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Biomedical subjects

K Szyfter

Publications and source records attributed to K Szyfter.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Chromosome damage in the course of laryngeal squamous cell carcinoma].

The aim of the article is a review of own cytogenic studies on laryngeal cancer confronted with the literature data. Spontaneous and bleomycin-induced chromosome instability was analysed in peripheral blood lymphocytes in relation to genetic risk of cancer incidence and progression. Comparative genome hybridization (CGH) was applied to demonstrate gains and losses of DNA copy number in tumour and non-tumour laryngeal mucosa. The profiles of imbalances of DNA copy number were shown to differ between metastazing and non-metastazing tumours. Preliminary data indicate a frequent loss of Y chromosome in tumour cells. The loss of heterozygosity at chromosome p53 locus (17p) has been shown to be more frequent than at chromosome locus coding 16 gene (9p). Altogether, the experiments have proven that a dynamics of chromosome aberrations is highest at the stage of metastasis.

Antibiotics, Antineoplastic↗
PubMed1999

The protective effect of vitamins C and E against B(a)P-induced genotoxicity in human lymphocytes.

Polycyclic aromatic hydrocarbons (PAH) are a well-characterized group of mutagens and carcinogens. Benzo(a)pyrene [B(a)P], the best known compound in the group, exerts its genotoxic activity following metabolic activation, when it acquires the properties of an electrophilic reagent that is capable of interacting with DNA. Reactive oxygen species (ROS) can remerge during the PAH metabolic activation. Because of their antioxidant activity, vitamins C and E are thought to act as antimutagenic agents. We designed an in vitro protocol to study the potential protective effect of vitamins C and E toward B(a)P-induced DNA damage. In this study, we examined peripheral blood lymphocytes obtained from healthy nonsmoking female volunteers, 22 to 25 years of age. The cells were exposed in vitro to 1 microM B(a)P in the presence of 40 microM or 100 microM of vitamin C or, alternatively, to 30 microM or 100 microM of vitamin E. The B(a)P-induced DNA damage and repair were estimated as the generation and removal of single-strand DNA breaks measured by the alkaline version of the single-cell gel electrophoresis (comet) assay. The protective effect of vitamins C and E was demonstrated when the vitamins were applied simultaneously with or after the B(a)P. The background level of DNA damage in the presence of vitamins C and E was lower than in the system without the vitamins. The experiments were conducted according to various protocol schemes of the vitamin treatment and the results offer additional evidence of the antigenotoxic activity of vitamins C and E. The vitamin activity does not appear to be connected with the steps in metabolic activation or DNA repair. It seems that both vitamins act as competitors of DNA molecule in reaction with the reactive oxygen species.

Adult↗
PubMed1998

[Sex-dependence of larynx susceptibility to tobacco smoke carcinogens. The role of androgen hormones].

According to epidemiological data concerning laryngeal cancer there is almost ninefold higher morbidity in male population than in females. The aim of this study was to analyse on molecular level the genotoxic effects arising under the same exposure to tobacco smoke in males and females. In biopsies received from laryngectomy material we determined levels of aromatic and alkylated DNA adducts in tumours and in adjacent non-tumour tissue. It was established that levels of DNA adducts found in male DNA samples exceeded those in female DNA samples 1.5-3.8 times, which was recognised as a molecular evidence for epidemiological differences. Next, testosterone and sex hormones binding globulin (SHBG) were determined in male subjects blood serum. The levels of testosterone and SHBG very weakly correlated with DNA adduct levels even when subjects were separated into age groups. It is concluded that levels of testosterone and SHBG are not the proper markers of individual susceptibility to genotoxicity of tobacco smoke carcinogens.

Adult↗
PubMed1998

[Chromosome sensitivity to bleomycin-induced damage in patients with laryngeal cancer as a marker of genetic risk].

An inter-individual variability in sensitivity to mutagen-induced genotoxicity was studied in respect to an estimation of larynx cancer risk. Bleomycin induced chromosome breaks were analysed in blood lymphocytes proliferating in vitro in a group of 35 larynx cancer subjects and in 18 healthy controls. A significantly higher index of chromosome breaks was found in larynx cancer subjects as compared with the controls. The distribution of individual results indicates that subjects oversensitive to bleomycine were identified only among laryngeal tumour patients. A potential usage of bleomycin test in tumour prognosis is discussed.

