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Biomedical subjects

W Sawicki

Publications and source records attributed to W Sawicki.

At least 55 records · Page 3Linked to original sources
PubMed1987

Modification of cell division by phorbol ester in preimplantation mouse embryos.

2-cell mouse embryos were treated in vitro with a 2 h pulse of phorbol myristate acetate (PMA) at 32nd, 38th and 50th h after hCG, then chased in culture for up to 46 h. Embryos were fixed at various time intervals of chasing, then stained and inspected. Some embryos were carefully inspected with a video recording system, every 1.44s and the cell divisions (cytokinesis) as well as formation of large, single blastomeres, each from two smaller ones, were recorded. PMA pulse let to the suppression of cell divisions. The rate of the suppression was time dependent: with a delay of 0-1, 12 and 18 h between the PMA pulse and time of scheduled cell division about 99, 87 and 44% of 2-cell embryos remained at this stage of development, for at least 10 h, respectively, and 90, 58 and 12% of their blastomeres revealed binuclearity. Since we found that PMA-mediated formation of binuclearity was not the effect of cell fusions, it was assumed that the inhibition of cytokinesis preceded by karyokinesis was responsible for binuclearity. PMA effect on cell divisions was reversible. PMA-treated embryos revealed formation of large, single blastomeres, each from two smaller ones. If cell division appeared after PMA pulse, in about 52% of 3- to 6-cell embryos, the large blastomere formation was recorded in the course of the subsequent 38 h. Large blastomere formation was concluded to be the result of either cell fusion or reversion of incompleted cytokinesis brought about by PMA.

Animals↗
PubMed1987

Fourier analysis of nuclear and cytoplasmic shape of blood lymphoid cells from healthy donors and chronic lymphocytic leukemia patients.

The folding rates of the contours of nuclei and entire lymphoid cells were analyzed by Fourier analysis of the shapes. Smears of peripheral blood from healthy subjects and from patients with chronic lymphocytic leukemia (CLL: type B, stage zero) were routinely prepared and stained. The shapes of lymphoid cells from CLL patients revealed a higher folding rate (from fifth to tenth harmonics) than did those of lymphocytes from healthy subjects. Accordingly, the roughness coefficient (describing the folding rate of the surface) for CLL cells was 0.036, as compared to 0.028 for the cells of healthy subjects. The shapes of nuclei of CLL lymphoid cells also had a higher folding rate than did those of lymphocytes from healthy subjects, but a significant difference was found only for the highest harmonic calculated (the tenth harmonic); the respective roughness coefficients for nuclei were 0.037 and 0.033.

Cell Nucleus↗
PubMed1987

Gastrointestinal therapeutic system delivering of a water insoluble drug: isosorbide dinitrate (ISDN).

An oral therapeutic system can only be effective for soluble drugs. If no suitable salt of a drug can be found, then an osmotic agent such as sodium chloride or mannitol has to be used in a modified two-chamber system, or the osmotic dispenser with collapsible supply container. A one-chamber gastrointestinal therapeutic system (GTS) is proposed which is capable of delivering insoluble drug at a relatively constant rate. The unit consists of a tablet containing the insoluble drug and the soluble carrier, surrounded by a rate-controlling membrane with a delivery orifice. If the unit is in contact with fluid, water will pass constantly through the membrane into the tablet, dissolve the carrier which will be pumping out the insoluble drug through the delivery orifice. The effect was studied of variable content and weight of the tablet, size of the delivery orifice and thickness of the membrane on the rate of insoluble drug release from the GTS.

Excipients↗
PubMed1982

Optical diffraction as a tool for semiautomatic, quantitative analysis of tissue specimens.

Optical diffraction was tested on electron micrographs of normal and malformed myelin sheaths as a method for semiautomatic quantitative analysis of tissue specimens. Both normal and malformed myelin sheaths were chosen for the analysis because of their characteristic internal structure and its alteration as a result of malformation. Optical diffraction patterns were obtained by means of an optical diffractometer coupled with a digital detector. The spacing and arrangement of the components of various types of myelin sheath were automatically calculated and determined and the results were verified with discriminant analysis. Out of 27 parameters of the radial and out of 25 parameters of the angular distributions of diffracted light intensity, 6 and 11, respectively, were found to have good discriminative power and were used for classification of myelin sheaths. The accuracy of automatic classification was tested by comparison with myelin sheath types of known origin. The samples visually similar by their appearance, e.g. control and regenerating myelin sheaths, were automatically classified with accuracy of 69%, whereas others were classified appropriately with 88-100% accuracy. It is believed that this kind of analysis may successfully be applied for specimens of other tissues and/or organs.

Animals↗