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M Kawalec

Publications and source records attributed to M Kawalec.

At least 19 recordsLinked to original sources
PubMed2001

Selection of a teicoplanin-resistant Enterococcus faecium mutant during an outbreak caused by vancomycin-resistant enterococci with the vanB phenotype.

Vancomycin-resistant enterococci (VRE) have recently become an increasing problem in hospitals in Poland, being responsible for a growing number of nosocomial outbreaks. In this work, we have analyzed the second outbreak of VRE with the VanB phenotype to be identified in the country. It was caused by clonal dissemination of a single strain of vancomycin-resistant Enterococcus faecalis (VRES) and horizontal transmission of vancomycin resistance genes among several vancomycin-resistant Enterococcus faecium (VREM) strains. Two similar restriction fragment length polymorphism types of the vanB gene cluster characterized VRES and VREM isolates, and they both contained the same vanB2 variant of the vanB gene. Two vancomycin-susceptible E. faecium (VSEM) isolates, recovered from the same wards during the outbreak, proved to be related to certain VREM isolates and could represent endemic strains that had acquired vancomycin resistance. One VSEM and four VREM isolates, all identified in the same patient, belonged to a single clone, although they revealed remarkable diversity in terms of susceptibility, PFGE patterns, plasmid content, and number of vanB gene cluster copies. Most probably they reflected the dynamic evolution of an E. faecium strain in the course of infection of a single patient. One of the VREM isolates turned out to be resistant to teicoplanin, which coincided with the use of this antibiotic in the patient's therapy. Its vanB gene variant differed by a single mutation from that found in other isolates; however, it also lacked a large part of the vanB gene cluster, including the regulatory genes vanR(B) and -S(B), and the vancomycin-inducible promoter P(YB). Expression of the resistance genes vanH(B), -B, and -X(B) was constitutive in the mutant, and this phenomenon was responsible for its unusual phenotype.

Anti-Bacterial Agents↗
PubMed2001

Vancomycin-resistant Enterococcus faecium strain carrying the vanB2 gene variant in a Polish hospital.

About 2.5 years after the first isolation of the VanA phenotype of vancomycin-resistant Enterococcus faecium (VREM) in Poland, the first VREM strains with the VanB phenotype have emerged independently in two different Warsaw hospitals. In one of these the VREM strain was selected during the long-term antimicrobial treatment of a patient with a wide variety of infection risk factors who died after 3 months of hospitalization. The strain was found to contain the transferable vanB2 gene cluster variant of the polymorphic type that was identified earlier in vancomycin-resistant enterococci from several different countries. In the course of infection the strain underwent genetic diversification due to DNA recombination.

Acute Disease↗
PubMed2001

Outbreak of vancomycin-resistant Enterococcus faecium of the phenotype VanB in a hospital in Warsaw, Poland: probable transmission of the resistance determinants into an endemic vancomycin-susceptible strain.

The first outbreak caused by vancomycin-resistant enterococci of the VanB phenotype in Poland was analyzed. It occurred in a single ward of a Warsaw hospital which is a specialized center for the treatment of hematological disorders. Between July 1999 and February 2000, 11 patients in the ward were found to be infected and/or colonized by Enterococcus faecium that was resistant in vitro to vancomycin and susceptible to teicoplanin. PCR analysis confirmed that the vancomycin-resistant E. faecium (VREM) isolates carried the vanB gene, which is responsible for the VanB phenotype. Pulsed-field gel electrophoresis (PFGE) typing revealed that the isolates belonged to four distinct PFGE types and that one of these was clearly predominant, including isolates collected from seven different patients. The isolates contained one or more copies of the vanB gene cluster of the identical, unique DraI/PagI (BspHI) restriction fragment length polymorphism type, which resided in either the same or different plasmid molecules or chromosomal regions. All this data suggested that the outbreak was due to both clonal spread of a single strain and horizontal transfer of resistance genes among nonrelated strains, which could be mediated by plasmids and/or by vanB gene cluster-containing transposons. The comparative analysis of vancomycin-susceptible E. faecium (VSEM) isolates collected from infections in the same ward at the time of the VREM outbreak has led to identification of a widespread VSEM strain that was possibly related to the major VREM clone. It is very likely that this endemic VSEM strain has acquired vancomycin-resistance determinants and that the acquisition occurred more than once during the outbreak.

Anti-Bacterial Agents↗
PubMed2001

[Adverse effects of parenteral administration of antisense oligonucleotides].

