Biomedical subjects

M Lewandowska

Publications and source records attributed to M Lewandowska.

At least 19 recordsLinked to original sources

PubMed2006

Microstructure evolution in age-hardenable aluminium alloy during processing by hydrostatic extrusion.

In the present work, scanning and transmission electron microscopy were used to investigate the microstructural evolution occurring during the hydrostatic extrusion of an age-hardenable aluminium alloy. It was shown that processing by hydrostatic extrusion leads to grain refinement to 95 nm in equivalent diameter. Hydrostatic extrusion also influences the geometrical parameters of two different types of particle: intermetallic inclusions and precipitates. The intermetallic inclusions slightly decrease in mean equivalent diameter, but their size remains at the micrometre level. The precipitates are fragmented to nanoscale spherical particles, and their evolution delays the process of grain refinement.

Journal Article↗

PubMed2003

Determination of the CCR2-64I/CCR5-59653T haplotype linkage disequilibrium in a sample of Polish population.

It has been reported that different polymorphisms in the regulatory regions of CCR5 and in the CCR2 gene of the chemokine receptors are associated with AIDS. We decided to determine the congruence between CCR5-59653T and CCR2-64I alleles in a group of 281 persons. Frequencies of combined CCR5-59653T and CCR2-64I haplotypes were examined in a group of 281 persons. Among 281 individuals 26 (9.3%) and 24 (8.5%) respectively were carriers of the CCR5-59653T and the CCR2-64I alleles. We also found that 24 persons (8.5%) were carriers of combined CCR2-64I/CCR5-59653T allele. The calculation of the congruence revealed that 92.0% of individuals exhibited the same genotype for both CCR2-64I and CCR5-59653T polymorphisms. Our results confirm that linkage between CCR5-59653T and CCR2-64I alleles is not absolute.

Acquired Immunodeficiency Syndrome↗

PubMed2002

The effect of high molecular weight dextran sulfate on the production of interleukin-8 in monocyte cell culture.

It has been demonstrated that high molecular weight dextran sulfate (HMDS) is involved in the activation of immune cells. We have shown that HMDS increases the concentration of interleukin (IL)-8 in the medium of monocyte cell culture, in a dose-dependent fashion, whereas under the same conditions, low molecular weight dextran sulfate (LMDS) does not exhibit any effect on IL-8 biosynthesis. The effect of HMDS on IL-8 production is additive to that of IL-1beta and tumor necrosis factor-a (TNFalpha). Flow cytometric analysis revealed the biosynthesis of IL-8 in monocytes incubated in the presence of the HMDS. We hereby postulate that HMDS induces IL-8 biosynthesis in monocyte cell culture.

Cells, Cultured↗

PubMed2002

Decreased density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages is associated with the CCR5-59653T transition in the promoter region.

We compared the density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the homozygote (CCR5-59653C) and the heterozygote (CCR5-59653T), bearing CCR2-64V alleles. Flow cytometric analysis revealed lower density of the CCR5 receptor on the surface of CD4+ lymphocytes and monocytes/macrophages of the heterozygote than in the same cells of the homozygote. Our observation might explain slower replication of HIV and the delay in progression to AIDS in the individuals bearing CCR5-59653T transition.

Alleles↗

PubMed2001

Dynamics and critical behavior of the q model.

The q model, a random walk model rich in behavior and applications, is investigated. We introduce and motivate the q model via its application proposed by Coppersmith et al. to the flow of stress through granular matter at rest. For a special value of its parameters the q model has a critical point that we analyze. To characterize the critical point we imagine that a uniform load has been applied to the top of the granular medium and we study the evolution with depth of fluctuations in the distribution of load. Close to the critical point explicit calculation reveals that the evolution of load exhibits scaling behavior analogous to thermodynamic critical phenomena. The critical behavior is remarkably tractable: the harvest of analytic results includes scaling functions that describe the evolution of the variance of the load distribution close to the critical point and of the entire load distribution right at the critical point, values of the associated critical exponents, and determination of the upper critical dimension. These results are of intrinsic interest as a tractable example of a random critical point. Of the many applications of the q model, the critical behavior is particularly relevant to network models of river basins, as we briefly discuss. Finally we discuss circumstances under which quantum network models that describe the surface electronic states of a quantum Hall multilayer can be mapped onto the classical q model. For mesoscopic multilayers of finite circumference the mapping fails; instead a mapping to a ferromagnetic supersymmetric spin chain has proved fruitful. We discuss aspects of the superspin mapping and give an elementary derivation of it making use of operator rather than functional methods.

Journal Article↗

PubMed2001

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract].

