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Background/Aims: Steal syndrome is a well-known complication of arteriovenous shunt placement. Increased frequency of Raynaud’s phenomenon (RP) especially concerning shunt limb is reported among hemodialysis (HD) patients. The aim of the study was to assess the relation of impairment of peripheral circulation diagnosed with cold stress test (CST) and thermography to the AV shunt location and markers of endothelial dysfunction in HD patients. Methods: The study group comprised 21 patients (6 male, 15 female, mean age 32.6 ± 15.0 years) treated with HD for a mean of 69 ± 54 months. 10 healthy individuals (4 male, 6 female, mean age 38.6 ± 14.7 years) served as controls. The diagnosis of RP was made upon the results of thermographic measurements during CST. Von Willebrand factor activity and antigen, endothelin-1 and plasma total homocysteine (tHcy) were measured in all subjects. Results: RP was found significantly more often in HD patients than in controls: 11/21 vs. 1/10 (p = 0.04). RP occurred in both hands in 7/11 (64%) patients. tHcy was higher in HD patients than in the controls (31.7 ± 13.9 vs. 10.9 ± 3.2 μg/l, p < 0.0001). tHcy and von Willebrand factor antigen were significantly higher in the RP-positive than RP-negative patients or controls. Conclusion: Small vessel dysfunction diagnosed as positive RP is a frequent finding in HD patients. It seems that endothelial injury rather than AV shunt steal syndrome is responsible for development of RP in HD patients.Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Body temperature is one of the most important physiological parameters of a human being used to assess his basic vital functions. In medical practice, various types of measuring instruments are used to measure temperature, such as liquid thermometers, electronic thermometers, non-contact ear thermometers, and non-contact forehead thermometers. Such body temperature measurement techniques require the connection of appropriate sensors to a person, and non-contact thermometers operate over short distances and force a specific position of the person during the measurement. As a result, using the above methods, it is practically impossible to perform body temperature measurements of a moving human being. A thermal imaging camera can be used effectively for the purpose of the temperature measurement of moving objects, but the remote measurement of a human body temperature using a thermal imaging camera is affected by many factors that are difficult to control. Accurate remote measurement of human body temperature requires a measurement system that implements a specialized temperature determination algorithm. This article presents a model of a measurement system that facilitates the development of a highly accurate temperature measurement method. For the model, its parameters were determined on the calibration stand. The correct operation of the developed method and the effectiveness of temperature measurement have been confirmed by tests on a test stand using reference radiation sources.

This paper presents a simple engineering method for evaluating the optical power emitted by light-emitting diodes (LEDs) using infrared thermography. The method is based on the simultaneous measurement of the electrical power and temperature of an LED and a heat source (resistor) that are enclosed in the same plastic packaging under the same cooling conditions. This ensures the calculation of the optical power emitted by the LED regardless of the value of the heat transfer coefficient. The obtained result was confirmed by comparing it with the standard direct measurement method using an integrated sphere. The values of the estimated optical power using the proposed method and the integrated sphere equipped with a spectrometer were consistent with each other. The tested LED exhibited a high optical energy efficiency, reaching approximately η ≈ 30%. In addition, an uncertainty analysis of the obtained results was performed. Compact modelling based on a thermal resistor network (R th ) and a 3D-FEM analysis were performed to confirm the experimental results.

We propose a new method of compensation for drifts in thermal cameras using a filter in place of a shutter. The latter method requires periodically closing the camera, thus causing the images to appear frozen frequently. Our technique of replacing the shutter with a filter eliminates this frozen image problem. In this paper we discuss the principles of the new method and present the obtained results.

Introduction: The aim of the study was to determine the effect of long-term cyclosporine A (CsA) treatment in children with idiopathic nephrotic syndrome on autonomic nerve function and peripheral blood flow assessed with thermography., Material and Methods: The study group consisted of 19 nephrotic children treated with cyclosporine A compared to 16 healthy children. The assessment of blood flow was made based on the results of thermographic measurements during the cold stress test by an infrared radiation registering camera. Ewing's battery of non-invasive tests was used to assess autonomic function., Results: The study showed diminished temperature increase after the cooling test in children with nephrotic syndrome treated with CsA. Sympathetic activity test results were comparable to healthy children., Conclusions: It may be hypothesized that cyclosporine A administered even in low doses induces small vessel dysfunction measured by the thermographic method. This effect seems to be independent of sympathetic nervous system involvement, which was absent in cyclosporine A treated nephrotic children.