardiography (SE) is an important modality in cardiovascular risk stratification and obstructive coronary artery disease (CAD) assessment. Binary sex-based parameters are classically used for interpretation of these studies, even among transgender women (TGW). CAD is a leading cause of morbidity and mortality in this population. Yet, it remains unclear whether TGW exhibit a distinct stress testing profile from their cisgender counterparts.

METHODS

Using a matched case-control study design, we compared the echocardiographic stress testing profiles of TGW (n=43) with those of matched cisgender men (CGM, n=84) and cisgender women (CGW, n=86) at a single center. Relevant data, including demographics, comorbidities, and cardiac testing data were manually extracted from the patients' charts.

RESULTS

The prevalence of hypertension and dyslipidemia was similar between TGW and CGW and lower than that of CGM (p= .003 and .009, respectively). The majority of comorbidities and lab values were similar. On average, TGW had higher heart rates than CGM (p=.002) and had lower blood pressures than CGM and CGW (p<.05). The TGW's double product and metabolic equivalents were similar to those among CGW and lower than those of CGM (p=.016, p=.018, respectively). On echocardiography, the left ventricular end-diastolic and end-systolic diameters among TGW were similar to those of CGW but lower than CGM's (p=.023, p=.018, respectively). Measures of systolic and diastolic function, except for the exercise mitral valve E:e' ratio which was lower in TGW than CGW (p=.029), were largely similar among the three groups. There was no difference in the wall motion score index, and therefore, no difference in the percentage of positive SE tests.

CONCLUSION

Our study shows, for the first time, that TGW have a SE profile that is distinct from that of their cisgender counterparts. Larger, multicenter, prospective studies are warranted to further characterize the SE profile of TGW.

Analysis of Anemia, Transfusions, and CABG Outcomes in The Society of Thoracic Surgeons National Database

BACKGROUND

This study characterized the association of preoperative anemia and intraoperative red blood cell (RBC) transfusion on outcomes of elective coronary artery bypass grafting (CABG).

METHODS

Data from 53,856 patients who underwent CABG included in The Society of Thoracic Surgeons (STS) Adult Cardiac Database in 2019 were used. The primary outcome was operative mortality. Secondary outcomes were postoperative complications. The association of anemia with outcomes was analyzed with multivariable regression models. The influence of intraoperative RBC transfusion on the effect of preoperative anemia on outcomes was studied using mediation analysis.

RESULTS

Anemia was present in 25% of patients. Anemic patients had a higher STS Predicted Risk of Operative Mortality (1.2% vs 0.7%; P < .001). Anemia was associated with operative mortality (odds ratio [OR], 1.27; 99.5% CI, 1.00-1.61; P = .047), postoperative RBC transfusion (OR, 2.28; 99.5% CI, 2.12-2.44; P < .001), dialysis (OR, 1.58; 99.5% CI, 1.19-2.11; P < .001), and prolonged intensive care unit and hospital length of stay. Intraoperative RBC transfusion largely mediated the effects of anemia on mortality (76%), intensive care unit stay (99%), and hospital stay, but it only partially mediated the association with dialysis (34.9%).

CONCLUSIONS

Preoperative anemia is common in patients who undergo CABG and is associated with increased postoperative risks of mortality, complications, and RBC transfusion. However, most of the effect of anemia on mortality is mediated through intraoperative RBC transfusion.

Prosthesis choice for tricuspid valve replacement: Comparison of clinical and echocardiographic outcomes

OBJECTIVES

There is limited evidence evaluating valve function and right heart remodeling after tricuspid valve replacement (TVR), as well as whether the choice of prosthesis has an impact on these outcomes.

METHODS

We reviewed 1043 consecutive adult patients who underwent first-time TVR; 33% had previous aortic and/or mitral valve operations. Severe tricuspid valve regurgitation (TR) was the indication for surgery in 94% patients. A mechanical valve was used in 149 (14%) patients and a bioprosthetic valve in 894 (86%). Concomitant major cardiac procedures were performed in 57% of patients.

RESULTS

The median age of the cohort was 68.8 (range, 25-94) years, and 57% were female. Overall survival at 5 and 10 years was 50% and 31%, respectively. Adjusted survival and cumulative incidence of reoperation after TVR were similar in patients with bioprosthetic and mechanical valves. Overall, right ventricular (RV) function and dilation improved postoperatively with the estimated proportion of patients with moderate or greater RV systolic dysfunction/dilatation decreasing by around 20% at 3 years follow-up. After adjusting for preoperative degree of dysfunction/dilatation, valve type had no effect on late improvement in RV function and dilation. Bioprosthetic TVR was associated with greater rates of recurrence of moderate or greater TR over late follow-up. Overall, a slight decline in tricuspid valve gradients was observed over time.

CONCLUSIONS

Mechanical and bioprosthetic valves provide comparable survival, incidence of reoperation, and recovery of RV systolic function and size after TVR. Bioprosthetic valves develop significant TR over time, and mechanical valves may have an advantage for younger patients and those needing anticoagulation.

The Simons Observatory: Cryogenic half wave plate rotation mechanism for the small aperture telescopes

We present the requirements, design, and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background polarization experiment at Parque Astronómico de Atacama in northern Chile that covers a wide range of angular scales using both small (⌀0.42 m) and large (⌀6 m) aperture telescopes. In particular, the small aperture telescopes (SATs) focus on large angular scales for primordial B-mode polarization. To this end, the SATs employ a CHWP to modulate the polarization of the incident light at 8 Hz, suppressing atmospheric 1/f noise and mitigating systematic uncertainties that would otherwise arise due to the differential response of detectors sensitive to orthogonal polarizations. The CHWP consists of a 505 mm diameter achromatic sapphire HWP and a cryogenic rotation mechanism, both of which are cooled down to ∼50 K to reduce detector thermal loading. Under normal operation, the HWP is suspended by a superconducting magnetic bearing and rotates with a constant 2 Hz frequency, controlled by an electromagnetic synchronous motor. We find that the number of superconductors and the number of magnets that make up the superconducting magnetic bearing are important design parameters, especially for the rotation mechanism's vibration performance. The rotation angle is detected through an angular encoder with a noise level of 0.07 μrad s. During a cooldown process, the rotor is held in place by a grip-and-release mechanism that serves as both an alignment device and a thermal path. In this paper, we provide an overview of the SO SAT CHWP: its requirements, hardware design, and laboratory performance.

Prevalence, sex differences, and implications of pulmonary hypertension in patients with apical hypertrophic cardiomyopathy

Introduction

Apical hypertrophic cardiomyopathy (ApHCM) is a subtype of hypertrophic cardiomyopathy (HCM) that affects up to 25% of Asian patients and is not as well understood in non-Asian patients. Although ApHCM has been considered a more "benign" variant, it is associated with increased risk of atrial and ventricular arrhythmias, apical thrombi, stroke, and progressive heart failure. The occurrence of pulmonary hypertension (PH) in ApHCM, due to elevated pressures on the left side of the heart, has been documented. However, the exact prevalence of PH in ApHCM and sex differences remain uncertain.

