Modelo predictivo del fracaso de la terapia eléctrica en la fibrilación auricular paroxística / Predictive model of electrical therapy failure in paroxysmal atrial fibrillation

Introducción: La fibrilación auricular es la arritmia recurrente más habitual en la práctica clínica. Su prevalencia se multiplica en la población actual y tiene diferentes causas fisiopatológicas que la convierten en una pandemia mundial. Objetivos: Diseñar un modelo predictivo de fracaso de la terapia eléctrica en pacientes con fibrilación auricular paroxística. Métodos: Se realizó un estudio de casos y controles, con 33 casos y 66 controles. Variables predictoras: edad, fracción de eyección ≤ 40 por ciento, volumen de aurícula izquierda ≥ 34 mL/m2. A partir de la regresión logística se obtuvo un modelo en el que fueron incluidos el valor predictivo positivo, valor predictivo negativo, la sensibilidad y especificidad. Resultados: Los factores de riesgo predictores fueron: edad ≥ 55 años (p= 0,013; odds ratio (OR)= 3,58; intervalo de confianza -IC- 95 por ciento: 1,33-9,67); la fracción de eyección del ventrículo izquierdo (FEVI) ≤ 40 por ciento se observó en 20 pacientes (22,7 por ciento) (p= 0,004; OR= 4,45; IC95 por ciento: 1,54-12,8); presión de aurícula izquierda elevada, volumen de aurícula izquierda elevado (p= 0,004; OR= 3,11; IC95 por ciento: 1,24-8,77), según el modelo de regresión logística. Se realizó la validación interna por división de datos; se confirmó que el modelo pronostica bien los que van a tener éxito en el resultado terapéutico. Conclusiones: El modelo predictivo elaborado está compuesto por los predictores edad > 55 años, FEVI; volumen de aurícula izquierda; presenta un buen ajuste y poder discriminante, sobre todo valor predictivo positivo(AU)

Introduction: Atrial fibrillation is the most common recurrent arrhythmia in clinical practice. Its prevalence is multiplying in the current population and has different pathophysiological causes that make it a global pandemic. Objectives: To design a predictive model for failure of electrical therapy in patients with paroxysmal atrial fibrillation. Methods: A case-control study was carried out with 33 cases, and 66 controls. Predictor variables: age, ejection fraction ≤ 40 percent, left atrial volume ≥ 34 mL/m2. From logistic regression, a model was obtained in which the positive predictive value, negative predictive value, sensitivity and specificity were included. Results: The predictive risk factors were: age ≥ 55 years (p= 0.013; odds ratio (OR)= 3.58; 95 percent confidence interval -CI-: 1.33-9.67); left ventricular ejection fraction (LVEF) ≤ 40 percent was observed in 20 patients (22.7 percent) (p= 0.004; OR= 4.45; 95 percent CI: 1.54-12.8); elevated left atrial pressure, elevated left atrial volume (p= 0.004; OR= 3.11; 95 percent CI: 1.24-8.77), according to the logistic regression model. Internal validation was carried out by data division; It was confirmed that the model predicts very well those who will be successful in the therapeutic result. Conclusions: The predictive model developed is composed of the predictors age > 55 years, LVEF; left atrial volume; It presents a good fit and discriminating power, especially positive predictive value(AU)

Diagnóstico matemático del infarto agudo de miocardio y de la falla cardiaca mediante la entropía proporcional / Mathematical Diagnosis of Acute Myocardial Infarction and Failure Using Proportional Entropy

