Biomedical subjects

M Stańczyk

Publications and source records attributed to M Stańczyk.

10 recordsLinked to original sources

PubMed2005

Increased incidence of micronuclei assessed with the micronucleus assay and the fluorescence in situ hybridization (FISH) technique in peripheral blood lymphocytes of nurses exposed to nitrous oxide.

It has been postulated that exposure to nitrous oxide and halogenated anaesthetics is associated with various adverse health effects such as neurological and reproductive abnormalities or impairment of hepatic functions. In spite of the quite well known genotoxic effects of exposure to nitrous oxide in vivo, the mechanisms of these effects are still not clear. The aim of this study was to assess the frequency of micronuclei and to identify the type of chromosomal damage (clastogenic or aneugenic) in peripheral blood lymphocytes of operating-room nurses exposed to nitrous oxide. The study group comprised 46 women working at departments where the concentration of nitrous oxide ranged from 14 to 2308 mg/m3. The control population was composed of 28 women employed in the same hospitals but in non-surgical departments. The clastogenic/aneugenic effect of nitrous oxide was evaluated in lymphocytes using the standard micronucleus (MN) assay in combination with the fluorescence in situ hybridization (FISH) technique with pancentromeric probes. The results show a significant increase of the MN frequency in lymphocytes of exposed nurses compared with the control group (4.36+/-2.23 versus 9.02+/-4.67). The multiple regression analysis revealed a statistically significant relationship (p=0.0009) between MN frequency and exposure status, indicating that the level of exposure was the main factor affecting chromosomal damage. As assessed by FISH analysis, the overall frequencies of centromere-positive MN in the control and exposed groups were 43 and 49%, respectively. The increase observed in the exposed group may suggest a slight, statistically insignificant pro-aneugenic effect of exposure to nitrous oxide.

Adult↗

PubMed2005

Study on modelling of PMMA bone cement polymerisation.

This contribution is concerned with the modelling of PMMA-based bone cement polymerisation process and the associated heat effect. While existing models use description in terms of the so-called polymerisation fraction to fit the experimental data, the new model is constructed in such a way as to mimic the chemical processes taking place in the cement dough. The important phenomena are identified and the mathematical formulation is proposed.

Bone Cements↗

PubMed2004

Thermal analysis of bone cement polymerisation at the cement-bone interface.

The two major problems that have been reported with the use of polymethylmethacrylate (PMMA) cement are thermal necrosis of surrounding bone due to the high heat generation during polymerisation and chemical necrosis due to unreacted monomer release. Computer models have been used to study the temperature and monomer distribution after cementation. In most of these models, however, polymerisation is modelled as temperature independent and cancellous bone is modelled as a continuum. Such models thus cannot account for the expected important role of the trabecular bone micro-structure. The aim of this study is to investigate the distribution of temperature and monomer leftover at the cancellous bone-cement interface during polymerisation for a realistic trabecular bone-cement micro-structure and realistic temperature-dependent polymerisation kinetics behaviour. A 3-D computer model of a piece of bovine cancellous bone that underwent pressurization with bone-cement was generated using a micro-computed tomography scanner. This geometry was used as the basis for a finite element model and a temperature-dependent problem for bone cement polymerisation kinetics was solved to simulate the bone cement polymerisation process in the vicinity of the interface. The transient temperature field throughout the interface was calculated, along with the polymerisation fraction distribution in the cement domain. The calculations revealed that the tips of the bone trabeculae that are embedded in the cement attain temperatures much higher than the average temperature of the bone volume. A small fraction of the bone (10%) is exposed to temperatures exceeding 70 degrees C, but the exposure time to these high temperatures is limited to 50s. In the region near the bone, the cement polymerisation fraction (about 84%) is less than that in the centre (where it is reaching values of over 96%). An important finding of this study thus is the fact that the bone tissue that is subjected to the highest temperatures is also subjected to high leftover monomer concentration. Furthermore the maximum bone temperature is reached relatively early, when monomer content in the neighbouring cement is still quite high.

Animals↗

PubMed2001

[Sevofluran in pediatric practice--personal experience].

Sevofluran a new inhalational anesthetic is a preferred anesthetic agent for induction and maintenance of pediatric anesthesia because of its rapid induction, recovery characteristics and acceptable cardiovascular profile--now also accessible in Poland. Sevofluran isn't an ideal anesthetic, and the issue of postoperative excitement, potential nephrotoxicity requires clarification. This study was designed to compare the emergence characteristics of sevoflurane with halotane anaesthesia in paediatric patients having various surgical intervention. 102 children divided for subgroup of premedicated and nonpremedicated, underwent inhalation induction with nitrous oxide/oxygen and sevofluran or halotane. Incremental doses of either study drug were added until loss of eyelash reflex was achieved. We didn't use higher concentrations of sevoflurane than 5.5 Vol% and 3.5 Vol% for halothane. Sevoflurane patients has a greater incidence of emergence agitation.

Adolescent↗

PubMed1974