To characterize the toxicity of phosphorothioate antisense oligodeoxynucleotides ([S]ODNs) in vivo, the mice received intravenously 26-mer bcr-abl antisense oligodeoxynucleotides (1 mg/mice/day) for 9 consecutive days. The organs and tissues were removed on the indicated days (+1, +7, +30) after the treatment. Our investigation revealed middle elevation of aminotransferases activity, lactate dehydrogenase level, total protein level and globulin level, decrease of glucose, albumin and blood urea nitrogen level in the peripheral blood. The mild anaemia and thrombocytopenia were observed too. The most significant treatment-related findings in the antisense treated mice were splenomegaly, reactive hepatitis and atrocytosis of kidney. These findings together with previous results demonstrate little and temporary toxicity effects mainly in organs known from cumulating of [S]ODNs.

Animals↗
PubMed2000

Outbreak of vancomycin-resistant enterococci in a hospital in Gdask, Poland, due to horizontal transfer of different Tn1546-like transposon variants and clonal spread of several strains.

Twenty-two vancomycin-resistant enterococcal (VRE) isolates of the VanA phenotype (21 Enterococcus faecium isolates and 1 E. faecalis isolate), representative of a large outbreak that occurred in a hospital in Gdańsk, Poland, were studied. All of the isolates demonstrated resistance to a wide variety of other antimicrobial agents in addition to glycopeptides. Several lines of evidence suggested that the outbreak most probably consisted of two epidemics that followed the independent introduction of VanA determinants into two separate hematological wards of the hospital. This hypothesis is supported by the fact that isolates recovered in these wards possessed two different polymorphs of the highly conserved DNA region encompassing the vanRSHAX genes and two distinct polymorph types of Tn1546-like transposons, which contain these genes. According to pulsed-field gel electrophoresis data, the outbreak in the adult hematology ward (HW) was highly polyclonal, which suggested a major role for the horizontal transmission of Tn1546-like elements among nonrelated strains of E. faecium and E. faecalis in this environment. On the other hand, the outbreak in the pediatric hematology ward (PHW) was most probably due to the clonal spread of two epidemic E. faecium strains, which had exchanged a plasmid carrying the Tn1546-like transposon. Restriction fragment length polymorphism studies of transposons and their insertion loci in plasmid DNA have suggested that numerous isolates from both HW and PHW contained two or more copies of Tn1546-like elements that underwent diversification due to various genetic modifications. The reported data demonstrated a very complex epidemiology of the first, and up to now the only, VanA VRE outbreak characterized in Poland.

Adult↗
PubMed1998

Susceptibility patterns of Enterococcus spp. isolated in Poland during 1996.

Susceptibility of Enterococcus spp. isolated from various clinical specimens to different antimicrobial agents was evaluated. Of the 346 enterococcal isolates obtained from four regional Polish hospitals during 6 months of 1996, 261 (75.4%) were identified as Enterococcus faecalis, 75 (21.7%) as Enterococcus faecium and ten (2.9%) as other enterococcal species. High-level resistance to gentamicin was expressed by 33.4% of E. faecalis and 86.5% of E. faecium strains and corresponding streptomycin resistance by 43.9 and 82.4%, respectively. Over 80% of E. faecium isolates were resistant to ampicillin. None of the isolates was resistant to teicoplanin, however 7.9% of E. fecalis and 1.4% of E. faecium strains were moderately susceptible to vancomycin.

Anti-Bacterial Agents↗
PubMed1998

Photochemical labeling of HL-60 cell membrane proteins with radioiodinated, 4-azidosalicylic acid acylated derivatives of gangliosides.

To detect HL-60 human promyelocytic leukemia cell proteins involved in the uptake of gangliosides from the culture medium we used photoreactive, 4-azidosalicylic acid (ASA) acylated and radioiodinated (200 Ci/mmole) derivatives of GM3, GD3, GM1, and FucGM1 gangliosides. Gangliosides-ASA, added to the medium at 15-20 nM concentration, followed a similar time course of uptake. After 1 min incubation cell bound gangliosides-ASA could not be removed with trypsin, but only 5-10% remained after incubation with BSA. The proportion of cell bound gangliosides-ASA resistant to BSA treatment increased with time of incubation up to 76% after 20 h. As shown on TLC, GM3- and GD3-ASA were catabolized to LacSph-ASA and ceramide-ASA, while GM1-ASA was hydrolyzed to GM2-ASA. FucGM1-ASA was converted to GM1-ASA very slowly. Upon irradiation with UV lamp, cell bound gangliosides-ASA crosslinked to and photolabeled many proteins but the distribution of radioactivity after SDS/PAGE was very uneven and did not correlate with Coomassie staining. In all experiments the 42 kDa protein bands were most intensely photolabeled. Photolabeling of 42 kDa proteins decreased with time of incubation as compared to lower molecular mass pro teins. With all gangliosides-ASA used similar but not identical protein photolabeling patterns were obtained. Photolabeling patterns with GM3- and GD3-ASA differed from those with GM1- and FucGM1-ASA.

