Routine antiseptic baths and MRSA decolonization: diverse approaches across Singapore's acute-care hospitals.

To determine the variation in practices on meticillin-resistant Staphylococcus aureus (MRSA) surveillance and management of MRSA-colonized patients amongst 17 acute healthcare facilities in Singapore, the Ministry of Health convened a sharing session with Infection Prevention and Control Leads. All hospitals practised close to universal MRSA entry swabbing in keeping with national policy. There were, however, major variations in the response to both positive and negative surveillance swabs across facilities including the role of routine antiseptic bathing and MRSA decolonization. Most undertaking decolonization considered its role to be in 'bioburden reduction' rather than longer-term clearance.

Mechanical stimuli for left ventricular growth during pressure overload.

BACKGROUND: The mechanical stimulus (i.e. stress or stretch) for growth occurring in the pressure-overloaded left ventricle (LV) is not exactly known. OBJECTIVE: To address this issue, we investigate the correlation between local ventricular growth (indexed by local wall thickness) and the local acute changes in mechanical stimuli after aortic banding. METHODS: LV geometric data were extracted from 3D echo measurements at baseline and 2 weeks in the aortic banding swine model (n = 4). We developed and calibrated animal-specific finite element (FE) model of LV mechanics against pressure and volume waveforms measured at baseline. After the simulation of the acute effects of pressure-overload, the local changes of maximum, mean and minimum myocardial stretches and stresses in three orthogonal material directions (i.e., fiber, sheet and sheet-normal) over a cardiac cycle were quantified. Correlation between mechanical quantities and the corresponding measured local changes in wall thickness was quantified using the Pearson correlation number (PCN) and Spearman rank correlation number (SCN). RESULTS: At 2 weeks after banding, the average septum thickness decreased from 10.6 ± 2.92mm to 9.49 ± 2.02mm, whereas the LV free-wall thickness increased from 8.69 ± 1.64mm to 9.4 ± 1.22mm. The FE results show strong correlation of growth with the changes in maximum fiber stress (PCN = 0.5471, SCN = 0.5111) and changes in the mean sheet-normal stress (PCN= 0.5266, SCN = 0.5256). Myocardial stretches, however, do not have good correlation with growth. CONCLUSION: These results suggest that fiber stress is the mechanical stimuli for LV growth in pressure-overload.

Left ventricular geometry, tissue composition, and residual stress in High Fat Diet Dahl-Salt sensitive rats.

BACKGROUND: Hypertension drives myocardial remodeling, leading to changes in structure, composition and mechanical behavior, including residual stress, which are linked to heart disease progression in a gender-specific manner. Emerging therapies are also targeting constituent-specific pathological features. All previous studies, however, have characterized remodeling in the intact tissue, rather than isolated tissue constituents, and did not include sex as a biological variable. OBJECTIVE: In this study we first identified the contribution of collagen fiber network and myocytes to the myocardial residual stress/strain in Dahl-Salt sensitive rats fed with high fat diet. Then, we quantified the effect of hypertension on the remodeling of the left ventricle (LV), as well as the existence of sex-specific remodeling features. METHODS: We performed mechanical tests (opening angle, ring-test) and histological analysis on isolated constituents and intact tissue of the LV. Based on the measurements from the tests, we performed a stress analysis to evaluate the residual stress distribution. Statistical analysis was performed to identify the effects of constituent isolation, elevated blood pressure, and sex of the animal on the output of both experimental measures and modeling results. RESULTS: Hypertension leads to reduced residual stress/strain intact tissue, isolated collagen fibers, and isolated myocytes in male and female rats. Collagen remains the largest contributor to myocardial residual stress in both normotensive and hypertensive animals. We identified sex-differences in both hypertensive and normotensive animals. CONCLUSIONS: We observed both constituent- and sex-specific remodeling features in the LV of an animal model of hypertension.

Population-based trend analysis of voiding cystourethrogram ordering practices in a single-payer healthcare system before and after the release of evaluation guidelines.

