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Biomedical subjects

Z Walter

Publications and source records attributed to Z Walter.

At least 19 recordsLinked to original sources
PubMed2001

Apoptotic effect of cyanobacterial extract on rat hepatocytes and human lymphocytes.

Toxic cyanobacterial blooms are an increasing problem in Poland. The production of cyanobacterial toxins and their presence in drinking and recreational waters represent a growing danger to human and animal health. This is connected with the increase of cyanobacterial biomass caused by excessive eutrophication of the water ecosystem. There is evidence that cyanobacterial hepatotoxins can act as a potent promoter of primary liver cancer. The apoptotic effect of microcystins in Polish cyanobacterial bloom samples on rat hepatocytes and human lymphocytes was observed using light and fluorescence microscopy, flow cytometry, and electrophoretic analysis. The incubation time needed to observe the first morphological apoptotic changes in hepatocytes was approximately 30 min; however, the characteristic biochemical changes in DNA were not observed even after 120 min. In lymphocyte cultures the morphological changes characteristic for apoptosis were observed after 24 h of incubation and a 48-h incubation was found to be optimal for analysis of internucleosomal DNA fragmentation, which is one of the main biochemical hallmarks of programmed cell death. These cells are an easily isolated and inexpensive material for medical diagnostics. Therefore the apoptotic changes, together with the clastogenic effect seen in lymphocyte cultures, are proposed as a future analytical method for these toxins.

Animals↗
PubMed2001

The quantitative PCR technique resolves ambiguities concerning a small rearrangement of human chromosome 6q12-13.

Karyotype analysis, performed on the basis of chromosome banding pattern, is a standard method used for identification of chromosomal aberrations, both numerical and structural. The application of classic cytogenetic techniques fails, however, to solve all diagnostic problems in certain types of chromosome aberrations. In this study, quantitative polymerase chain reaction technique (Q-PCR) application was applied to verify a cytogenetic diagnosis, which assumed that a difference observed in the banding pattern of homologous chromosome 6q12-13 region of a foetus had resulted from an inversion and/or duplication of the region in question. The obtained results indicate a possibility to use the Q-PCR method in the diagnostics of unbalanced chromosomal aberrations.

Journal Article↗
PubMed2000

Does potassium dichromate induce apoptosis in lymphocytes?

The aim of this work was to investigate the possibility of apoptosis in the human peripheral blood lymphocytes after treatment with potassium dichromate (K2Cr2O7), a potential occupational carcinogenic and mutagenic agent. Lymphocytes were stimulated by phytohemagglutinin, cultured for 72 h and incubated with either 0.2 mM or 0.4 mM K2Cr2O7 for the last 24 h or 48 h of culture. The condensation and margination of chromatin with emerging 'half-moon' structure, characteristic of apoptosis were observed. Phosphatidylserine displaced from the inner to outer side of the cellular membrane in 54% of cells after a 48-h incubation with 0.4 mM K2Cr2O7 (annexin-V+/PI-); 39% of these cells were of late apoptotic--secondary necrotic form (annexin-V+/PI+). Following the agarose gel electrophoresis of DNA, a 'ladder pattern' typical of apoptosis, was found. The results of the present study demonstrate that K2Cr2O7 can induce in the human peripheral blood lymphocytes changes similar to apoptotic ones.

Apoptosis↗
PubMed2000

Apoptotic effect of cyanobacterial blooms collected from Polish water reservoirs.

Recently in many countries, including Poland, the problem of toxicity of cyanobacterial blooms has been of great importance. In many cases it is connected with the increase of microcystins (MCYSTs) concentration in fresh water. This problem is caused by excessive eutrophication of drinking and recreational water bodies. In humans, the most frequent symptoms of the MCYST effect are: cutaneous rash, fever, vomiting, diarrhoea, gastroenteritis and acute damage of the liver. The aim of this work was to estimate apoptotic effects of five different cyanobacterial hepatotoxic extracts containing MC-LR and other variants of MCYSTs (MC-RR, MC-YR, and MC-WR). These effects were analysed in rat hepatocytes--primary target of cyanobacterial hepatotoxins. Morphological changes in hepatocytes were examined by means of fluorescence and differential interference contrast microscopy with the DNA-specific dye, Hoechst 33342. The hepatocytes were treated with each cyanobacterial extracts containing MC-LR in the range between 100 nM-2000 nM for 30 min, 60 min and 120 min. The first characteristic apoptotic changes: shrinking and budding of cells were seen after 30 min, MC-LR = 100 nM. During the next 30 min the percentage of apoptotic cells increased by over 50%, MC-LR at concentrations ranging from 100 to 250 nM (the value dependent on a bloom sample). Highly condensed chromatin and apoptotic bodies were observed in 85-90% of hepatocytes after 120 min of treatment with MC-LR in concentration of 1000 nM. The apoptotic changes in rat hepatocytes confirm the high cytotoxic potential of cyanobacterial bloom samples collected during different months and years from reservoirs of drinking and recreational water in central Poland.

Apoptosis↗
PubMed1999

[Methods of mobilizing hematopoietic cells, their collection using cell separation, purging--processing of pathologic cells and enrichment with CD 34+ cells--negative and positive selection].

