Zlatko Trajanoski

Zlatko Trajanoski
Medizinische Universität Innsbruck · Division of Bioinformatics

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66
Publications
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1,428
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Publications

Publications (66)
Article
Glucocorticoids are the major immunomodulating hormones in the human body. Recently, increasing interest in androgens as immunomodulators has emerged. In particular, Dehydroepiandrosterone (DHEA) has been suggested as beneficial in the treatment of some autoimmune disorders. However, the action and role of testicular and adrenal androgens on human...
Article
Full-text available
We determined whether the physiologic changes that accompany food intake or sympathetic activation by beta-adrenergic stimulation result in alterations in the secretion of leptin, tumor necrosis factor-alpha (TNF alpha), or interleukin-6 (IL-6) by serially sampling sc abdominal adipose interstitial fluid by open-flow microperfusion before and after...
Article
Full-text available
Recent experimental evidence suggests that estimates of glucose effectiveness (S(G)) from the minimal model of unlabeled glucose disappearance (Cold-MM) are in error. The single-compartment glucose distribution assumption embedded in the model has been indicated as a possible source of error. In this study, to directly examine the single-compartmen...
Article
To gain direct access to the interstitial fluid (ISF), a new technique called open-flow microperfusion has been evaluated. This method is based on a double-lumen catheter with macroscopic (0.3-0.5 mm diameter) perforations that is inserted into the subcutaneous adipose tissue and constantly perfused. Thus partial equilibration between the ISF and t...
Article
Full-text available
Open flow microperfusion and a novel calibration technique (ionic reference technique) were evaluated for the frequent measurement of the absolute lactate concentration in sc adipose tissue. Furthermore, the influence of the plasma insulin concentration on the lactate concentration of sc adipose tissue was investigated during hyperglycemia. Sixteen...
Article
The objective of the study was to evaluate the performance of an amperometric enzyme based lactate sensor and to investigate the possibility of replacing a double lumen catheter based blood withdrawal system with a heparin coated single lumen system. The inner lumen of a double lumen catheter which was placed in a peripheral vein was perfused with...
Article
The objective of the study was to evaluate the performance of an amperometric enzyme based lactate sensor and to investigate the possibility of replacing a double lumen catheter based blood withdrawal system with a heparin coated single lumen system. The inner lumen of a double lumen catheter which was placed in a peripheral vein was perfused with...
Article
The present study was carried out to investigate in vivo in healthy humans the method of open-flow microperfusion for monitoring of the subcutaneous (s.c.) lactate concentration during rest and cycle ergometer exercise. Using open-flow microperfusion, a perforated double lumen catheter with an inflow and an outflow connection is inserted into the s...
Article
A neural predictive controller for closed-loop control of glucose using subcutaneous (s.c.) tissue glucose measurement and s.c. infusion of monomeric insulin analogs was developed and evaluated in a simulation study. The proposed control strategy is based on off-line system identification using neural networks (NN's) and nonlinear model predictive...
Article
A novel strategy for closed-loop control of glucose using subcutaneous (s.c.) tissue glucose measurement and s.c. infusion of monomeric insulin analogues was developed and evaluated in a simulation study. The proposed control strategy is an amalgamation of a neural network and nonlinear model predictive control (NPC) technique. A radial basis funct...
Article
Full-text available
To evaluate the clinical and analytical accuracy of home blood glucose meters. Six blood glucose meters--Reflolux S (Boehringer Mannheim, Mannheim, Germany), One Touch II (LifeScan, Milpitas, CA), Glucocard Memory (Menarini, Florence, Italy), Precision QID (Medisense, Cambridge, U.K.), HaemoCue (HaemoCue, Angelholm, Sweden), and Accutrend alpha (Bo...
Article
The purpose of this study was to begin the development and testing of an Expert System (ES) to screen officer personnel records being considered for Command and General Staff College (CGSC). The study included a review of the Artificial Intelligence (AI) literature relevant to the military and human resource management, problem selection, knowledge...
Article
The aim of this study was the measurement of the absolute subcutaneous lactate concentration in the interstitial fluid of subcutaneous adipose tissue using open flow microperfusion and a established calibration protocol (no net flux protocol). Using open flow microperfusion a perforated double lumen catheter was set into the subcutaneous adipose ti...
Article
The objective of this study was to develop and evaluate a strategy for closed-loop control of glucose using subcutaneous (s.c.) glucose measurement and s.c. infusion of monomeric insulin analogues. The method was based on off-line identification of the glucoregulatory system using neural networks and a nonlinear model predictive controller. Numeric...
Article
A mass producible miniaturized device for the simultaneous monitoring of different metabolites was realized by assembling of a biosensor array produced by thin film technology with a flow through cell produced by printed circuit board technology. The biosensor array comprises four working electrodes which can be individually configured. Glucose-lac...
Article
Full-text available
To evaluate a novel technique for on-line continuous glucose measurement in subcutaneous adipose tissue, and to investigate its accuracy for detection of hypoglycemia. The method combined an open-flow microperfusion of subcutaneous adipose tissue using a double lumen catheter and an extracorporeal sensor cell. An isotonic ion-free solution was perf...
