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Biomedical subjects

A Haugen

Publications and source records attributed to A Haugen.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Lung cancer].

Significant progress is being made in understanding molecular events leading to lung cancer. Both susceptibility factors (molecular markers of risk) and the genetic alterations involved have been discovered. New techniques for early detection of lung cancer based on molecular changes (i.e. mutations in p53, K-ras and rb, amplification of myc and Her-2/neu, deletion of 3p, and microsatellite instability) in sputum or bronchoalveolar lavage fluid may be used as tools in diagnosis and prognosis, as well as in screening programs. These new findings should be transferred to the clinical environment. Multiple markers should be used, thereby increasing the chance of detecting the tumor or premalignant lesions. In the future, such research should be carried out in large prospective studies.

Biomarkers, Tumor↗
PubMed1998

Urinary excretion of 1-hydroxypyrene as a marker for exposure to urban air levels of polycyclic aromatic hydrocarbons.

A cross-sectional study was conducted among 94 traffic police officers from the Municipality Police of Genoa, Italy, exposed to airborne pollutants and 52 referent subjects exposed to indoor air pollution levels to investigate the relationships between exposure to ambient air polycyclic aromatic hydrocarbons (PAHs) and urinary excretion of 1-hydroxypyrene (1-OH-P). The effects of smoking, lifestyle factors such as exposure to ETS, and diet, along with the role played by the cytochrome P4501A1 (CYP1A1), and glutathione S-transferase M1 and theta metabolic susceptibility gene polymorphisms were examined. The geometric mean of benzo(a)pyrene air measurements (an index compound of PAH levels) was 70 times higher in traffic police officers (3.67 ng/m3) than in referents (0.05 ng/m3). The urinary concentration of 1-OH-P was clearly associated with cigarette smoking and, to a lesser extent, with exposure to ETS and particulate PAH pollution. No association was detected between 1-OH-P excretion and diet. Women exhibited a higher excretion level than did men, and an apparent effect of age was due to differences in cigarette smoking habits. Exposure to PAHs resulted in higher levels of 1-OH-P excretion in all groups except heavy smokers. Overall, no significant role of any metabolic polymorphism was detected. However, stratification of study subjects according to their smoking habits revealed higher levels of excretion of 1-OH-P in subjects smoking < or =15 cigarettes/day carrying the CYP1A1 polymorphism. No such effect was seen either with nonsmokers or with people smoking more than 15 cigarettes/day. These findings are suggestive of a gene-environment interaction, in which subjects with the CYP1A1 polymorphism, relative to subjects without it, have higher levels of 1-OH-P in their urine at low doses of exposure to PAHs.

Age Distribution↗
PubMed1997

Rare alleles at different VNTR loci among lung-cancer patients with microsatellite instability in tumours.

Work in our laboratory has shown a significantly higher frequency of microsatellite mutations in tumours from lung-cancer patients with rare alleles at the HrasI VNTR locus compared with those with common alleles. In 137 lung-cancer patients, the association between microsatellite instability and rare alleles at the HrasI VNTR locus was confirmed with 17 microsatellite markers. We found a significant association between LOH in lung tumours of marker D3s966 with microsatellite instability. In samples with LOH at marker D3s966 (3p21.3) 22% of loci tested showed instability, whereas 8% showed instability without LOH at D3s966. To investigate whether rare alleles at the HrasI locus are linked to rare alleles at other loci, a second minisatellite (D17S4) was genotyped. In a population of 406, 4 individuals with D 17S4 rare alleles were detected of whom 3 also had rare alleles at the HrasI VNTR locus. The probability of this association to occur by chance is low. Thus, rare alleles at the HrasI locus may be associated with rare alleles at other loci, and could be an indication of germline instability. The findings indicate that microsatellite instability in lung tumours is not strictly associated with features in the HrasI proto-oncogene, but may be the result of the same mechanism(s) that generate(s) new alleles at the HrasI and D17S4 loci.

Alleles↗
PubMed1997

Genotypes of glutathione transferase M1 and P1 and their significance for lung DNA adduct levels and cancer risk.

