Dosimetry in MARS spectral CT: TOPAS Monte Carlo simulations and ion chamber measurements

Spectral computed tomography (CT) is an up and coming imaging modality which shows great promise in revealing unique diagnostic information. Because this imaging modality is based on X-ray CT, it is of utmost importance to study the radiation dose aspects of its use. This study reports on the implementation and evaluation of a Monte Carlo simulation tool using TOPAS for estimating dose in a pre-clinical spectral CT scanner known as the MARS scanner. Simulated estimates were compared with measurements from an ionization chamber. For a typical MARS scan, TOPAS estimated for a 30 mm diameter cylindrical phantom a CT dose index (CTDI) of 29.7 mGy; CTDI was measured by ion chamber to within 3% of TOPAS estimates. Although further development is required, our investigation of TOPAS for estimating MARS scan dosimetry has shown its potential for further study of spectral scanning protocols and dose to scanned objects.     

An integrated family-oriented problem-oriented medical record.

A charting system has been developed that integrates in one place the master problems of individual members of the family whether they be physical, psychological, or socioeconomic. In addition to the Family Problem List, there is a geneology as well as a family profile. The use of the INFO-POMR helps the clinician approach the family as a unit of providing family information at the provider-patient interface.     

Three approaches to problem solving in medicine and some problems they create.

Three general approaches to problem solving in medicine are examined: Basic Science Problem Solving, Clinical Medicine Problem Solving, and Human Values Problem Solving. These three approaches employ different--indeed contradictory--search strategies. Not infrequently, students of medicine become versed in one or another problem solving approach only to flounder when they try to apply it inappropriately. Recognition of this problem may help to solve it.     

The Benefits of Telephone-Access Medical Consultation

A major disadvantage of rural medical practice is the limited reserve of consultative options. To determine the perceived clinical utility and educational impact of the West Virginia University Medical Access and Referral System (MARS), a 24-hour prompt telephone-consultation service, a mailed questionnaire was administered to 303 West Virginia clinicians who had used MARS for infectious disease problems. The overall questionnaire response rate was 62 percent. Callers included family practitioners (35%), medical specialists (32%), surgical specialists (13%), pediatricians (11%), obstetricians (5%), and nonphysicians (4%). Major referral questions posed were therapeutic (60%), diagnostic (48%), and epidemiologic (10%) in nature. On a scale of 1 (not useful) to 5 (very useful), survey responders rated the overall clinical usefulness of MARS as either a 4 (22%) or 5 (76%). Callers felt that MARS consultation assisted in accurate case diagnosis in 80 percent of cases, and aided in successful therapeutic management of 96 percent of cases. An educational benefit was reported by 96 percent of responders. Physicians located in more rural, underserved areas tended to use MARS to a greater degree than colleagues in more populated, medically accessible areas (P < 0.005). These findings suggest that an academic telephone-access consultation program can be a clinically relevant and educational consultative tool for practicing clinicians, especially those located in rural areas.     

Implementation of an optical disk system for medical record storage

MARS was a joint developmental effort between Maine Medical Center and Advanced Healthcare Systems, Inc. It has taken nearly three years to get the system (hardware, software, and staff) to a point where it can now meet daily production requirements. This project was truly unique, so there was no opportunity to learn from the experiences of others. The optical disk system has been an attractive solution to some of the problems experienced at Maine Medical Center. The result was worth the effort in terms of both dollars and other less quantifiable benefits that have had a positive impact on patient care.     

Partner attachment as a predictor of long-term response to treatment with couples therapy

Vulnerability factors such as insecure attachment may have a lasting effect on the outcome of couples therapy, even long after discharge from treatment. Given that attachment has never been examined as an outcome predictor for couples therapy in the long term, the authors studied its effect on outcome during and after couples therapy. This prospective study included 71 inpatients participating in group couples therapy who the authors measured at baseline, immediately posttreatment at 2 months, and at 8 and 20 months, regarding two outcomes: problem-solving capacity (using the Interactional Problem Solving Questionnaire) and psychopathology (using the 90-item Symptom Check List). At baseline, the authors measured partner attachment (using the Experiences in Close Relationships Questionnaire). Mixed model analyses showed that attachment-related dysfunctional working models of self and others predicted less improvement in psychopathology (p = .04) and problem-solving capacity (p = .01), respectively. Special attention to insecure attachment in couples therapy may therefore prove valuable in terms of outcome in the long run.     

