Estimation of stochastic behaviour in cardiac myocytes: I. Ca2+ movements inside the cytosol and sarcoplasmic reticulum on curvilinear domains.

Since the discovery of Ca2+ sparks and their stochastic behaviour in cardiac myocytes, models have focused on the inclusion of stochasticity in their studies. While most models pay much attention to the stochastic modelling of cytosolic Ca2+ concentration the coupling of Ca2+ sparks and blinks in a stochastic model has not been explored fully. The cell morphology in in silico studies in the past is assumed to be Cartesian, spherical or cylindrical. The application on curvilinear grids can easily address certain restrictions posed by such grid set up and provide more realistic cell morphology. In this paper, we present a stochastic reaction-diffusion model that couples Ca2+ sparks and blinks in realistic shapes of cells in curvilinear domains. Methodology: Transformation of the model was performed to the curvilinear coordinate system. The set of equations is used to produce Ca2+ waves initiated from sparks and blinks. A non-buffered and non-dyed version as well as a buffered and dyed version of these equations were studied in light of observing the dynamics on the two different systems. For comparison, results for both the Cartesian and curvilinear grids are provided. Results and conclusions: A successful demonstration of the application of curvilinear grids serving as basis for future developments.

Understanding narrative effects: the role of discrete negative emotions on message processing and attitudes among low-income African American women.

This study tests the processes through which breast cancer narrative messages are effective by taking a functional approach. We explore how discrete negative emotions (i.e., sadness, fear, and anger) induced by breast cancer survivor stories affect African American women's message processing, recall of message content, and attitudinal outcomes. Structural equation modeling was performed for narrative and informational versions of a breast cancer screening video shown to 489 low-income African American women ages 40 years and older. The model was well fitted. Sadness enhanced the persuasive process, while fear inhibited it. Sadness also helped participants recall more message-relevant content, while fear inhibited recall. Anger was not related to the persuasive process. Implications of these findings for narrative research and application are discussed.

Use of cancer control referrals by 2-1-1 callers: a randomized trial.

BACKGROUND: Callers to 2-1-1 have greater need for and lesser use of cancer control services than other Americans. Integrating cancer risk assessment and referrals to preventive services into 2-1-1 systems is both feasible and acceptable to callers. PURPOSE: To determine whether callers will act on these referrals. METHODS: In a randomized trial, 2-1-1 callers (n=1200) received standard service and those with at least one cancer risk factor or need for screening were assigned to receive verbal referrals only, verbal referrals + a tailored reminder mailed to their home, or verbal referrals + a telephone health coach/navigator. All data were collected from June 2010 to March 2012 and analyzed in March and April 2012. RESULTS: At 1-month follow-up, callers in the navigator condition were more likely to report having contacted a cancer control referral than those receiving tailored reminders or verbal referrals only (34% vs 24% vs 18%, respectively; n=772, p<0.0001). Compared to verbal referrals only, navigators were particularly effective in getting 2-1-1 callers to contact providers for mammograms (OR=2.10, 95% CI=1.04, 4.22); Paps (OR=2.98, 95% CI=1.18, 7.54); and smoking cessation (OR=2.07, 95% CI=1.14, 3.74). CONCLUSIONS: Given the extensive reach of 2-1-1s and the elevated risk profile of their callers, even modest response rates could have meaningful impact on population health if proactive health referrals were implemented nationally.

Exploring 2-1-1 service requests as potential markers for cancer control needs.

BACKGROUND: Delivering health information and referrals through 2-1-1 is promising, but these systems need efficient ways of identifying callers at increased risk. PURPOSE: This study explores the utility of using 2-1-1 service request data to predict callers' cancer control needs. METHODS: Using data from a large sample of callers (N=4101) to United Way 2-1-1 Missouri, logistic regression was used to examine the relationship between caller demographics and type of service request, and cancer control needs. RESULTS: Of six types of service requests examined, three were associated with one or more cancer control needs. Two of the service request types were associated also with health insurance status. CONCLUSIONS: Findings suggest routinely collected 2-1-1 service request data may be useful in helping to efficiently identify callers with specific cancer prevention and control needs. However, to apply this approach in 2-1-1 systems across the country, further research and ongoing surveillance is necessary.

Evaluating the Ozioma cancer news service: a community randomized trial in 24 U.S. cities.