The A-G polymorphism at codon 104 in the glutathione S-transferase P1 (GSTP1) gene was examined in 138 male lung cancer patients and 297 healthy controls. The patients had significantly higher frequency of the GG genotype (15.9%) and a lower frequency of AA (38.4%) than the controls (9.1% and 51.5%, respectively). The level of hydrophobic DNA-adducts were determined in lung tissue from 70 current smokers. Patients with the GG genotype had a significantly higher adduct level than patients with AA (15.5 +/- 10.2 vs 7.9 +/- 5.1 per 10(8) nucleotides, P = 0.006). We also analyzed the deletion polymorphism in the GSTM1 gene in 135 male patients and 342 controls. The patients were stratified according to histology, smoking dose, age, adduct level and mutational types found in the tumors (Ki-ras and p53 genes). The results consistently indicated that the GSTM1 null genotype was associated with a slightly increased lung cancer risk. When the combined GST M1 and P1 genotypes were examined, patients with the combination null and AG or GG had significantly higher adduct levels than all other genotype combinations (P = 0.011). The distribution of combined genotypes was also significantly different in cases and controls, mainly due to increased frequency of the combination GSTM1 null and GSTP1 AG or GG among patients.

Adult↗
PubMed1997

Absence of mutations in the transforming growth factor-beta type II receptor in sporadic lung cancers with microsatellite instability and rare H-ras1 alleles.

The transforming growth factor-beta type II receptor (RII) is commonly mutated in colon and gastric cancers with microsatellite instability (MI). We utilized our series of lung cancers with MI and rare alleles of the H-ras1 gene to determine the association between MI and RII mutations and searched the entire RII coding region in 33 lung cancers with MI by polymerase chain reaction-single-strand conformation polymorphism analysis. We found no mutations, and these data support other recent evidence that RII mutations rarely occur except in colon and gastric tumors with MI.

Alleles↗
PubMed1997

Benzo(a)pyrene-albumin adducts in humans exposed to polycyclic aromatic hydrocarbons in an industrial area of Poland.

OBJECTIVES: The interaction of benzo(a)pyrene with serum albumin was measured in an attempt to identify the actual exposure and to evaluate albumin adduct measurements as biomarkers for exposure monitoring. METHODS: Benzo(a)pyrene-diol-epoxide (BPDE)-albumin adducts were measured by competitive enzyme linked immunosorbent assay (ELISA) in plasma of coke oven plant workers from three plants and from people living in a highly industrialised area of Silesia in Poland. Due to the high air concentrations of polycyclic aromatic hydrocarbons (PAHs) in this area, a control group was selected from a rural non-industrialised area in Poland. Breathing zone air measurements of PAHs were collected from some of the participants. RESULTS: Coke oven plant workers and non-occupationally exposed people had similar concentrations of albumin adducts whereas the rural controls were significantly lower (2.74 fmol adducts/microgram albumin (SEM 0.124)). The mean concentration of BPDE-albumin adduct in plasma of both the occupational and the environmental groups were significantly higher in the summer samples (4.34 fmol adducts/microgram albumin (SEM 0.335) and 4.55 fmol adducts/microgram albumin (SEM 0.296), respectively) than in the winter samples (3.06 fmol adducts/microgram albumin (SEM 0.187) and 3.04 fmol adducts/microgram albumin (SEM 0.184), respectively) even though the air measurements showed higher concentrations of PAHs in the winter. The statistical analysis did not show any effects of air exposures on concentrations of BPDE-albumin adduct. CONCLUSIONS: A multiple regression analysis of the measured concentrations of BPDE-albumin adducts for all the groups, during both seasons, indicates that occupational exposures do not contribute significantly to the formation of adducts. In general, the concentrations of albumin adducts found vary within relatively small limits for the two seasons and between the various groups of participants. No extreme differences were found.

Adolescent↗
PubMed1996

Comparative synchronous fluorescence spectrophotometry and 32P-postlabeling analysis of PAH-DNA adducts in human lung and the relationship to TP53 mutations.

Polycyclic aromatic hydrocarbon (PAH)-DNA adducts were studied in human lung from 39 lung cancer patients by synchronous fluorescence spectrophotometric (SFS) and 32P-postlabeling assays. Regression analysis of the samples failed to detect any correlation between benzo[a]pyrene-diolepoxide (BPDE)-DNA adducts detected by SFS and the BPDE co-migrating spot detected by 32P-postlabeling. We have also analyzed the relationship between adduct levels and TP53 mutations. By postlabeling diagonal radioactive zone (DRZ) adducts were detected in 37 of 39 (95%) lung tissues from lung cancer patients and the adduct level ranged from 6.81 to 108.50 adducts/10(8) nucleotide. Thirty-three of 39 (85%) had detectable levels of BPDE-DNA adducts (> 1 adduct/10(9) nucleotide). Current heavy smokers (> 20 cigarettes/day) have significantly higher DRZ adduct levels compared to individuals smoking less than 20 cigarettes/day. By SFS combined with immunoaffinity column (IAC), 11 of 39 (28%) samples had detectable adduct levels, and 6 of 11 (55%) were detectable by SFS following purification of benzo[a]pyrene (BP)-tetrols by high pressure liquid chromatography (HPLC). Six of 33 (18%) samples were positive for BPDE-DNA adducts by both postlabeling and HPLC/SFS. No correlation was observed between the SFS and 32P-postlabeling assays for the detection of BPDE-DNA adducts. However, there was a good correlation between adduct levels detected by IAC/SFS and HPLC/SFS. We found a weak association between total PAH-DNA adduct levels in lung tissue and TP53 mutations.