Introducción: Las teorías físicas y matemáticas han permitido el desarrollo de nuevas metodologías diagnósticas de la dinámica cardiaca. Entre estas se encuentra la evaluación de las proporciones de la entropía proporcional para diferenciar la normalidad de la enfermedad cardiaca, aunque su capacidad diagnóstica debe comprobarse en escenarios clínicos críticos específicos, como en la falla cardiaca y el infarto agudo de miocardio. Objetivo: Describir evaluaciones diagnósticas de la dinámica cardiaca en pacientes con infarto agudo de miocardio o falla cardiaca aguda. Métodos: En un estudio a doble ciegos con 20 Holter, 5 normales, 8 con falla cardiaca aguda y 7 con infarto agudo de miocardio, se aplicó un método fundamentado en las proporciones de la entropía tomando los valores máximos y mínimos de la frecuencia cardiaca y el número total de latidos por hora, en un mínimo de 18 horas, generando un atractor numérico. Se evaluó cada dinámica con base en la entropía y sus proporciones. Finalmente, se comparó la precisión diagnóstica del método matemático con respecto al diagnóstico clínico convencional. Resultados: Se diferenciaron matemáticamente los casos normales y patológicos mediante la evaluación en 18 horas con el método descrito, encontrando valores de sensibilidad y especificidad del 100 por ciento y un coeficiente Kappa de uno, indicando una concordancia diagnóstica perfecta del método matemático con respecto al diagnóstico clínico. Conclusiones: Las proporciones de la entropía permiten establecer diagnósticos objetivos de la dinámica cardiaca, diferenciando matemáticamente dinámicas normales de aquellas que presentan infarto agudo de miocardio y falla cardiaca aguda(CU)

Introduction: Physical and mathematical theories have allowed the development of new diagnostic methodologies of cardiac dynamics, as one based on the evaluation of entropy proportions to differentiate normality from cardiac disease, although its diagnostic capacity must be yet determined in specific critical scenarios as acute heart failure and acute myocardial infarction Objective: To describe diagnostic evaluations of cardiac dynamics in patients diagnosed with acute myocardial infarction or acute heart failure. Methods: A blind study was developed with 20 Holter registries; 5 normal, 8 with acute cardiac failure and 7 with acute myocardial infarction. Then, a method based on the proportions of the entropy of the numerical attractors was applied. The maximum and minimum values of the heart rate and the total number of beats per hour were taken for at least 18 hours, with which numerical attractors were generated, which measure the probability of consecutive heart rate pairs. An evaluation of all dynamics was made based on the entropy and its proportions. Finally, a comparison between the diagnostic precision of the mathematical method with respect to the conventional clinical diagnosis was performed. Results: Normal cases were mathematically differentiated from the pathological ones through the evaluation of Holter registries for 18 hours, achieving values of sensitivity and specificity of 100 percent as well as a Kappa coefficient of 1, indicating a perfect diagnostic concordance between the mathematical method to diagnose the cardiac dynamics with respect to the clinical diagnosis. Conclusions: The proportions of entropy allow to establish objective diagnoses of cardiac dynamics, mathematically differentiating normal dynamics from those with acute myocardial infarction and with acute cardiac failure(AU)

The 2019 mathematical oncology roadmap.

Whether the nom de guerre is Mathematical Oncology, Computational or Systems Biology, Theoretical Biology, Evolutionary Oncology, Bioinformatics, or simply Basic Science, there is no denying that mathematics continues to play an increasingly prominent role in cancer research. Mathematical Oncology-defined here simply as the use of mathematics in cancer research-complements and overlaps with a number of other fields that rely on mathematics as a core methodology. As a result, Mathematical Oncology has a broad scope, ranging from theoretical studies to clinical trials designed with mathematical models. This Roadmap differentiates Mathematical Oncology from related fields and demonstrates specific areas of focus within this unique field of research. The dominant theme of this Roadmap is the personalization of medicine through mathematics, modelling, and simulation. This is achieved through the use of patient-specific clinical data to: develop individualized screening strategies to detect cancer earlier; make predictions of response to therapy; design adaptive, patient-specific treatment plans to overcome therapy resistance; and establish domain-specific standards to share model predictions and to make models and simulations reproducible. The cover art for this Roadmap was chosen as an apt metaphor for the beautiful, strange, and evolving relationship between mathematics and cancer.