Methods

We sought to evaluate the prevalence, risk associations, and sex differences in elevated pulmonary pressures in the largest cohort of patients with ApHCM at a single tertiary center. A total of 542 patients diagnosed with ApHCM were identified using ICD codes and clinical notes searches, confirmed by cross-referencing with cardiac MRI reports extracted through Natural Language Processing and through manual evaluation of patient charts and imaging records.

Results

In 414 patients, echocardiogram measurements of pulmonary artery systolic pressure (PASP) were obtained at the time of diagnosis. The mean age was 59.4 ± 16.6 years, with 181 (44%) being females. The mean PASP was 38 ± 12 mmHg in females vs. 33 ± 9 mmHg in males (p < 0.0001). PH as defined by a PASP value of > 36 mmHg was present in 140/414 (34%) patients, with a predominance in females [79/181 (44%)] vs. males [61/233 (26%), p < 0.0001]. Female sex, atrial fibrillation, diagnosis of congestive heart failure, and elevated filling pressures on echocardiogram remained significantly associated with PH (PASP > 36 mmHg) in multivariable modeling. PH, when present, was independently associated with mortality [hazard ratio 1.63, 95% CI (1.05-2.53), p = 0.028] and symptoms [odds ratio 2.28 (1.40, 3.71), p < 0.001].

Conclusion

PH was present in 34% of patients with ApHCM at diagnosis, with female sex predominance. PH in ApHCM was associated with symptoms and increased mortality.

Characterization of a half-wave plate for cosmic microwave background circular polarization measurement with POLARBEAR

A half-wave plate (HWP) is often used as a modulator to suppress systematic error in the measurements of cosmic microwave background (CMB) polarization. A HWP can also be used to measure circular polarization (CP) through its optical leakage from CP to linear polarization. The CP of the CMB is predicted from various sources, such as interactions in the Universe and extension of the standard model. Interaction with supernova remnants of population III stars is one of the brightest CP sources. Thus, the observation of the CP of CMB is a new tool for searching for population III stars. In this paper, we demonstrate the improved measurement of the leakage coefficient using the transmission measurement of an actual HWP in the laboratory. We measured the transmittance of linearly polarized light through the HWP used in Polarbear in the frequency range of 120-160 GHz. We evaluate the properties of the HWP by fitting the data with a physical model using the Markov Chain Monte Carlo method. We then estimate the band-averaged CP leakage coefficient using the physical model. We find that the leakage coefficient strongly depends on the spectra of CP sources. We thus calculate the maximum fractional leakage coefficient from CP to linear polarization as 0.133 ± 0.009 in the Rayleigh-Jeans spectrum. The nonzero value shows that Polarbear has a sensitivity to CP. Additionally, because we use the bandpass of detectors installed in the telescope to calculate the band-averaged values, we also consider systematic effects in the experiment.

The Interaction of FEV1 and NT-Pro-BNP with Outcomes after Transcatheter Aortic Valve Replacement

OBJECTIVES

Low forced expiratory volume in 1 second (FEV1) and elevated N-terminal Pro form B-type natriuretic peptide (NT-Pro-BNP) have been individually associated with poor outcomes after transcatheter aortic valve replacement (TAVR). We hypothesized a combination of the two would provide prognostic indication after TAVR.

METHODS

We categorized 871 patients who received TAVR from 2008 to 2018 into 4 groups according to baseline FEV1 (< or ≥ 60% predicted) and NT-Pro-BNP (< or ≥ 1601 pg/ml): group A (n = 312, high FEV1, low NT-Pro-BNP), group B (n = 275, high FEV1, high NT-Pro-BNP), group C (n = 123 low FEV1, low NT-Pro-BNP), and group D (n = 161, low FEV1, high NT-Pro-BNP). The primary endpoint was survival at 1 and 5 years.

RESULTS

Patients in group A had more severe aortic stenosis and achieved the best long-term survival at 1- (93% (95% CI: 90-96) and 5- years (45.3% (95% CI: 35.4-58). Low FEV1 and high NT-Pro-BNP (group D) patients had more severe symptoms, higher Society of Thoracic Surgeons predicted risk of operative mortality, lower ejection fraction and aortic valve gradient at baseline. They had the worst survival at 1- (76% (95% CI: 69-83) and at 5-years (13.1% (95% CI: 7-25), Hazard Ratio compared to group A: 2.29 (95% CI: 1.6-3.2, p < 0.001) with 25.7% of patients in NYHA class III-IV. Patients in groups B and C had intermediate outcomes.

CONCLUSIONS

The combination of FEV1 and NT-Pro-BNP stratify patients into 4 groups with distinct risk profiles and clinical outcomes. Patients with low FEV1 and high NT-Pro-BNP have increased comorbidities, poor functional outcomes, and decreased long term survival after TAVR.

Prevalence and Natural History of Mitral Annulus Calcification and Related Valve Dysfunction

OBJECTIVE

To evaluate the prevalence and natural history of mitral annulus calcification (MAC) and associated mitral valve dysfunction (MVD) in patients undergoing clinically indicated echocardiography.

METHODS

A retrospective review was conducted of all adults who underwent echocardiography in 2015. Mitral valve dysfunction was defined as mitral regurgitation or mitral stenosis (MS) of moderate or greater severity. All-cause mortality during 3.0 (0.4 to 4.2) years of follow-up was compared between groups stratified according to the presence of MAC or MVD.

RESULTS

Of 24,414 evaluated patients, 5502 (23%) had MAC. Patients with MAC were older (75±10 years vs 60±16 years; P<.001) and more frequently had MVD (MS: 6.6% vs 0.5% [P<.001]; mitral regurgitation without MS: 9.5% vs 6.1% [P<.001]). Associated with MS in patients with MAC were aortic valve dysfunction, female sex, chest irradiation, renal dysfunction, and coronary artery disease. Kaplan-Meier 1-year survival was 76% in MAC+/MVD+, 87% in MAC+/MVD-, 86% in MAC-/MVD+, and 92% in MAC-/MVD-. Adjusted for age, diabetes, renal dysfunction, cancer, chest irradiation, ejection fraction below 50%, aortic stenosis, tricuspid regurgitation, and pulmonary hypertension, MAC was associated with higher mortality during follow-up (adjusted hazard ratio, 1.40; 95% CI, 1.31 to 1.49; P<.001); MVD was associated with even higher mortality in patients with MAC (adjusted hazard ratio, 1.79; 95% CI, 1.58 to 2.01; P<.001). There was no significant interaction between MAC and MVD for mortality (P=.10).

CONCLUSION

In a large cohort of adults undergoing echocardiography, the prevalence of MAC was 23%. Mitral valve dysfunction was more than twice as prevalent in patients with MAC. Adjusted mortality was increased in patients with MAC and worse with both MAC and MVD.

Incidence Trends and Epidemiology of Staphylococcus aureus Bacteremia: A Systematic Review of Population-Based Studies

Objectives: To determine incidence trends of Staphylococcus aureus bacteremia (SAB) from population-based studies from multiple countries.