Adult↗
PubMed1997

Alteration of p53 gene structure and function in laryngeal squamous cell cancer.

The p53 gene is known as an anti-oncogene that manifests its function by controlling the cell cycle and is responsible for apoptosis of cells with unrepaired DNA. An accelerated p53 protein synthesis is the first response of a cell following DNA damage. However, mutations of the p53 gene can disturb protein synthesis or may be responsible for synthesis of a changed protein unable to control the cell cycle. Laryngeal tissue specimens from 120 patients were tested by immunohistopathological staining to detect mutated wild-type p53 protein. It was found that p53-positive specimens correlated with TNM staging and histopathological grading. Another indication of entering the cell cycle and undertaking an active proliferation by laryngeal cells was shown by detection of proliferating cell nuclear antigen (PCNA) and Ki67 nuclear antigen, which appeared in proliferating cells (late G1, S-G2 and M phase), but was absent in resting cells. Scoring of the staining for p53 protein, PCNA and Ki67 correlated with each other. DNA from 40 specimens was then isolated, amplified by polymerase chain reaction and analysed by single-strand conformation polymorphism and DNA sequencing for mutation in the p53 gene. Fifteen DNA samples were found to be positive, while mutations were detected in exons 5-8 in 13 samples. The majority of mutations were found in tissue specimens from T3 and T4 tumors. A possible explanation is almost half was attributable to genotoxic effects of tobacco smoking. Changes in the p53 gene and its products may also reflect early changes in laryngeal carcinogenesis and be of prognostic value.

Adult↗
PubMed1997

Bleomycin-induced DNA damage and its removal in lymphocytes of breast cancer patients studied by comet assay.

The studies concerned the response to bleomycin treatment in peripheral blood lymphocytes (PBL) of breast cancer (BC) subjects. The level of BLM-induced DNA strand breaks was evaluated using alkaline comet assay followed by visual scoring. The sensitivity to genotoxic exposure as well as the time-course of damage removal were estimated and analysed in comparison to control (healthy) subjects. Despite high inter-individual variability, the differences between the BC and non-cancer groups still proved to be statistically significant. Lymphocytes of the BC subjects appeared to be more sensitive to BLM exposure as shown by higher level of DNA damage. The DNA repair capacity was weaker in PBL obtained from BC patients than that in lymphocytes of controls.

Adult↗
PubMed1996

Tobacco smoke-associated N7-alkylguanine in DNA of larynx tissue and leucocytes.

The presence of N7-alkylguanine adducts in DNA was analysed in a group of 46 patients with larynx tumours. All patients were subjected to laryngectomy and the tissues accessible for analysis by (32)P-post-labelling assay were larynx tumour, larynx non-tumour and peripheral blood leucocytes. N7-Alkylguanine adducts were detected in all the studied DNA samples. The average level of N7-alkylguanines was 26.2/10(7) nucleotides in tumour cells, 22.7/10(7) in non-tumour cells and 13.1/10(7) in blood leucocytes. There was significantly higher level of N7-alkylguanines in the larynx tissues in males than in females. The effect of tobacco smoking on DNA adduct levels was shown by an increase in the average levels of N7-alkylguanines in the subject groups classified according to their smoking habits. A moderate age-related increase in levels of N7-alkylguanine was demonstrated in larynx tumour tissue. The levels of N7-alkylguanine adducts in larynx cells were compared with that of aromatic DNA adducts. Pearson correlation coefficients (0.28 for tumour tissue and 0.30 for non-tumour tissue) indicate independent formation and removal of N7-alkylguanine and aromatic DNA adducts resulting from tobacco smoke exposure.

Adult↗
PubMed1995

Studies of biomarkers in aluminum workers occupationally exposed to polycyclic aromatic hydrocarbons.

Evaluation of biomarkers for genotoxic exposure are important for future use of such biomarkers in cancer prevention. We have studied a group of aluminum plant workers for a period of 2.5 years. The level of polycyclic aromatic hydrocarbons (PAHs) has been monitored at the work place (cathode relining). During the study period, urine and blood were sampled up to seven times from the same workers. Mean level of urinary 1-hydroxypyrene varied from 1.08 to 2.44 mumol/mol creatinine in the exposed groups compared with 0.36 and 0.20 mumol/mol creatinine in the two reference groups. For a group of 14 workers the intraindividual variation of urinary 1-hydroxypyrene was analyzed. The relative standard deviation of the values was < or = 0.50 for half of the workers; the relative standard deviation was calculated for individual values divided by mean of each time point. Polycyclic aromatic hydrocarbon-DNA adducts in white blood cells from exposed and nonexposed workers were measured by both immunoassay and 32P-postlabeling. By 32P-postlabeling mean values of 12.0 adducts/10(8) and 10.8 adducts/10(8) nucleotides were found in a PAH-exposed group and a reference group, respectively. Intraindividual variation of PAH-DNA adducts was also analyzed.