Between Open Sets and Semi-Open Sets / Intermedio entre conjuntos abiertos y semiabiertos / Intermédio entre conjuntos abertos e semiaberto

Abstract We introduce and investigate ω s-open sets as a new class of sets which lies strictly between open sets and semi-open sets. Then we use ω s-open sets to introduce ω s-continuous functions as a new class of functions between continuous functions and semi-continuous functions. We give several results and examples regarding our new concepts. In particular, we obtain some characterizations of ω s-continuous functions.

Resumen Introducimos e investigamos los conjuntos ω s -abiertos como una nueva clase de conjuntos que se ubica estrictamente entre los conjuntos abiertos y semi-abiertos. Usamos los conjuntos ω s -abiertos para introducir las funciones ω s -continuas como un nuevo tipo de funciones que se encuentran entre las funciones continuas y semicontinuas. Proporcionamos varios resultados y ejemplos relacionados con nuestros nuevos conceptos. En particular, obtenemos algunas caracterizaciones de las funciones ω s -continuas.

Resumo Introduzimos e investigamos os conjuntos ω s-abertos como uma nova classe de conjuntos que se localiza estritamente entre os conjuntos abertos e semiabertos. Usamos os conjuntos ω s-abertos para introduzir as funções ω s-contínuas como um novo tipo de função que se encontram entre as funções contínuas e semicontinuas. Proporcionamos vários resultados e exemplos relacionados com nossos novos conceitos. Particularmente, obtemos algumas caracterizações das funções ω s-contínuas.

Ley matemática exponencial aplicada a la evaluación de la dinámica cardíaca en 18 horas / Mathematical exponential law applied to the evaluation of the cardiac dynamics in 18 hours

Antecedentes: la teoría de los sistemas dinámicos estudia la evolución de los sistemas. Mediante esta teoría y la geometría fractal se desarrolló una ley matemática de ayuda diagnóstica a los sistemas dinámicos cardiacos, que permite diferenciar entre normalidad y enfermedad, y la evolución entre los dos estados. Objetivo: confirmar la capacidad diagnóstica de la ley matemática exponencial desarrollada inicialmente para dinámicas cardiacas en 21 horas, para dinámicas evaluadas en 18 horas. Método: se tomaron 400 registros electrocardiográficos, 80 de dinámicas normales y 320 de dinámicas anormales. Se generó una sucesión pseudoaleatoria con el número de latidos/hora y las frecuencias máximas y mínimas cada hora; luego, se construyó el atractor de cada dinámica, para así calcular los espacios de ocupación y la dimensión fractal. Finalmente, se estableció el diagnóstico físico-matemático en 18 y 21 horas y se comparó con el diagnóstico clínico tomado como Gold Standard, obteniendo valores de sensibilidad, especificidad y coeficiente Kappa. Resultados: se encontraron valores de ocupación espacial en la rejilla Kp para normalidad entre 236 y 368 y para estados patológicos entre 22 y 189, lo que permitió diferenciar entre normalidad, enfermedad, y estados de evolución hacia la enfermedad en 18 horas. Se obtuvieron valores de sensibilidad y especificidad del 100 por ciento y coeficiente Kappa igual a 1. Conclusión: la ley matemática permitió dictaminar diagnósticos reduciendo el tiempo de evaluación a 18 horas confirmando así su aplicabilidad clínica(AU)

Dynamical systems theory aims to study the evolution of systems. With this theory and fractal geometry, it was developed a mathematical law of diagnostic utility in cardiac dynamical systems that may differentiate normality from disease and evolution between these two states. Objective: To confirm the diagnostic capacity of the exponential mathematical law initially developed for cardiac dynamics in 21 hours, for dynamics evaluated in 18 hours. Method: There were taken 400 electrocardiographic records, 80 from normal dynamics and 320 from abnormal dynamics. A pseudorandom sequence was generated with the number of beats per hour and the maximum and minimum frequencies each hour; then, the attractors were built for each dynamic, in order to calculate the space occupation and the fractal dimension. Finally the physical and mathematical diagnosis in 18 and 21 hours was established, and compared to clinical diagnosis taken as Gold Standard, obtaining values of sensitivity, specificity and Kappa coefficient. Results: There were found values for spatial occupation in the Kp grid between 236 and 368 for normal cases, and between 22 and 189 for pathological states, which allowed distinguish normality from disease and states of progression to disease in 18 hours. There were obtained values for sensitivity and specificity of 100 percent and a Kappa coefficient equal to 1. Conclusion: The mathematical law allowed to stablish diagnostics by reducing the evaluation time to 18 hours confirming its clinical applicability(AU)

