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Biomedical subjects

I Hrazdira

Publications and source records attributed to I Hrazdira.

At least 19 recordsLinked to original sources
PubMed2005

[Possibilities of ultrasonographic differentiation of neck and axillary lymphadenopathy].

Technical development of ultrasonography connected with improvement of resolving power has enlarged possibilities in detection and differentiation of lymph nodes. In the current clinical practice ultrasonic examination is most frequently requested for assessment of lymph nodes in neck and axillary regions in connection with inflammatory or tumour diseases. Although the final diagnosis must be confirmed histopathologically, there exist some echographic criteria enabling with a great probability to appoint the malignant character of lymph nodes: round shape expressed by the shape index near to 1, sharp edges, heterogeneous echostructure and mainly loss of the hilar sign. In highly enlarged lymph nodes these criteria can be completed by colour Doppler examination revealing a peripheral type of intranodal vascularity and increased value of impedance indices in supply artery (RI > 0.8, PI > 1.8).

Axilla↗
PubMed2003

[Color Doppler methods and their diagnostic significance].

Colour Doppler methods represent an important progress in diagnostics of vascular diseases. Conventional spectral and colour imaging of blood flow velocity have been during last years completed by new modalities, such as power Doppler, application of echocontrast agents, contrast harmonic imaging and tissue Doppler imaging. These new methods have improved diagnostics in several ways, especially in identification of small vessels, in detection of low flows and in perfusion assessment.

Blood Flow Velocity↗
PubMed2001

Changes in microtubules and microfilaments due to a combined effect of ultrasound and cytostatics in HeLa cells.

Treatment of HeLa cells with low intensity ultrasound and two cytostatic drugs, cycloplatin and methotrexate, resulted in a partial disassembly of microtubules and microfilaments. This disassembly was due to depolymerization and subsequent erroneous repolymeration of essential cytoskeletal proteins, resulting in formation of unusual arrangements, mainly small, granule-like structures. The combined action of ultrasound and cytostatics had a synergistic effect dependent on both the concentration of the drug and the time of sonication. The demonstrated changes in the cytoskeleton are considered to be non-specific to ultrasound treatment, reflecting only an altered vital state of the treated cells.

Actin Cytoskeleton↗
PubMed1998

Ultrasonically induced alterations of cultured tumour cells.

OBJECTIVE: The aim of this study was to establish: (i) which phase of the cell cycle is most sensitive to ultrasonic action; and (ii) whether and in which way ultrasound can influence components of the cytoskeleton. METHODS: HeLa cell monolayers grown on glass cover-slips in DEM medium were used in all experiments. For proliferation studies, the cell monolayers were trypsinized and the cells were resuspended in fresh medium. The structure of the cytoskeleton was studied by means of the indirect immunofluorescence method. The cells were sonicated by a cw ultrasound of 0.8 MHz at low SA intensities (50, 100 and 500 mW/cm2) for 5 and 10 min. RESULTS: The analysis of proliferation demonstrated that cells were most sensitive when undergoing M- and S-phases of the cell cycle. The ultrasonically induced disassembly of cytoskeleton components was most marked in microtubules and microfilaments due to depolymerization of basic proteins (tubulin and actin). The reaction of intermediate filaments was distinctly weaker. CONCLUSIONS: In-vitro treatment of tumour cells with low intensity ultrasound results in partial inhibition of proliferation as well as in partial disassembly of all components of the cytoskeleton. Ultrasonically induced changes of the cytoskeleton seem to be non-specific and temporary.

Actins↗
PubMed1995

Effect of ultrasound on DNA synthesis in tumor cells.

The objective of this study was to consider the influence of continuous-wave (CW) ultrasound (800 kHz) on DNA synthesis in Ehrlich ascitic tumor cells in vitro. The 10-min irradiation was carried out in rotating polyethylene tubes (5 rpm). Incorporation of 3H-thymidine was employed to detect DNA synthesis. Replication and unscheduled (repair) DNA synthesis were distinguished by means of hydroxyurea treatment before insonation. It was established that the use of 0.5 W/cm2 and 1.0 W/cm2 (ISA) CW ultrasound interfered with DNA synthesis showing up as inhibition. The inhibition became most noticeable when starting insonation in a sample cooled to 5 degrees C. During insonation, the sample temperature was allowed to increase to the ambient (water bath) temperature of 37 degrees C. However, at an ultrasound intensity (SA) of 0.1 W/cm2 such inhibition was not proven, but a moderate stimulation of DNA synthesis was demonstrated. Changes in DNA synthesis after insonation were found to be transient because of a lack of stimulatory and/or inhibitory ultrasound effects after 1-h incubation at 37 degrees C. In our experimental conditions no effects on DNA synthesis due to the effects of the insonated medium on the cells were discernible. No statistically significant changes in unscheduled DNA synthesis were observed. Possible action mechanisms are discussed.

Animals↗
PubMed1993

Disassembly of microtubules due to low intensity ultrasound.

HeLa and MCF cell monolayers growing on glass cover-slips were sonicated using continuous wave ultrasound at low intensity levels approaching diagnostic conditions. The disassembly of cytoplasmic microtubules immediately after sonication was demonstrated using indirect immunofluorescence. The recovery from exposure to ultrasound, i.e. the reassembly of microtubules, was observed in the cultured cells 2 h after the sonication was discontinued.

Fluorescent Antibody Technique↗
PubMed1992

[Abdominal ultrasonography].

The author characterizes ultrasonography as a modern diagnostic imaging method. The main attention is drawn to abdominal ultrasonography, especially to its indications and differential diagnostics. The author evaluates critically the present state and further foreseen development of this method. Finally he makes a statement on the question of safety.

Abdomen↗