Chromosomal abnormalities and DNA image cytometry of haematological neoplasms in fine needle aspirates of lymph nodes.

The current diagnostics of haematological neoplasms along with morphological analysis, immunophenotyping and molecular analysis inevitably includes cytogenetic analysis. In this work the possibility of cytomorphological subclassification of haematological neoplasms from lymph node fine needle aspirates was examined without depending upon the referential histological diagnosis and cytogenetic analysis. In addition, the feasibility of cytogenetic analysis of the material obtained by lymph node fine needle aspiration (FNA) was examined. By analysing the findings of cytogenetic analysis and DNA image cytometry, it was decided to examine the possibility of comparing the findings and supplementing diagnostic possibilities of these methods. In 15 cases cytological diagnoses and cytogenetic analysis of haematological neoplasms were performed on the material obtained by lymph node FNA. In 12 of 15 cases histological diagnosis was made separately. A good cytohistological correlation was available in 9 of 12 cases (75%). Cytomorphological diagnoses in 10 of 15 cases (76%) were confirmed by the finding of a specific chromosomal translocation. In two cases cytological diagnosis did not correlate with the histological diagnosis and was confirmed only with specific chromosomal translocations. The lymphocytes obtained by lymph node FNA were adequate material for cytogenetic analysis - in 15 of 18 (83%) cases mitoses in cell cultures were obtained. In 13 of 15 (87%) cases clonal chromosomal abnormalities were detected, whereas in 2 of 15 (13%) cases a normal karyotype was found. DNA image cytometry was performed on nine samples, whereas in six samples the material was not sufficient. Although a small number of samples was analysed in the cases with identical cytomorphological diagnoses, the analysed histograms regarding the DNA index values showed heterogeneity. In conclusion, a cell culture sampled by FNA of lymph nodes is an adequate method for the chromosomal analysis. The specific cytogenetic abnormality associated with cytological diagnosis provides an opportunity to make a definitive diagnosis and provides a powerful approach when reference diagnosis on biopsy material cannot be obtained.

Determination of curing time in visible-light-cured composite resins of different thickness by electron paramagnetic resonance.

The irradiation time of a visible-light-activated composite necessary to achieve full polymerization throughout the material was studied. Curing-time dependence on the thickness of the material was also investigated. To monitor the visible light-activation effect, the free radical concentration was measured as a function of irradiation time. If the composite sample is less than 0.5 mm thick and exposed to light for a time interval recommended by the manufacturer, full radical concentration is indeed created uniformly. This is not the case in thicker samples. Electron paramagnetic resonance (EPR) was used to monitor the concentration of free radicals in the samples. The number of radicals was monitored as a function of irradiation time during which the radicals were generated in samples 0.5, 0.8, 2.0, 3.0 and 5.0 mm thick. An EPR X-band spectro-meter was used to detect the free radical spectra. The number of free radicals per unit mass as a function of irradiation time shows that 60% of the maximum concentration of radicals in a 1 mm sample is reached in 24 s curing time, while in thicker samples it takes hundreds of seconds. On the basis of the experiments, a depth and irradiation time-dependent radical concentration model was developed. This model shows that a 2.0 mm thick sample is cured at the bottom side if irradiated for 60 s. It is proposed that the measure of the degree of polymerization in composite materials should be the polymerization of the bottom layer of the sample which is modelled from the number of free radicals generated in the sample.