Diagnóstico matemático de dinámica cardiaca en 16 horas y evaluación de variables hemodinámicas en la Unidad de Cuidados Intensivos / Mathematical diagnosis of cardiac dynamics in 16 hours and evaluation of hemodynamic variables in the Intensive Care Unit

Antecedentes: desde los sistemas dinámicos se desarrolló un diagnóstico de la dinámica cardiaca de aplicación clínica en 16 horas, de utilidad en pacientes de Unidad de Cuidados Intensivos. Objetivos: confirmar la capacidad diagnóstica de la nueva metodología de evaluación de la dinámica cardiaca en 16 horas y determinar la evolución de la presión arterial y venosa de oxígeno y dióxido de carbono. Metodología: se tomaron 50 dinámicas, 10 normales y 40 con patologías agudas, tomando la frecuencia cardiaca mínima y máxima, y número de latidos cada hora. Se construyeron atractores y se evaluaron los espacios de ocupación y la dimensión fractal en 21 y 16 horas, comparando ambos diagnósticos físico-matemáticos entre sí. Posteriormente se realizó una confirmación del diagnóstico establecido en 16 horas mediante un estudio ciego de comparación con el diagnóstico convencional. Adicionalmente se tomaron los valores de la presión arterial y venosa de oxígeno y dióxido de carbono de 7 pacientes de Unidad de Cuidados Intensivos y se construyeron atractores caóticos, evaluando los valores mínimos y máximos del atractor en el mapa de retardo. Resultados: se confirmó la capacidad diagnóstica de la metodología en 16 horas para la dinámica cardiaca, con sensibilidad y especificidad de 100 por ciento y coeficiente kappa de 1 respecto al diagnóstico convencional; los valores mínimos y máximos de los atractores de la presión arterial y venosa de oxígeno y dióxido de carbono se encontraron entre 29,60 y 194,40; 24,20 y 56,10; 16,40 y 65,60 y 21,40 y 97,90 respectivamente. Conclusiones: se confirmaron predicciones diagnósticas en 16 horas diferenciando normalidad, enfermedad crónica y enfermedad aguda, útiles para el seguimiento clínico en pacientes de Unidad de Cuidados Intensivos. Las variables se comportaron caóticamente; estos resultados podrían fundamentar aplicaciones clínicas y predicciones de mortalidad. Palabras claves: frecuencia cardiaca, presión arterial de oxígeno, presión arterial de dióxido de carbono, presión venosa de oxígeno, presión venosa de dióxido de carbono, Sistemas Dinámicos, caos, fractales, dinámica no lineal(AU)