Azides↗
PubMed1997

Lymphocyte phenotyping in systemic sclerosis: a flow cytometry analysis of lymphocytes in bronchoalveolar lavage fluid.

OBJECTIVE: Patients with scleroderma (systemic sclerosis [SSc]) frequently develop interstitial lung disease. The purpose of this work was to evaluate the cell profile in the bronchoalveolar lavage fluid (BALF) in patients suffering from a diffuse form of systemic sclerosis as compared with healthy controls. STUDY DESIGN: Bronchoalveolar lavage was carried out in the right middle lobe of 25 untreated, nonsmoking patients with SSc and 12 healthy, nonsmoking volunteers. For the analysis of lymphocyte subsets, the following monoclonal antibodies were used: anti-CD3, anti-CD4, anti-CD8, anti-CD14, anti-CD16, anti-CD19, anti-CD25, anti-CD45, anti-CD56. Also, anti-HLA-DR and flow cytometry were used. RESULTS: We found an increase in the total number of cells with an increase in the percentage of lymphocytes and neutrophils in BALF from patients when compared with controls (P < .05). The proportion of lymphocytes, cytotoxic/suppressor CD8+ and activated lymphocytes T CD25+ were higher in patients' BALF (P < .05). The CD4+/CD8+ ratio in BALF from subjects was significantly lower than in controls. These findings were characteristic of patients with early-stage disease. CONCLUSION: Analysis of the BALF lymphocyte phenotype may be useful in the early detection of lung involvement in patients with SSc.

Adult↗
PubMed1997

A novel restriction endonuclease UnbI, a neoschizomer of Sau96I from an unidentified psychrofilic bacterium from Antarctica is inhibited by phosphate ions.

A novel type II restriction endonuclease UnbI was isolated from an unidentified psychrofilic bacterial strain from Antarctica. UnbI recognizes and cleaves the sequence 5'-GGNCC-3', producing 5 nucleotide long sticky ends. In this respect it differs from its neoschizomer Sau96I and all other restriction enzymes recognizing this sequence. UnbI has a relatively low temperature optimum of 15 degrees C to 20 degrees C and its activity is completely inhibited by inorganic phosphate.

Antarctic Regions↗
PubMed1996

The influence of phosphorothioate oligodeoxynucleotides on various organs in vivo.

To characterize the distribution and toxicity of phosphorothioate antisense oligodeoxynucleotides ([S]ODNs) in vivo, the mice, previously injected with BV173 leukemic cells (Philadelphia chromosome-positive chronic myeloid leukemia blast-crisis), received intravenously 26-mer BCR-ABL antisense oligodeoxynucleotides (1 mg/mouse/day) for 9 consecutive days. Our investigation revealed that [S]ODNs were distributed to almost all organs except the brain with the highest level in the liver, spleen and kidneys. They were also detected in CD10+ leukemic cells isolated from spleen and bone marrow. Intracellular distribution assay showed the presence of [S]ODNs most prominently in nuclear and cytoplasmic fractions. Our data demonstrated no significant toxicity of [S]ODNs except the increase in spleen weight.

Animals↗
PubMed1993

Immunogenic and nondividing mafosfamide-treated L 1210 cells--comparison of lines resistant and nonresistant to cyclophosphamide.

Cyclophosphamide/mafosfamide-resistant L 1210 cell line [L 1210(Cy)R] was established from a sensitive parental line. The L 1210(Cy)R line was resistant to cyclophosphamide at the dose of 100 mg/kg. Cells of L 1210(Cy)R line were more immunogenic for semisyngeneic CD2F1, mice as compared with parental line. They grew slower in immunocompetent mice compared to immunosuppressed mice. It has been shown that L 1210(Cy)R cells treated with mafosfamide at high concentration not only retained immunogenicity but were even more immunogenic than parental L 1210 cells. In conclusion, it was possible to produce immunogenic, nondividing leukemia cells even when cells were resistant to the cytostatic used for cell modification.