INTRODUCTION: While voiding cystourethrogram (VCUG) is a widely-accepted test, it is invasive and associated with radiation exposure. Most cases of primary vesicoureteral reflux (VUR) are low-grade and unlikely to be associated with acquired renal scarring. To select patients at greatest risk, in 2011 the American Academy of Pediatrics (AAP) published guidelines for evaluation of children ages 2 - 24 months with urinary tract infections (UTIs). Similarly, in 2010 the Society for Fetal Urology (SFU) published guidelines for patients with hydronephrosis. Herein a prospectively-collected database was queried through the Institute of Clinical Evaluative Sciences (ICES), exploring trends in VCUG ordering within the Ontario Health Insurance Program (OHIP), which guarantees universal access to care. MATERIAL AND METHODS: A dedicated ICES analyst extracted data on all patients younger than 18 years in Ontario, Canada, with billing codes for VCUG and ICD-9 codes for VUR, from 2004-2014. The baseline characteristics included patient age, gender, geographic region, specialty of ordering provider and previous diagnoses of UTI and/or antenatal hydronephrosis to determine the indication for ordering the test. Of these, patients were subsequently incurred OHIP procedure codes for endoscopic injection or ureteral reimplantation. Patients who had a VCUG in the setting of urethral trauma, posterior urethral valves, and neurogenic bladder were excluded. RESULTS AND DISCUSSION: Trend analysis demonstrated that the total number of VCUGs ordered in the province has decreased over a decade (Figure 1), with a concurrent decrease in VUR diagnosis. On multivariate regression analysis, the decrease in VCUG ordering could not be explained by changes in population demographics or other baseline patient variables. Most VCUGs obtained per year were ordered by pediatricians or family physicians (mean 2,022+523.8), compared with urologists and nephrologists (mean 616+358.3). Interestingly, while the rate of VCUG requests decreased, the annual number of surgeries performed for VUR (endoscopic or open) did not show a significant reduction over time. CONCLUSIONS: We present a large population-based analysis in a universal access to care system, reporting a decreasing trend in the number of cystograms and differences by primary care versus specialist providers. While it is reassuring to see practice patterns favorably impacted by guidelines, it is also encouraging to note that the number of surgeries has remained stable. This suggests that patients at risk continue to be detected and offered surgical correction. These data confirm previous institution-based assessments and affirm changes in VCUG ordering independent of variables not relevant to the healthcare system, such as the insurance status.

Stent-related complications after hypospadias repair: a prospective trial comparing Silastic tubing and Koyle urethral stents.

INTRODUCTION: There is a paucity of data comparing urethral stents after hypospadias repair. The aim of this study is to compare Silastic tubing vs Koyle stents (Cook Medical), addressing outcomes related to stent-related complications, added visits to healthcare providers in the early postoperative period, and postoperative complications at clinic follow-up. MATERIALS AND METHODS: Following an alternate week allocation, 150 patients were prospectively assigned to have Silastic tubes (n = 76) and Koyle stents (n = 74) after hypospadias repair. Exclusion criteria included fistula repairs, drainage via alternative catheter, or stentless repairs. Silastic tubes were secured with 5-0 Prolene and removed during a planned clinic visit. Koyle stents were secured with 7-0 PDS and left to fall out spontaneously. Questionnaires capturing postoperative outcomes were completed. RESULTS AND DISCUSSION: Median age was 13 and 11 months in the Silastic and Koyle stent groups, respectively (P = 0.48). There was no statistically significant difference in hypospadias location. Blockage/kinking of stents occurred in 8% (n = 6) of the Silastic and 9% (n = 7) Koyle stent groups, P = 0.78. Although follow-up was short, there was no difference in fistula rate among the Silastic (21%, n = 14) versus Koyle stent group (17%, n = 11), P = 0.66. There was a twofold higher rate of emergency department (ED) visits in the Silastic (32%, n = 24) versus Koyle stent group (16%, n = 12), P = 0.03. Half of ED visits in the Silastic group were related to stents falling out before planned removal. The authors propose that Silastic stents falling out before the removal date may have led to increased parental anxiety and thus a visit to the ED. With improved parental education, the authors propose that many of these visits may have been preventable. CONCLUSIONS: There were no significant differences in stent-related complications or fistula rate between the Silastic and Koyle stent groups. Although there were a twofold higher number of visits to the ED in the Silastic stent group, the authors propose that this was due to parental education rather than the stent itself.

Equilibrated warping: Finite element image registration with finite strain equilibrium gap regularization.

In this paper, we propose a novel continuum finite strain formulation of the equilibrium gap regularization for image registration. The equilibrium gap regularization essentially penalizes any deviation from the solution of a hyperelastic body in equilibrium with arbitrary loads prescribed at the boundary. It thus represents a regularization with strong mechanical basis, especially suited for cardiac image analysis. We describe the consistent linearization and discretization of the regularized image registration problem, in the framework of the finite elements method. The method is implemented using FEniCS & VTK, and distributed as a freely available python library. We show that the equilibrated warping method is effective and robust: regularization strength and image noise have minimal impact on motion tracking, especially when compared to strain-based regularization methods such as hyperelastic warping. We also show that equilibrated warping is able to extract main deformation features on both tagged and untagged cardiac magnetic resonance images.