Methods: A contemporary systematic review was conducted using Ovid Cochrane Central Register of Controlled Trials (1991+), Ovid Embase (1974+), Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE) (1946+ including epub ahead of print, in-process & other non-indexed citations), and Web of Science Core Collection (Science Citation Index Expanded 1975+ and Emerging Sources Citation Index 2015+). Two authors (J.R.H. and J.A.Q.M.) independently reviewed all studies and included those that reported population-based incidence of SAB in patients aged 18 years and older.

Results: Twenty-six studies met inclusion criteria with the highest number (n=6) of studies conducted in Canada. The incidence of SAB ranged from 9.3 to 65 cases/100,000/year. The median age of patients with SAB ranged from 62 to 72 years and SAB cases were more commonly observed in men than in women. The most common infection sources were intravascular catheters and skin and soft tissue infections. SAB incidence trends demonstrated high variability for geographic regions and calendar years. Overall, there was no change in the incidence trend across all studies during the past two decades.

Conclusion: Multiple factors, both pros, and cons are likely responsible for the overall stable SAB incidence in countries included in this systematic review. Some of these factors vary in geographic location and prompt additional investigations from countries not included in the current review so that a more global characterization is defined.

Optimal Management of Mitral Regurgitation Due to Ruptured Mitral Chordae Tendineae in Patients With Hypertrophic Cardiomyopathy

There is continued controversy regarding surgical management of patients with hypertrophic cardiomyopathy (HCM) and intrinsic mitral valve disease; some clinicians favor prosthetic replacement as this corrects left ventricular outflow tract (LVOT) obstruction and valve leakage. In this study, we investigated the management and late outcome of operation for mitral regurgitation (MR) due to ruptured chordae tendineae in patients with HCM. We analyzed 49 consecutive patients with HCM and MR due to ruptured mitral valve chordae. Echocardiograms and operative reports were reviewed to classify valve anatomy and surgical methods. Information on late outcomes was obtained from electronic medical records and follow-up surveys. The mean age of the 36 men and 13 women was 61.9 ± 12.5 years; significant resting or provoked LVOT obstruction was present at the time of surgery in 46 patients. During the index operation, mitral valve repair was performed in 45 patients, and prosthetic replacement was necessary for 4 patients. Concomitant septal myectomy was performed in 46 patients. There were no hospital deaths or deaths within 30 days of operation. Five and ten-year survival estimates (Kaplan-Meier) were 92% and 71%. During follow-up at a median of 7.9 years, 3 patients underwent reoperation for MV replacement, 5 days, 3 years, and 14 years following valve repair. Ruptured mitral chordae may result in severe mitral valve regurgitation in patients with hypertrophic cardiomyopathy. Valvuloplasty at the time of septal myectomy is safe with an acceptably low rate of recurrent MR requiring prosthetic replacement.

Effect of Shared Decision-Making for Stroke Prevention on Treatment Adherence and Safety Outcomes in Patients With Atrial Fibrillation: A Randomized Clinical Trial

Background Guidelines promote shared decision-making (SDM) for anticoagulation in patients with atrial fibrillation. We recently showed that adding a within-encounter SDM tool to usual care (UC) increases patient involvement in decision-making and clinician satisfaction, without affecting encounter length. We aimed to estimate the extent to which use of an SDM tool changed adherence to the decided care plan and clinical safety end points. Methods and Results We conducted a multicenter, encounter-level, randomized trial assessing the efficacy of UC with versus without an SDM conversation tool for use during the clinical encounter (Anticoagulation Choice) in patients with nonvalvular atrial fibrillation considering starting or reviewing anticoagulation treatment. We conducted a chart and pharmacy review, blinded to randomization status, at 10 months after enrollment to assess primary adherence (proportion of patients who were prescribed an anticoagulant who filled their first prescription) and secondary adherence (estimated using the proportion of days for which treatment was supplied and filled for direct oral anticoagulant, and as time in therapeutic range for warfarin). We also noted any strokes, transient ischemic attacks, major bleeding, or deaths as safety end points. We enrolled 922 evaluable patient encounters (Anticoagulation Choice=463, and UC=459), of which 814 (88%) had pharmacy and clinical follow-up. We found no differences between arms in either primary adherence (78% of patients in the SDM arm filled their first prescription versus 81% in UC arm) or secondary adherence to anticoagulation (percentage days covered of the direct oral anticoagulant was 74.1% in SDM versus 71.6% in UC; time in therapeutic range for warfarin was 66.6% in SDM versus 64.4% in UC). Safety outcomes, mostly bleeds, occurred in 13% of participants in the SDM arm and 14% in the UC arm. Conclusions In this large, randomized trial comparing UC with a tool to promote SDM against UC alone, we found no significant differences between arms in primary or secondary adherence to anticoagulation or in clinical safety outcomes. Registration URL: https://www.clinicaltrials.gov; Unique identifier: clinicaltrials.gov. Identifier: NCT02905032.

Mitral Annular Calcification in Obstructive Hypertrophic Cardiomyopathy: Prevalence and Outcomes

BACKGROUND

The prevalence and clinical impact of mitral annular calcification (MAC) in patients with obstructive hypertrophic cardiomyopathy (HCM) are largely unknown.

METHODS

We reviewed 2113 HCM patients who underwent septal myectomy from January 2000 to April 2016. Preoperative and intraoperative echocardiograms along with operative notes were reviewed to identify MAC. Survival was estimated and compared using Kaplan-Meier analysis and log-rank test. Cox regression analysis was used to identify factors independently associated with mortality.

RESULTS

MAC was identified in 390 (18.5%) patients. Older age, female sex, and presence of mitral valve leaflet calcification were strongly associated with higher odds of having MAC. Patients with MAC had higher resting LVOT gradients, more likely to have worse mitral valve regurgitation (MR) preoperatively, and more likely to undergo a concomitant mitral valve replacement (6% vs 1%, P<0.001) compared to those without MAC. Postoperatively, patients with MAC had marginally higher residual MR (13% vs 8%). After a median follow-up of 6.95 (IQR 3.7- 12.1) years, survival of patients with MAC at 1, 5 and 10 years was 99%, 92% and 69% respectively. Adjusted analysis identified MAC as an independent predictor of poor survival (HR 1.46, 95% CI 1.08 to 1.97; P=.014).

CONCLUSIONS

MAC is a frequent finding in older patients with obstructive HCM, more likely to be seen in females, and is associated with higher rates of concomitant mitral valve replacement. Despite higher prevalence of comorbidities, MAC remained an independent predictor for overall mortality following septal myectomy.

The Role of Rho GTPases During Fibroblast Spreading, Migration, and Myofibroblast Differentiation in 3D Synthetic Fibrous Matrices

Introduction

Connective tissue repair and mechanosensing are tightly entwined in vivo and occur within a complex three-dimensional (3D), fibrous extracellular matrix (ECM). Typically driven by activated fibroblasts, wound repair involves well-defined steps of cell spreading, migration, proliferation, and fibrous ECM deposition. While the role of Rho GTPases in regulating these processes has been explored extensively in two-dimensional cell culture models, much less is known about their role in more physiologic, 3D environments.

