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Many end stage renal disease (ESRD) patients suffer from anemia due to insufficient endogenous production of erythropoietin (EPO). The discovery of recombinant human EPO (rHuEPO) over 30 years ago has shifted the treatment of anemia for patients on dialysis from blood transfusions to rHuEPO therapy. Many anemia management protocols (AMPs) used by clinicians comprise a set of experience-based rules...
We test the robustness of a closed-loop treatment scheduling method to realistic HIV viral load measurement error. The purpose of the algorithm is to allow the accurate detection of an induced viral load minimum with a reduced number of samples. Therapy must be switched at or near the viral-load minimum to achieve optimal therapeutic benefit; therapeutic benefit decreases logarithmically with increased...
Bivalirudin is direct thrombin inhibitor used in patients with heparin-induced thrombocytopenia. A pharmacokinetic and — dynamic model that predicts the partial thromboplastin time (PTT) based on the past infusion rates of bivalirudin following dose adjustment would be useful to guide optimal therapy. In this retrospective study we randomized 132 patients to a derivation and a validation cohort, and...
Machine learning has been largely applied to analyze data in various domains, but it is still new to personalized medicine, especially dose individualization. In this paper, we focus on the prediction of drug concentrations using Support Vector Machines (S VM) and the analysis of the influence of each feature to the prediction results. Our study shows that SVM-based approaches achieve similar prediction...
A multiple dataset model fitting approach for improving parameter reliability in action potential modeling is presented. A robust generic cardiac ionic model employing membrane currents based on two-gate Hodgkin-Huxley kinetics is described. Its generic nature allows it to accurately reproduce action potential waveforms in heterogeneous cardiac tissue by optimizing parameters governing ion channel...
The TASER® Conducted Electrical Weapon (CEW) is used by law enforcement agencies about 900 times per day worldwide and has been shown to reduce suspect and officer injuries by about 65%. However, since a CEW delivers rapid electrical pulses through injected probes, the risk of inducing ventricular fibrillation (VF) has been considered. Animal studies have shown that the tip of the probe must come...
Gastrointestinal (GI) motility disorders are not well understood, resulting in patient management that typically controls symptoms. Patients suffer from reduced quality of life and incur large costs from chronic GI disorders. It is imperative to elucidate underlying mechanisms causing GI motility disorders that, in turn, can facilitate development of treatment such as drug therapeutics. To this end,...
Neurological disease is often associated with changes in firing activity in specific brain areas. Accurate statistical models of neural spiking can provide insight into the mechanisms by which the disease develops and clinical symptoms manifest. Point process theory provides a powerful framework for constructing, fitting, and evaluating the quality of neural spiking models. We illustrate an application...
Efficient methods for Local Field Potential (LFP) signal analysis amenable to interpretation are becoming increasingly relevant. LFP signals are believed, in part, to reflect neural action potential activity, and LFP frequency modulations are linked to spiking events. Furthermore, LFP signals are increasingly accessible in human brain regions previously unreachable due to a proliferation of deep brain...
In this paper we present an autonomic cardiovascular model of a preterm infant of 28 weeks of gestation with a birth weight of 1000 g and a closed ductus arteriosus by the end of the first week, that is capable of describing the complex interactions between heart rate, blood pressure and respiration. The hemodynamic model consists of a pulsatile heart and several vascular compartments, and is regulated...
Analysis of exhaled trace gases is a novel methodology for gaining continuous and non-invasive information on the clinical state of an individual. This paper serves to explore some potential applications of breath gas analysis in anesthesia, describing a monitoring scheme for target site concentrations and cardiac output via physiological modeling and real-time breath profiles of the anesthetic agent...
The application of respiratory mechanics models combined with standardized ventilation maneuvers enable investigations of patients' lung mechanics at the bedside in order to optimize ventilation therapy. Therefore, the underlying dynamic effects of respiratory mechanics (viscoelasticity, inhomogeneity and recruitment) are uncovered by applying various ventilation maneuvers and subsequently captured...
The ability to provide sensory feedback is desired to enhance the functionality of neuroprosthetics. Somatosensory feedback provides closed-loop control to the motor system, which is lacking in feedforward neuroprosthetics. In the case of existing somatosensory function, a template of the natural response can be used as a template of desired response elicited by electrical microstimulation. In the...
Digital stethoscopes are medical devices that can collect, store and sometimes transmit acoustic auscultation signals in a digital format. These can then be replayed, sent to a colleague for a second opinion, studied in detail after an auscultation, used for training or, as we envision it, can be used as a cheap powerful tool for screening cardiac pathologies. In this work, we present the design,...
Chronic cardiovascular diseases directly account for millions of deaths, billions of Euros and a big number of disabilities affecting the world's population. Even though primary and secondary prevention factors are well known, the awareness and the concern of citizens and patients is not big enough to cause a significant change in lifestyle that modifies the increasing trends. Patients and families,...
Heterogeneity in the electrical action potential (AP) properties can provide a substrate for atrial arrhythmias, especially at rapid pacing rates. In order to quantify such substrates, we develop a family of detailed AP models for canine atrial cells. An existing model for the canine right atrial (RA) myocyte was modified based on electrophysiological data from dog to create new models for the canine...
Understanding the physiological impact of drug treatments on patients is important in assessing their performance and determining possible side effects. While this effect might be best determined in individual subjects, conventional methods assess treatment performance by averaging a physiological measure of interest before and after drug administration for n subjects. Summarizing large numbers of...
Most existing human activity classification systems require a large training dataset to construct statistical models for each activity of interest. This may be impractical in many cases. In this paper, we proposed a semi-supervised HMM based activity monitoring system, that adapts the HMM for a specific subject from a general model in order to alleviate the requirement of a large training data set...
Electrical impedance myography (EIM) is a surface-based, non-invasive technique of evaluation of muscle health, involving the application of high frequency, low-amplitude current to the skin over a muscle of interest. Results from a previous animal study suggest that the finite element method can relate disease-induced changes in electrical properties of the muscle to alterations in surface impedance...
In recent years, our group has developed a comprehensive cardiopulmonary (CP) model that comprises the heart, systemic and pulmonary circulations, lung mechanics and gas exchange, tissue metabolism, and cardiovascular and respiratory control mechanisms. In this paper, we analyze the response of the model to hypercapnic conditions and hence focus on the chemoreflex control mechanism. Particularly,...
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