Search PubMed⌕ Search

Biomedical subjects

V Blazek

Publications and source records attributed to V Blazek.

49 records · Page 3Linked to original sources
PubMed1980

[The DIN colour chart 6164 for visual colour characterization in forensic autopsies (author's transl)].

From a series of various colour schemes differently constructed to characterize colour, the colour chart system DIN 6164 is tested here. This system uses three parameters: hue (T), degree of saturation (S), and shadow (D) in such a way that their units represent approximately equal steps in terms of sensation. The advantage over colour atlases is that the normed colour tablets (format 22 X 34 mm) can be taken out and used for direct comparison with the object. Moreover, they may be washed with water or alcohol, a useful property for application in anatomy classrooms. Finally, the values of D, T, and S are printed on their reverse parts and may thus be transformed into the equivalent valence measures Xc, Yc, Zc of DIN 5033 sheet 3.

Adult↗
PubMed1977

[Forensic applications of human skin spectral remission analysis employing a movable integrated sphere (author's transl)].

Spectral remission analysis has been known for long in the medical sciences [1,2,3] but has gained practical importance only in the last years due to the existence of modern techniques and components [4,5]. In this paper a method is presented which enlarges the range of applications of spectral remission and transmission analysis for wavelengths between 380 and 1100 nm considerably. This is achieved by a novel conception of the measuring instrumentation, the advantages of which are discussed and compared with the conventional technique. In detail these advantages are a) employment of a movable instead of a fixed detector (integrated sphere) b) illumination of standard and probe with radiation from a common source c) considerable increase of sensibility due to the use of selective lock-in amplifiers. As a demonstration of the proposed method results are given for 5 different probes of human skin.

Autopsy↗
PubMed1976

[Behavior of the human skin under the influence of electromagnetic radiation in the visible and near infrared region (author's transl)].

In legal medicine and also in other fields of medicine a unique characterization of the optical parameters of biological objects is often necessary. In this paper a method for the description of such probes is presented. The range of wavelength considered is the 400 nm... 1100 nm part of the electromagnetic spectrum. The method is based on the determination of reflection-, transmission and extinction-coefficients. The importance of scattering in the case of nonhomogenous, anisotropic biological matter is stressed.

Electromagnetic Phenomena↗
PubMedDate not supplied

Value of quantitative photoplethysmography for functional vascular diagnostics. Current status and prospects.

The paper presents recent advances in photoplethysmography (PPG) and the role played by PPG in the noninvasive diagnostics of venous and arterial disease. The technical principles of the new self-calibrating photoplethysmographs are explained. These units allow a quantitative evaluation of all measurement data (e.g. time values, amplitudes, flow rates, blood volume kinetics) and hence a precise analysis of both venous and arterial hemodynamics. In combination with appropriate tests (muscle pump test, vein occlusion test, noninvasive venous pressure test, arterial pulse and pressure test), they are suitable for diagnosing and assessing the severity of vascular disease and monitoring its course and the efficacy of therapy. Now that PPG has gained worldwide acceptance as a routine diagnostic technique for venous disease, its spectrum should be expanded to the arterial side as well.

Hemodynamics↗
PubMedDate not supplied

Synergetic interpretation of patterned vasomotor activity in microvascular perfusion: discrete effects of myogenic and neurogenic vasoconstriction as well as arterial and venous pressure fluctuations.

Synergetic concepts allow to identify emergent coordination phenomena between interacting physiological systems, for example between the cutaneous microcirculation, the sympathetic nervous system and the cardiac and pulmonary systems. The temporal patterns (oscillations of various frequencies) that are found in the data obtained with laser-Doppler anemometers (LDA; e.g. Periflux 2 used in the study) can be investigated by simultaneous recording of photoplethysmographic data obtained in the identical region of interest, as well as in cutaneous regions treated with vasoparalytic procedures which permit to record the dynamics of the arterial system. These strategies were applied to studies in the cutaneous microcirculation (volar side of the index fingers) as well as to mucosal microcirculation (maxillar gingiva) in healthy subjects and in patients suffering from autonomic dysfunction (cutaneous microcirculation) or gingivitis. By this procedure, it could be corroborated that - contrary to popular notions - the temporal fluctuations in the LDA records do not necessarily reflect myogenic vasomotion, but can have multiple causes. In a confirming recent study [Schmid-Schönbein et al., J Auton Nerv Syst, 57, 136-140, 1996], we have demonstrated that the LDA fluctuations under conditions of normal ambient temperature and hand position most likely reflect neurogenic vasoconstriction. Under exceptional conditions, different patterns emerge. Prolonged exposure to ambient temperature (18 degrees C) leads to marked vasoconstriction, with occasional vasodilator escape ('miniature hunting reaction'). Normal subjects under gravitational load and in warm environment (28 degrees C ambient) silence their neurogenetic vasoconstriction reactions, which allows sinusoidal vasomotion to dominate. A similar phenomenon is seen in neuropathic patients at 21-24 degrees C (presumably due to structural defects). Fluctuations in LDA signal taken from the healthy gingiva are entrained to arterial, those taken from inflamed gingiva to respiratory activity. The theory and practice of nonlinear analysis is discussed, and data compression procedures allowing to portray characteristic temporal patterns for future diagnostic procedures are presented.

Autonomic Nervous System Diseases↗
PubMedDate not supplied

[Microwave volumetry of the extremities: a technical measuring alternative to the noninvasive venous occlusion test].

Venous occlusion plethysmography is a well-established noninvasive procedure for the investigation of venous outflow disorders. Various different sensor systems are available for the purpose, e.g. photoplethysmography, strain-gauge plethysmography and impedance plethysmography. The technique of microwave volumetry described in this paper is based on the interaction of the electromagnetic fields within the loss medium, tissue, and uses an air-filled resonant cavity as a sensor. As in the case of a microwave oven, this is excited by a high-frequency generator, but involves the use of far less power. As the volume of the measured objects (foot, arm) increases, the losses in the resonator also increase and can be analysed in a computer. The results can be represented in the form of a classical venous occlusion curve.

Arm↗