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Biomedical subjects

K Smetana

Publications and source records attributed to K Smetana.

At least 19 recordsLinked to original sources
PubMed1992

[Nucleolar asynchrony in human acute myeloid leukemia blast cells].

Nucleolar asynchrony (the presence of "active" and "sleeping" nucleoli with respect to the RNA synthesis in one and the same nucleus) was noted and studied in blastic cells of the peripheral blood in patients of acute myeloid leukemias (M1 - M4 according to FAB classification) by means of light microscopy of smears after visualization of RNA containing structures. Nucleolar asynchrony seems to be a regular phenomenon in a certain number of blastic cells in the peripheral blood and has been also verified by electron microscopy. No significant difference has been noted in the incidence of blasts with nucleolar asynchrony between the peripheral blood of patients treated and untreated by cytostatic therapy at the time of taking samples for the present study: The presence of the nucleolar asynchrony/might contribute to the resistance of a certain population of leukemic blasts to the cytostatic therapy. This supposition is supported by the present experiments "in vitro" on mouse leukemic myeloblasts sensitive and resistant to Doxorubicin. The Doxorubicin resistant myeloblasts were characterized by a significantly larger incidence of the nucleolar asynchrony as compared with myeloblasts of the Doxorubicin sensitive cell line.

Acute Disease↗
PubMed1992

Implantation of p(HEMA)-collagen composite into bone.

The replacement of bone defects is very important in clinical practice. This study compares biological properties of poly(2-hydroxyethyl methacrylate)-collagen composite with those exhibited by pure p(HEMA), an insoluble fraction of calf skin collagen (ISC-40) and demineralized bone matrix after implantation into pig or dog femurs. The levels of biodegradation or destruction of implants and healing of bone defects were studied using X-ray photography, histology and enzyme histochemistry. The results indicated a significant effect of collagen on biological destruction of the p(HEMA)-composite implants; even a minute amount of collagen influences this process dramatically. A stimulatory action of collagen on new bone formation may be of importance in bone defect healing.

Animals↗
PubMed1992

[The first stage of clinical trials of hydrogel lenses manufactured in Czechoslovakia].

The authors give an account of the results of the first stage of clinical trials of Czechoslovak disc-shaped hydrogel lenses made from the copolymer HEMA and methacrylic acid. Hitherto assembled experience provided evidence that the envelope technique for opening of the anterior capsule does not ensure sufficient stability of these lenses in the later stage and their decentration may cause serious complications. Therefore the optimal solution is to place the implant in the capsule after circular capsulorhexy. Improvement of the geometrical and optic properties of the lenses during the subsequent follow-up and their perfect harmony with the surgical technique will produce even better functional results in operated patients.

Aged↗
PubMed1992

Electrostatic interaction influences cell adhesion?

The effect of electrostatic forces on the adhesion of LEP-19 diploid embryonal fibroblasts, Hep-2 laryngeal carcinoma cells, Raji lymphoblastoma cells and Sp 2/0 myeloma cells was examined in vitro. Adhesivity of all tested cell lines was higher on the cationized glass than on untreated or anionized glass. The negatively charged sialic acids on the cell surface play a role in cell adhesion. The participation of electrostatic interaction is independent of the energy metabolism in serum-free conditions.

Anions↗
PubMed1992

Biochemical properties of cartilage and multinucleate chondroclast formation.

This study demonstrates a relationship between the biochemical properties of the extracellular matrix of a cartilaginous model of long bone and the fusion of mononuclear clastic elements into multinucleate chondroclasts. The results suggest that the chondroitin sulphate level in the extracellular matrix has an inhibitory effect on this process.

Animals↗
PubMed1991

Detection of fibrillarin in nucleolar remnants and the nucleolar matrix.

In order to gain further insights into the fundamental structure of the nucleolus, nucleolar remnants of Xenopus and chickens were examined for the presence of fibrillarin and nucleolus organizer region (NOR) silver staining. Nucleolar remnants of Xenopus nucleated red blood cells were found to contain easily detectable amounts of fibrillarin and NOR silver staining. Upon examination of various tissues, fibrillarin and NOR silver staining were detected in nucleoli of Xenopus liver hepatocytes and within nucleoli of oocytes and follicle cells from ovaries of mature female toads. By comparison, nucleolar remnants of adult chicken nucleated red blood cells contained only trace amounts of fibrillarin and NOR silver staining, whereas red blood cell nucleolar remnants of immature chicks had easily detectable amounts of fibrillarin and NOR silver staining. Nucleoli from hepatocytes of both adult and immature chickens demonstrated comparable levels of fibrillarin and NOR silver staining. Since fibrillarin was found in nucleolar remnant structures, we tested for (and detected) its presence in residual nucleoli of in situ nuclear matrix derived from HeLa cells. These findings are discussed in terms of the basic structural and functional organization of the nucleolus.