Animals↗
PubMed1991

Early induction of immune resistance against leukemia in mice after lethal irradiation followed by syngeneic bone marrow transplantation and injection of syngeneic leukocytes.

BALB/cxDBA/2Wf F1 (CD2F1) mice were lethally irradiated and reconstituted with syngeneic bone marrow cells untreated or treated with 75 micrograms/ml of mafosfamide. One day after bone marrow transplantation some groups of mice were injected with syngeneic splenocytes, peripheral blood leukocytes, or thymocytes. Seven days after marrow grafting the anti-L1210 leukemia immunization of mice, consisting of four i.p. injections of 10(6) L1210-Maf cells (L1210 cells treated in vitro with mafosfamide for inhibition of their growth in vivo), was started. Strong resistance against leukemia could be obtained only in mice receiving splenocytes or peripheral blood leukocytes, not in mice injected with thymocytes or in those not receiving any cells. In vitro elimination of various subpopulations from among the splenocytes before their injection into the mice made it possible to deduce which are necessary for early induction of antitumor resistance after bone marrow transplantation in mice. These cells are: Thy 1.2-, Ig-, AsGM 1-, Mac 1+, 1-Ad+/-, are adherent and nonsusceptible to carrageenan toxicity.

Animals↗
PubMed1991

Changes of thymocyte subpopulations induced by activities diffusing from leukemia L1210 cells.

Mice with intraperitoneally inoculated leukemia L1210 cells had a lower total number of thymocytes and a markedly reduced percentage of L3T4+ Lyt2+ (CD4+ 8+) thymocytes, but increased subpopulations of L3T4+ Lyt2-, L3T4- Lyt2+, L3T4-Lyt2-. The percentage of Thy 1.2+ thymocytes was unchanged as compared with control animals. A similar effect was observed is suggested that leukemia L1210 cells produce some activities which diffuse through 0.22 microns filters and influence the subpopulations of thymocytes.

Animals↗
PubMed1991

Induction of immune resistance against L1210 lymphatic leukemia in mice after lethal irradiation and reconstruction with fetal liver cells.

The immunohematopoietic potential of syngeneic fetal liver cells (SFLC) was examined and compared with syngeneic bone marrow cells (SBMC). SFLC generated about 3 times less 12th-day spleen colonies (CFU-S) than adult SBMC did. To test the SFLC ability for reconstitution of the immune system, mice were lethally total body irradiated (TBI) and transplanted i.v. with 3 x 10(7) SFLC or 1 x 10(7) SBMC. Thus, injected hematopoietic cells contained the same number of CFU-S. On days 28, 35, 42, and 49 after transplantation the mice were injected i.p. with 10(6) immunogenic L1210-Maf cells (L1210 leukemia cells treated in vitro with mafosfamide for inhibition of their growth in vivo) to test the ability for generation of immune response against L1210 leukemia. On day 56 the animals were challenged with 10(3) L1210 leukemia cells. Strong resistance against the leukemia was induced in TBI + SFLC and TBI + SBMC mice, suggesting that the SFLC similarly as SBMC are able to reconstitute immune system of the TBI host.

Animals↗
PubMed1990

Successful adoptive immunotherapy of minimal residual disease after chemoradiotherapy and transplantation of bone marrow purged of leukaemia with mafosfamide.

The effectiveness of adoptive immunotherapy in eliminating minimal residual disease in tumour-bearing mice after bone marrow transplantation was tested. This model mimics the human clinical condition when autologous bone marrow was purged ex vivo of leukaemia with mafosfamide or was not purged, and stored in liquid nitrogen before transplantation. Animals with minimal residual disease were prepared with marrow-ablative but leukaemia-noncurative doses of cyclophosphamide (CY) and total body irradiation followed by bone marrow transplantation. The next day after transplantation the recipients were injected with splenocytes immunized against the leukaemia cells (Imm-SPL) or monoclonal antibody (mAb). All the control mice died from leukaemia relapse, but 51% of purged bone marrow recipients, which received Imm-SPL, were cured. In similar conditions mAb did not exert a therapeutic effect. Imm-SPL were not able to eradicate minimal residual disease in the recipients of nonpurged bone marrow. Thus, in an animal model, we demonstrated that purging of bone marrow before grafting seems to be indispensable for successful adoptive immunotherapy of minimal residual disease (MRD) after autologous bone marrow transplantation.

Adjuvants, Immunologic↗