Article
In this study, intravenous glucose tolerance tests were performed in a group of insulin-dependent diabetic subjects who had no residual insulin secretion. Under these circumstances, it was possible to measure directly glucose-mediated glucose disappearance in response to intravenous glucose administration. Two models, the minimal model of unlabeled...
Article
The objective of this study was to develop and evaluate a strategy for closed-loop control of glucose using subcutaneous (s.c.) glucose measurement and s.c. infusion of monomeric insulin analogues. The method was based on off-line identification of the glucoregulatory system using neural networks and a nonlinear model predictive controller. Numeric...
Conference Paper
The objective of this study was to evaluate a system for continuous measurement of lactate in whole blood. The continuously withdrawn samples were obtained by means of two different methods for the prevention of blood coagulation. The first one dealt with a double lumen catheter. The tip of the catheter was rinsed with heparin solution via the inne...
Article
Full-text available
The objective of the study was to develop and evaluate a portable device for continuous fractionated blood sampling and continuous ex vivo monitoring of blood glucose. The inner lumen of a double lumen catheter (18 gauge x 45 mm) was placed in a peripheral vein and perfused with heparin solution (1.4 U min-1). The outer lumen was used to collect he...
Article
Full-text available
To evaluate the accuracy of home blood glucose meters during hypoglycemia. Six blood glucose meters-One Touch II (LifeScan, Milpitas, CA), Companion II (Medisense, Cambridge, U.K.), Reflolux (Boehringer Mannheim, Mannheim, Germany), Accutrend (Boehringer Mannheim), Elite (Bayer, Munich, Germany), and HemoCue (HemoCue, Angelholm, Sweden)-were compar...
Article
A miniaturized device for simultaneous measurement of glucose and lactate levels was produced by means of photopatterning of enzyme-containing photosensitive membrane precursors. This device shows no cross-talk and a lifetime for both the glucose and the lactate sensors of more than 2 weeks when continuously operated in undiluted bovine serum. Line...
Article
A filter based on fuzzy logic for state estimation of a glucoregulatory system is presented. A published non-linear model for the dynamics of glucose and its hormonal control including a single glucose compartment, five insulin compartments and a glucagon compartment was used for simulation. The simulated data were corrupted by an additive white no...
Conference Paper
The objective of the study was to develop a measurement system for blood glucose and lactate and to evaluate a portable blood withdrawal system. For the blood withdrawal system a double lumen catheter was used. The inner lumen of the catheter was perfused with heparin solution and the outer lumen was used to collect the blood samples into 56 vacuum...
Article
Ziel dieser Studie war die Evaluierung eines Hypoglykämiewarnsystems für Diabetes Patienten nach dem Prinzip der offenen Mikroperfusion. Das System basiert auf einem perfundierten im subkutanen Gewebe liegenden doppellumigen Katheter und einer ex vivo liegenden Durchflußmeßzelle zur enzymatischen Bestimmung der Glucosekonzentration und zur Messung...
Article
In der vorliegenden Studie wurde die hepatische Glukoseproduktion (HGP) während eines euglykämischen hyperinsulinämischen Clamps mit deuterium-markierter Glukose bestimmt Es konnte gezeigt werden, daβ die aus einem Ein-Kompartment-Modell berechnete HGP einen physiologischen Verlauf aufweist, wenn die Plasmaanreicherung konstant gehalten wird.
Conference Paper
In order to directly measure glucose-mediated effects on glucose disappearance, intravenous glucose tolerance tests were performed in insulin-dependent diabetic subjects without dynamic insulin response after glucose administration. Two models, the minimal model of unlabeled glucose kinetics and a linear two-compartment model, were identified from...
Conference Paper
The aim of this study was to evaluate a system for measurement of lactate concentration in subcutaneous adipose tissue during exercise. The system is based on a monitoring device, an enzyme based lactate sensor and a conductivity measurement for the estimation of the recovery. The system was evaluated in five healthy volunteers. It could be shown t...
Conference Paper
The objective of this study was to evaluate a novel method for interstitial fluid sampling. The method combines open flow microperfusion of subcutaneous adipose tissue and conductivity measurement of the sampled fluid for the estimation of the recovery. Interstitial fluid samples were obtained from 6 healthy volunteers in the fasting state and from...
Conference Paper
A system to monitor the subcutaneous tissue glucose concentration continuously and ex vivo with a portable device is presented. The method of open flow microperfusion was evaluated during hyperinsulinemic hypoglycaemic clamp experiments in 6 healthy volunteers. During these experiments good agreement (correlation coefficients 0.85-0.95, n=65-91) be...
Conference Paper
A 63 channel body surface potential mapping system has been developed. The system consists of a signal conditioning unit and a personal computer based data aquisition unit. Sixty-three Ag/AgCl electrodes are positioned on the anterior and posterior side of the human thorax. The positions of the electrodes are determined with a magnetic tracker syst...