Methods

We employed a 3D, fibrous and protease-sensitive hydrogel model of interstitial ECM to study the interplay between Rho GTPases and fibrous matrix cues in fibroblasts during wound healing.

Results

Modulating fiber density within protease-sensitive hydrogels, we confirmed previous findings that heightened fiber density promotes fibroblast spreading and proliferation. The presence of matrix fibers furthermore corresponded to increased cell migration speeds and macroscopic hydrogel contraction arising from fibroblast generated forces. During fibroblast spreading, Rac1 and RhoA GTPase activity proved crucial for fiber-mediated cell spreading and contact guidance along matrix fibers, while Cdc42 was dispensable. In contrast, interplay between RhoA, Rac1, and Cdc42 contributed to fiber-mediated myofibroblast differentiation and matrix contraction over longer time scales.

Conclusion

These observations may provide insights into tissue repair processes in vivo and motivate the incorporation of cell-adhesive fibers within synthetic hydrogels for material-guided wound repair strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-021-00698-5.

Artificial Intelligence-Augmented Electrocardiogram Detection of Left Ventricular Systolic Dysfunction in the General Population

OBJECTIVE

To validate an artificial intelligence-augmented electrocardiogram (AI-ECG) algorithm for the detection of preclinical left ventricular systolic dysfunction (LVSD) in a large community-based cohort.

METHODS

We identified a randomly selected community-based cohort of 2041 subjects age 45 years or older in Olmsted County, Minnesota. All participants underwent a study echocardiogram and ECG. We first assessed the performance of the AI-ECG to identify LVSD (ejection fraction ≤40%). After excluding participants with clinical heart failure, we further assessed the AI-ECG to detect preclinical LVSD among all patients (n=1996) and in a high-risk subgroup (n=1348). Next we modelled an imputed screening program for preclinical LVSD detection where a positive AI-ECG triggered an echocardiogram. Finally, we assessed the ability of the AI-ECG to predict future LVSD. Participants were enrolled between January 1, 1997, and September 30, 2000; and LVSD surveillance was performed for 10 years after enrollment.

RESULTS

For detection of LVSD in the total population (prevalence, 2.0%), the area under the receiver operating curve for AI-ECG was 0.97 (sensitivity, 90%; specificity, 92%); in the high-risk subgroup (prevalence 2.7%), the area under the curve was 0.97 (sensitivity, 92%; specificity, 93%). In an imputed screening program, identification of one preclinical LSVD case would require 88.3 AI-ECGs and 8.7 echocardiograms in the total population and 65.7 AI-ECGs and 5.5 echocardiograms in the high-risk subgroup. The unadjusted hazard ratio for a positive AI-ECG for incident LVSD over 10 years was 2.31 (95% CI, 1.32 to 4.05; P=.004).

CONCLUSION

Artificial intelligence-augmented ECG can identify preclinical LVSD in the community and warrants further study as a screening tool for preclinical LVSD.

Effectiveness of a Weight Loss Program Using Digital Health in Adolescents and Preadolescents

Objective: To identify an efficacious intervention on treating adolescents with overweight and obesity, this might result in health benefits. Methods: Adolescents with overweight or obesity aged 10-17 years with BMI percentile ≥85th were included in this historical observational analysis. Subjects used an entirely remote weight loss program combining mobile applications, frequent self-weighing, and calorie restriction with meal replacement. Body weight changes were evaluated at 42, 60, 90, and 120 days using different metrics including absolute body weight, BMI, and BMI z-score. Chi-square or Fisher exact tests (categorical variables) and Student's t-test (continuous variables) were used to compare subjects. Results: In total, 2,825 participants, mean age 14.4 ± 2.2 years, (54.8% girls), were included from October 27, 2016, to December 31, 2017, in mainland China; 1355 (48.0%) had a baseline BMI percentile ≥97th. Mean BMI and BMI z-score were 29.20 ± 4.44 kg/m² and 1.89 ± 0.42, respectively. At day 120, mean reduction in body weight, BMI, and BMI z-score was 8.6 ± 0.63 kg, 3.13 ± 0.21 kg/m², and 0.42 ± 0.03; 71.4% had lost ≥5% body weight, 69.4% of boys and 73.2% of girls, respectively. Compared with boys, girls achieved greater reduction on BMI z-score at all intervals (p < 0.004 for all comparisons). Higher BMI percentile at baseline and increased frequency of use of the mobile application were directly associated with more significant weight loss. Conclusions: An entirely remote digital weight loss program is effective in facilitating weight loss in adolescents with overweight or obesity in the short term and mid term.

Myocardial Histopathology in Patients With Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by multiple pathological features including myocyte hypertrophy, myocyte disarray, and interstitial fibrosis.

OBJECTIVES

This study sought to correlate myocardial histopathology with clinical characteristics of patients with obstructive HCM and post-operative outcomes following septal myectomy.

METHODS

The authors reviewed the pathological findings of the myocardial specimens from 1,836 patients with obstructive HCM who underwent septal myectomy from 2000 to 2016. Myocyte hypertrophy, myocyte disarray, interstitial fibrosis, and endocardial thickening were graded and analyzed.

RESULTS

The median age at operation was 54.2 years (43.5 to 64.3 years), and 1,067 (58.1%) were men. A weak negative correlation between myocyte disarray and age at surgery was identified (ρ = -0.22; p < 0.001). Myocyte hypertrophy (p < 0.001), myocyte disarray (p < 0.001), and interstitial fibrosis (p < 0.001) were positively associated with implantable cardioverter-defibrillator implantation. Interstitial fibrosis (p < 0.001) and endocardial thickening (p < 0.001) were associated with atrial fibrillation pre-operatively. In the Cox survival model, older age (p < 0.001), lower degree of myocyte hypertrophy (severe vs. mild hazard ratio: 0.41; 95% confidence interval: 0.19 to 0.86; p = 0.040), and lower degree of endocardial thickening (moderate vs. mild hazard ratio: 0.75; 95% confidence interval: 0.58 to 0.97; p = 0.019) were independently associated with worse post-myectomy survival. Among 256 patients who had genotype analysis, patients with pathogenic or likely pathogenic variants (n = 62) had a greater degree of myocyte disarray (42% vs. 15% vs. 20%; p = 0.022). Notably, 13 patients with pathogenic or likely pathogenic genetic variants of HCM had no myocyte disarray.

CONCLUSIONS

Histopathology was associated with clinical manifestations including the age of disease onset and arrhythmias. Myocyte hypertrophy and endocardial thickening were negatively associated with post-myectomy mortality.

