Biomedical subjects

Jacek Miedzobrodzki

Publications and source records attributed to Jacek Miedzobrodzki.

5 recordsLinked to original sources

PubMed2006

Methylotrophic extremophilic yeast Trichosporon sp.: a soil-derived isolate with potential applications in environmental biotechnology.

A yeast isolate revealing unique enzymatic activities and substrate-dependent polymorphism was obtained from autochthonous microflora of soil heavily polluted with oily slurries. By means of standard yeast identification procedures the strain was identified as Trichosporon cutaneum. Further molecular PCR product analyses of ribosomal DNA confirmed the identity of the isolate with the genus Trichosporon. As it grew on methanol as a sole carbon source, the strain appeared to be methylotrophic. Furthermore, it was also able to utilize formaldehyde. A multi-substrate growth potential was shown with several other carbon sources: glucose, glycerol, ethanol as well as petroleum derivatives and phenol. Optimum growth temperature was determined at 25 degrees C, and strong inhibition of growth at 37 degrees C together with the original soil habitat indicated lack of pathogenicity in warm-blooded animals and humans. The unusually high tolerance to xenobiotics such as diesel oil (>30 g/l), methanol (50 g/l), phenol (2 g/l) and formaldehyde (7.5 g/l) proved that the isolate was an extremophilic organism. With high-density cultures, formaldehyde was totally removed at initial concentrations up to 7.5 g/l within 24 h, which is the highest biodegradation capability ever reported. Partial biodegradation of methanol (13 g/l) and diesel fuel (20 g/l) was also observed. Enzymatic studies revealed atypical methylotrophic pathway reactions, lacking alcohol oxidase, as compared with the conventional methylotroph Hansenula polymorpha. However, the activities of glutathione-dependent formaldehyde dehydrogenase, formaldehyde reductase, formate dehydrogenase and unspecific aldehyde dehydrogenase(s) were present. An additional glutathione-dependent aldehyde dehydrogenase activity was also detected. Metabolic and biochemical characteristics of the isolated yeast open up new possibilities for environmental biotechnology. Some potential applications in soil bioremediation and wastewater decontamination are discussed.

Biodegradation, Environmental↗

PubMed2006

Comparison of PCR-based methods for typing Staphylococcus aureus isolates.

In this study, we compared the potentials of (i) a multiplex PCR-based multilocus variable-number tandem repeat (VNTR) assay; (ii) a triplex PCR coamplifying fragments of spa, coa, and the hypervariable region adjacent to the mecA gene; (iii) restriction profile analysis of the STAR repetitive element; (iv) randomly amplified polymorphic DNA analysis; (v) inter-IS256 PCR; and (vi) rep-MP3 PCR. Multilocus VNTR typing and triplex PCR (coa, spa, and hypervariable region) approaches showed excellent reproducibility and high discriminatory power; however, only multilocus VNTR typing could distinguish all pulsed-field gel electrophoresis and spa types. Multilocus VNTR typing appears to be the most useful PCR-based method for the rapid genotyping of Staphylococcus aureus strains.

Bacterial Typing Techniques↗

PubMed2005

Comparison of multiple-locus variable-number tandem-repeat analysis with pulsed-field gel electrophoresis, spa typing, and multilocus sequence typing for clonal characterization of Staphylococcus aureus isolates.

Multiple-locus variable-number tandem-repeat analysis (MLVA), a new PCR-based method of typing Staphylococcus aureus, was compared to pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) on a group of 59 S. aureus (mostly methicillin-resistant) clinical isolates. The aim of the study was to establish possible criteria of clustering MLVA patterns and to check concordance levels between the results produced by MLVA and the three other typing methods. As in our earlier study, MLVA turned out to have discriminatory power similar to that of PFGE. Comparison of data obtained by the two approaches allowed us to propose a 70% or ca. 80% cutoff value of the similarity between two MLVA patterns, depending on a cutoff level applied to interpret the PFGE results, 75% or ca. 90%, respectively. The cutoff values corresponded to the difference of up to six or four bands, respectively, among maximum 14 bands in total produced by two isolates in the analysis. The MLVA clusters matched well those obtained by PFGE, and they were also consistent in general with clusters generated by spa typing and MLST, these latter methods characterized lower resolution. Our results suggest that MLVA may be reliable in shorter-term S. aureus epidemiological studies, including analyses of outbreaks and hospital-to-hospital strain transmission events. Well-known advantages of typing methods based on PCR (low cost, short time, and easiness of performance) make MLVA a method that may be useful in a variety of laboratories, including those performing routine microbiological analyses within medical centers.