Objectives: to confirm the diagnostic ability of the new assessment methodology of cardiac dynamics in 16 hours and determine the evolution of the arterial and venous pressure of oxygen and carbon dioxide. Methodology: 50 dynamic were taken, 10 normal and 40 with acute pathologies, taking the minimum and maximum heart rate, and number of beats per minute. Attractors were constructed and areas of occupation and the fractal dimension in 21 and 16 hours were evaluated, comparing both physical and mathematical diagnosis each other. Subsequently a confirmation of the diagnosis made in 16 hours by a blinded study compared to conventional diagnosis. Additionally, values of the arterial and venous pressure of oxygen and carbon dioxide from 7 Intensive Care Unit patients were taken and chaotic attractors were constructed to evaluate the minimum and maximum values of the attractor on the delay map. Results: The diagnostic capability of the methodology in 16 hours for cardiac dynamic was confirmed, with sensitivity and specificity of 100 percent and kappa coefficient 1 over conventional diagnosis; the minimum and maximum values of the arterial and venous pressure of oxygen and carbon dioxide were found between 29.60 and 194.40; 24.20 and 56.10; 16,40 and 65,60 and 21,40 and 97,90 respectively. Conclusions: Diagnostic predictions were confirmed in 16 hours differentiating normal, chronic and acute disease useful for clinical monitoring in Intensive Care Unit patients. The variables behaved chaotically; these results may inform clinical applications and predictions of mortality. Keywords: heart rate, arterial oxygen pressure, carbon dioxide arterial pressure, venous oxygen pressure, carbon dioxide venous pressure, dynamical systems, chaos, fractals, nonlinear dynamics(AU)

Cancer-meter: measure and cure.

OBJECTIVE: This paper presents a theory and system on "Cancer-Meter'. This idea came through the statement that "cancer is curable if it is measurable". The Cancer-Meter proves that it is possible. This paper proposes the cancer-meter in two ways, theoretical and electronically, as per the measurement and treatment. By the mathematics, first part is defined but the second part is based on computer programming, electrical and electronics. Thus, the cancer-meter is a programmed-electrical-electronic device which measures and cures the cancer both.

Effects of Web-Based Instruction on Nursing Students' Arithmetical and Drug Dosage Calculation Skills.

Drug dosage calculation skill is critical for all nursing students to ensure patient safety, particularly during clinical practice. The study purpose was to evaluate the effectiveness of Web-based instruction on improving nursing students' arithmetical and drug dosage calculation skills using a pretest-posttest design. A total of 63 nursing students participated. Data were collected through the Demographic Information Form, and the Arithmetic Skill Test and Drug Dosage Calculation Skill Test were used as pre and posttests. The pretest was conducted in the classroom. A Web site was then constructed, which included audio presentations of lectures, quizzes, and online posttests. Students had Web-based training for 8 weeks and then they completed the posttest. Pretest and posttest scores were compared using the Wilcoxon test and correlation coefficients were used to identify the relationship between arithmetic and calculation skills scores. The results demonstrated that Web-based teaching improves students' arithmetic and drug dosage calculation skills. There was a positive correlation between the arithmetic skill and drug dosage calculation skill scores of students. Web-based teaching programs can be used to improve knowledge and skills at a cognitive level in nursing students.

Comparison of creatinine and cystatin formulae with 51 Chromium-ethylenediaminetetraacetic acid glomerular filtration rate in patients with decompensated cirrhosis.

BACKGROUND AND AIM: Evaluation of renal function, that is, glomerular filtration rate (GFR), has become very important, but conventional mathematical formulae for GFR assessment are inaccurate in patients with cirrhosis. The aim of the present study was to compare serum creatinine (sCr)-based and serum cystatin C (cysC)-based estimated GFR (eGFR) formulae with 51 Chromium-ethylenediaminetetraacetic acid GFR (51 Chr-GFR) in patients with stable decompensated cirrhosis. METHODS: In 129 Caucasian patients with decompensated cirrhosis, we assessed sCr-based GFRs [Modification of Diet in Renal Disease and chronic kidney disease-epidemiology (CKD-EPI)-sCr formulae], cysC-based GFRs [Hoek, Larsson, and CKD-EPI-cysC equations], and the mathematical formulae, which combined both sCr and cysC [i.e. CKD-EPI-sCr-cysC and the specific for cirrhotics formula recently proposed by Mindikoglu et al. (Mindikoglu-eGFR)]. Multivariate linear regression analysis was used for GFR predictors in our cohort. RESULTS: The correlations between 51 Chr-GFR and all mathematical formulae were good (Spearman r2 > 0.68, P < 0.001). Modification of Diet in Renal Disease and CKD-EPI-sCr had lower bias (6.6 and -4.8, respectively), compared with the other eGFRs, while Mindikoglu-eGFR and CKD-EPI-sCr-cysC formulae had greater precision (17.1 and 17.3, respectively), compared with the other eGFRs. CKD-EPI-sCr and Mindikoglu-eGFR had higher accuracy (39% and 41%, respectively), compared with the other eGFRs. The factors independently associated with the 51 Chr-GFR were age, cysC, and sCr, and the new derived formula had lower bias (0.89) and similar precision (17.2) and accuracy (41%) with Mindikoglu-eGFR formula. CONCLUSION: The specific mathematical formulae derived from patients with cirrhosis seem to provide superior assessment of renal function, compared with the conventional used sCr-based and cysC-based formulae.