OBJECTIVES: The aim of this study was preoperative estimation of serum level glicoprotein--CA 125, CA 19-9 and beta-hCG in ovarian tumors and comparison obtained values in groups divided according to postoperative pathologic examination. MATERIALS AND METHODS: In every patients with ovarian tumors before surgery the level above mentioned antigens was evaluated and compared in following groups: malignant, non-malignant and controls. In control group cut-off values was estimated. RESULTS: The levels of all investigated glycoproteins were significantly higher in malignant group comparing to benign and controls. The test differentiating non-malignant from malignant tumors was accepted as positive if at least one from markers level was elevated. Specificity of the test was 70%, sensitivity--94%, positive prognostic value--74%, negative prognostic value--94%. In the selected subgroups from non-malignant tumors the serum level of all glycoproteins was surprisingly high. CONCLUSIONS: Preoperative estimation of CA 125, CA 19-9 and beta-hCG subunit in ovarian tumors permits--at negative result--with probability 93% to qualify tumor as non-malignant and sensitivity of test is 94%.

Adult↗

PubMed2001

[Antibiotic resistance of Staphylococcus aureus strains isolated in two different Warsaw hospitals].

S. aureus strains isolated in the same period from different specimens obtained from patients of two different hospitals were compared. The significant differences were observed in the frequency of resistance determinants between strains of these hospitals. The most important was the difference in the prevalence of MRSA. In the first hospital the percentage of MRSA was 40% whereas in the second one only 20%. The resistance to the other antibiotics was also compared, and independently from the compared group: MRSA, MSSA or all, the prevalence of resistance determinants was higher in the first hospital than in the second. Although the frequencies of MRSA in both investigated hospitals were relatively high comparing to the other European countries and in the first hospital even alarming, isolated MRSA strains are less resistant to other antibiotics than MRSA in other countries.

Cross Infection↗

PubMed2000

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract. Endometrial cancer].

OBJECTIVES: There are few conflicting reports in regards of markers appearing in the patients with endometrial cancer. The aim of this study was to evaluate the serum levels: CA 125 antigen, CA 19-9 antigen and beta-hCG subunit in this group of patients and comparing obtained results with normal controls. MATERIALS AND METHODS: In both groups--with endometrial cancer (n = 43)- and controls-(n = 214)--CA125 antigen, CA 19-9 antigen and beta-hCG subunit the serum level were determined two = site of immunometric method. The differences of the means, correlations, specificity, sensitivity, positive predictive value, negative predictive value and efficiency were calculated. RESULTS: The women with endometrial cancer exhibited the significantly higher level of all antigens. The positive correlation between CA 125 serum level and staging and grading and between beta-hCG subunit and endometrial cancer staging was found. The positive test had: specificity--62%, sensitivity--93%, positive predictive value--66%, negative predictive value--92% and efficiency--92.5%. CONCLUSIONS: In the women with endometrial cancer appears non-specific antigens characteristic for the müllerian duct derivatives tissue, exhibiting Lewis blood group antigen and involving in membrane cell structures in normal and cancer cells. The level of these antigens correlates with grading and staging of the neoplasms.

Adult↗

PubMed1999

[Giant placental angioma with polyhydramnios, high level of alpha-fetoprotein and neonatal congenital lactic acidosis].

Placental tumors are rare in pregnancy. They cause nonspecific complications such as polyhydramnios, fetal anemia, fetal thrombocytopenia and cardiac decompensation with non-immunological hydrops fetalis. In the presented case a very large placental hemangioma was connected with polyhydramnios, premature delivery, fetal anemia and thrombocytopenia, maternal serum alpha fetoprotein elevation and congenital lactic acidosis. After delivery a severe state of the newborn was caused by oligovolemic shock. In the course of the disease the neonatal state steadily deteriorated mainly because of sepsis, cerebral hemorrhage and metabolic acidosis despite adequate therapy. The organic acids assessment in the blood serum of a newborn child showed a very strong signal of lactic acid and an increase in parahydroksyfenylolactic acid. Postmortal examination confirmed prematurity, respiratory distress syndrome, sepsis and cerebral hemorrhage. These symptoms probably resulted from the presence of a placental tumor of considerable size of 12 cm and congenital lactic acidosis, which to our knowledge, have not been described in the available literature until now. In conclusion it should be underlined, that there exists difficult to explain relationship between the presence of a placental haemangioma and severe metabolic changes resulting in high mortality and morbidity of the newborn.

Acidosis, Lactic↗

PubMed1999

[Beta subunit of human chorionic gonadotropin, CA 125 antigen and CA 19-9 antigen with non-trophoblastic malignancy of genital tract. Vulval cancer].