Adult↗
PubMed1996

Differential effect of polyunsaturated fatty acids on cell proliferation during human epithelial in vitro carcinogenesis: involvement of epidermal growth factor receptor tyrosine kinase.

Polyunsaturated fatty acids (PUFAs) have been implicated in tumour development and have been shown to influence cell proliferation in vitro. We report here that n-3 and n-6 PUFAs at concentration > 10 microM inhibited the proliferation of a human kidney epithelial cell line (21HKE), which has retained phenotypic characteristics of normal kidney epithelial cells. In contrast, the proliferation was stimulated by n-3 and n-6 PUFAs at concentrations < 10 microM under defined growth conditions. The stimulatory effect of n-3 and n-6 PUFAs was even more profound in the presence of EGF. In human kidney epithelial cell lines reflecting different stages of transformation (11HKE and 1THKEras), the stimulatory effect was abrogated both in the presence and absence of EGF. Saturated fatty acids did not show any stimulatory effect on cell growth. The tyrosine kinase inhibitors genistein and tyrphostin-47 inhibited EGF-induced protein tyrosine phosphorylation dose-dependently in the 21HKE cells, and abolished the growth stimulatory effect of docosahexaenoic acid (DHA). This indicates the involvement of EGF receptor tyrosine kinase activity in the observed increase in cell proliferation.

Cell Division↗
PubMed1996

p53 mutations in lung tumours: relationship to gender and lung DNA adduct levels.

Human lung cancer exhibits a high frequency of transversion mutations at G:C base pairs of the p53 gene, possibly the result of DNA damage by cigarette smoke constituents, most notably benzo[a]pyrene. We have investigated gender differences in the p53 mutational spectrum and levels of hydrophobic DNA adducts. Tumour tissue was obtained from 115 non-small cell lung cancer tumours and examined for mutational alterations in the p53 gene (exons 4-9) using PCR and single-strand conformational polymorphism analysis. We have previously examined exons 5-8 in lung cancer. Sequence analysis of exons 4 and 9 revealed that almost 20% of the mutations were located in exons 4 and 9. The levels of hydrophobic DNA adducts in non-tumorous lung tissue of 55 of the patients were analyzed by the 32P-postlabelling assay. There were both a higher frequency of G:C-->T:A mutations and a higher average hydrophobic DNA adduct level in females than in male patients, even though the level of exposure to carcinogens from cigarette smoking was lower among the females than among the males. Frameshift mutations were more common in women than in men (30 versus 15%). These preliminary findings lend support to epidemiological evidence that women may be at greater risk than men of contracting tobacco-induced lung cancer.

Adenocarcinoma↗
PubMed1996

Modulation of gap junctional intercellular communication by EGF in human kidney epithelial cells.

Modulation of gap junctional intercellular communication (GJIC) was studied in a multistep model of human renal epithelial carcinogenesis. We report that the majority of primary human kidney epithelial cells (NHKE) grown from fetal kidney explants did not communicate through gap junctions. Communication could, however, be observed within a subpopulation of the cells. Ni(II)-immortalized cells (IHKE) showed GJIC at a level of 10-20 communicating cells, but with heterogeneous regions on the dish, with regard to both communication and distribution of connexin43. The heterogeneity was less pronounced in a ras-transfected tumourigenic cell line (THKE), which also showed communication of approximately 10-20 dye-coupled cells. Communication within the IHKE sub-clone K7 decreased from 55 dye-coupled cells communicating on day 1 after seeding to approximately 13 in cells grown for 4 days. Daily change of growth medium reduced the decrease in GJIC. EGF enhanced communication following a lag period which depended on days in culture. The largest increase in GJIC was observed in 2-day-old cultures, where the number of communicating cells in some experiments increased from approximately 45 to 130 dye-coupled cells 4 h following change to medium with EGF. The induction was concentration dependent and communication was enhanced gradually between 2 and 7 h after exposure to EGF. A 15 min pulse of EGF was sufficient to induce the GJIC increase if the total incubation period was unchanged. Cycloheximide completely blocked the EGF-induced enhancement of communication, while actinomycin D had no effect. EGF exposure resulted in an increase in the cellular level of connexin43 protein in parallel with the enhancement in communication. Together, these results indicate that the EGF-induced enhancement of GJIC in human kidney epithelial cells was mediated through translational control of connexin43 expression.