Using multivariate adaptive regression splines to QSAR studies of dihydroartemisinin derivatives

QSAR models for analogs of antiplasmodial artemisinin compounds were established, based on atomic net charges by using multivariate adaptive regression splines (MARS) in comparison with some other methods such as multiple linear regression, alternating conditional expectations and projection pursuit regression. The established models were then evaluated by an Anova decomposition procedure so that the effects of each predictor (additive or interaction) could be viewed graphically, facilitating the interpretation of the underlying relationship. It was found that the QSARs derived from the MARS method are the most satisfactory predictive models, and that the artemisinin pharmacophore identification is in agreement with previous experimental findings.     

Multivariate adaptive regression splines: a powerful method for detecting disease-risk relationship differences among subgroups

In a wide variety of medical research scenarios one is interested in the question whether regression curves differ for subgroups in the sample. Examples are gender differences in the effect of drug treatment or the study of genotype-environment interactions. To address this question exploratory techniques are often required because detailed knowledge concerning the shape of the regression curves and how that shape differs across subgroups is lacking. In this article we explored the power of two such exploratory techniques: multivariate adaptive regression splines (MARS) and least squares curve fitting using polynomials. For this purpose simulations were performed using linear, logistic, and complex non-linear curves. The power obtained from MARS was on average 1.4 times higher than with polynomials. It was shown that power was higher even if the regression curve was linear, that gains increased with the complexity of the curve, and that for highly non-linear curves model-free methods such as MARS might be the only alternative.     

'Artificial support in case of hepatic failure'; a report from the Dutch Health Council

Acute liver failure has a high mortality (40-95%) depending on the cause. Emergency liver transplantation is the only way to improve survival: a one-year survival of 5o-6o%. In the past, many different modalities of artificial liver support have been studied. None of them appeared to be able to improve survival compared to maximal intensive care treatment. Two rather recent approaches are the development of a bioartificial liver (BAL), charged with billions of porcine liver cells, and albumin dialysis (MARS). A signalling report has been sent to the Dutch Minister of Health to resume the current position of BAL and MARS in the treatment of severe liver failure. The outcome is that no firm conclusions can yet be drawn as to the applicability of these modalities. Only two small-scale controlled clinical trials have been published on the MARS technique and the only published large-scale controlled clinical trial of a BAL in acute liver failure is not conclusive. On theoretical grounds, BAL treatment has more potential than MARS since a BAL will replace not only the failing hepatic detoxification but also the synthetic and metabolic functions. So far, no evidence has been found for transmission ofporcine pathogens to patients despite numerous phase 1 studies of bioartificial livers charged with porcine hepatocytes. More well-designed controlled clinical trials are needed. Therefore, the Dutch moratorium on xenotransplantation should be revised.     

基于微信平台的健康教育对精神分裂症患者服药依从性、精神症状及再住院率的影响

目的 探讨基于微信平台的健康教育对社区精神分裂症患者服药依从性、精神症状及再住院率的影响。方法通过简单随机抽样的方法从上海市虹口区精神卫生信息管理系统中选取160例社区精神分裂症患者,按随机数字表法分为观察组和对照组。对照组给予常规健康教育干预,观察组在常规健康教育干预的基础上,实施微信健康教育干预。分别在干预前(入组时)、干预6个月及12个月,对两组患者的药物依从性量表(medication adherence rating scale,MARS)和阳性与阴性症状量表(positive and negative symptom scale, PANSS)的评分及再住院率进行比较,以t检验或χ²检验进行统计分析。结果 160例患者中观察组和对照组各80例,干预前两组患者MARS和PANSS评分差异无统计学意义(P>0.05),干预6个月和12个月时,观察组患者MARS评分均高于对照组[(6.84±2.68)vs(5.90±2.16)和(7.26±2.33)vs(5.97±1.77)]、PANSS评分均低于对照组[(46.33±7.50)vs(50.52±6....     

A comparison of regression trees, logistic regression, generalized additive models, and multivariate adaptive regression splines for predicting AMI mortality

Clinicians and health service researchers are frequently interested in predicting patient-specific probabilities of adverse events (e.g. death, disease recurrence, post-operative complications, hospital readmission). There is an increasing interest in the use of classification and regression trees (CART) for predicting outcomes in clinical studies. We compared the predictive accuracy of logistic regression with that of regression trees for predicting mortality after hospitalization with an acute myocardial infarction (AMI). We also examined the predictive ability of two other types of data-driven models: generalized additive models (GAMs) and multivariate adaptive regression splines (MARS). We used data on 9484 patients admitted to hospital with an AMI in Ontario. We used repeated split-sample validation: the data were randomly divided into derivation and validation samples. Predictive models were estimated using the derivation sample and the predictive accuracy of the resultant model was assessed using the area under the receiver operating characteristic (ROC) curve in the validation sample. This process was repeated 1000 times-the initial data set was randomly divided into derivation and validation samples 1000 times, and the predictive accuracy of each method was assessed each time. The mean ROC curve area for the regression tree models in the 1000 derivation samples was 0.762, while the mean ROC curve area of a simple logistic regression model was 0.845. The mean ROC curve areas for the other methods ranged from a low of 0.831 to a high of 0.851. Our study shows that regression trees do not perform as well as logistic regression for predicting mortality following AMI. However, the logistic regression model had performance comparable to that of more flexible, data-driven models such as GAMs and MARS.     