Use and Misuse of Laplace's Law in Ophthalmology.

PURPOSE: Laplace's Law, with its compactness and simplicity, has long been employed in ophthalmology for describing the mechanics of the corneoscleral shell. We questioned the appropriateness of Laplace's Law for computing wall stress in the eye considering the advances in knowledge of ocular biomechanics. METHODS: In this manuscript we recapitulate the formulation of Laplace's Law, as well as common interpretations and uses in ophthalmology. Using numerical modeling, we study how Laplace's Law cannot account for important characteristics of the eye, such as variations in globe shape and size or tissue thickness, anisotropy, viscoelasticity, or that the eye is a living, dynamic organ. RESULTS: We show that accounting for various geometrical and material factors, excluded from Laplace's Law, can alter estimates of corneoscleral wall stress as much as 456% and, therefore, that Laplace's Law is unreliable. CONCLUSIONS: We conclude by illustrating how computational techniques, such as finite element modeling, can account for the factors mentioned above, and are thus more suitable tools to provide quantitative characterization of corneoscleral biomechanics.

Uso de modelos geométricos tridimensionais para melhorar a eficácia e segurança da lipoaspiração a laser: estudo prospectivo / Use of 3D geometrical models to improve efficacy and safety of Laser-assisted liposuction: a prospective study

INTRODUÇÃO: Baseada na informação disponível encontram-se dificuldades em estabelecer a dose apropriada de energia a laser para alcançar resultados previsíveis na lipoaspiração a laser. Este estudo avaliou a segurança e eficácia do laser diodo 980-nm com uso de fórmulas geométricas. Essas fórmulas permitem uma qualificação precisa do volume do tecido, e como consequência, uma estimativa da dose de laser necessária. MÉTODOS: Tratase de estudo prospectivo que avaliou consecutivamente 39 pacientes submetidos a lipoaspiração a laser diodo (LLD) 980-nm entre Novembro de 2011 e Novembro de 2013. Quatro padrões geométricos foram adotados para determinar o volume de gordura antes da aplicação do laser. A ultrassonografia foi utilizada para determinar a profundidade da gordura. Foram realizadas biópsias para estabelecer a reação imediata do tecido ao laser relativo à dose do laser. Os resultados estéticos e as complicações foram documentadas. Utilizou-se o coeficiente de correlação de Pearson para determinar a relação entre a energia aplicada e o volume do tecido. RESULTADOS: Um total de 163 áreas anatômicas foram tratadas com LLD 980-nm. A energia aplicada foi baseada no volume de cada área (R = 0,8786). Foi necessário dose de 8 a 14 J/cm3 para produzir dose de hemostase efetiva, e lipectomia mínima. Os resultados foram muito satisfatórios na maioria dos casos. A biópsia relevou lipectomia, balonamento, ruptura de membrana, e rompimento de banda de colágeno; essas mudanças variaram com a dose de radiação. As complicações foram somente edema e hematoma transitório. CONCLUSÃO: O uso de modelos geométricos tridimensionais melhoraram a segurança e eficácia da lipoaspiração a laser, pois permitiram determinar o volume do tecido.