Cell Communication↗
PubMed1996

Nickel(II) induces alterations in EGF- and TGF-beta 1-mediated growth control during malignant transformation of human kidney epithelial cells.

We have previously described immortalization of normal human kidney epithelial cells by nickel(II) and the subsequent tumorigenic conversion by v-Ha-ras transfection. We report here that nickel(II) induces alterations in growth regulatory control. Normal human kidney epithelial cells (NHKE) were growth inhibited by transforming growth factor beta 1 (TGF-beta 1). This effect was abrogated in both the immortalized (IHKE) and transformed (THKE) cells. NHKE expressed approximately 4700 high-affinity binding sites/cell for TGF-beta 1. IHKE and THKE showed reduced binding of 47% and 44% relative to NHKE respectively. On the other hand, expression of epidermal growth factor (EGF) receptors was elevated in IHKE (260%) and THKE (236%) relative to NHKE, which expressed 1.5 x 10(5) receptors/cell. Preincubation of IHKE and THKE with TGF-beta 1 resulted in reduced EGF binding, whereas this binding was unaltered in NHKE. Exposure of human kidney epithelial cells to EGF led to tyrosine phosphorylation of the EGF receptor and other cellular proteins in the mol. wt range from 42 to > 300 kDa. The level of receptor phosphorylation induced by EGF reflected receptor expression. Tyrosine phosphorylated proteins appear to be identical in all three cell lines, and reach phosphorylation maxima independently of EGF receptor expression. These studies indicate that nickel carcinogenesis may involve changes in sets of genes important in normal growth regulation.

Cell Division↗
PubMed1996

Biomonitoring human exposure to environmental carcinogenic chemicals.

A coordinated study was carried out on the development, evaluation and application of biomonitoring procedures for populations exposed to environmental genotoxic pollutants. The procedures used involved both direct measurement of DNA or protein damage (adducts) and assessment of second biological effects (mutation and cytogenetic damage). Adduct detection at the level of DNA or protein (haemoglobin) was carried out by 32P-postlabelling, immunochemical, HPLC or mass spectrometric methods. Urinary excretion products resulting from DNA damage were also estimated (immunochemical assay, mass spectrometry). The measurement of adducts was focused on those from genotoxicants that result from petrochemical combustion or processing, e.g. low-molecular-weight alkylating agents, PAHs and compounds that cause oxidative DNA damage. Cytogenetic analysis of lymphocytes was undertaken (micronuclei, chromosome aberrations and sister chromatid exchanges) and mutation frequency was estimated at a number of loci including the hprt gene and genes involving in cancer development. Blood and urine samples from individuals exposed to urban pollution were collected. Populations exposed through occupational or medical sources to larger amounts of some of the genotoxic compounds present in the environmental samples were used as positive controls for the environmentally exposed population. Samples from rural areas were used as negative controls. The project has led to new, more sensitive and more selective approaches for detecting carcinogen-induced damage to DNA and proteins, and subsequent biological effects. These methods were validated with the occupational exposures, which showed evidence of DNA and/or protein and/or chromosome damage in workers in a coke oven plant, garage workers exposed to diesel exhaust and workers exposed to ethylene oxide in a sterilization plant. Dose reponse and adduct repair were studied for methylated adducts in patients treated with methylating cytostatic drugs. The biomonitoring methods have also demonstrated their potential for detecting environmental exposure to genotoxic compounds in nine groups of non-smoking individuals, 32P-postlabelling of DNA adducts being shown to have the greatest sensitivity.

Antineoplastic Agents, Alkylating↗
PubMed1995

A hereditary genetic marker closely associated with microsatellite instability in lung cancer.

