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M Radkowski

Publications and source records attributed to M Radkowski.

At least 19 recordsLinked to original sources
PubMed2006

Selection of different 5' untranslated region hepatitis C virus variants during post-transfusion and post-transplantation infection.

BACKGROUND: Hepatitis C virus (HCV) translation is initiated in a cap-independent manner by an internal ribosome entry site (IRES) located within the 5' untranslated region (5'UTR). Sequence changes in this region could affect translation efficiency and presumably viral replication. AIM: To determine translation efficiency of 5'UTR variants developing during post-transfusion hepatitis C in two immunocompetent subjects and in two immunosuppressed liver recipients with recurrent HCV. METHODS: Sequential samples were screened for 5'UTR changes by single-strand conformation polymorphism followed by cloning and sequencing whenever band pattern suggested sequence changes. 5'UTR variants were tested for IRES activity using a bicistronic dual luciferase expression plasmid transfected into HepG2 and Huh7 cell-lines. RESULTS: In the transfused patients, translation efficiency of 5'UTR variants from early post-transfusion samples was 5.1- to 13.7-fold higher than that of predominant variants found in late follow-up samples. Post-transplant variants in the other two patients had 2.6- to 5.9-fold higher translation efficiency than those present only in pretransplant samples. CONCLUSION: In the immunocompetent host there may be selection of low translation efficiency HCV variants over the course of infection. However, in immunosuppressed subjects the opposite seems to be true as low translation efficiency variants are superseded by high translation efficiency variants.

5' Untranslated Regions↗
PubMed2006

The effect of polyphosphates on streptococci isolated from mastitis cases.

The effect of 0.01, 0.02, 0.03, 0.05, 0.6, 0.8 and 0.9% of polyphosphate mixture on 5 strains of Streptococcus agalactiae, 2 strains of Streptococcus dysgalactiae and 3 strains of Steptococcus uberis in blood agar in vitro and in milk was examined. It was found that the growth of all strains of the above mentioned bacteria was completely inhibited by 0.03% phosphate mixture in blood agar. In milk, however, the amount of polyphosphate mixture necessary for total inhibition was, from 0.6 to 0.9%, depending on the strain.

Animals↗
PubMed2006

The legal requirements concerning transport of slaughter animals in Poland.

Conditions of trading and handling of animals during transportation are regulated by numerous norms which cover the humanitarian, sanitary, veterinary as well as technical and construction requirements to transportation means. Veterinary services play a particular role in trade of slaughter animals due to their controlling authority. They execute sanitary supervision over animal trading according to the regulations. Polish legislation related to the transport of animals is adjusted to the European Union standards.

Abattoirs↗
PubMed2004

Natural history of acute symptomatic hepatitis type C.

BACKGROUND: Spontaneous clearance of hepatitis C virus (HCV) after acute hepatitis C, and the course of chronic HCV infection in patients who did not clear the virus, were studied. PATIENTS AND METHODS: Patients with acute C or non-A, non-B hepatitis who were hospitalized between 1988 and 1998 were called for evaluation in 2001. They were tested for anti-HCV, serum HCV-RNA, HCV-RNA in peripheral blood mononuclear cells (PBMC) and liver enzymes. A liver biopsy was performed on chronically infected patients. The course of acute hepatitis C was compared between HCV-RNA-positive and negative subjects to look for factors that might influence spontaneous viral clearance. Factors influencing more progressive liver disease were analyzed in chronic hepatitis C. RESULTS: Out of 159 acute hepatitis C patients, 77 (48.4%) participated in the study, and the median observation time was 8 years. Spontaneous clearance of serum HCV was found in 23 subjects (29.9%), but in two cases HCV-RNA was detected in peripherical blood mononuclear cells (PBMC). Only three patients negative for HCV-RNA in serum and PBMC lost anti-HCV. Severity of acute HCV infection and previous alcohol abuse seemed to influence resolution. In non-alcoholic patients, older age at time of primary infection was a significant predictor of virus clearance. In chronic hepatitis C, more than 75% of patients had minimal or mild activity in biopsy, but 40% had advanced fibrosis. Older age at infection, male gender, alcohol abuse, and higher iron content were connected with advanced fibrosis. CONCLUSION: Studies on HCV infection resolution should include at least PBMC testing for HCV-RNA. A healthy carrier state of HCV can be discussed. A longer observation time increased the likelihood of seroreversion. Fibrosis in chronic hepatitis C probably is not a direct result of inflammatory activity.

Acute Disease↗
PubMed2002

Elimination of Salmonella spp. by lactic acid.