Brief Report: Self-Injurious Behaviors in Preschool Children with Autism Spectrum Disorder Compared to Other Developmental Delays and Disorders.

We compared the prevalence of self-injurious behaviors (SIB) in preschoolers aged 30-68 months with autism spectrum disorder (ASD) (n = 691) versus other developmental delays and disorders (DD) (n = 977) accounting for sociodemographic, cognitive, and medical factors. SIB prevalence was higher in ASD versus all DD [adjusted odds-ratio (aOR) 2.13 (95% confidence interval (95% CI) 1.53, 2.97)]. In subgroup analyses, SIB prevalence was higher in ASD versus DD without ASD symptoms [aOR 4.42 (95% CI 2.66, 7.33)], but was similar between ASD and DD with ASD symptoms [aOR 1.09 (95% CI 0.68, 1.77)]. We confirmed higher prevalence of SIB in ASD versus DD, independent of confounders. In children with DD, SIB prevalence increased with more ASD symptoms. These findings are informative to clinicians, researchers, and policymakers.

Cancer-related hypercalcemia in oral cancer.

Cancer-related hypercalcemia (CRH) is a critical paraneoplastic disorder in advanced cancer patients. In clinical practice, patients with CRH have a poor prognosis. The medical records of 3198 oral cancer patients with CRH diagnosed at Taichung Veterans General Hospital from 1 January 2003 to 31 December 2015 were reviewed. The criteria for patient enrolment were a diagnosis of hypercalcemia or the use of antihypercalcemia medication. Patients who met any of the following criteria were excluded: use of total parenteral nutrition, incomplete serum calcium data, and unknown date of death. The total incidence of CRH was 6.95‰ per year. A total of 91 patients were enrolled; their median survival time was 28 days. The patients were divided into two groups by survival time, with a cut-off point of 30 days. Reduced serum albumin, leucocytosis, and clodronate use had a statistically significant effect on survival in the univariate analysis (all P<0.05). Forty-five patients (49.5%) had recurrence of CRH, of whom nine died within 30days. These nine patients had a shorter interval to the first episode of CRH recurrence (median 13 days) than those who survived ≥30days (median 28 days) (P<0.001). It was observed that a short interval to the first episode of CRH recurrence is a poor prognostic factor.

Solar Open Flux Migration from Pole to Pole: Magnetic Field Reversal.

Coronal holes are solar regions with low soft X-ray or low extreme ultraviolet intensities. The magnetic fields from coronal holes extend far away from the Sun, and thus they are identified as regions with open magnetic field lines. Coronal holes are concentrated in the polar regions during the sunspot minimum phase, and spread to lower latitude during the rising phase of solar activity. In this work, we identify coronal holes with outward and inward open magnetic fluxes being in the opposite poles during solar quiet period. We find that during the sunspot rising phase, the outward and inward open fluxes perform pole-to-pole trans-equatorial migrations in opposite directions. The migration of the open fluxes consists of three parts: open flux areas migrating across the equator, new open flux areas generated in the low latitude and migrating poleward, and new open flux areas locally generated in the polar region. All three components contribute to the reversal of magnetic polarity. The percentage of contribution from each component is different for different solar cycle. Our results also show that the sunspot number is positively correlated with the lower-latitude open magnetic flux area, but negatively correlated with the total open flux area.

Factors Associated with Self-Injurious Behaviors in Children with Autism Spectrum Disorder: Findings from Two Large National Samples.

In this study, we explored potential associations among self-injurious behaviors (SIB) and a diverse group of protective and risk factors in children with autism spectrum disorder from two databases: Autism and Developmental Disabilities Monitoring (ADDM) Network and the Autism Speaks-Autism Treatment Network (AS-ATN). The presence of SIB was determined from children's records in ADDM and a parent questionnaire in AS-ATN. We used multiple imputation to account for missing data and a non-linear mixed model with site as a random effect to test for associations. Despite differences between the two databases, similar associations were found; SIB were associated with developmental, behavioral, and somatic factors. Implications of these findings are discussed in relation to possible etiology, future longitudinal studies, and clinical practice.

Mathematical modeling of cardiac growth and remodeling.