A cryogenic continuously rotating half-wave plate mechanism for the POLARBEAR-2b cosmic microwave background receiver

We present the design and laboratory evaluation of a cryogenic continuously rotating half-wave plate (CHWP) for the POLARBEAR-2b (PB-2b) cosmic microwave background receiver, the second installment of the Simons Array. PB-2b will observe at 5200 m elevation in the Atacama Desert of Chile in two frequency bands centered at 90 GHz and 150 GHz. In order to suppress atmospheric 1/f noise and mitigate systematic effects that arise when differencing orthogonal detectors, PB-2b modulates linear sky polarization using a CHWP rotating at 2 Hz. The CHWP has a 440 mm clear aperture diameter and is cooled to ≈50 K in the PB-2b receiver cryostat. It consists of a low-friction superconducting magnetic bearing and a low-torque synchronous electromagnetic motor, which together dissipate <2 W. During cooldown, a grip-and-release mechanism centers the rotor to <0.5 mm, and during continuous rotation, an incremental optical encoder measures the rotor angle with a noise level of 0.1 μrad/Hz. We discuss the experimental requirements for the PB-2b CHWP, the designs of its various subsystems, and the results of its evaluation in the laboratory. The presented CHWP has been deployed to Chile and is expected to see first light on PB-2b in 2020 or 2021.

Assessment of Shared Decision-making for Stroke Prevention in Patients With Atrial Fibrillation: A Randomized Clinical Trial

IMPORTANCE

Shared decision-making (SDM) about anticoagulant treatment in patients with atrial fibrillation (AF) is widely recommended but its effectiveness is unclear.

OBJECTIVE

To assess the extent to which the use of an SDM tool affects the quality of SDM and anticoagulant treatment decisions in at-risk patients with AF.

DESIGN, SETTING, AND PARTICIPANTS

This encounter-randomized trial recruited patients with nonvalvular AF who were considering starting or reviewing anticoagulant treatment and their clinicians at academic, community, and safety-net medical centers between January 30, 2017 and June 27, 2019. Encounters were randomized to either the standard care arm or care that included the use of an SDM tool (intervention arm). Data were analyzed from August 1 to November 30, 2019.

INTERVENTIONS

Standard care or care using the Anticoagulation Choice Shared Decision Making tool (which presents individualized risk estimates and compares anticoagulant treatment options across issues of importance to patients) during the clinical encounter.

MAIN OUTCOMES AND MEASURES

Quality of SDM (which included quality of communication, patient knowledge about AF and anticoagulant treatment, accuracy of patient estimates of their own stroke risk [within 30% of their estimate], decisional conflict, and satisfaction), decisions made during the encounter, duration of the encounter, and clinician involvement of patients in the SDM process.

RESULTS

The clinical trial enrolled 922 patients (559 men [60.6%]; mean [SD] age, 71 [11] years) and 244 clinicians. A total of 463 patients were randomized to the intervention arm and 459 patients to the standard care arm. Participants in both arms reported high communication quality, high knowledge, and low decisional conflict, demonstrated low accuracy in their risk perception, and would similarly recommend the approach used in their encounter. Clinicians were significantly more satisfied after intervention encounters (400 of 453 encounters [88.3%] vs 277 of 448 encounters [61.8%]; adjusted relative risk, 1.49; 95% CI, 1.42-1.53). A total of 747 of 873 patients (85.6%) chose to start or continue receiving an anticoagulant medication. Patient involvement in decision-making (as assessed through video recordings of the encounters using the Observing Patient Involvement in Decision Making 12-item scale) scores were significantly higher in the intervention arm (mean [SD] score, 33.0 [10.8] points vs 29.1 [13.1] points, respectively; adjusted mean difference, 4.2 points; 95% CI, 2.8-5.6 points). No significant between-arm difference was found in encounter duration (mean [SD] duration, 32 [16] minutes in the intervention arm vs 31 [17] minutes in the standard care arm; adjusted mean between-arm difference, 1.1; 95% CI, -0.3 to 2.5 minutes).

CONCLUSION AND RELEVANCE

The use of an SDM encounter tool improved several measures of SDM quality and clinician satisfaction, with no significant effect on treatment decisions or encounter duration. These results help to calibrate expectations about the value of implementing SDM tools in the care of patients with AF.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02905032.

Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment

Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.

Broadband, millimeter-wave antireflection coatings for large-format, cryogenic aluminum oxide optics

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

Detection of CMB-Cluster Lensing using Polarization Data from SPTpol

We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500  deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

The POLARBEAR Fourier transform spectrometer calibrator and spectroscopic characterization of the POLARBEAR instrument

We describe the Fourier Transform Spectrometer (FTS) used for in-field testing of the POLARBEAR receiver, an experiment located in the Atacama Desert of Chile which measures the cosmic microwave background (CMB) polarization. The POLARBEAR-FTS (PB-FTS) is a Martin-Puplett interferometer designed to couple to the Huan Tran Telescope (HTT) on which the POLARBEAR receiver is installed. The PB-FTS measured the spectral response of the POLARBEAR receiver with signal-to-noise ratio >20 for ∼69% of the focal plane detectors due to three features: a high throughput of 15.1 sr cm², optimized optical coupling to the POLARBEAR optics using a custom designed output parabolic mirror, and a continuously modulated output polarizer. The PB-FTS parabolic mirror is designed to mimic the shape of the 2.5 m-diameter HTT primary reflector, which allows for optimum optical coupling to the POLARBEAR receiver, reducing aberrations and systematics. One polarizing grid is placed at the output of the PB-FTS and modulated via continuous rotation. This modulation allows for decomposition of the signal into different harmonics that can be used to probe potentially pernicious sources of systematic error in a polarization-sensitive instrument. The high throughput and continuous output polarizer modulation features are unique compared to other FTS calibrators used in the CMB field. In-field characterization of the POLARBEAR receiver was accomplished using the PB-FTS in April 2014. We discuss the design, construction, and operation of the PB-FTS and present the spectral characterization of the POLARBEAR receiver. We introduce future applications for the PB-FTS in the next-generation CMB experiment, the Simons Array.

Effects of Organized Colorectal Cancer Screening on Cancer Incidence and Mortality in a Large Community-Based Population

BACKGROUND & AIMS

Little information is available on the effectiveness of organized colorectal cancer (CRC) screening on screening uptake, incidence, and mortality in community-based populations.

METHODS

We contrasted screening rates, age-adjusted annual CRC incidence, and incidence-based mortality rates before (baseline year 2000) and after (through 2015) implementation of organized screening outreach, from 2007 through 2008 (primarily annual fecal immunochemical testing and colonoscopy), in a large community-based population. Among screening-eligible individuals 51-75 years old, we calculated annual up-to-date status for cancer screening (by fecal test, sigmoidoscopy, or colonoscopy), CRC incidence, cancer stage distributions, and incidence-based mortality.

RESULTS

Initiation of organized CRC screening significantly increased the up-to-date status of screening, from 38.9% in 2000 to 82.7% in 2015 (P < .01). Higher rates of screening were associated with a 25.5% reduction in annual CRC incidence between 2000 and 2015, from 95.8 to 71.4 cases/100,000 (P < .01), and a 52.4% reduction in cancer mortality, from 30.9 to 14.7 deaths/100,000 (P < .01). Increased screening was initially associated with increased CRC incidence, due largely to greater detection of early-stage cancers, followed by decreases in cancer incidence. Advanced-stage CRC incidence rates decreased 36.2%, from 45.9 to 29.3 cases/100,000 (P < .01), and early-stage CRC incidence rates decreased 14.5%, from 48.2 to 41.2 cases/100,000 (P < .04).