Conference Paper
The subcutaneous (s.c.) route for closed-loop control of glucose was evaluated. Experimental studies on s.c. tissue glucose monitoring and numerical studies on continuous s.c. infusion of monomeric insulin analogues, and neural predictive control of glucose were carried out. The control framework combines: (1) off-line system identification using t...
Article
Full-text available
A pharmacokinetic model is modified to enable quantitation of subcutaneous insulin absorption following insulin injections of soluble insulin and monomeric insulin analogues. The model for soluble insulin includes diffusion, equilibration between hexameric and dimeric insulin and absorption of dimeric insulin molecules. Numerical approximation is c...
Article
Eine Methode zur Messung der subkutanen Gewebsglucose sowohl im hyper- als auch im hypoglykämischen Bereich wird in dieser Arbeit vorgestellt. Dabei kommt das Prinzip der offenen Perfusion zur Anwendung: ein Doppellumenkatheter wird in das subkutane Gewebe gesetzt, wobei durch das innere Lumen isotones, ionenfreies Perfusat strömt und über das äuße...
Article
In der-vorliegenden Studie wird der intravenöse Glucosetoleranztest (FVGTT) mit deuterium-markierter Glucose untersucht. Es wurden drei Minimalmodelle, aus denen die Insulinsensitivität und die hepatische Glucoseproduktion (HGP) berechnet werden können, analysiert. Aus einem FVGTT mit markierter Glucose bei einem gesunden Probanden konnten die Mode...
Article
A deconvolution method based on a simple clinical protocol for evaluating pathological gastric emptying is presented. 22 patients witb type I diabetes mellitus and 11 healthy volunteers were given a semisolid test meal containing D-xylose. In ten subjects a scintigrapbic method was simultaneously applied in order to validate the presented method. U...
Article
A neural network for non-linear system identification and prediction is presented. A regularization network which is equivalent to radial basis function neural network was used for identification of a Non-linear AutoRegressive Moving Avarage model with/without eXogenous inputs (NARMAX/NARMA). NARMAX system identification and validation was performe...
Conference Paper
A framework for non-linear identification of glucose kinetics using neural networks is presented. The framework combines: recursive input-output system representation (Non-linear AutoRegressive model with eXogenous inputs (NARX)); approximation method derived from regularization theory and based on radial basis function neural networks; and validat...
Conference Paper
A system for continuous simultaneous ex vivo monitoring of blood glucose (b.g.) and subcutaneous tissue fluid glucose (s.g.) is presented. The system is based on two portable devices: (1) a continuous ambulatory blood sampler with a miniaturized thin-film glucose sensor in the sampling line and (2) a s.g. monitoring device using open tissue perfusi...
Conference Paper
A PC-based monitoring system has been developed, which is able to acquire and analyse up to 32 physiological signals of different modality with maximum overall sample frequency of 48 kHz. New algorithms can be added and polygraphical presentation of results can be adjusted for special applications. The system was used to study noninvasively stroke...
Article
A mathematical model for the absorption of subcutaneously administered soluble insulin is presented. A dissociation-diffusion model with distributed parameter was transformed into a lumped parameter model by spatial discretization. Simulations of various insulin injections with this model demonstrate volume and concentration dependant absorption as...
Conference Paper
A 192 channel intraoperative cardiac activation mapping system is presented for clinical investigations and routine surgery. The system consists of a signal conditioning unit with software programmable gains (40,100,200,500 in blocks of 48 channels, and 1,2, 4, 8, 16 individually), bandwidths (200, 500 Hz low pass, and DC, 0.1,15 Hz high pass), and...
Article
A subcutaneous insulin absorption model is presented for parameter estimation from the time course of plasma insulin. Modifications of a published model were made for the absorption of soluble insulin and monomeric insulin analogues in the range of therapeutic concentrations and volumes. The modified diffusion-dissociation model with distributed pa...
Article
Ein Radial Basis Function Neuronales Netzwerk wurde als NARMAX-Modell zur Vorhersage von Blutzuckerwerten bei Patienten mit Typ I Diabetes Mellitus verwendet. Ambulant aufgezeichnete Daten von 10 Patienten wurden zunächst einem Compartment Modell zugeführt. Die so berechneten Zustandsgrößen stellten den Eingangsvektor und die gemessene Blutzuckerwe...
Article
Ein pharmakokinetisches Modell der subkutanen Insulinabsorption wurde modifiziert, um Insulinabsorption von klinisch relevanten Dosierungen und Ronzentrationen zu simulieren. Es wird angenommen, daß das Insulin nur in dimerer Form absorbiert wird und daß die reversible Insulinbindung im subkutanen Depot vernachlässigbar ist. Die Insulin-umwandlung...
Article
Introduction Continuous estimation of glucose concentration is an important prerequisite for the development of an artificial pancreas or of a system for hypoglycaemia detection. Recently, two minimally invasive systems based on interstitial fluid sampling and ex-vivo glucose measurement using enzymatic sensors were developed. In this study we revi...

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