Common Disease Analysis Using Multivariate Adaptive Regression Splines (MARS): Genetic Analysis Workshop 12 Simulated Sequence Data

A newly developed modern analytic approach, Multivariate Adaptive Regression Splines (MARS), was used to identify both genetic and non‐genetic factors involved in the etiology of a common disease. We tested this method on the simulated data provided by the Genetic Analysis Workshop (GAW) 12 in problem 2 for the isolated population. MARS simultaneously analyzes all inputs, in this case DNA sequence variants and non‐genetic data, and selectively prunes away variables contributing insignificantly to fit by internal cross‐validation to arrive at a generalizable predictive model of the response. The relevant factors identified, by means of an importance value computed by MARS, were assumed to be associated with risk to the disease. The application of a series of subsequent models identified the quantitative traits and a single major gene contributing directly to risk liability using five sets of 7,000 individuals. © 2001 Wiley‐Liss, Inc.     

The selection and use of essential medicines. Report of the WHO expert committee, 2005 (including the 14th model list of essential medicines)

This report presents the recommendations of the WHO Expert Committee responsible for updating the WHO Model List of Essential Medicines. The first part contains a summary of the Committee's considerations and justifications for additions and changes to the Model List, including its recommendations. Annexes to the main report include the revised version of the WHO Model List of Essential Medicines (the 14th) and a list of all items on the Model List sorted according to their 5-level Anatomical Therapeutic Chemical (ATC) classification codes.     

Quality and Presence of Behaviour Change Techniques in Mobile Apps for the Mediterranean Diet: A Content Analysis of Android Google Play and Apple App Store Apps

Smartphone apps might represent an opportunity to promote adherence to the Mediterranean diet (MedDiet). This study aimed to evaluate the quality of commercially available apps for the MedDiet and the presence of behavioural change techniques (BCTs) used by these apps. A systematic search was conducted on the Apple App and Google Play stores in November 2021. Apps were included if they provided information on the MedDiet or if their objective was to promote a healthy lifestyle through adherence to the MedDiet. Eligible apps were independently evaluated by two reviewers with regard to their quality (engagement, functionality, aesthetics and information quality) using the 5-point Mobile App Rating Scale (MARS; with higher scores indicating higher quality), and the presence of BCTs using an established 26-item BCT taxonomy. Of the 55 analysed apps, 52 (94.5%) were free, 50 (90.9%) provided recipe ideas, 29 (52.7%) provided meal plans, and 22 (40%) provided information on the health benefits of the MedDiet. The overall quality mean MARS score was 2.84 (standard deviation (SD) = 0.42), with functionality being the highest scored MARS domain (mean = 3.58, SD = 0.44) and engagement the lowest (mean = 2.29, SD = 0.61). The average number of BCTs in the analysed apps was 2.3 (SD = 1.4; range: 0–6 per app). The number of BCTs was positively correlated with app information quality (r_rho = 0.269, p = 0.047), overall MARS score (r_rho = 0.267, p = 0.049), app subjective quality (r_rho = 0.326, p = 0.015) and app-specific quality (r_rho = 0.351, p = 0.009). These findings suggest that currently available apps might provide information on the MedDiet, but the incorporation of more BCTs is warranted to maximise the potential for behaviour change towards the MedDiet.     

The selection and use of essential medicines

This report presents the recommendations of the WHO Expert Committee responsible for updating the WHO Model List of Essential Medicines. The first part contains a summary of the Committee's considerations and justifications for additions and changes to the Model List, including its recommendations. Annexes to the main report include the revised version of the WHO Model List of Essential Medicines (the 15th) and a list of all items on the Model List sorted according to their 5-level Anatomical Therapeutic Chemical (ATC) classification codes. Other annexes cover the proposed procedure for updating and disseminating the WHO Model List of Essential Medicines, and the revised procedure for updating the content of the Interagency Emergency Health Kit.     