OBJECTIVE: This community randomized trial evaluated effects of the Ozioma News Service on the amount and quality of cancer coverage in Black weekly newspapers in 24 U.S. cities. METHOD: We created and operated Ozioma, the first cancer information news service specifically for Black newspapers. Over 21 months, Ozioma developed community- and race-specific cancer news releases for each of 12 Black weekly newspapers in intervention communities. Cancer coverage in these papers was tracked before and during the intervention and compared to 12 Black newspapers in control communities. RESULTS: From 2004 to 2007, we coded 9257 health and cancer stories from 3178 newspaper issues. Intervention newspapers published approximately 4 times the expected number of cancer stories compared to control newspapers (p(12,21 mo)<.01), and also saw an increase in graphics (p(12,21 mo)<.01), local relevance (p(12 mo)=.01), and personal mobilization (p(12 mo)<.10). However, this increased coverage supplanted other health topics and had smaller graphics (NS), had less community mobilization (p(21 mo)=.01), and is less likely to be from a local source (NS). CONCLUSION: Providing news releases with localized and race-specific features to minority-serving media outlets can increase the quantity of cancer coverage. Results are mixed for the journalistic and public health quality of this increased cancer coverage in Black newspapers.

Two-level time-domain decomposition based distributed method for numerical solutions of pharmacokinetic models.

In order to predict variations of drug concentration during a given period of time, numerical solutions of pharmacokinetic models need to be obtained efficiently. Analytical solutions of linear pharmacokinetic models are usually obtained using the Laplace transform and inverse Laplace tables. The derivations of solutions to complex nonlinear models are tedious, and such solution process may be difficult to implement as a robust software code. For nonlinear models, the fourth-order Runge-Kutta (RK4) is the most classical numerical method in obtaining approximate numerical solutions, which is impossible to be implemented in distributed computing environments without much modification. The reason is that numerical solutions obtained by using RK4 can only be computed in sequential time steps. In this paper, time-domain decomposition methods are adapted for nonlinear pharmacokinetic models. The numerical Inverse Laplace method for PharmacoKinetic models (ILPK) is implemented to solve pharmacokinetic models with iterative inverse Laplace transform in each time interval. The distributed ILPK algorithm, which is based on a two-level time-domain decomposition concept, is proposed to improve its efficiency. Solutions on the coarser temporal mesh at the top level are obtained one by one, and then those on the finer temporal mesh at the bottom level are calculated concurrently by using those initial solutions that have been obtained at the top level decomposition. Accuracy and efficiency of the proposed algorithm and its distributed equivalent are investigated by using several test models. Results indicate that the ILPK algorithm and its distributed equivalent are good candidates for both linear and nonlinear pharmacokinetic models.

An economic analysis of an aggressive diagnostic strategy with single photon emission computed tomography myocardial perfusion imaging and early exercise stress testing in emergency department patients who present with chest pain but nondiagnostic electrocardiograms: Results from a randomized trial.

STUDY OBJECTIVE: Conventional emergency department testing strategies for patients with chest pain often do not provide unequivocal diagnosis of acute coronary syndromes. This study was conducted to determine whether the routine use of single photon emission computed tomography (SPECT) imaging at rest and early exercise stress testing to assess intermediate-risk patients with chest pain and no ECG evidence of acute ischemia will lead to earlier discharges, more discriminate use of coronary angiography, and an overall reduction in average costs of care with no adverse clinical outcomes. METHODS: All patients in this study had technetium 99m tetrofosmin SPECT imaging at rest and were randomly assigned to either a conventional (results of the imaging test blinded to the physician) or perfusion imaging-guided (results of the imaging test unblinded to the physician) strategy. Patients in the conventional arm were treated at their physician's discretion. Patients in the perfusion imaging-guided arm were treated according to a predefined protocol based on SPECT imaging test results: coronary angiography after a positive scan result and exercise treadmill testing after a negative scan result. Study endpoints consisted of total in-hospital costs and length of stay. Hospital costs were calculated using hospital department-specific Medicare cost/charge ratios. Length of stay was calculated as total hospital room days billed (regular and intensive care). RESULTS: We enrolled 46 patients, 9 with acute myocardial infarctions. Patients randomly assigned to the perfusion imaging-guided arm had $1,843 (95% confidence interval [CI] $431 to $6,171) lower median in-hospital costs and 2.0-day (95% CI 1.0 to 3.0 days) shorter median lengths of stay but similar rates of in-hospital and 30-day follow up events as patients in the conventional arm. CONCLUSION: An ED chest pain diagnostic strategy incorporating acute resting 99mTc tetrofosmin SPECT imaging and early exercise stress testing may lead to reduced in-hospital costs and decreased length of stay for patients with acute chest pain and nondiagnostic ECGs. [Stowers SA, Eisenstein EL, Wackers FJTh, Berman DS, Blackshear JL, Jones AD Jr, Szymanski TJ Jr, Lam LC, Simons TA, Natale D, Paige KA, Wagner GS. An economic analysis of an aggressive diagnostic strategy with single photon emission computed tomography myocardial perfusion imaging and early exercise stress testing in emergency department patients who present with chest pain but nondiagnostic electrocardiograms: results from a randomized trial. Ann Emerg Med. January 2000;35:17-25.].