The aim of the present study was to determine the elimination of Salmonella by different lactic acid concentrations in microbiological media and on turkey carcass elements. The average bacteria counts in the control samples without lactic acid were: 1.8 x 10(8), 1.1 x 10(8) and 2.3 x 10(8), for S. Enteritidis, S. Anatum and S. Typhimurium, respectively. The concentration of lactic acid of 0.1% in the agar media completely inhibited the growth of all Salmonella strains. At 0.05% lactic acid concentration, the bacteria count was 2 log cycles lower and at a 0.03% solution it was 1 log cycle lower than that in the respective control samples. However, the examined bacteria developed in the presence of 0.02% and 0.01% lactic acid concentrations and their counts fell into the same log brackets. An analysis of the experimental results obtained from turkey carcass elements immersed in the lactic acid solution showed that the Salmonella identification rate was determined by the bacteria inoculum spread over the turkey carcass surface. The contamination of 10(1) CFU of Salmonella spread onto the turkey carcass was completely eliminated by immersing the carcasses in 1% or 2% lactic acid solutions. The contamination of turkey carcass elements with 10(2) CFU of S. Enteritidis and their immersion in 2% lactic acid solution for 15 min resulted in the reduction of the number of samples with Salmonella compared to the number of control samples with Salmonella. At contaminations of 10(3) CFU on the carcass surfaces, the immersions in 1% and 2% lactic acid solutions did not reduce Salmonella counts.

Animals↗
PubMed2001

Changes in hepatitis C virus population in serum and peripheral blood mononuclear cells in chronically infected patients receiving liver graft from infected donors.

BACKGROUND: We have previously studied hepatitis C (HCV)-infected recipients of livers from HCV-infected donors and found that either the donor's strain or the recipient's strain predominate in serum. The current study was undertaken to determine whether these changes are complete and whether they are reflected in the population of virus associated with peripheral blood mononuclear cells (PBMCs). METHODS: We analyzed HCV ribonucleic acid from sequential serum and PBMC samples from 11 and 8 patients, respectively. The relatively stable NS5 region was chosen for analysis because it allowed for dependable identification of donor and recipient strains. Viral sequences were analyzed by direct sequencing and by sensitive strain-specific polymerase chain reaction assays. These assays were capable of detecting the minor sequence present at a concentration 1:104-10-7 below that of the major sequence. RESULTS: Five patients retained their original infecting strain; the donor strain was detected only transiently. In the remaining six patients, recipient strain was detected for the first few weeks, after which only the donor strain was consistently present. However, in one patient the second nondominant strain was detected from the background of the major strain on a single occasion 8 months after transplantation. All changes in serum were closely paralleled by those occurring in PBMCs. CONCLUSIONS: Viral population changes in the setting of liver transplantation from HCV-infected donors to HCV-infected recipients occur simultaneously in PBMCs and serum. The takeover of one strain by another in PBMC- and serum-derived viral populations seemed to be complete and long lasting.

Base Sequence↗
PubMed2001

Occurrence of Salmonella spp. in consumption eggs in Poland.

The purpose of this study was to determine the prevalence of Salmonellae on egg shells in markets in Olsztyn, Poland. An investigation carried out by the Sanitary and Epidemiological Station into cases of food poisoning caused in Poland by Salmonella spp. in recent years showed that the largest number of outbreaks is connected with consuming foods containing hens eggs which had not undergone heat treatment, such as mayonnaise, creams, ice-cream and other products. The world egg production amounts to 400 billion, in Poland it reaches the level of around 8 billion per year. A total of 1200 eggs were purchased in 40 local markets in Olsztyn were examined for the presence of Salmonella between June 1997 and December 1998. Salmonella was not found on the shell or inside the eggs. From this study it would appear that the incidence of Salmonellae on eggs from Olsztyn shops is very low.

Eggs↗
PubMed2001

Exposure of hepatitis C virus-negative recipients to > or =2 infected blood donors.

This study analyzed 4 cases of hepatitis C virus (HCV)-naive transfusion recipients who developed hepatitis after receiving blood from >1 HCV-infected donor. One recipient was exposed to 4 donors, 2 were exposed to 3 donors, and 1 was exposed to 2 donors. For 3 recipients, the strain from 1 of the donors predominated in all follow-up samples collected for 8-40 months. For 2 recipients, the strain from the second donor was occasionally detectable with sensitive strain-specific assays. For the fourth recipient, the initially dominant strain was later supplanted by a strain from the other donor. Simultaneous exposure to multiple HCV strains may result in concomitant infection by >1 strain, although a single strain rapidly establishes its dominance. These observations are compatible with the presence of competition among infecting HCV strains that results in the dominance of 1 strain and competitive exclusion or suppression of other strains.

Adult↗
PubMed2001

Exposure of hepatitis C virus (HCV) RNA-positive recipients to HCV RNA-positive blood donors results in rapid predominance of a single donor strain and exclusion and/or suppression of the recipient strain.

