PubMed Health⌕ Search

Biomedical subjects

V Blazek

Publications and source records attributed to V Blazek.

At least 19 recordsLinked to original sources
PubMed1991

[D-SGP Duo--a new plethysmography for acral, arterial and venous blood pressure measurement].

This is to present a new portable plethysmograph using modern microprocessor technology, a two-channel digital strain gauge plethysmograph (D-SGP Duo). This system contains two strain gauges and a pressure gauge and has measuring programmes for thrombosis screening (venous occlusion test) and for the acral blood pressure measurement. For the first time it is possible to determine not only the acral systolic arterial pressure but also the acral venous blood pressure. Examples of application are given.

Blood Pressure↗
PubMed1991

[Computer simulation of the dynamics of the arterial system for various cardiovascular situations].

The simulation model describes the basic characteristics of the pulse in a wide range of arterial vessels. By comparison of simulated stenosis with photoplethysmographic registered curves of patients suffering from stenosis, it could be shown, that also pathologic hemodynamics can be adequately described. A new sight of dicrotic pulse generation was derived by the simulated removal of large arteries. This led to the hypothesis of decoupled, autonomous multiple reflections in the arteries of the arm, the leg and the head.

Arterial Occlusive Diseases↗
PubMed1989

[Laser ablation of the nucleus pulposus: optical properties of degenerated intervertebral disk tissue in the wavelength range 200 to 2200 nm].

Percutaneous ablation of degenerative disk material by laser has been introduced recently as an alternative to enzymatic or mechanical discectomy. The optical properties of degenerative disk material were evaluated in the range from 200 to 2200 nm, which includes most of the laser wavelengths used for medical purposes. Remittance rate was determined in 16 post-mortem disks using a spectrophotometric unit and rate of absorption and scatter were calculated. High rates of diffuse remittance were found for classical laser wavelengths such as the argon or the Nd:YAG II laser indicating only low rates of absorption. In contrast, much higher rates of absorption were determined for excimer or mid-infrared lasers as well as for the Nd:YAG I (1320 nm), which appear more appropriate for laser discectomy than the Nd:YAG (1064 nm) laser.

Humans↗
PubMed1987

Optical properties of human brain tissue, meninges, and brain tumors in the spectral range of 200 to 900 nm.

Considering the increasing use of lasers in neurosurgery and the increasing number of wavelengths of laser light becoming available, we evaluated optical properties between 200 and 900 nm of meninges, normal human brain tissue, and brain tumors. We used a two-beam spectral photometer with an integrating sphere as the measuring instrument. The material consisted of 13 brains and 1 specimen each of dura mater, falx, and arachnoid obtained at autopsy and 30 samples of brain tumors removed during operation. In tissue samples more than 5 mm thick, the relative levels of absorption and scattering were estimated from the relative level of reflection measured according to the Kubelka-Munk theory. In thin tissue slices, penetration depth was calculated according to Beer's law from measurements of reflection and transmission. Generally, in all tissues there was an increase of reflection, scattering, and penetration depth and a decrease of absorption from the ultraviolet up to the near infrared spectral range interrupted by the absorption bands of hemoglobin. Within the ultraviolet spectral range, no major differences of optical properties were observed. Within the visible and near infrared spectral range, white matter reflected most of the incident power and showed the lowest level of absorption and the shortest penetration depth. Low grade gliomas revealed optical properties similar to those of gray matter. In comparison with normal brain tissue, meningiomas and glioblastomas showed significantly higher levels of absorption calculated according to the Kubelka-Munk theory from reflection measurements in thick tissue samples, but also deeper penetration obtained from measurements of reflection and transmission in thin slices, especially within the near infrared spectral range.

Aged↗
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↗