This review provides an overview of the current state of mathematical models of cardiac growth and remodeling (G&R). We concisely describe the experimental observations associated with cardiac G&R and discuss existing mathematical models that describe this process. To facilitate the discussion, we have organized the G&R models in terms of (1) the physical focus (biochemical vs mechanical) and (2) the process that they describe (myocyte hypertrophy vs extracellular matrix remodeling). The review concludes with a discussion of some possible directions that can advance the existing state of cardiac G&R mathematical modeling. WIREs Syst Biol Med 2016, 8:211-226. doi: 10.1002/wsbm.1330 For further resources related to this article, please visit the WIREs website.

Modeling Pathologies of Diastolic and Systolic Heart Failure.

Chronic heart failure is a medical condition that involves structural and functional changes of the heart and a progressive reduction in cardiac output. Heart failure is classified into two categories: diastolic heart failure, a thickening of the ventricular wall associated with impaired filling; and systolic heart failure, a dilation of the ventricles associated with reduced pump function. In theory, the pathophysiology of heart failure is well understood. In practice, however, heart failure is highly sensitive to cardiac microstructure, geometry, and loading. This makes it virtually impossible to predict the time line of heart failure for a diseased individual. Here we show that computational modeling allows us to integrate knowledge from different scales to create an individualized model for cardiac growth and remodeling during chronic heart failure. Our model naturally connects molecular events of parallel and serial sarcomere deposition with cellular phenomena of myofibrillogenesis and sarcomerogenesis to whole organ function. Our simulations predict chronic alterations in wall thickness, chamber size, and cardiac geometry, which agree favorably with the clinical observations in patients with diastolic and systolic heart failure. In contrast to existing single- or bi-ventricular models, our new four-chamber model can also predict characteristic secondary effects including papillary muscle dislocation, annular dilation, regurgitant flow, and outflow obstruction. Our prototype study suggests that computational modeling provides a patient-specific window into the progression of heart failure with a view towards personalized treatment planning.

Training-induced Increase in Bone Mineral Density between Growing Male and Female Rats.

The purpose of this study was to determine the existence of sex differences in the resistance training-induced elevation in bone mineral density (BMD) and bone strength (Fmax) during the growth period in rats. 16 male (M) and 16 female (F) rats (approx. 8 weeks old) were randomly divided into sedentary control (MC=8, FC=8), and resistance-trained (RT) groups (M-RT=8, F-RT=8). The RT groups were conditioned to climb a vertical ladder 4 consecutive times (per exercise session) with weights attached to their tail 3 days per week for a total of 6 weeks. After 6 weeks, there were no interaction effects (sex×exercise). The main effect of sex indicated no difference in tibial BMD (in g/cm(2)) for males (0.226±0.005) compared to females (0.221±0.004). However, Fmax (in Newtons) was significantly greater for males (131.3±5.3) compared to females (89.9±3.0). The main effect of exercise indicated that tibial BMD and Fmax were significantly greater for RT groups (0.234±0.004 g/cm(2) and 120.9±7.4 Newtons) compared to controls (0.212±0.003 g/cm(2) and 100.3±5.1 Newtons). The results indicate that during growth, there were no sex differences in the training-induced elevation in BMD and bone mechanical properties.

Heterogeneous growth-induced prestrain in the heart.

Even when entirely unloaded, biological structures are not stress-free, as shown by Y.C. Fung׳s seminal opening angle experiment on arteries and the left ventricle. As a result of this prestrain, subject-specific geometries extracted from medical imaging do not represent an unloaded reference configuration necessary for mechanical analysis, even if the structure is externally unloaded. Here we propose a new computational method to create physiological residual stress fields in subject-specific left ventricular geometries using the continuum theory of fictitious configurations combined with a fixed-point iteration. We also reproduced the opening angle experiment on four swine models, to characterize the range of normal opening angle values. The proposed method generates residual stress fields which can reliably reproduce the range of opening angles between 8.7±1.8 and 16.6±13.7 as measured experimentally. We demonstrate that including the effects of prestrain reduces the left ventricular stiffness by up to 40%, thus facilitating the ventricular filling, which has a significant impact on cardiac function. This method can improve the fidelity of subject-specific models to improve our understanding of cardiac diseases and to optimize treatment options.

A computational model that predicts reverse growth in response to mechanical unloading.