Autological transplantation of bone marrow as well as hematopoietic and precursor cells obtained from peripheral blood with the use of cell apheresis is a therapy applied in the treatment of hematological diseases and solid tumours. The mobilization of hematopoietic cells is performed by applying cytostatic drugs and/or recombinant growth factors (G-CSF, GM-CSF). The collection of CD 34+ cells is performed by using cell separators. An important role in the transplantation procedure is played by purging techniques of transplantation material from residual neoplastic cells (negative selection) or isolation of hematopoietic cells (positive selection). The considerable progress in this field is connected with the implementation of Immunoadsorbtive or magnetic methods as well as those of molecular biology. The improvement of the procedure of hematopoietic cells transplantation and its efficacy is caused by the stimulation of the hematopoiesis by using the combination of cytokines (G-CSF, GM-CSF, IL-3, SCF) and purging of the hematopoietic cells obtained from the cellular apheresis.

Antigens, CD34↗
PubMed1999

[Methods for freezing, thawing and viability estimation of hemopoietic stem cells].

Freezing and thawing of hemopoietic stem cells (CD34+) are indispensable stages between their collection from peripheral blood or bone marrow and transfusion to the patient who has previously undergone myeloablative chemotherapy. At present there are two methods of the cells freezing: non-controlled--placing CD34+ cells directly in the final temperature and rate-controlled--gradual cooling them at programmed speed. Non-controlled freezing leads to the considerable loss of cells viability (up to 50%), but it doesn't require the expensive equipment used for rate-controlled freezing (viability loss up to 10%). In order to reduce the loss resulting from intra-cellular crystallization of water the haemopoietic cells are mixed with one of the cryopreservative substances: dimethylsulphoxide-DMSO, hydro-xyethylstarch-HES, polyvinylpyrrolidone-PVP or glycerol. The most important moment of freezing procedure is the phase transition of water. The adequate shape of the cooling curve leads to a considerable reduction of the loss of the cells viability. Further cooling is the most effective when it takes place at max. speed of 5 degrees C/min. The storage of the frozen cells is the best in very low temperatures (-170-180 degrees C-vapour phase of liquid nitrogen), but mechanical freezers (-80 degrees C) are used, too. The thawing procedure should be very fast (up to 90 degrees C/min.) and the defrosted cells must be immediately transfused to the patient because of very high toxicity of cryopreservative agents to non-frozen cells. The cells viability estimation is carried out with trypan blue or cytofluorometrically after incubation with propidine iodide.

Cell Count↗
PubMed1996

[Bone mineral disorders in patients with multiple myeloma].

The aim of the study was to evaluate bone mineralization in the patients with multiple myeloma. The examinations were performed in 49 patients (25 men and 24 women). Seven patients were before chemotherapy and 42 patients were treated with chemotherapy. All of them received prednisone. The bone mineral density was measured by dual-energy X-ray absorptiometry with Lunar spine (L2-L4) in AP projection, femoral neck and total body were examined. There was a decrease of bone mineral density in 35 patients in at least one place (T-score more than 2 SD below normal of young healthy persons). There was no correlation between densitometric results and the duration of multiple myeloma, or chemotherapy. The decrease of bone mineral density (expressed es T-score) of lumbar spine (for the patients without spinal degenerative changes) was higher than that of femoral neck (p < 0.05). The decrease of bone mineral density (expressed as T-score) of lumbar spine and femoral neck was more pronounced than that of total body (p < 0.001). Bone densitometry, especially of lumbar spine and femoral neck and less of total body is indicated in the patients with multiple myeloma. The result of this examination may be considered as an independent parameter of disease intensity.

Adult↗
PubMed1995

[Effect of calcitonin treatment on bone mineralization in patients with multiple myeloma].

The aim of the study was to evaluate the efficacy of half-year treatment of bone mineral disturbances with calcitonin in the patients with multiple myeloma. Thirty five patients (11 men and 24 women) were examined. They were treated among other with prednisone. Nineteen patients (15 patients with normal bone mineral density of lumbar spine and femoral neck and 4 with low bone mineral density who could not be treated with calcitonin) were treated only with chemotherapy. Other 16 patients with low bone mineral density have received also calcitonin (100 units subcutaneous daily) with vitamin D3 and calcium carbonate. Bone mineral density was evaluated with dual energy X-ray absorptiometry in lumbar spine and femoral neck. After treatment with calcitonin there was more pronounced influence on bone mineral density in lumbar spine and femoral neck than after treatment with chemotherapy only but the difference was not statistically significant. Because the bone mineral disturbances in the patients with multiple myeloma is the big problem there is a need for further and longer evaluation of the treatment of these disturbances.

Aged↗
PubMed1991

The effect of cis-diamminedichloroplatinum (II) on the formation of DNA-Pt-DNA cross-links.

The effect of cis-diamminedichloroplatinum (II) (cis-DDP) on the formation of interstrand cross-links in DNA and in DNA and chromatin complex from leukocytes was studied. Following the use of cis-DDP the number of DNA-DNA interstrand cross-links was elevated with the increase of cis-DDP concentration and elongation of reaction time. It was also found that nucleic proteins reduce the quantity of the cis-DDP induced DNA-DNA interstrand cross-links in the DNA in nucleoprotein complex when compared with the links in the isolated DNA.

Animals↗