Geographic studies of pediatric cancer near hazardous waste sites

The incidence of pediatric (i.e., 0-17 y of age) cancers in North Carolina was studied for the years 1990-1993 in counties and ZIP-code areas that contained a National Priorities List hazardous-waste site. We analyzed the areas to determine if there was an excess incidence of cancer among the pediatric population. We used geographic information systems technology to address-match and map the cancer cases, along with county and National Priorities List hazardous waste-site location. No significantly elevated cancer incidence rates were found at the county level. Two ZIP-code areas had statistically significant elevations in cancer incidence (p < .05). Only 3 of the cancer cases we mapped resided within a 1.6-km (1 mi) buffer zone of a National Priorities List hazardous-waste site. These 3 cases were not in the ZIP-code areas that had increased incidence rates. The small numerators throughout the study led us to question the accuracy of the assessment of underlying rates. The general capabilities of the geographic information systems, as well as advantages and limitations of the system, are discussed. As an exploratory study, this study serves as a springboard into more in-depth environmental-health hypotheses and more-specific investigations of point sources of hazardous exposures.     

Hesitancy towards COVID-19 vaccines on social media in Canada

To effectively end the pandemic, the acceptance of effective vaccines against COVID-19 is critical. Comments posted in online platforms act as a barometer for understanding public concerns regarding vaccination and can be used to inform communication strategies for the ‘moveable middle’. The aim of this exploratory study was to identify online dialogue regarding the nature of vaccine hesitancy related to COVID-19 vaccine(s). We analyzed user comment threads in response to news reports regarding COVID-19 vaccines on the Canadian Broadcasting Corporation national news website (with as many as 9.4 million unique visitors per day). User comments (n = 1145) were extracted from 19 articles between March 2020 and June 15th, 2020. Comments were then coded inductively for content to establish a coding framework that was subsequently applied to the dataset. Our data provide empirical support for misrepresentation as a form of misinformation and further demonstrate the utility of social media content as data for social research that informs public health communication materials. The data point to the need for, and value of, rapid communication interventions to foster vaccine acceptance. False information will continue to create challenges for delivering COVID-19 vaccines. Communication strategies to get ahead of the pace of misinformation are critical, particularly in light of boosters and the possibility of COVID-19 vaccination on an annual basis.     

Residual-based tree-structured survival analysis.

Extensions of various non-parametric regression techniques (for example, additive models, trees, MARS) have been devised for right censored survival data. These approaches directly handle the difficulties posed by censoring. However, it is possible to bypass these difficulties by utilizing standard non-parametric regression procedures applied with (say) martingale residuals as outcome. Analytic correspondences between the direct and residual-based approaches have been established for additive models while more qualitative comparisons have been provided for MARS. Here we develop such correspondences for tree-structured regression. In particular, we provide an analytic relationship between logrank and martingale residual sum-of-squares split functions that explains the widely observed similarity of the resultant trees. Further investigation is provided by simulation and an illustrative example using time to AIDS with data deriving from a Western Australian HIV cohort study.     

De-Implementation of Detrimental Feeding Practices in Childcare: Mixed Methods Evaluation of Community Partner Selected Strategies

This pilot evaluated strategies to decrease detrimental feeding practices in early care and education, which are hypothesized to compete with evidence-based feeding and obesity prevention practices. This study made two key comparisons: (1) a between-site comparison of sites receiving (a) no implementation or de-implementation strategies (i.e., Basic Support; B), (b) implementation strategies only (i.e., Enhanced Support; E), and (c) implementation and de-implementation strategies (i.e., De-implementation + Enhanced Support; D + E) and (2) a within-site pre-post comparison among sites with D + E. At nutrition lessons, the D + E group had more Positive Comments (Hedege’s g = 0.60) and higher Role Model fidelity (Hedege’s g = 1.34) compared to the E group. At meals, assistant teachers in the D + E group had higher Positive Comments than in the B group (g = 0.72). For within-group comparisons, the D + E group decreased Negative Comments (t(19) = 2.842, p = 0.01), increased Positive Comments (t(20) = 2.314, p = 0.031), and improved use of the program mascot at nutrition lessons (t(21) = 3.899, p = 0.001). At meals, lead teachers’ Negative Comments decreased (t(22) = 2.73, p = 0.01). Qualitative data identified strengths and opportunities for iteration. Despite a COVID interruption, mid-point comparisons and qualitative feedback suggest promise of the de-implementation strategy package.     

The long-term value of the selected list as a method of controlling drug costs in a district general hospital.

The results of a study aimed at evaluating the long-term effects of the Limited List (now officially referred to as the Selected List Scheme) on inpatient drug costs in a district general hospital (DGH) are presented. Study periods of six months duration were examined before, shortly after, and a further year after implementation of the List on 1 April 1985. Eight therapeutic classes affected by the regulations were examined; in four of these (antacids, expectorants, mucolytics and anxiolytics, hypnotics and sedatives) statistically significant reductions in costs were demonstrated over the study periods. There was no significant change in the costs of the other four classes (vitamins, laxatives, nasal preparations and analgesics). Overall, inpatient expenditure for the hospital showed no significant change. The changes in cost demonstrated can be attributed to the Selected List and occurred despite the prior existence of a local formulary.