INTRODUCTION: On the basis of the available information, it is difficult to establish the appropriate dose of laser energy with which to obtain predictable results in laser-assisted liposuction. The purpose of this study is to evaluate the safety and efficacy of a 980-nm diode laser by using geometrical formulas. These formulas allow a precise quantification of tissue volume and, as a result, an estimation of the required laser dose. METHODS: This prospective study was conducted to evaluate 39 consecutive patients who underwent 980-nm diode laser-assisted liposuction (LAL) between November 2011 and November 2013. Four geometric patterns were used to determine the volume of fat before laser application. Ultrasonography was used to determine fat depth. Biopsies were conducted to determine immediate laser tissue reaction relative to laser dose. The aesthetic results and complications were recorded. Pearson's correlation coefficient was used to determine the relationship between the applied energy and tissue volume. RESULTS: 163 anatomic regions were treated with 980-nm LAL. The applied energy was relative to the volume in each area (R = 0.8786). 8 to 14 J/cm3 was the dose needed to produce effective hemostasis and minimal lipolysis. The results were very satisfactory in most cases. Biopsy results revealed lipolysis, ballooning, membrane rupture, and collagen band breakage; these changes varied with the radiation dose. The only complications were edema and transient bruising. CONCLUSION: The use of 3D geometrical models improved safety and efficacy of laser-assisted liposuction by permitting accurate determination of the tissue volume.

Improving the accuracy of simulation of radiation-reaction effects with implicit Runge-Kutta-Nyström methods.

The Landau-Lifshitz equation provides an efficient way to account for the effects of radiation reaction without acquiring the nonphysical solutions typical for the Lorentz-Abraham-Dirac equation. We solve the Landau-Lifshitz equation in its covariant four-vector form in order to control both the energy and momentum of radiating particles. Our study reveals that implicit time-symmetric collocation methods of the Runge-Kutta-Nyström type are superior in accuracy and better at maintaining the mass-shell condition than their explicit counterparts. We carry out an extensive study of numerical accuracy by comparing the analytical and numerical solutions of the Landau-Lifshitz equation. Finally, we present the results of the simulation of particle scattering by a focused laser pulse. Due to radiation reaction, particles are less capable of penetrating into the focal region compared to the case where radiation reaction is neglected. Our results are important for designing forthcoming experiments with high intensity laser fields.

Linking physical function outcomes in rheumatology: performance of a crosswalk for converting Health Assessment Questionnaire scores to Short Form 36 physical functioning scale scores.

OBJECTIVE: To evaluate the reliability of a crosswalk, developed in The Netherlands, between the Health Assessment Questionnaire (HAQ) disability index (DI) and the Short Form 36 physical functioning scale (PF-10) in a sample of patients with various rheumatic diseases in the US. METHODS: Baseline data from patients with rheumatoid arthritis (RA; n = 29,020), fibromyalgia (FM; n = 3,776), and systemic lupus erythematosus (SLE; n = 1,609) participating in the National Data Bank for Rheumatic Diseases were analyzed. Reliability of the crosswalk was evaluated by calculating intraclass correlation coefficients (ICCs), and agreement between observed and predicted scores was evaluated using the Bland-Altman approach. RESULTS. The crosswalk produced reliable conversions for both the HAQ DI (ICC range 0.70-0.77) and PF-10 (ICC range 0.73-0.78) in all 3 disease groups. The mean difference between observed and expected scores was close to zero in US patients with RA. For all 3 disease groups, the limits of agreement were fairly wide and conversion at the level of individual patients is not recommended. CONCLUSION: The crosswalk produced reliable conversions at the group level in a crosscultural setting and can be used to convert HAQ DI to PF-10 scores and vice versa in US patients with RA, FM, or SLE.

Substantial risk affects the stage-dependent outcomes of cisplatin-based adjuvant chemotherapy for completely resected non-small cell lung cancer.