Ventricular growth is widely considered to be an important feature in the adverse progression of heart diseases, whereas reverse ventricular growth (or reverse remodeling) is often considered to be a favorable response to clinical intervention. In recent years, a number of theoretical models have been proposed to model the process of ventricular growth while little has been done to model its reverse. Based on the framework of volumetric strain-driven finite growth with a homeostatic equilibrium range for the elastic myofiber stretch, we propose here a reversible growth model capable of describing both ventricular growth and its reversal. We used this model to construct a semi-analytical solution based on an idealized cylindrical tube model, as well as numerical solutions based on a truncated ellipsoidal model and a human left ventricular model that was reconstructed from magnetic resonance images. We show that our model is able to predict key features in the end-diastolic pressure-volume relationship that were observed experimentally and clinically during ventricular growth and reverse growth. We also show that the residual stress fields generated as a result of differential growth in the cylindrical tube model are similar to those in other nonidentical models utilizing the same geometry.

The long-term predictive value of the neutrophil-to-lymphocyte ratio in Type 2 diabetic patients presenting with acute myocardial infarction.

BACKGROUND: Patients with diabetes mellitus have worse long-term outcomes after acute myocardial infarction (AMI) than non-diabetics. This may be related to differential contribution of neutrophil and lymphocyte to inflammation during AMI in diabetics vs. non-diabetics. We aim to determine the predictive value of neutrophil-to-lymphocyte ratio (NLR) for major adverse events post-AMI in Type 2 diabetics vs. non-diabetics. METHODS AND RESULTS: A total of 2559 consecutive patients admitted for AMI (61 ± 14 years, 73% male and 43% diabetic) were analyzed. A complete blood count was obtained and the NLR computed for each patient on admission. Across the cohort, the 1-year reinfarction rate was 8.4% (n = 214) and 1-year mortality was 14.5% (n = 370). Univariate determinants of the composite endpoint included age, hypertension, hyperlipidemia, smoking, revascularization and NLR (P < 0.001 for all). The cohort was divided into NLR quartiles. Admission NLR was significantly higher in the diabetic group, 5.2 ± 5.8 vs. 4.6 ± 5.4 (P = 0.007). A step-wise increase in the incidence of the composite endpoint was noted across NLR quartiles for diabetic subjects; hazard ratio (HR) was 2.41 for fourth vs. first quartile (95% confidence interval = 1.63-3.53, P < 0.001). Multivariate analysis of the diabetic group showed that NLR remains as an independent predictor of the composite endpoint (adjusted HR = 1.53, 95% confidence interval = 1.00-2.33, P = 0.048). However, in non-diabetics, HR for NLR was not significant (P = 0.35). CONCLUSION: Increased NLR post-AMI is an independent predictor of major adverse cardiac events in diabetics. Monitoring this easily obtainable new index allows prognostication and risk stratification.

Elimination of subterranean termite (Isoptera: Rhinotermitidae) colonies using a refined cellulose bait matrix containing noviflumuron when monitored and replenished quarterly.

Using a quarterly (3-mo) monitoring and bait-replenishment interval, 122 subterranean termite colonies throughout the United States were baited with a refined cellulose bait matrix containing 0.5% noviflumuron. All colonies were eliminated in less than 1 yr after initiation of baiting as determined by long-term monitoring and genetic markers. Sixty-three percent of the colonies were eliminated during the first quarter after the initiation of baiting and 77% of colonies were eliminated after consuming two bait tubes or less. This suggests that a single baiting cycle and bait installed in response to a single active monitoring device were sufficient to eliminate the majority of colonies. Although termites temporarily abandoned stations after depleting bait, workers resumed feeding when baits were replenished. Colonies that consumed large amounts of bait before elimination foraged into multiple stations, thus allowing adequate amounts of bait to sustain feeding. The time to eliminate termite colonies with bait replenished quarterly was similar to that previously reported for laminated cellulose bait replenished monthly. Our data support the conclusion that extending the bait replenishment interval from monthly to quarterly for bait tubes with refined cellulose containing 0.5% noviflumuron did not adversely impact colony elimination.

Managing ventricular ectopics: are ventricular ectopic beats just an annoyance?

How important are PVCs and what should we do about them? PVCs are not a disease in themselves, but a marker of possible underlying conditions that may increase the risk of cardiac death. They serve as a flag to alert us to exclude structural heart disease, the presence of which is the strongest predictor of adverse events. However, it is important to know that PVCs are common in people with no structural heart disease. In this situation, the prognosis is generally excellent. Suppression of PVCs with antiarrhythmic medication is not indicated routinely, unless the patient is symptomatic or at risk of tachycardia-induced cardiomyopathy owing to the very high frequency of PVCs. Where pharmacological therapy has failed, there is now the option of radiofrequency ablation for elimination of frequent symptomatic PVCs. The ECG is a simple yet useful tool to improve risk assessment, especially in those with known cardiovascular disease.