Animals↗
PubMed1991

Ossification in nude mice. 2. A histological, histochemical and immunohistochemical study.

The autopodia of proximal limbs as well as the proximal growth plates of the tibia of newborn nu/nu including super nu/nu, nu/+ and +/+ mice were studied. No differences in the ossification of proximal limb autopodia (regarding the distribution of alkaline phosphatase, acid phosphatase or glycosaminoglycans) were observed in mice of genotypes studied. On the other hand, a thinner proximal tibial growth plate characterizes one-month-old nu/nu mice, and also the architecture and alkaline phosphatase pattern were altered. The results suggest a postnatal secondary effect of the nu/nu genotype on skeletal development.

Alkaline Phosphatase↗
PubMed1990

The influence of hydrogel functional groups on cell behavior.

This study provides information on the behavior of macrophages on the surface of the subcutaneously implanted hydrogel strips. Hydrogel containing -OH, -CO-NH-, and (CH3)2N- groups induced a spreading of macrophages on the implants. The materials containing -SO3H groups slightly, and materials containing -COOH groups more intensively, inhibited spreading of the macrophages. The fusion of macrophages into multinucleate cells was inhibited on the surface of materials containing acidic groups (-SO3H, -COOH) and increased on the hydrogels containing 30 mol% of alkaline (CH3)2N- groups in comparison with hydrogels containing -OH or -CO -NH- groups. The differences of the behavior of macrophages on the surface of individual types of hydrogels are probably independent on the adsorption of plasma fibronectin onto the hydrogels. The correlation between the macrophages spreading and fusion and surface charge of the hydrogel implant can be hypothetically explained by electrostatic interaction between macrophages cell membrane and implant.

Animals↗
PubMed1990

Ossification in nude mice. 1. Macroscopical study.

Ossification was studied in cleared fetuses, newborns, 1- and 6-week-old nu/nu and nu/+ mice of the B 10 LP background. The same ossification pattern was observed in nu/nu and nu/+ in the embryonal period as well as in newborn animals and mice aged 1 or 6 weeks. On the other hand, 6-week-old nu/nu mice exhibited a lower X-ray density of the skeleton and a lower thickness of the proximal tibial growth plate than 6-week-old nu/+ litter mates. The results indicate the influence of postnatal factors on the skeletal development of nu/nu mice.

Animals↗
PubMed1990

Studies on satellite nucleoli in human blastic cells of acute leukaemias.

Blastic cells of acute lymphoid, acute myeloid and acute myelomonocytic leukaemias were studied by means of indirect immunofluorencence to provide more information on the presence of satellite nucleoli in blood cells. According to results, satellite nucleoli were found in a small but constant number of blastic cells disregarding their type and type of acute leukaemia. Satellite nucleoli exhibited a positive immunoreaction for fibrillarin and protein B23 which are characteristic for main nucleolar components. These findings suggest that satellite nucleoli contain fibrillar centers as well as dense fibrillar and granular components or at least proteins characteristic for these nucleolar components. Similarly as in normal and pathological cells of completely different origin, in blastic cells of acute leukaemias the number of satellite nucleoli per cells ranged between 1 and 2.

Cell Nucleolus↗
PubMed1990

Nucleoli in the cells of the erythrocyte and granulocyte series in the albino rat.

In albino rats, as in other mammals, nucleoli with nucleolonemata and compact nucleoli in the stem cells of the erythrocyte and granulocyte series are progressively replaced during maturation and differentiation first by ring shaped nucleoli and then by micronucleoli with low and finally with inhibited RNA synthesis. There are, however, differences between the nucleolar coefficient values and the proportion of ring shaped nucleoli and micronucleoli in maturing neutrophils in the albino rat, the mouse and man. In the case of the erythroblasts, the differences between the proportion of various nucleolar types in the three given species are smaller. The results thus indicate that the developmental trend of nucleolar changes related to cell maturation and differentiation is the same, but that there are interspecies differences because of which the results obtained in one species cannot be applied mechanically to another, i.e. results obtained in a laboratory animal cannot be applied automatically to man.

Animals↗
PubMed1989

Foreign body reaction against cellophane in the athymic nude mice.

There are no differences in the multinucleate cell formation in normal and athymic mice after the subcutaneous implantation of a cellophane strip. The number of Ia+ epitheloid cells and multinucleate foreign body giant cells was lower and the number of epitheloid cells sharing the marker of activated macrophages (M 57) was higher in athymic compared to normal mice. The epitheloid cells of athymic and euthymic animals exhibited no difference in the expression of Mac-2 molecule. The difference of the expression of surface markers between athymic and euthymic animals does not influence the foreign body giant cell formation.