Our investigations embraced the group of patients with vulval cancer before surgical treatment (n = 10). We measured in serum of blood the level of the total human chorionic gonadotrophin hCG, beta subunit of human Chorionic Gonadotrophin, CA 125 and CA 19-9 antigen. We ascertained significant elevation the beta subunit of hCG level in the group of women with neoplasms in comparison with control group (n = 96) and significant positive correlation between beta subunit level and degree of cancer cells maturity (r = 0.66, p < 0.05). We also ascertained strong positive correlation among beta subunit of hCG and CA 19-9 antigen level in the serum of the patients with vulval cancer (r = 0.55 and p < 0.05).

CA-125 Antigen↗

PubMed1998

Identification of the Yc1 glutathione S-transferase mRNA as the overexpressed species in a nitrogen mustard-resistant rat mammary carcinoma cell line.

Glutathione transferase (GSTs) have been shown to be overexpressed in a number of tumor cell lines selected for resistance to chemotherapeutic drugs and have been implicated in some studies of clinical specimens. In tumor cell lines selected for resistance to chemicals that alkylate DNA, the isoform most frequently overexpressed is GST-Yc, a member of the alpha class GSTs. To date, two variations of the cDNA designated Yc1 with subtle differences have been described, and Yc2 is shown to be clearly distinct. Transfection of a Yc1 cDNA constitutively expressed in rat liver into rat mammary cancer cells confers resistance to alkylators, however, to a lesser extent than is observed in the cells selected for resistance. It has therefore been widely suggested that the GST that is overexpressed in selected resistant cells represents a distinct and novel isoform. We have previously described a rat mammary carcinoma cell line (MLNr) that is resistant to alkylating agents, and overexpresses a GST with characteristics similar to GST-Yc1 and not Yc2. It has many features common to the several other GST-Yc overexpressing alkylator resistant cell lines. We have cloned the specific Yc cDNA overexpressed in MLNr and analyzed it in detail and found that it is identical to one of the previously reported Yc1 cDNAs, suggesting that there is no additional Yc gene specifically induced by nitrogen mustards. Another hypothesis to explain the difference in the level of resistance in selected versus GST-Yc transfected cells is the lack of concurrent increased glutathione (GSH) in the transfectants, which is a common feature in the selected resistant cells. Experiments in which we modulated GSH levels suggest that this is not likely. These studies add to our speculation that other mechanisms may be involved in alkylator resistance.

Animals↗

PubMed1997

[Cathepsin D activity in amniotic fluid and serum during labor and puerperium in normal cases and those complicated by EPH-gestosis].

Cathepsin D activity during labour and puerperium in normal cases and those complicated by mild or moderate EPH-Gestosis was examined. Sera from maternal and umbilical cord blood, as well as the extraplacental blood and amniotic fluid were used for determinations. The gestational age of physiologic pregnancies and pregnancies complicated by EPH-Gestosis was 40 weeks. The first stage of labour was from 4 to 6 hours. The second stage of labour was over 10 minutes. In the group of women with mild and moderate EPH-Gestosis, the maternal serum activities on the third and fifth day of puerperium were significantly lower than in nonaffected subjects. In patients with moderate EPH-Gestosis, the activities in the maternal sera on the first day of puerperium, and in the umbilical blood were decreased when compared to controls. Uniformly, activities of the studied enzyme have been found to be lower in the umbilical cord blood sera than in the sera of the parturients. In cases of mild and moderate EPH-Gestosis the enzyme activity in the amniotic fluid was much lower than in controls, whereas in the extraplacental blood it was much higher.

Amniotic Fluid↗

PubMed1988

Sulphate and methionine as sulphur sources for cysteine and cephalosporin C synthesis in Cephalosporium acremonium.

Three prototrophic strains of Cephalosporium acremonium with different potentials for cephalosporin C production show pronounced differences in pools of intracellular sulphur amino acids. The superior strain exhibits the largest pool, particularly of cysteine (four times that of the non-producing strain). In fermentations with this strain methionine was found to be a much better sulphur source than sulphate for both cysteine and antibiotic synthesis. In the presence of methionine the utilization of sulphate is strongly depressed.

Acremonium↗

PubMed1987

Regulation of sulphur amino acids metabolic enzymes in Cephalosporium acremonium strains differing in antibiotic production.

Three strains of Cephalosporium acremonium with different potential of cephalosporin C production show differences in the levels of sulphur amino acid metabolic enzymes. The regulation of these enzymes is also different in the strains. In the superior producing strain two enzymes directly involved in cysteine synthesis are the least susceptible to repression by methionine. In this strain cystathionine metabolizing enzymes seem to favour cysteine synthesis. Antibiotic producing strains, in contrast to the non-producing strain, are highly sensitive to chromate.

Acremonium↗

PubMed1977