PURPOSE: Effective adjuvant chemotherapy (Adj.C) for completely resected non-small cell lung cancer (NSCLC) was recently established. However, there may be some unresolved adverse effects, as have been observed in early stage populations or long-term survivors after other types of Adj.C. The substantial risk in such patients was examined by a mathematical method. METHODS: Variables X and Y were defined by two outcomes of Adj.C: X = the ability to eliminate micro-metastasis and Y = the development of effects that threaten life. Then, the following formula was generated: Survival benefit = (death rate) X - (death rate) X Y - (survival rate) Y. We then solved for X and Y and verified our findings using reported data from clinical trials. RESULTS: By solving two simultaneous equations for the formula applied to the data for stage (1) IA and (2) IIIA in the LACE study (J Clin Oncol 26:5043-5051, 2008), X and Y were 2.6 and 1.9, respectively. When these values were applied in the formula for stage IB patients in the same study, the theoretical (-2.3 %) and reported values (2.5 %) were close. When these were applied for stage IB-IIIA patients in the IALT study (N Engl J Med 350:351-360, 2004), the theoretical (5.0 %) and reported values (4.1 %) were also similar. CONCLUSION: Assuming a substantial risk provides an explanation for the stage-dependent outcomes of Adj.C for completely resected NSCLC.

The applicability of eGFR equations to different populations.

The Cockcroft-Gault equation for estimating glomerular filtration rate has been learnt by every generation of medical students over the decades. Since the publication of the Modification of Diet in Renal Disease (MDRD) study equation in 1999, however, the supremacy of the Cockcroft-Gault equation has been relentlessly disputed. More recently, the Chronic Kidney Disease Epidemiology (CKD-EPI) consortium has proposed a group of novel equations for estimating glomerular filtration rate (GFR). The MDRD and CKD-EPI equations were developed following a rigorous process, are expressed in a way in which they can be used with standardized biomarkers of GFR (serum creatinine and/or serum cystatin C) and have been evaluated in different populations of patients. Today, the MDRD Study equation and the CKD-EPI equation based on serum creatinine level have supplanted the Cockcroft-Gault equation. In many regards, these equations are superior to the Cockcroft-Gault equation and are now specifically recommended by international guidelines. With their generalized use, however, it has become apparent that those equations are not infallible and that they fail to provide an accurate estimate of GFR in certain situations frequently encountered in clinical practice. After describing the processes that led to the development of the new GFR-estimating equations, this Review discusses the clinical situations in which the applicability of these equations is questioned.

Geometrical analysis results of 42 resurfacing shoulder prostheses: A CT scan study.

BACKGROUND: Shoulder resurfacing arthroplasty was introduced in Scandinavia in the early 1980s then developed by SA Copeland. HYPOTHESIS: Resurfacing prostheses restore the normal anatomy of the proximal humerus. Here, our objective was to evaluate humeral resurfacing prosthesis position on radiographs and computed tomography (CT) images. MATERIALS AND METHODS: We retrospectively reviewed 42 consecutive cases seen at a single centre between 2004 and 2009. Mean patient age was 65 years. CT was performed routinely before prosthesis implantation and at re-evaluation. The Copeland Mark III(®) (Biomet France SARL, 26903 Valence, France) implant was used in 32 cases and the Aequalis Resurfacing Head(®) (Tornier France, 38334 Saint-Ismier, France) in 10 cases. The post-implantation CT images were used to measure the angle of inclination, medial humeral offset, lateral glenohumeral offset, and version of the implant. RESULTS: Mean follow-up was 18 months. Compared to baseline, no significant changes were found at re-evaluation for the angle of inclination or lateral glenohumeral offset. In contrast, medial humeral offset increased by 3.47mm, and excessive anteversion of 4.23° compared to the bicondylar line was noted. DISCUSSION: Humeral head resurfacing prostheses restore the overall anatomy of the proximal humeral head. Our CT scan evaluation protocol seems reproducible and enables an evaluation of implant geometry. In our experience, resurfacing arthroplasty restored the native humeral offset. Inadequate retroversion was noted and was probably related to insufficient exposure during surgery. LEVEL OF EVIDENCE: Level IV, retrospective study.