We have analyzed three cases of hepatitis C virus (HCV)-infected recipients who received blood from HCV-infected donors. Two recipients were exposed to two different HCV RNA-positive donors, and one was exposed to a single donor. All parental genomes from the actual infecting units of blood and the recipients were defined, and their presence in the follow-up serum samples was determined using sensitive strain-specific assays. The strain from one of the donors was found to predominate in all recipients' serum samples collected throughout the follow-up period of 10 to 30 months. In two recipients exposed to two infected donors, the strain from the second donor was occasionally found at very low level. However, the original recipients' strains were not detected. Our observations show that HCV-infected individuals can be superinfected with different strains, and this event may lead to eradication or suppression of the original infecting strain. Furthermore, our findings demonstrate that simultaneous exposure to multiple HCV strains may result in concomitant infection by more than one strain, although a single strain could rapidly establish its dominance. The results of the present study suggest the existence of competition among infecting HCV strains which determines the ultimate outcome of multiple HCV exposure.

Adult↗
PubMed2000

Detection of active hepatitis C virus and hepatitis G virus/GB virus C replication in bone marrow in human subjects.

We have analyzed the presence of hepatitis C virus (HCV) and hepatitis G virus (HGV) sequences in bone marrow and serum samples from 48 patients of a hematologic outpatient clinic. HCV RNA was detected in 18 (38%) and 15 (31%) and HGV RNA was detected in 6 (13%) and 9 (19%) of serum and bone marrow samples, respectively. In 3 patients, HGV RNA was detectable in bone marrow but not in the serum; 2 of these patients were negative for the presence of specific antibodies. Using a highly strand-specific Tth-based reverse transcriptase-polymerase chain reaction (RT-PCR), the presence of HCV RNA and HGV RNA negative strand was demonstrated in 4 and 5 bone marrow samples, respectively. Our study shows that HCV and HGV can replicate in bone marrow; in the case of HGV, analysis of serum may underestimate the true prevalence of infection. (Blood. 2000;95:3986-3989)

Adult↗
PubMed2000

Hepatitis C virus in lymphoid cells of patients coinfected with human immunodeficiency virus type 1: evidence of active replication in monocytes/macrophages and lymphocytes.

It has been reported that hepatitis C virus (HCV) may be lymphotropic in the setting of human immunodeficiency virus type 1 (HIV-1) coinfection. The present study was undertaken to determine the phenotype of lymphoid cells harboring replicating HCV in HIV-1-positive subjects. By means of highly strand-specific thermostable enzyme Tth-based reverse-transcriptase polymerase chain reaction, the presence of viral RNA-negative strand was sought in different subpopulations of peripheral blood mononuclear cells from 10 HIV-positive patients. HCV RNA-negative strand was most commonly present in monocytes/macrophages (4 cases), followed by CD8+ and CD4+ lymphocytes (2 cases) and CD19+ cells (1 case). In 2 cases that were further analyzed, viral-negative strand remained detectable in monocytes/macrophages cultured for 3 weeks. Moreover, monocyte/macrophage- and serum-derived viral sequences differed in the 5' untranslated region. These findings imply that, in HIV-infected subjects, HCV may replicate in the same cells as HIV-1, which raises the possibility of direct interactions between these pathogens.

5' Untranslated Regions↗
PubMed2000

Uneven distribution of hepatitis C virus quasispecies in tissues from subjects with end-stage liver disease: confounding effect of viral adsorption and mounting evidence for the presence of low-level extrahepatic replication.

We have found differences among the populations of hepatitis C virus sequences in serum, peripheral blood mononuclear cells (PBMCs), and various tissues in patients with chronic hepatitis C. These results are compatible with the existence of independent viral compartments in the infected host. Our results also suggest that PBMCs, and probably various tissues, can selectively adsorb viral subpopulations differing in the E2 region.

5' Untranslated Regions↗
PubMed2000

Hypertonicity of dialysis fluid suppresses intraperitoneal inflammation.

We studied acute and chronic intraperitoneal inflammation during dialysis performed in rats injected with phosphate-buffered saline alone (PBS) or PBS supplemented with glucose (Glu) or with mannitol (Man). In acute experiments, the result of a first dialysis with PBS in every rat (dialysis I) was compared with a second dialysis performed 24 hours later (dialysis II) using a different dialysis fluid: either PBS with 3.86 g/dL Man or PBS with 3.86 g/dL Glu. In rats exposed to hypertonic dialysis solutions (both Glu and Man), inflammatory reaction was decreased (cell count: p < 0.05; nitric oxide secretion: p < 0.05; protein in dialysate: p < 0.05). In control animals treated only with PBS (dialysis I and dialysis II), the inflammatory reactions during dialysis I and dialysis II were comparable. In chronic experiments, rats were dialyzed with the tested fluids for four weeks. Weekly, dialysate samples were taken and analyzed. At the end of the study, cell counts and protein losses were higher in the PBS-treated rats than in the other groups (cell count: p < 0.05, Glu vs PBS, and p < 0.05, Man vs PBS; protein in dialysate: p < 0.001, Glu vs PBS, and p < 0.01, Man vs PBS). We conclude that hypertonicity of the dialysis fluid inhibits the inflammatory reaction in the peritoneal cavity during peritoneal dialysis.