CONCLUSIONS

Implementing an organized CRC screening program in a large community-based population rapidly increased screening participation to the ≥80% target set by national organizations. Screening rates were sustainable and associated with substantial decreases in CRC incidence and mortality within short time intervals, consistent with early detection and cancer prevention.

Colorectal Cancer Screening Participation Among Asian Americans Overall and Subgroups in an Integrated Health Care Setting with Organized Screening

Background

Screening reduces colorectal cancer deaths, but <50% of Asian Americans are screening up-to-date according to surveys, with variability across Asian subgroups. We examined colorectal cancer screening participation among Asian Americans overall and Asian subgroups in a large integrated health care system with organized screening.

Methods

Data were electronically accessed to characterize screening in 2016 for Asians overall and subgroups relative to the National Colorectal Cancer Roundtable target of ≥80% screening and compared with non-Hispanic whites. Screening up-to-date was defined as a colonoscopy with 10 years, a sigmoidoscopy within 5 years, or a fecal immunochemical test (FIT) completed in 2016.

Results

Among 436,398 patients, 69,826 (16.0%) were Asian, of whom 79.8% were screening up-to-date vs. 77.6% of non-Hispanic whites (p < 0.001). Almost all subgroups met the 80% target: Chinese (83.3%), Vietnamese (82.4%), Korean (82.1%), other Asian (80.3%), Filipino (78.7%), Asian Indian (79.6%), and Japanese (79.0%). Among Asians overall and non-Hispanic whites, 50.6% and 48.4% of members were up-to-date with screening by colonoscopy, and 28.0% and 28.2% were up-to-date by FIT, respectively. Across Asian subgroups, colonoscopy most frequently accounting for being screening up-to-date (range: 47.4–59.7%), followed by FIT (range: 21.6–31.5%).

Conclusions

In an organized screening setting, there were minimal differences in screening participation among Asian subgroups and almost all met the 80% screening target, despite differences in language preference. Screening test type differences across subgroups suggest possible preferences in screening modality, which can inform future research into tailored education or outreach.

Abstract P2-07-09: Integrative analysis of miRNA and mRNA expression in metastatic versus non-metastatic triple negative breast cancer

Background: Triple Negative Breast Cancer (TNBC) is a subset of breast cancer that is difficult to treat clinically and is characterized by being estrogen receptor (ER) negative, progesterone receptor (PR) negative, and does not overexpress human epidermal growth factor receptor 2 (HER2). Patients with TNBC tend to have a worse prognosis than other breast cancer subtypes.

Methods: We obtained fifteen TNBC sample FFPE tissue blocks with corresponding plasma samples. All samples were from primary tumors; seven samples having metastasized, four samples that had not metastasized and four samples with unknown metastatic status. The total RNA was isolated from FFPE blocks using the RecoverAll Total Nucleic Acid Isolation Protocol. miRNA from plasma was isolated using Ambion's mirVANA kit. The plasma and tissue miRNAs were evaluated using the QuantStudio qPCR platform, capturing ˜750 miRNAs. The mRNA was processed using the TruSeq RNA Access kit and sequenced on the Illumina NextSeq platform. Analysis of the miRNA and mRNA individually was performed using limma and DESeq2 packages, respectively. Gene enrichment analysis of the mRNA expression was done using the GAGE package on KEGG pathways while the integrative analysis was done with sparse Canonical Correlation Analysis (sCCA) using the PMA pacakge.

Results: Analysis of plasma miRNA had four miRNAs with a significant difference in raw p-value (p &lt; 0.05) between metastatic and non-metastatic TNBC; miRNA 708, 483-3p, 518f, and 766; in the tissue there were fifteen miRNA with p &lt; 0.05, with one miR-872 still having significance after adjusting for multiple testing. mRNA had 33 genes being significant after multiple testing correction with several immune KEGG pathways being downregulated in metastatic samples (adjusted p &lt; 0.05). The integrative analysis revealed five microRNA (miR-216, miR-127, miR-370, miR-382, and miR-487b) and 312 gene modules enriched in integrin (Fisher p &lt; 10^-5) and extracellular matrix (Fisher p &lt; 10^-6) signaling.

Conclusions: One of the circulating plasma miRNAs, miR483-3p, has been found to promote tumorigenesis, while miR581f and miR766 have not been reported in cancer to date. Further investigation into these miRNA could provide a feasible biomarker. The downregulation of immune pathways observed within the metastatic TNBC subjects implies immune evasion is of particular importance for metastasis and a targeted immunotherapy may be a viable treatment option. The integrative analysis of the miRNA and mRNA showed an enrichment in pathways previously linked to increased proliferation and chemoresistance, with an increased signal compared to either miRNA or mRNA alone.

Citation Format: Shih AJ, Korsunsky I, Guttadauria B, Bhuiya T, Liew A, Khalili H, Gregersen PK, Lee AT. Integrative analysis of miRNA and mRNA expression in metastatic versus non-metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-07-09.

Association Between Time to Colonoscopy After a Positive Fecal Test Result and Risk of Colorectal Cancer and Cancer Stage at Diagnosis

IMPORTANCE

The fecal immunochemical test (FIT) is commonly used for colorectal cancer screening and positive test results require follow-up colonoscopy. However, follow-up intervals vary, which may result in neoplastic progression.

OBJECTIVE

To evaluate time to colonoscopy after a positive FIT result and its association with risk of colorectal cancer and advanced-stage disease at diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study (January 1, 2010-December 31, 2014) within Kaiser Permanente Northern and Southern California. Participants were 70 124 patients aged 50 through 70 years eligible for colorectal cancer screening with a positive FIT result who had a follow-up colonoscopy.

EXPOSURES

Time (days) to colonoscopy after a positive FIT result.

MAIN OUTCOMES AND MEASURES

Risk of any colorectal cancer and advanced-stage disease (defined as stage III and IV cancer). Odds ratios (ORs) and 95% CIs were adjusted for patient demographics and baseline risk factors.

RESULTS

Of the 70 124 patients with positive FIT results (median age, 61 years [IQR, 55-67 years]; men, 52.7%), there were 2191 cases of any colorectal cancer and 601 cases of advanced-stage disease diagnosed. Compared with colonoscopy follow-up within 8 to 30 days (n = 27 176), there were no significant differences between follow-up at 2 months (n = 24 644), 3 months (n = 8666), 4 to 6 months (n = 5251), or 7 to 9 months (n = 1335) for risk of any colorectal cancer (cases per 1000 patients: 8-30 days, 30; 2 months, 28; 3 months, 31; 4-6 months, 31; and 7-9 months, 43) or advanced-stage disease (cases per 1000 patients: 8-30 days, 8; 2 months, 7; 3 months, 7; 4-6 months, 9; and 7-9 months, 13). Risks were significantly higher for examinations at 10 to 12 months (n = 748) for any colorectal cancer (OR, 1.48 [95% CI, 1.05-2.08]; 49 cases per 1000 patients) and advanced-stage disease (OR, 1.97 [95% CI, 1.14-3.42]; 19 cases per 1000 patients) and more than 12 months (n = 747) for any colorectal cancer (OR, 2.25 [95% CI, 1.89-2.68]; 76 cases per 1000 patients) and advanced-stage disease (OR, 3.22 [95% CI, 2.44-4.25]; 31 cases per 1000 patients).