Adult↗
PubMed1995

[Estimation of aromatic DNA adduct levels in laryngeal tumors in relation to cancer staging].

Genotoxical agents as PAH, nitrosamines, aromatic amines located in tobacco smoke are responsible for disorders of structure and function of DNA chromosomes, proteins and also initiation of carcinogenesis. DNA adducts are recognized as measure of the biological effective dose of exposure to environmental genotoxicant. So far most studies on DNA adducts after human exposure to tobacco smoke have ben carried out on white blood cells, lungs and oral cavities tissue. The aim of this work was estimation of relationship between state of neoplastic disease (TNM system) and number of aromatic DNA adducts. The subject were 37 patients with primary larynx tumor. In every case histopathological investigation revealed squamous cell carcinoma. There were 33 total and 4 partial laryngectomies performed. From tumour and nontumour larynx tissue DNA was isolated. Analysis of DNA adducts was performed by the 32P-postlabelling method. The results were characterized by individual differentiation. The highest level of DNA adducts was found in larynx tumour cells. In case of strong smokers (30-40 cigarettes per day) the level of aromatic adducts was higher then in non- or ex-smokers. In both tissues (tumour and non-tumour) the highest level of aromatic adducts was in T3 stage, the lowes in cause of T2 stage. In tissues with T4 stage the level of DNA adducts was intermediate. One has been observed decrease tendency in level of DNA adducts which is connected with increase of TNM stage.

Adult↗
PubMed1994

Aromatic DNA adducts in larynx biopsies and leukocytes.

Larynx cancer is strongly associated with tobacco smoking. The objective of this work was an analysis of aromatic DNA adducts in tumour and non-tumour larynx cells by means of the 32P-postlabelling method. Peripheral blood leukocytes were used as a reference tissue. The presence of aromatic DNA adducts was demonstrated in all the studied tissues obtained after surgery of larynx tumours. The highest level of DNA adducts was found in larynx tumour cells, followed by non-tumour larynx cells, which exceeded that found in leukocytes almost 2.5 times. Large interindividual differences were detected between subjects. The adduct level in tumour/non-tumour correlated only moderately. However a high correlation was found between the level of DNA adducts in larynx (tumour and non-tumour) cells and that in leukocytes.

Adult↗
PubMed1994

p53 mutations in larynx cancer.

The objective of this work was an analysis of mutations in the p53 gene detected from fresh tumor samples of larynx cancer patients using single-strand conformation polymorphism (SSCP) and direct DNA sequencing of exons 5-8. From 40 patient samples, 15 showed an extra band in SSCP. In 13 samples mutations were detected in exons 5-8. They constituted six transitions and seven transversions, four of them being T to A transversions. Mutations in codons 205 and 248 occurred in two and in codon 246 in three samples. Larynx cancer is strongly associated with tobacco smoking and alcohol consumption. The typical p53 mutations in lung cancer, G to T transversions and G to A and C to T transitions, associated with smoking, accounted for 46% of the mutations detected. Fifty-four per cent of the mutations were detected in a reported hotspot region covering codons 238-248.

Adult↗
PubMed1994

Biological monitoring of exposure to polycyclic aromatic hydrocarbon in an electrode paste plant.

We have compared several biomarkers for polycyclic aromatic hydrocarbon (PAH) exposure among electrode paste plant workers and workers not occupationally exposed to PAH. The PAH exposure was quantitated from samples collected with person-attached sampling devices. The mean particulate PAH exposure level in the plant was 14.4 micrograms/m3. The level of pyrene was significantly correlated with both PAH level and the level of selected carcinogenic PAHs in this type of exposure. The mean concentration of the biomarker 1-hydroxypyrene in the PAH exposed workers' urine was 6.98 mumol of 1-hydroxypyrene per mole of creatinine compared with 0.08 and 0.14 mumol of 1-hydroxypyrene per mole of creatinine in the two reference groups. PAH-DNA adducts were measured in DNA from white blood cells by the ultrasensitive enzyme radioimmunoassay (USERIA) and the 32P-postlabeling technique. Only urinary 1-hydroxypyrene was significantly increased in the PAH-exposed group.