Animals↗
PubMed1989

Fibrillar center distribution in nucleoli of PHA-stimulated human lymphocytes.

We have utilized acidic toluidine blue staining for RNA and immunofluorescence staining for RNA polymerase 1 to visualize the distribution of fibrillar centers (FCs) in nucleoli of PHA-stimulated human lymphocytes. At 0 h, there is a single large fibrillar center in each nucleolus which splits into smaller and more numerous FCs until the number of FCs reaches five, the number of nucleolus organizers in normal haploid human cells. With time, each FC then "unwinds" to form linear arrays of smaller FCs until the maximum number of FCs approaches the ribosomal gene copy number of 200 at 48 h in culture. It is hypothesized that in the most active state, each nucleolar FC visualized by RNA polymerase 1 staining actually represents a single transcription unit and the distance between adjacent FCs is occupied by the nontranscribed spacer region. We conclude that the number of fibrillar centers per nucleolus can be used as a direct quantitative measure of nucleolar transcriptional activity.

Cell Cycle↗
PubMed1989

Three-dimensional reconstructions of nucleolus-organizing regions in PHA-stimulated human lymphocytes.

Ultrastructure and three-dimensional distribution of nucleolus-organizing regions have been studied on ultrathin serial sections of PHA-stimulated human lymphocytes. During the 48 hr of activation the size of fibrillar centers (FCs) decreased from 0.6-0.9 microns to 0.2-0.3 microns and the number of FCs increased rapidly from one to 75-107 per cell. The number of fibrillar complexes (i.e. associations of a different number of FCs connected by the dense fibrillar component) also increased but did not reach the maximum number of nucleolar organizers presented here. Three-dimensional computer reconstructions of fibrillar complexes showed that lymphocyte activation was accompanied by early (2-4 hr) changes in the shape of the primary fibrillar center. Invagination of the dense fibrillar component on its surface occurred and division into two or more smaller FCs followed. Gradually, the typical structure of the nucleolus with several fibrillar complexes and many FCs was formed. These results confirm the hypothesis of fibrillar complex-nucleolar organizer correlation published recently.

Humans↗
PubMed1989

[Clinico-pathologic evaluation of one type of intraocular lens].

Four intraocular lenses of Saturn type (extrapupillar iris lens fixated in the posterior chamber) were surgically removed when bullous pseudophakic keratopathy was present, without loss of the eye-bulb, during the period of 2-6.5 years after the performed implantation. Cytologic examination of the surface of the implanted lens displayed the individual tolerance of the implant in various patients. In all cases on the surface of the lenses there was observed a reactive membrane, also in the cases of the low biological tolerance.

Adult↗
PubMed1989

Positive effect of direct current on cytotoxicity of human lymphocytes.

Normal or leukemic human lymphocytes treated with direct current (DC) showed enhanced antileukemic cytotoxicity. The enhancing effect of DC-treated lymphocytes was dependent on current density and time exposure. A desirable effect was achieved with current densities ranging from 5 to 10 mA/cm2 at a short exposition time (5--10s). Enhanced lymphocyte cytotoxicity occurred after a 48 h cultivation at 37 degrees C in a humidified atmosphere containing 5% CO2 and was proved by the increased number of trypan blue stained target cells, tumor-binding cells, and lymphocytes with activated nucleoli. Lymphocyte cytotoxicity measured immediately after DC-treatment was not enhanced. Furthermore, the cytotoxic effect was potentiated using media conditioned with interleukin-2 (IL-2) or cytosol fraction (F3) isolated from human leukemic cells. Such in vitro stimulated cytotoxic cells displayed reactivity against K 562 cells as well as fresh leukemic cells of allogeneic origin. Of considerable clinical interest is the observation that lymphocytes treated with DC in IL-2 or F3 conditioned media may enhance antileukemic cytotoxicity in peripheral lymphocytes of patients with hematological malignancies.

Cytosol↗
PubMed1988

The lymphocytic basophilia after incubation of blood smears in distilled water.

The incubation of peripheral blood smears in distilled water frequently used for the control of the digestion with ribonuclease produced distinct changes of basophilic ribonucleic acid containing structures in peripheral lymphocytes. The alteration of these structures was apparently produced by the activity of the endogenous ribonuclease since it was reduced or prevented by the lowering of the temperature or addition of the ribonuclease inhibitor. In addition, marked differences were found between peripheral blood lymphocytes of healthy persons and patients suffering from chronic lymphocytic leukaemia with respect to the sensitivity of lymphocytic basophilia to the incubation in distilled water.

Basophils↗