CONCLUSIONS AND RELEVANCE

Among patients with a positive fecal immunochemical test result, compared with follow-up colonoscopy at 8 to 30 days, follow-up after 10 months was associated with a higher risk of colorectal cancer and more advanced-stage disease at the time of diagnosis. Further research is needed to assess whether this relationship is causal.

Fecal Immunochemical Test Program Performance Over 4 Rounds of Annual Screening: A Retrospective Cohort Study

BACKGROUND

The fecal immunochemical test (FIT) is a common method for colorectal cancer (CRC) screening, yet its acceptability and performance over several rounds of annual testing are largely unknown.

OBJECTIVE

To assess FIT performance characteristics over 4 rounds of annual screening.

DESIGN

Retrospective cohort study.

SETTING

Kaiser Permanente Northern and Southern California.

PATIENTS

323 349 health plan members aged 50 to 70 years on their FIT mailing date in 2007 or 2008 who completed the first round of FIT and were followed for up to 4 screening rounds.

MEASUREMENTS

Screening participation, FIT positivity (≥20 µg of hemoglobin/g), positive predictive values for adenoma and CRC, and FIT sensitivity for detecting CRC obtained from Kaiser Permanente electronic databases and cancer registries.

RESULTS

Of the patients invited for screening, 48.2% participated in round 1. Of those who remained eligible, 75.3% to 86.1% participated in subsequent rounds. Median follow-up was 4.0 years, and 32% of round 1 participants crossed over to endoscopy over 4 screening rounds-7.0% due to a positive FIT result. The FIT positivity rate (5.0%) and positive predictive values (adenoma, 51.5%; CRC, 3.4%) were highest in round 1. Overall, programmatic FIT screening detected 80.4% of patients with CRC diagnosed within 1 year of testing, including 84.5% in round 1 and 73.4% to 78.0% in subsequent rounds.

LIMITATION

Screening detection, rather than long-term cancer prevention, was evaluated.

CONCLUSION

Annual FIT screening was associated with high sensitivity for CRC, with high adherence to annual follow-up screening among initial participants. The findings indicate that annual programmatic FIT screening is feasible and effective for population-level CRC screening.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

Detection of B-mode polarization in the cosmic microwave background with data from the South Pole Telescope

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

Invited article: millimeter-wave bolometer array receiver for the Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument

The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the Sunyaev-Zel'dovich effect from the 12 m APEX telescope on the Atacama plateau in Chile. The receiver contains a focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with a frequency-domain multiplexed readout system. The bolometers are cooled to 280 mK via a three-stage helium sorption refrigerator and a mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, and a horn array couple the TES bolometers to the telescope. APEX-SZ observes in a single frequency band at 150 GHz with 1' angular resolution and a 22' field-of-view, all well suited for cluster mapping. The APEX-SZ receiver has played a key role in the introduction of several new technologies including TES bolometers, the frequency-domain multiplexed readout, and the use of a pulse-tube cooler with bolometers. As a result of these new technologies, the instrument has a higher instantaneous sensitivity and covers a larger field-of-view than earlier generations of Sunyaev-Zel'dovich instruments. The TES bolometers have a median sensitivity of 890 μK(CMB)√s (NEy of 3.5 × 10(-4) √s). We have also demonstrated upgraded detectors with improved sensitivity of 530 μK(CMB)√s (NEy of 2.2 × 10(-4) √s). Since its commissioning in April 2007, APEX-SZ has been used to map 48 clusters. We describe the design of the receiver and its performance when installed on the APEX telescope.

Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Objectives

The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis.

Methods

The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent.

Results

None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects.

Conclusions

Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.

European population substructure correlates with systemic lupus erythematosus endophenotypes in North Americans of European descent

Previous work has demonstrated that Northern and Southern European ancestries are associated with specific systemic lupus erythematosus (SLE) manifestations. In this study, 1855 SLE cases of European descent were genotyped for 4965 single-nucleotide polymorphisms and principal components analysis of genotype information was used to define population substructure. The first principal component (PC1) distinguished Northern from Southern European ancestry, PC2 differentiated Eastern from Western European ancestry and PC3 delineated Ashkenazi Jewish ancestry. Compared with Northern European ancestry, Southern European ancestry was associated with autoantibody production (odds ratio (OR)=1.40, 95% confidence interval (CI) 1.07-1.83) and renal involvement (OR 1.41, 95% CI 1.06-1.87), and was protective for discoid rash (OR=0.51, 95% CI 0.32-0.82) and photosensitivity (OR=0.74, 95% CI 0.56-0.97). Both serositis (OR=1.46, 95% CI 1.12-1.89) and autoantibody production (OR=1.38, 95% CI 1.06-1.80) were associated with Western compared to Eastern European ancestry. Ashkenazi Jewish ancestry was protective against neurologic manifestations of SLE (OR=0.62, 95% CI 0.40-0.94). Homogeneous clusters of cases defined by multiple PCs demonstrated stronger phenotypic associations. Genetic ancestry may contribute to the development of SLE endophenotypes and should be accounted for in genetic studies of disease characteristics.

Linearized superconducting quantum interference device array for high bandwidth frequency-domain readout multiplexing

We have designed and demonstrated a superconducting quantum interference device (SQUID) array linearized with cryogenic feedback. To achieve the necessary loop gain, a 300-element series array SQUID is constructed from three monolithic 100-element series arrays. A feedback resistor completes the loop from the SQUID output to the input coil. The short feedback path of this linearized SQUID array (LISA) allows for a substantially larger flux-locked loop bandwidth as compared to a SQUID flux-locked loop that includes a room temperature amplifier. The bandwidth, linearity, noise performance, and 3 Phi(0) dynamic range of the LISA are sufficient for its use in our target application: the multiplexed readout of transition-edge sensor bolometers.

A novel dephosphorylation-activated conductance in a mouse renal collecting duct cell line

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited renal diseases. It is associated with the progressive development of renal tubular cysts, which may subsequently lead to renal failure. Studies into the genetic basis of ADPKD have identified two genes, PKD1 and PKD2, that are mutated in ADPKD patients. The PKD1 and PKD2 genes encode for two different proteins, TRPP1 and TRPP2. Previous studies have demonstrated the presence of both TRPP1 and TRPP2 in the renal collecting duct cell line M8. The aim of the following study was to investigate the functional properties of cation currents in these cells and to examine the effect of overexpression of TRPP1 using a transgenic cell model (M7). In M8 cells, initial whole cell currents were low. However, over time there was activation of a flow-sensitive current, which was inhibited by gadolinium (I(Gd)). The I(Gd) was more selective for cations over anions, but did not discriminate between monovalent cations and was Ca2+ permeable. Activation of I(Gd) was dependent on the presence of Ca2+ and also required dephosphorylation. The protein phosphatase 2A inhibitor okadaic acid prevented activation of I(Gd), suggesting that protein phosphatase 2A plays an important role in channel activation. The properties and magnitude of I(Gd) were unaffected in M7 cells, suggesting that overexpression of TRPP1 was without effect. I(Gd) was selectively inhibited by an antibody raised against the C-terminus of TRPP2. However, its selectivity profile was different to TRPP2, suggesting that it is attributable to a TRPP2-like channel or a TRPP2-containing heteromeric channel. In conclusion, these data describe the functional identification of a novel dephosphorylation- and flow-activated TRPP2-related channel in mouse collecting duct cells.