Adult↗
PubMed1993

[Analysis of the DNA adducts in patients with laryngeal cancer].

There is known a strong association between induction of cancer of respiratory tracts and tobacco smoking. Exposure to polycyclic aromatic hydrocarbons (PAH) present in tobacco smoke can induce DNA lesions including bulky DNA adducts. The studied group consisted of 6 men, aged 46-71 years, all intensive cigarette smokers, without reported occupational exposition to PAH. Treatment did not include radio- and chemotherapy. DNA isolated from surgically removed tumors, surrounding tissue histologically characterized as non-malignant and peripheral blood white cells was analyzed by 32P-postlabelling assay with P1 nuclease enhancement. Both, P1 nuclease digestion and the chromatographic systems used for separation of DNA adducts were established for PAH: DNA analysis. The main adduct was identified as diol-epoxide metabolite of B (a) P. The mean number of adducts in tumor samples, surrounding tissue and white blood cells was calculated, respectively, to 82.3, 59.9 and 41.7 PAH: DNA adducts per 10(8) nucleotides. The only accessible reference was for DNA from white blood cells. The amount of PAH: DNA adducts in white blood cells of larynx cancer patients exceeded that found in healthy blood donors (both: smokers and non-smokers) as well as in workers exposed occupationally to high concentration of PAHs in the ambient air. Hence, it is concluded that carcinogen: DNA adducts as pre-mutagenic lesions can provide a diagnostic information. It concerns the target cells as well as a surrogate tissue. In any case the study has only a preliminary character because of limited number of subjects studied.

Aged↗
PubMed1992

Analysis of deoxyribonucleic acid adducts in workers.

Repeated blood samples were obtained from volunteers who were occupationally exposed to polycyclic aromatic hydrocarbons in a Finnish iron foundry. Aromatic adducts were determined in white blood cell deoxyribonucleic acid of the subjects with the 32P-postlabeling technique after nuclease P1 treatment and butanol extraction, which showed no major difference. When repeated samples were analyzed, it appeared that the oldest ones displayed the lowest adduct levels, probably due to the instability of the adducts upon storage at -20 degrees C. The workers tended to maintain their adducts at a uniform level, a finding suggesting the contribution of host factors in the control of adduct levels.

DNA↗
PubMed1991

Quantitation of the 32P-postlabeling reaction using cyclic N1,N2 and C8 modified deoxyguanosine 3'-monophosphates as substrates.

The 32P-postlabeling technique was used to investigate the efficiency of phosphorylation reaction by T4 polynucleotide kinase using seven synthetic adducted deoxyguanosine 3'-monophosphates. The adducts included cyclic N1,N2 derivatives and the C8 adduct of 4-aminobiphenyl. The adducted substrates were detected at a subfemtomole sensitivity except for one of the diastereomeric propanoguanine derivatives. In general, the recommended conditions were found to be proper for an efficient phosphorylation of the adducts studied. Sensitivity of the adducts to the 3'-dephosphorylation reaction of nuclease P1 was also tested. All the complex cyclic adducts were resistant towards P1. However, the ethenoguanine and 4-aminobiphenyl adducts were relatively sensitive towards P1. No differences were noted between diastereomers.

Chromatography, Thin Layer↗
PubMed1991

Quantitative and kinetic examination of 32P-postlabeling of etheno-substituted nucleotides.

1,N6-ethenodeoxyadenosine-, 1,N2-ethenodeoxyguanosine- and 3,N4-ethenodeoxycytidine-3'-monophosphates were labeled by [gamma-32P] ATP using T4 polynucleotide kinase in conditions commonly used for the 32P-postlabeling assay. Kinetic studies showed that the reaction is fast reaching a plateau after 15-30 min. The efficiency of phosphorylation, as studied by substrate-product concentration dependency, was between 50-100% at the lower substrate concentrations. The adducts are labeled efficiently at sub-femtomole levels. All the adducts were sensitive to the 3'-dephosphorylation by P1 nuclease although the guanine derivative appeared to be more resistant than the two other adducts.

Adenosine Triphosphate↗