Anti-Bacterial Agents↗

PubMed2004

Functional role of NADPH oxidase in activation of platelets.

Involvement of phagocyte NADPH oxidase in host defense response is well established. In contrast, little is known about the functional role of NADPH oxidase in platelets. In this study, we analyzed involvement of platelet NADPH oxidase in aggregation of human platelets and in amplification of production of reactive oxygen species (ROS) by activated human neutrophils. Apocynin, a known NADPH oxidase inhibitor, as well as superoxide dismutase mimetic Mn(III)tetrakis(1-methyl-1-pyridyl)porphyrin, inhibited ROS generation by collagen-activated platelets, collagen-induced aggregation of platelets, as well as collagen-induced release of thromboxane B2. These data suggest the key role of intracellular ROS derived from NADPH oxidase in the control of thromboxane A2 (TXA2) production in platelets stimulated by collagen. Apocynin also inhibited thrombin-induced ROS production and thrombin-induced platelet aggregation. Activation of neutrophils with latex resulted in an outburst of ROS that was inhibited by apocynin. ROS production by latex-stimulated platelets was modest and also inhibited by apocynin. However, when a mixture of platelets and neutrophils was stimulated with latex, ROS production was three to six times higher in comparison with activation of neutrophils alone. Platelet-dependent augmentation of neutrophil ROS production was abrogated by TXA2 synthase inhibitor (furegrelate, 1 microM) or by aspirin (300 microM). In summary, NADPH oxidase in platelets seems to play a major role as an intracellular signaling mechanism in the activation of platelets. However, in host defense response involving neutrophils and platelets, platelets enhance ROS production by neutrophils and possibly their cytotoxic potential via the release of TXA2, which in turn in platelets is not affected by the extracellular release of free radicals.

Acetophenones↗

PubMed2002

[Influence of treating atopic dermatitis with oral antihistamine and topical steroids on selected parameters of cell and humoral immunity].

UNLABELLED: Pathogenesis of atopic dermatitis (AD) is multifactorial, therefore despite many different treatment protocols none of the available methods is effective enough. In the present study we analysed the effects of oral antihistamines and topical steroids on selected parameters of humoral (immunoglobulin levels) and cellular (lymphocyte proliferation index, granulocyte oxidative burst, lymphocyte phenotype CD4:CD8) immunity. These parameters were analysed in 34 AD subjects during the exacerbation of the disease and after 4 and 12 weeks of the treatment. RESULTS: Along with the clinical status improvement (change form 3.17 +/- 0.1 to 1.3 +/- 0.2; 0-4 scale; p < 0.001), total serum IgE levels decreased significantly from 1563 +/- 459 to 1266 +/- +/- 364 IU/ml (p < 0.05). Other immunoglobulin levels did not change. Total blood chemiluminescence in response to latex stimulation was relatively higher during exacerbation than during remission, but this difference was not significant (p = 0.1). Mean spontaneous or PMA stimulated chemiluminescence did not differ either. CD4:CD8 index decreased significantly during the treatment (from 2.7 +/- 0.3 to 1.8 +/- 0.2; p = 0.03). Lymphocyte proliferation in response to PHA was significantly lower during exacerbation than during remission (10.4 +/- 2.8 vs. 27.1 +/- +/- 5.2; p < 0.03) and the improvement was observed after first 4 weeks of the treatment reaching the levels found in healthy controls. Proliferation index in response to anti-CD3 mAb (OKT-3) was in turn significantly higher during exacerbation (19.1 +/- 3.4 vs. 11.2 +/- 2.0; p = 0.04). CONCLUSIONS: Oral antihistamine in combination with topical steroids leads to several significant changes in the immune parameters (IgE levels, CD4:CD8 and proliferation indexes) which may explain its high effectiveness in majority of patients with AD.

Administration, Oral↗