South Pole Telescope optics

The South Pole Telescope is a 10 m diameter, wide-field, offset Gregorian telescope with a 966-pixel, millimeter-wave, bolometer array receiver. The telescope has an unusual optical system with a cold stop around the secondary. The design emphasizes low scattering and low background loading. All the optical components except the primary are cold, and the entire beam from prime focus to the detectors is surrounded by cold absorber.

An inward-facing conformation of a putative metal-chelate-type ABC transporter

The crystal structure of a putative metal-chelate-type adenosine triphosphate (ATP)-binding cassette (ABC) transporter encoded by genes HI1470 and HI1471 of Haemophilus influenzae has been solved at 2.4 angstrom resolution. The permeation pathway exhibits an inward-facing conformation, in contrast to the outward-facing state previously observed for the homologous vitamin B12 importer BtuCD. Although the structures of both HI1470/1 and BtuCD have been solved in nucleotide-free states, the pairs of ABC subunits in these two structures differ by a translational shift in the plane of the membrane that coincides with a repositioning of the membrane-spanning subunits. The differences observed between these ABC transporters involve relatively modest rearrangements and may serve as structural models for inward- and outward-facing conformations relevant to the alternating access mechanism of substrate translocation.

The PTPN22 R620W polymorphism associates with RF positive rheumatoid arthritis in a dose-dependent manner but not with HLA-SE status

We have recently described the association between rheumatoid arthritis and a coding single-nucleotide polymorphism in the intracellular protein tyrosine phosphatase, PTPN22. The disease-associated polymorphism, 1858 C/T (rs2476601), encodes an amino-acid change (R620W) in one of four SH3 domain binding sites in the PTPN22 molecule. We have now extended our initial studies to address three questions: (1) Is the association with rheumatoid arthritis limited to rheumatoid factor (RF) positive disease? (2) Does homozygosity for PTPN22 R620W substantially increase disease susceptibility? (3) Is there an interaction between PTPN22 and the rheumatoid arthritis (RA)-associated HLA-DRB1 shared epitope alleles? A total of 1413 Caucasian rheumatoid arthritis patients and 1401 Caucasian controls were genotyped. The results support the view that PTPN22 was strongly and preferentially associated with RF positive disease (OR=1.75, 95% CI 1.46-2.10, P=1.3 x 10(-9)). The PTPN22 risk allele was not significantly associated with RF negative disease (OR=1.19, 95% CI 0.92-1.53, P=0.18), although a very weak association cannot be completely excluded. There was a strong dose effect on disease risk; two copies of the PTPN22 R620W allele more than doubles the risk for RF positive RA (OR=4.57, 95% CI 2.35-8.89). There was no evidence of a genetic association between PTPN22 and HLA susceptibility alleles.

Estimate of the cosmological bispectrum from the MAXIMA-1 cosmic microwave background map

We use the measurement of the cosmic microwave background taken during the MAXIMA-1 flight to estimate the bispectrum of cosmological perturbations. We propose an estimator for the bispectrum that is appropriate in the flat sky approximation, apply it to the MAXIMA-1 data, and evaluate errors using bootstrap methods. We compare the estimated value with what would be expected if the sky signal were Gaussian and find that it is indeed consistent, with a chi(2) per degree of freedom of approximately unity. This measurement places constraints on models of inflation.

Tests for Gaussianity of the MAXIMA-1 cosmic microwave background map

Gaussianity of the cosmological perturbations is one of the key predictions of standard inflation, but it is violated by other models of structure formation such as cosmic defects. We present the first test of the Gaussianity of the cosmic microwave background (CMB) on subdegree angular scales, where deviations from Gaussianity are most likely to occur. We apply the methods of moments, cumulants, the Kolmogorov test, the chi(2) test, and Minkowski functionals in eigen, real, Wiener-filtered, and signal-whitened spaces, to the MAXIMA-1 CMB anisotropy data. We find that the data, which probe angular scales between 10 arcmin and 5 deg, are consistent with Gaussianity. These results show consistency with the standard inflation and place constraints on the existence of cosmic defects.

Model for excess noise in voltage-biased superconducting bolometers

We are developing superconducting transition-edge bolometers for far-infrared and millimeter wavelengths. The bolometers described here are suspended by thin legs of silicon nitride for thermal isolation. At frequencies between 200 mHz and 10-50 Hz these devices show white noise at their thermal fluctuation limit (NEP approximately 10(-17) W/ radicalHz). At higher frequencies a broad peak appears in the noise spectrum, which we attribute to a combination of thermal fluctuations in complex thermal circuits and electrothermal feedback. Detailed noise calculations fit the noise measured in three different devices that were specifically designed to test the model. We discuss how changes in bolometer materials can shift the noise peak above the frequency range of interest for most applications.

Cosmology from MAXIMA-1, BOOMERANG, and COBE DMR cosmic microwave background observations

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis of the combined data yields 68% (95%) confidence limits on the total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), the baryon density, Omega(b)h(2) approximately 0.032(+0.005)(-0.004) (+0.009)(-0.008), and the scalar spectral tilt, n(s) approximately 1.01(+0.09)(-0.07) (+0.17)(-0.14). These data are consistent with inflationary initial conditions for structure formation. Taken together with other cosmological observations, they imply the existence of both nonbaryonic dark matter and dark energy in the Universe.

Clinical studies of angiogenesis inhibitors: the University of Texas MD Anderson Center Trial of Human Endostatin

Most solid-tumor malignancies remain incurable. Novel agents that target and counteract biologic mechanisms are now being developed. It is hoped that these drugs will allow for more effective, less toxic cancer treatments and long-term maintenance approaches. One important class of agents functions by an anti-angiogenic mechanism, targeting the blood vessel supply of the tumor and inhibiting tumor growth. Several principles are common to these new agents. First, because many of these agents are growth-inhibiting molecules that work exclusively against the tumor vasculature, single agents will have little effect on tumor size in advanced disease. Second, because these agents are relatively non-toxic, they are unlikely to induce the side effects associated with chemotherapy. Because endothelial cells seldom divide in a human host, anti-angiogenic compounds are expected to produce little toxicity. Third, most of these agents work synergistically with chemotherapy and/or radiotherapy. Ironically, combining these relatively non-toxic agents with chemotherapy often produces the toxicities usually associated with anticancer regimens. Anti-angiogenic agents might ultimately be studied in minimal disease. Clinical studies must demonstrate that these agents affect tumor vasculature, and phase I trials should include built-in surrogate endpoints. This article defines the general principles of anti-angiogenic drug action and explains how these principles have been used to design a phase I trial of human endostatin.