Acute Disease↗
PubMed1999

Analysis of hepatitis G virus/GB virus C quasispecies and replication sites in human subjects.

Although the hepatitis G virus is unlikely to be a primary hepatotropic virus, its replication sites remain unclear. Using highly strand-specific Tth-based reverse transcriptase PCR we searched for the presence of the viral RNA negative strand in various autopsy tissues in two patients who died of end-stage liver disease. In addition, amplified viral sequences were compared in the 5' untranslated and the putative capsid regions by the single-strand conformation polymorphism (SSCP). Negative strand HGV RNA was detected in bone marrow and spleen from both patients and in lymph node tissue from one. All amplified sequences from a given patient were identical when compared by SSCP and direct sequencing. This lack of difference in the composition of quasispecies recovered from various tissues suggests the presence of a single, common viral compartment in the infected host.

5' Untranslated Regions↗
PubMed1999

Hepatitis C virus in peripheral blood mononuclear cells from a chronically infected patient receiving liver graft from infected donor.

BACKGROUND: In hepatitis C virus (HCV)-positive patients receiving HCV-positive liver allografts either the donor or recipient strain overtakes the other strain. Whether these changes are reflected in peripheral blood mononuclear cell (PBMC)-associated virus is unknown. METHODS: We analyzed by single-strand conformation polymorphism and sequencing HCV RNA from serum and PBMCs from a liver transplant recipient whose indigenous strain was replaced by the donor strain. RESULTS: Only the recipient strain was detectable in serum and PBMCs 3 and 5 days after transplantation; at day 7 and 8, a mixture of both was present in the PBMCs, but only recipient strain was detectable in serum. This coincided with the peak presence of donor DNA in recipient PBMCs. From day 14 on, HCV sequences in serum and PBMCs were indistinguishable. CONCLUSIONS: Overtake phenomenon in the setting of liver transplantation from infected donors to infected recipients is manifested in PBMCs. Cells released from infected graft carry donor HCV strain.

Aged↗
PubMed1999

Outcome of liver transplantation in hepatitis C virus-infected patients who received hepatitis C virus-infected grafts.

BACKGROUND & AIMS: The present organ shortage has brought into question the suitability of hepatitis C virus (HCV)-positive grafts. This study reviewed the outcome of such transplantations in our institution. METHODS: Twenty-three HCV-positive patients who underwent orthotopic liver transplantation (OLT) for end-stage liver disease with HCV-positive grafts in 1992-1995 were studied. Only patients who survived more than 30 days were included in the analysis. Control group included 169 patients who underwent transplantation for HCV-related cirrhosis and received HCV-negative organs. RESULTS: Patients who received HCV-infected organs had a cumulative survival rate of 89% and 72% at 1 and 5 years, respectively, vs. 88% and 73% for the control group (NS). There was no difference in graft survival, incidence of cirrhosis, mean hepatitis activity index score, fibrosis, or mean activity of serum transaminases. There was a trend toward lower incidence of recurrent hepatitis C in the study group compared with control (21% vs. 23% at 1 year and 47% vs. 64% at 5 years; NS). Patients in whom the donor strain became predominant after transplantation had significantly longer disease-free survival than patients who retained their own HCV strain (P < 0.003). CONCLUSIONS: HCV-infected livers transplanted into HCV-infected recipients do not appear to convey a worse outcome in the initial years after OLT than HCV-negative grafts.

Adult↗
PubMed1999

Differences between hepatitis C virus 5' untranslated region quasispecies in serum and liver.

It is unclear whether the sequence populations of hepatitis C virus (HCV) quasispecies in the liver and in serum are different, as a variety of studies on this subject provide conflicting results. In the current study, the populations of HCV 5' untranslated region (5' UTR) sequences in paired serum and liver samples from six patients with chronic hepatitis were analysed. Liver-derived, negative-strand viral RNA was amplified with a highly strand-specific Tth-based assay, and extensive measures, including accounting for template copy number, were undertaken to lower the risk of sporadic artefactual polymorphism. Amplified sequences were compared by single-strand conformation polymorphism analysis and by direct sequencing of identified differences. In four patients, liver samples were found to contain variants within the quasispecies which were not found in serum or negative-strand viral RNA, while in the remaining two patients, low virus titre prevented a reliable quasispecies analysis. These results suggest the presence in the same individual of HCV variants differing in the 5' UTR and possibly replicating with different kinetics.

5' Untranslated Regions↗