Alterations in 5 microsatellite loci were analyzed in tumors from 137 patients with primary non-small cell lung carcinomas that were also genotyped for the Hras1 variable number of tandem repeats (VNTR) locus. Twenty-nine patients (21%) had changes in at least one microsatellite locus. A majority of these cases (24 of 29, 83%) had VNTR alleles classified as rare in the population. The frequency of these rare alleles were significantly higher among lung cancer patients than in healthy controls (P = 0.016 or 1.80; 95% confidence interval = 1.13-2.85). Microsatellite alterations were significantly more frequent among patients with at least one rare Hras1 VNTR allele (24 of 40, 60%) compared to patients with two common alleles (5 of 97, 5%; P < 0.001 or 27.6; 95% confidence interval = 8.18-82.9). Microsatellite alterations were also more frequent among patients below 50 years of age (8 of 21, 38%) than for older patients (21 of 112, 19%).

Aged↗
PubMed1995

DNA and protein adducts.

Application of methods for the measurement of DNA and protein adducts in environmental studies was surveyed. The methods included the 32P-postlabelling assay, immunoassay and synchronous fluorescence spectroscopy for DNA adducts. Additionally, methods for detecting excreted urinary RNA and DNA adducts were discussed. The protein adduct techniques included both immunological and chemical assays. The techniques have been applied in occupational and environmental studies, but usually one assay at a time. As specific DNA adducts can now be assayed for, it would be important to use these methods and specific protein adduct assays in the same studies. It is important to develop further specific adduct tests. This can be done with the help of standard compounds, which also allow quantitation in the assays. An international bank of standard compounds would be a major advancement to human biomonitoring.

Biomarkers↗
PubMed1995

Effects of n-3 fatty acids during neoplastic progression and comparison of in vitro and in vivo sensitivity of two human tumour cell lines.

Several studies have shown that dietary lipid exerts an effect on carcinogenesis. We report here that progression to malignancy in vitro is associated with changes in the response to fatty acids (FAs). Tumorigenic (THKE) cells were more sensitive to the n-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than immortalised (IHKE) cells. The growth of THKE cells was inhibited 25% more than the growth of IHKE cells at 80 microM EPA (P < 0.01) and 35% more at 40 microM DHA (P < 0.001). Furthermore, the results indicate that there is a wide cell type variation in the response to FAs. We found that the in vitro inhibition by FAs correlated with the reduction in the growth rate of the tumour in nude mice fed K85 (55% EPA and 30% DHA). A significant difference in tumour latency was observed for the A427 cell tumour groups (10 days, P < 0.05). Tumours in the animals fed n-3 FA exhibited significantly higher levels of EPA and DHA; the level of arachidonic acid (ARA) was significantly lower in THKE tumours and the level of linoleic acid (LA) was significantly lower in A427 tumours than in controls fed corn oil. The higher sensitivity of the A427 cell line was not explained by higher uptake of EPA/DHA.

Adenocarcinoma↗
PubMed1995

Evaluation of biomarkers in plasma, blood, and urine samples from coke oven workers: significance of exposure to polycyclic aromatic hydrocarbons.

OBJECTIVE: The aim was to assess the significance of two biomarkers; antibody to benzo(a)pyrene DNA adducts and concentration of hydroxyethylvaline haemoglobin adducts in samples from a well studied group of coke oven workers. As a measure of exposure we have used 1-hydroxypyrene in urine. METHODS: Urine and blood samples were collected from coke oven workers and a control group. Samples from coke oven plant workers were collected in January and June. 1-Hydroxypyrene was measured in urine by high performance liquid chromatography (HPLC), antibodies to benzo(a)pyrene DNA adducts were measured by ELISA and hydroxyethylvaline haemoglobin adducts were measured by gas chromatography-mass spectrometry (GC-MS). RESULTS: Mean urinary 1-hydroxypyrene in samples from coke oven workers varied from 1.11 to 5.53 umol/mol creatinine and 0.14 umol/mol creatinine in the control group. Workers at the top side had the highest values of urinary 1-hydroxypyrene. Antibody to benzo(a)pyrene DNA adducts did not correlate with either 1-hydroxypyrene nor length of work at the coke oven plant. But antibody concentration in samples collected in January was predictive of the concentration in samples collected in June. A small non-significant increase in hydroxyethylvaline haemoglobin adducts was found in samples from coke oven workers relative to the control group when comparing smokers and nonsmokers separately. CONCLUSION: 1-Hydroxypyrene correlates well with exposure groups based on job description. Antibodies to benzo(a)-pyrene DNA adducts was related to people and not exposure. Work at a coke oven plant might lead to increased hydroxyethylvaline haemoglobin adducts.

Adult↗